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What is the difference between abiogenesis and spontaneous generation?

What is the difference between abiogenesis and spontaneous generation?



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As we all should know, abiogenesis and spontaneous generation are far from identical. For one, spontaneous generation was disproven with Pasteur, and abiogenesis seems to be a solid scientific theory. However, one can loosely summarize both as "the emergence of life from non-living materials" which, at the very least, is confusing for the layman.

My question is: What truly differentiates abiogenesis from spontaneous generation? For example, if abiogenesis were to happen again, how would we differentiate the two terms?

Is time the most contributing factor (abiogenesis happened over hundreds of millions of years)? Or the fact that abiogenesis generates "primitive organisms", while spontaneous generation assumes the generation of evolved, complex organisms?


One important difference is that spontaneous generation is a form of "mechanism" by which a certain species is "born", so it is repeated many times. For such complex organisms this would be part of their "life cycle". It would also need to be a regulated, robust process.

Abiogenesis, on the other hand, would create an organism which from that point on does not rely on abiogenesis in any way, so it would be a unique event. Abiogenesis is highly probabilistic which is why it would result in very simple organisms.


What truly differentiates abiogenesis from spontaneous generation?

There are three differences.

  1. Frequency

Abiogenesis occurs very infrequently. Perhaps only once in all of earth's 4.5 billion year history.

Spontaneous generation happens very frequently, in fact every new species could be a product of spontaneous generation. It occurs so frequently you just need to wait a week (given the Spontaneous generation example of fly generation from rotting meat)

  1. Complexity.

Abiogenesis only make very primitive organism… there are even thoughts that the abiogenesis event on Earth produced something that was only half alive, the ability to multiple and maintain a separate internal environment with a very basic and simple metabolism.

Spontanous generation on the other hand can produce both simple and complex organism. Bacteria, worms, cows, flies, humans. Anything.

  1. Reproducibility

Abiogenesis if it were done again… we might get very different biology. There are more than the 20 types of amino acid. There are actually a few more bases than the 4 we have in our DNA. And the codon usage… ie which 3bp of DNA encode for which amino acid could also be very different.

In spontanous generation events, you can get it to produce the same organism multiple times, right down to ability to mate with each other. Flies were the example.


The only reason abiogenesis is not disproved is because it can't be tested like evolution it is supposed to have happened in the past and won't happen again (at least not in the same way) abiogenesis is a theory proposed only because the origin of life is unexplainable by normal natural means.

Spontaneous generation was an earlier attempt at answering the origin of life that could more easily be proven or disproven.


What is the difference between spontaneous generation and biogenesis?

spontaneous generation is Abiogenesis life from non life
biogenesis is life from life.

Explanation:

Before the experiments of Louis Pasteur most scientists believed that life come come from non life by spontaneous generation. The idea that life could come from non life was foundational to the theories of organic evolution by natural causes such as Darwin's descent with modification.

The experiments of Louis Pasteur were foundational to cell theory that life came from life. Cell theory that life came from life has become known as biogenesis. Biogenesis is the theory that life only comes from life. This is also known as univocal generation that the offspring of cells are the same as the parental cells that they came from.

Spontaneous generation or abiogenesis is the exact opposite of biogenesis. Spontaneous generation says that life can come from non life. Biognesis says that it impossible for life to come from non living matter. The philosophy of material realism requires that somehow life came from non living matter by totally natural causes.


What are abiogenesis and spontaneous generation?

abiogenesis is the theory that life can come from non life. Spontaneous generation was the theory that life came from non life as observed with maggots in meat and other natural process.

Explanation:

Spontaneous generation was widely believed before Redi's and Louis Pastour's experiments. Life springing into existence could be observed in multiple places in the world.

Redi's experiment excluding flies from the meat proved that without life no life came into existence spontaneously

Louis Pastour's experiments with wine proved that if "germs" in the air could be prevented from entering the wine no life came into existence spontaneously.
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These experiment formed the basis of the theory of biogenesis that life comes only from life and the cells come only from cells.

However the world view of the enlightenment believed that everything must happen by natural cause. So if there was a time when there was no life then life must have logically come from non life. This view gave rise to the theory of abiogensis that somehow in the early history of the earth a living cell was formed by accidental natural causes.

The living cell is an amazingly complex structure requiring information codes that can be replicated and passed on to future generations. The living cell also requires complex proteins and enzymes in order to survive an environment that always moves toward destruction and disorder.

At this point in time there are no credible theories about how the first cell could have come about by totally natural causes. So abiogensis remains an unsupported theory demanded only by the world view of material realism


What's the difference between abiogenesis and spontaneous generation?

Spontaneous generation was the notion that a whole organism could spontaneously arise from something that was previously inanimate. For example, before the full life cycle of fleas had been observed, it was believed they arose spontaneously from dust.

Abiogenesis is the theory that the components of precursors to living cells can arise naturally from chemical and physical processes. The exact mechanism by which the first truly living cells arose on Earth is still a mystery, but there are a lot of reasons to believe rudimentary cells can form naturally. For example, we have learned by spectroscopy that complex organic molecules are abundant in some nebulae, and we have no reason that life created them. Experiments have also learned that cell-like structures like liposomes form spontaneously from mixtures of organic and inorganic molecules, catalyzed by sunlight or heat.


Difference Between Abiogenesis and Biogenesis

The origin of life is a controversial topic and also it has a long history. Ancient people believed that the origin of life is a spontaneous mechanism and occurs due to nonliving substances. This opinion was known as “Abiogenesis”. However, finally scientists proved that the origin of life is actually caused by preexisting living organism, not by nonliving substances, and this opinion was known as “Biogenesis”.

Abiogenesis

Abiogenesis is an ancient belief about the origin of life. This is also known as the theory of spontaneous generation of life. The theory of abiogenesis stated that the origin of living organism is due to nonliving substances, or it is a spontaneous incident. However, until now scientists have been unable to accomplish this theory by experiments.

Biogenesis is the currently accepted theory regarding the origin of a new life. The theory of biogenesis states that the origin of life is because of preexisting living cells or an organism. Louis Pasteur, Francesco Reddy, and Lazzaro Spallanzani experimentally proved this theory.

Abiogenesis vs Biogenesis

• Abiogenesis states that the origin of life is due to another nonliving material, or it is a spontaneous mechanism, whereas biogenesis reveals that the origin of life is due to another preexisting living organism or cells.

• Abiogenesis failed to prove experimentally while biogenesis was experimentally proved by many scientists.


The Theory of Spontaneous Generation

The Greek philosopher Aristotle (384–322 BC) was one of the earliest recorded scholars to articulate the theory of spontaneous generation, the notion that life can arise from nonliving matter. Aristotle proposed that life arose from nonliving material if the material contained pneuma (“vital heat”). As evidence, he noted several instances of the appearance of animals from environments previously devoid of such animals, such as the seemingly sudden appearance of fish in a new puddle of water. [1]

This theory persisted into the seventeenth century, when scientists undertook additional experimentation to support or disprove it. By this time, the proponents of the theory cited how frogs simply seem to appear along the muddy banks of the Nile River in Egypt during the annual flooding. Others observed that mice simply appeared among grain stored in barns with thatched roofs. When the roof leaked and the grain molded, mice appeared. Jan Baptista van Helmont, a seventeenth century Flemish scientist, proposed that mice could arise from rags and wheat kernels left in an open container for 3 weeks. In reality, such habitats provided ideal food sources and shelter for mouse populations to flourish.

However, one of van Helmont’s contemporaries, Italian physician Francesco Redi (1626–1697), performed an experiment in 1668 that was one of the first to refute the idea that maggots (the larvae of flies) spontaneously generate on meat left out in the open air. He predicted that preventing flies from having direct contact with the meat would also prevent the appearance of maggots. Redi left meat in each of six containers (Figure 1). Two were open to the air, two were covered with gauze, and two were tightly sealed. His hypothesis was supported when maggots developed in the uncovered jars, but no maggots appeared in either the gauze-covered or the tightly sealed jars. He concluded that maggots could only form when flies were allowed to lay eggs in the meat, and that the maggots were the offspring of flies, not the product of spontaneous generation.

Figure 1. Francesco Redi’s experimental setup consisted of an open container, a container sealed with a cork top, and a container covered in mesh that let in air but not flies. Maggots only appeared on the meat in the open container. However, maggots were also found on the gauze of the gauze-covered container.

In 1745, John Needham (1713–1781) published a report of his own experiments, in which he briefly boiled broth infused with plant or animal matter, hoping to kill all preexisting microbes. [2] He then sealed the flasks. After a few days, Needham observed that the broth had become cloudy and a single drop contained numerous microscopic creatures. He argued that the new microbes must have arisen spontaneously. In reality, however, he likely did not boil the broth enough to kill all preexisting microbes.

Lazzaro Spallanzani (1729–1799) did not agree with Needham’s conclusions, however, and performed hundreds of carefully executed experiments using heated broth. [3] As in Needham’s experiment, broth in sealed jars and unsealed jars was infused with plant and animal matter. Spallanzani’s results contradicted the findings of Needham: Heated but sealed flasks remained clear, without any signs of spontaneous growth, unless the flasks were subsequently opened to the air. This suggested that microbes were introduced into these flasks from the air. In response to Spallanzani’s findings, Needham argued that life originates from a “life force” that was destroyed during Spallanzani’s extended boiling. Any subsequent sealing of the flasks then prevented new life force from entering and causing spontaneous generation (Figure 2).

Figure 2. (a) Francesco Redi, who demonstrated that maggots were the offspring of flies, not products of spontaneous generation. (b) John Needham, who argued that microbes arose spontaneously in broth from a “life force.” (c) Lazzaro Spallanzani, whose experiments with broth aimed to disprove those of Needham.

Think about It

  • Describe the theory of spontaneous generation and some of the arguments used to support it.
  • Explain how the experiments of Redi and Spallanzani challenged the theory of spontaneous generation.

What is the theory of abiogenesis?

Abiogenesis is the idea of life originating from non-living material (non-life). This concept has expanded a great deal as mankind’s understanding of science has grown, but all forms of abiogenesis have one thing in common: they are all scientifically unsupportable. There have been no experiments demonstrating abiogenesis in action. It has never been observed in a natural or artificial environment. Conditions believed to have existed on earth are either incapable of producing the building blocks needed, or self-contradictory. No evidence has been found suggesting where or when such life might have generated. In fact, everything we know of science today seems to indicate that abiogenesis could not have happened under any naturally possible conditions.

Early concepts of abiogenesis were very simplistic. Rotting meat was soon covered in maggots, and so it was assumed that the meat turned into maggots. Mice were usually seen in places where hay was stored, so it was assumed that hay turned into mice. This type of abiogenesis is known as “spontaneous generation.” This was actually the popular scientific explanation for the reproduction of living things as recently as a few hundred years ago. It wasn’t until the mid-1800s that men like Pasteur proved experimentally that living things can only come from other living things. That is, science eventually proved conclusively that the only supportable origin for any living cell is another living cell.

Modern ideas of abiogenesis can be very complex, and some are more outrageously unlikely than others. Guesses are widely varied, from deep-sea lava vents to meteoric impact sites and even radioactive beaches. In general, all modern theories of abiogenesis imagine some scenario in which natural conditions create, combine, and arrange molecules in such a way that they begin to self-replicate. These theories vary widely as to the nature of these conditions, the complexity of the molecules, and so forth. All share at least one common factor: they are implausible to the point of impossibility, based on established science.

One problem with modern abiogenesis is the extraordinary complexity of living organisms. Experiments have proven that very simple amino acids can be formed in laboratory conditions. However, these separate acids are nowhere near sufficient to create a living cell. The conditions which create these acids would not only kill any such cell as soon as it was formed, but are also unlikely to have ever actually existed at any time in earth’s history. Any evolutionary theory that seems to suggest how ultra-simple life could have developed from a single newly formed cell has no answer for how that cell could have been formed in the first place. There is no “prototype first cell.” Science has never even come close to producing a self-sustaining living cell that could have been produced by, or survived in, the conditions needed to form its components.

It has been said that “death is philosophy’s only problem.” This may or may not be true, but dealing with death presents a major challenge to any philosophical view. In much the same way, abiogenesis is the scientific naturalist’s biggest problem. There are naturalistic guesses about how life could have begun without any Creator or Designer. And yet, these purely natural explanations are thoroughly refuted by science itself. It is ironic that so many people proclaim scientific naturalism to be “proven,” “established,” or “demonstrated” so clearly. And yet, naturalism is necessarily linked to abiogenesis, which is scientifically impossible.

The overwhelming evidence that life cannot come from non-life is a powerful indication that naturalism is not a realistic worldview. Life either had a natural origin (abiogenesis) or a supernatural origin (intelligent design). The scientific impossibility of abiogenesis is an argument for, at least, a supernatural originator. The only way to create even the most basic building blocks of life is in non-natural, highly designed, and tightly controlled conditions. That, by itself, makes it reasonable to presume that life cannot begin without intelligent intervention.


Contents

Spontaneous generation refers both to the supposed processes by which different types of life might repeatedly emerge from specific sources other than seeds, eggs, or parents, and also to theoretical principles presented in support of any such phenomena. Crucial to this doctrine are the ideas that life comes from non-life and that no causal agent, such as a parent, is needed. The hypothetical processes by which life routinely emerges from nonliving matter on a time scale of minutes, weeks, or years (e.g. in the supposed seasonal generation of mice and other animals from the mud of the Nile) are sometimes referred to as abiogenesis. [9] Such ideas have no operative principles in common with the modern hypothesis of abiogenesis, which asserts that life emerged in the early ages of the planet, over a time span of at least millions of years, and subsequently diversified, and that there is no evidence of any subsequent repetition of the event. [10]

The term equivocal generation, sometimes known as heterogenesis or xenogenesis, describes the supposed process by which one form of life arises from a different, unrelated form, such as tapeworms from the bodies of their hosts. [11]

In the years following Louis Pasteur's 1859 experiment, the term "spontaneous generation" fell increasingly out of favor. Experimentalists used a variety of terms for the study of the origin of life from nonliving materials. Heterogenesis was applied to the generation of living things from once-living organic matter (such as boiled broths), and Henry Charlton Bastian proposed the term archebiosis for life originating from inorganic materials. Disliking the randomness and unpredictability implied by the term "'spontaneous' generation," in 1870 Bastian coined the term biogenesis to refer to the formation of life from nonliving matter. Soon thereafter, however, English biologist Thomas Henry Huxley proposed the term abiogenesis to refer to this same process and adopted biogenesis for the process by which life arises from existing life it is this latter set of definitions that became dominant. [12]

Presocratic philosophers Edit

Active in the 6th and 5th centuries BCE, early Greek philosophers, called physiologoi in antiquity (Greek: φυσιολόγοι in English, physical or natural philosophers), attempted to give natural explanations of phenomena that had previously been ascribed to the agency of the gods. [13] The physiologoi sought the material principle or arche (Greek: ἀρχή) of things, emphasizing the rational unity of the external world and rejecting theological or mythological explanations. [14]

Anaximander, who believed that all things arose from the elemental nature of the universe, the apeiron (ἄπειρον) or the "unbounded" or "infinite", was likely the first western thinker to propose that life developed spontaneously from nonliving matter. The primal chaos of the apeiron, eternally in motion, served as a substratum in which elemental opposites (e.g., wet and dry, hot and cold) generated and shaped the many and varied things in the world. [15] According to Hippolytus of Rome in the third century CE, Anaximander claimed that fish or fish-like creatures were first formed in the "wet" when acted on by the heat of the sun and that these aquatic creatures gave rise to human beings. [16] Censorinus, writing in the 3rd century, reports:

Anaximander of Miletus considered that from warmed up water and earth emerged either fish or entirely fishlike animals. Inside these animals, men took form and embryos were held prisoners until puberty only then, after these animals burst open, could men and women come out, now able to feed themselves. [17]

Anaximenes, a pupil of Anaximander, thought that air was the element that imparted life and endowed creatures with motion and thought. He proposed that plants and animals, including human beings, arose from a primordial terrestrial slime, a mixture of earth and water, combined with the sun's heat. Anaxagoras, too, believed that life emerged from a terrestrial slime. However, he held that the seeds of plants existed in the air from the beginning, and those of animals in the aether. Xenophanes traced the origin of man back to the transitional period between the fluid stage of the earth and the formation of land, under the influence of the sun. [18]

In what has occasionally been seen as a prefiguration of a concept of natural selection, [19] Empedocles accepted the spontaneous generation of life but held that different forms, made up of differing combinations of parts, spontaneously arose as though by trial and error: successful combinations formed the species present in the observer's lifetime, whereas unsuccessful forms failed to reproduce.

Aristotle Edit

In his biological works, the natural philosopher Aristotle theorized extensively the reproduction of various animals, whether by sexual, parthenogenetic, or spontaneous generation. In accordance with his fundamental theory of hylomorphism, which held that every physical entity was a compound of matter and form, Aristotle's basic theory of sexual reproduction contended that the male's seed imposed form, the set of characteristics passed down to offspring on the "matter" (menstrual blood) supplied by the female. Thus female matter is the material cause of generation—it supplies the matter that will constitute the offspring—while the male semen is the efficient cause, the factor that instigates and delineates the thing's existence. [20] Yet, as proposed in the History of Animals, many creatures form not through sexual processes but by spontaneous generation:

Now there is one property that animals are found to have in common with plants. For some plants are generated from the seed of plants, whilst other plants are self-generated through the formation of some elemental principle similar to a seed and of these latter plants some derive their nutriment from the ground, whilst others grow inside other plants . So with animals, some spring from parent animals according to their kind, whilst others grow spontaneously and not from kindred stock and of these instances of spontaneous generation some come from putrefying earth or vegetable matter, as is the case with a number of insects, while others are spontaneously generated in the inside of animals out of the secretions of their several organs. [22]

According to this theory, living things may come forth from nonliving things in a manner roughly analogous to the "enformation of the female matter by the agency of the male seed" seen in sexual reproduction. [21] Nonliving materials, like the seminal fluid present in sexual generation, contain pneuma (πνεῦμα, "breath"), or "vital heat". According to Aristotle, pneuma had more "heat" than regular air did, and this heat endowed the substance with certain vital properties:

The power of every soul seems to have shared in a different and more divine body than the so called [four] elements . For every [animal], what makes the seed generative inheres in the seed and is called its "heat". But this is not fire or some such power, but instead the pneuma that is enclosed in the seed and in foamy matter, this being analogous to the element of the stars. This is why fire does not generate any animal . but the heat of the sun and the heat of animals does, not only the heat that fills the seed, but also any other residue of [the animal's] nature that may exist similarly possesses this vital principle.

Aristotle drew an analogy between the "foamy matter" (τὸ ἀφρῶδες) found in nature and the "seed" of an animal, which he viewed as being a kind of foam itself (composed, as it was, from a mixture of water and pneuma). For Aristotle, the generative materials of male and female animals (semen and menstrual blood) were essentially refinements, made by male and female bodies according to their respective proportions of heat, of ingested food, which was, in turn, a byproduct of the elements earth and water. Thus any creature, whether generated sexually from parents or spontaneously through the interaction of vital heat and elemental matter, was dependent on the proportions of pneuma and the various elements which Aristotle believed comprised all things. [24] While Aristotle recognized that many living things emerged from putrefying matter, he pointed out that the putrefaction was not the source of life, but the byproduct of the action of the "sweet" element of water. [25]

Animals and plants come into being in earth and in liquid because there is water in earth, and air in water, and in all air is vital heat so that in a sense all things are full of soul. Therefore living things form quickly whenever this air and vital heat are enclosed in anything. When they are so enclosed, the corporeal liquids being heated, there arises as it were a frothy bubble.

With varying degrees of observational confidence, Aristotle theorized the spontaneous generation of a range of creatures from different sorts of inanimate matter. The testaceans (a genus which for Aristotle included bivalves and snails), for instance, were characterized by spontaneous generation from mud, but differed based upon the precise material they grew in—for example, clams and scallops in sand, oysters in slime, and the barnacle and the limpet in the hollows of rocks. [22]

Latin and early Christian sources Edit

Vitruvius, a Roman architect and writer of the 1st century BCE, advised that libraries be placed facing eastwards to benefit from morning light, but not towards the south or the west as those winds generate bookworms. [26]

Aristotle claimed that eels were lacking in sex and lacking milt, spawn and the passages for either. [27] Rather, he asserted eels emerged from earthworms. [28] Later authors dissented. Pliny the Elder did not argue against the anatomic limits of eels, but stated that eels reproduce by budding, scraping themselves against rocks, liberating particles that become eels. [29] Athenaeus described eels as entwining and discharging a fluid which would settle on mud and generate life. Athenaeus also dissented towards spontaneous generation, claiming that a variety of anchovy did not generate from roe, as Aristotle stated, but rather, from sea foam. [30]

As the dominant view of philosophers and thinkers continued to be in favour of spontaneous generation, some Christian theologians accepted the view. Augustine of Hippo discussed spontaneous generation in The City of God and The Literal Meaning of Genesis, citing Biblical passages such as "Let the waters bring forth abundantly the moving creature that hath life" (Genesis 1:20) as decrees that would enable ongoing creation. [31]

From the fall of the Roman Empire in 5th century to the East-West Schism in 1054, the influence of Greek science declined, although spontaneous generation generally went unchallenged. New descriptions were made. Of the numerous beliefs, some had doctrinal implications outside of the Book of Genesis. For example, the idea that a variety of bird known as the barnacle goose emerged from a crustacean known as the goose barnacle, had implications on the practice of fasting during Lent. In 1188, Gerald of Wales, after having traveled in Ireland, argued that the "unnatural" generation of barnacle geese was evidence for the virgin birth. [32] Where the practice of fasting during Lent allowed fish, but prohibited fowl, the idea that the goose was in fact a fish suggested that its consumption be permitted during Lent. The practice was eventually prohibited by decree of Pope Innocent III in 1215. [33]

Aristotle, in Latin translation, from the original Greek or from Arabic, was reintroduced to Western Europe. During the 13th century, Aristotle reached his greatest acceptance. With the availability of Latin translations, Saint Albertus Magnus and his student, Saint Thomas Aquinas, raised Aristotelianism to its greatest prominence. Albert wrote a paraphrase of Aristotle, De causis et processu universitatis, in which he removed some and incorporated other commentaries by Arabic scholars. [34] The influential writings of Aquinas, on both the physical and metaphysical, are predominantly Aristotelian, but show numerous other influences. [35]

Spontaneous generation is discussed as a fact in literature well into the Renaissance. Where, in passing, Shakespeare discusses snakes and crocodiles forming from the mud of the Nile (Ant 2.7 F1), Izaak Walton again raises the question of the origin of eels "as rats and mice, and many other living creatures, are bred in Egypt, by the sun's heat when it shines upon the overflowing of the river. ". While the ancient question of the origin of eels remained unanswered and the additional idea that eels reproduced from corruption of age was mentioned, the spontaneous generation of rats and mice engendered no debate. [36]

The Dutch biologist and microscopist Jan Swammerdam (1637–1680) rejected the concept that one animal could arise from another or from putrification by chance because it was impious like others, he found the concept of spontaneous generation irreligious, and he associated it with atheism and Godless opinion. [37]

Jan Baptist van Helmont (1580–1644) used experimental techniques, such as growing a willow for five years and showing it increased mass while the soil showed a trivial decrease in comparison. As the process of photosynthesis was not understood, he attributed the increase of mass to the absorption of water. [38] His notes also describe a recipe for mice (a piece of soiled cloth plus wheat for 21 days) and scorpions (basil, placed between two bricks and left in sunlight). His notes suggest he may even have done these things. [39]

Where Aristotle held that the embryo was formed by a coagulation in the uterus, William Harvey (1578–1657) by way of dissection of deer, showed that there was no visible embryo during the first month. [40] Although his work predated the microscope, this led him to suggest that life came from invisible eggs. In the frontispiece of his book Exercitationes de Generatione Animalium (Essays on the Generation of Animals), he made an expression of biogenesis: "omnia ex ovo" (everything from eggs). [31]

The ancient beliefs were subjected to testing. In 1668, Francesco Redi challenged the idea that maggots arose spontaneously from rotting meat. In the first major experiment to challenge spontaneous generation, he placed meat in a variety of sealed, open, and partially covered containers. [41] Realizing that the sealed containers were deprived of air, he used "fine Naples veil", and observed no worm on the meat, but they appeared on the cloth. [42] Redi used his experiments to support the preexistence theory put forth by the Church at that time, which maintained that living things originated from parents. [43] In scientific circles Redi's work very soon had great influence, as evidenced in a letter from John Ray in 1671 to members of the Royal Society of London:

Whether there be any spontaneous or anomalous generation of animals, as has been the constant opinion of naturalists heretofore, I think there is good reason to question. It seems to me at present most probable, that there is no such thing but that even all insects are the natural issue of parents of the same species with themselves. F. Redi has gone a good way in proving this, having cleared the point concerning generation ex materia putrida. But still there remain two great difficulties. The first is, to give an account of the production of insects bred in the by-fruits and excrescencies of vegetables, which the said Redi doubts not to ascribe to the vegetative soul of the plant that yields those excrescencies. But for this I refer you to Mr. Lister. The second, to render an account of insects bred in the bodies of other animals. I hope shortly to be able to give you an account of the generation of some of those insects which have been thought to be spontaneous, and which seem as unlikely as any to be after the ordinary and usual way. [44]

Pier Antonio Micheli, around 1729, observed that when fungal spores were placed on slices of melon the same type of fungi were produced that the spores came from, and from this observation he noted that fungi did not arise from spontaneous generation. [45]

In 1745, John Needham performed a series of experiments on boiled broths. Believing that boiling would kill all living things, he showed that when sealed right after boiling, the broths would cloud, allowing the belief in spontaneous generation to persist. His studies were rigorously scrutinized by his peers and many of them agreed. [41]

Lazzaro Spallanzani modified the Needham experiment in 1768, attempting to exclude the possibility of introducing a contaminating factor between boiling and sealing. His technique involved boiling the broth in a sealed container with the air partially evacuated to prevent explosions. Although he did not see growth, the exclusion of air left the question of whether air was an essential factor in spontaneous generation. [41] However, by that time there was already widespread scepticism among major scientists to the principle of spontaneous generation. Observation was increasingly demonstrating that whenever there was sufficiently careful investigation of mechanisms of biological reproduction, it was plain that processes involved basing of new structures on existing complex structures, rather from chaotic muds or dead materials. Joseph Priestley, after he had fled to America and not long before his death, wrote a letter that was read to the American Philosophical Society in 1803. It said in part:

There is nothing in modern philosophy that appears to me so extraordinary, as the revival of what has long been considered as the exploded doctrine of equivocal, or, as Dr. Darwin calls it, spontaneous generation by which is meant the production of organized bodies from substances that have no organization, as plants and animals from no pre-existing germs of the same kinds, plants without seeds, and animals without sexual intercourse. The germ of an organized body, the seed of a plant, or the embrio of an animal, in its first discoverable state, is now found to be the future plant or animal in miniature, containing every thing essential to it when full grown, only requiring to have the several organs enlarged, and the interstices filled with extraneous nutritious matter. When the external form undergoes the greatest change, as from an aquatic insect to a flying gnat, a caterpillar to a crysalis, a crysalis to a butterfly, or a tadpole to a frog, there is nothing new in the organization all the parts of the gnat, the butterfly, and the frog, having really existed, though not appearing to the common observer in the forms in which they are first seen. In like manner, every thing essential to the oak is found in the acorn. [46]

In 1837, Charles Cagniard de la Tour, a physicist, and Theodor Schwann, one of the founders of cell theory, published their independent discovery of yeast in alcoholic fermentation. They used the microscope to examine foam left over from the process of brewing beer. Where Leeuwenhoek described "small spheroid globules", they observed yeast cells undergo cell division. Fermentation would not occur when sterile air or pure oxygen was introduced if yeast were not present. This suggested that airborne microorganisms, not spontaneous generation, was responsible. [47]

However, although the idea of spontaneous generation had been in decline for nearly a century, its supporters did not abandon it all at once. As James Rennie wrote:

. inability to trace the origin of minute plants and insects led to the doctrine of what is called spontaneous or equivocal generation, of which the fancies above-mentioned are some of the prominent branches. The experiments of Redi on the hatching of insects from eggs, which were published at Florence in 1668, first brought discredit upon this doctrine, though it had always a few eminent disciples. At present it is maintained by a considerable number of distinguished naturalists, such as Blumenbach, Cuvier, Bory de St. Vincent, R. Brown, &c. "The notion or spontaneous generation", says Bory, "is at first revolting to a rational mind, but it is, notwithstanding, demonstrable by the microscope. The fact is averred : Willer has seen it, I have seen it, and twenty other observers have seen it: the pandorinia exhibit it every instant." These pandorinia he elsewhere describes as probably nothing more than "animated scions of Zoocarpae". It would be unprofitable to go into any lengthened discussion upon this mysterious subject and we have great doubts whether the ocular demonstration by the microscope would succeed except in the hands of a disciple of the school. Even with naturalists, whose business it is to deal with facts, the reason is often wonderfully influenced by the imagination. [48]

Pasteur and Tyndall Edit

Louis Pasteur's 1859 experiment is widely seen as having settled the question of spontaneous generation. [49] He boiled a meat broth in a swan neck flask the bend in the neck of the flask prevented falling particles from reaching the broth, while still allowing the free flow of air. The flask remained free of growth for an extended period. When the flask was turned so that particles could fall down the bends, the broth quickly became clouded. [41] However, minority objections were persistent and not always unreasonable, given that the experimental difficulties were far more challenging than the popular accounts suggest. The investigations of John Tyndall, a correspondent of Pasteur and a great admirer of Pasteur's work, were decisive in disproving spontaneous generation and dealing with lingering issues. Still, even Tyndall encountered difficulties in dealing with the effects of microbial spores, which were not well understood in his day. Like Pasteur, he boiled his cultures to sterilize them, and some types of bacterial spores can survive boiling. The autoclave, which eventually came into universal application in medical practice and microbiology to sterilise equipment, was not an instrument that had come into use at the time of Tyndall's experiments, let alone those of Pasteur. [5]

In 1862, the French Academy of Sciences paid a special attention to the issue and established a prize "to him who by well-conducted experiments throws new light on the question of the so-called spontaneous generation" and appointed a commission to judge the winner. [50]


Why Abiogenesis Is Impossible

If naturalistic molecules-to-human-life evolution were true, multibillions of links are required to bridge modern humans with the chemicals that once existed in the hypothetical &ldquoprimitive soup&rdquo. This putative soup, assumed by many scientists to have given birth to life over 3.5 billion years ago, was located in the ocean or mud puddles. Others argue that the origin of life could not have been in the sea but rather must have occurred in clay on dry land. Still others conclude that abiogenesis was more likely to have occurred in hot vents. It is widely recognized that major scientific problems exist with all naturalistic origin of life scenarios. This is made clear in the conclusions of many leading origin-of-life researchers. A major aspect of the abiogenesis question is &ldquoWhat is the minimum number of parts necessary for an autotrophic free living organism to live, and could these parts assemble by naturalistic means?&rdquo Research shows that at the lowest level this number is in the multimillions, producing an irreducible level of complexity that cannot be bridged by any known natural means.

Introduction

biogenesis is the theory that life can arise spontaneously from non-life molecules under proper conditions. Evidence for a large number of transitional forms to bridge the stages of this process is critical to prove the abiogenesis theory, especially during the early stages of the process. The view of how life originally developed from non-life to an organism capable of independent life and reproduction presented by the mass media is very similar to the following widely publicized account:

Science textbook authors Wynn and Wiggins describe the abiogenesis process currently accepted by Darwinists:

The question on which this paper focuses is &ldquoHow much evidence exists for this view of life&rsquos origin?&rdquo When Darwinists discuss &ldquomissing links&rdquo they often imply that relatively few links are missing in what is a rather complete chain which connects the putative chemical precursors of life that is theorized to have existed an estimated 3.5 billion years ago to all life forms existing today. Standen noted a half century ago that the term &ldquomissing link&rdquo is misleading because it suggests that only one link is missing whereas it is more accurate to state that so many links are missing that it is not evident whether there was ever a chain (Standen, 1950, p. 106). This assertion now has been well documented by many creationists and others (see Bergman, 1998 Gish, 1995 Lubenow, 1994, 1992 Rodabaugh, 1976 and Moore, 1976).

Scientists not only have been unable to find a single undisputed link that clearly connects two of the hundreds of major family groups, but they have not even been able to produce a plausible starting point for their hypothetical evolutionary chain (Shapiro, 1986). The first links— actually the first hundreds of thousands or more links that are required to produce life—still are missing (Behe, 1996, pp. 154𤪌)! Horgan concluded that if he were a creationist today he would focus on the origin of life because this

The major links in the molecules-to-man theory that must be bridged include (a) evolution of simple molecules into complex molecules, (b) evolution of complex molecules into simple organic molecules, (c) evolution of simple organic molecules into complex organic molecules, (d) eventual evolution of complex organic molecules into DNA or similar information storage molecules, and (e) eventually evolution into the first cells. This process requires multimillions of links, all which either are missing or controversial. Scientists even lack plausible just-so stories for most of evolution. Furthermore the parts required to provide life clearly have specifications that rule out most substitutions.

The logical order in which life developed is hypothesized to include the following basic major stages:

  1. Certain simple molecules underwent spontaneous, random chemical reactions until after about half-a-billion years complex organic molecules were produced.
  2. Molecules that could replicate eventually were formed (the most common guess is nucleic acid molecules), along with enzymes and nutrient molecules that were surrounded by membraned cells.
  3. Cells eventually somehow &ldquolearned&rdquo how to reproduce by copying a DNA molecule (which contains a complete set of instructions for building a next generation of cells). During the reproduction process, the mutations changed the DNA code and produced cells that differed from the originals.
  4. The variety of cells generated by this process eventually developed the machinery required to do all that was necessary to survive, reproduce, and create the next generation of cells in their likeness. Those cells that were better able to survive became more numerous in the population (adapted from Wynn and Wiggins, 1997, p. 172).

The problem of the early evolution of life and the unfounded optimism of scientists was well put by Dawkins. He concluded that Earth&rsquos chemistry was different on our early, lifeless, planet, and that at this time there existed

The Evidence for the Early Steps of Evolution

The first step in evolution was the development of simple self-copying molecules consisting of carbon dioxide, water and other inorganic compounds. No one has proven that a simple self-copying molecule can self-generate a compound such as DNA. Nor has anyone been able to create one in a laboratory or even on paper. The hypothetical weak &ldquoprimeval soup&rdquo was not like soups experienced by humans but was highly diluted, likely close to pure water. The process is described as life having originated

An astounding number of speculations, models, theories and controversies still surround every aspect of the origin of life problem (Lahav 1999). Although some early scientists proposed that &ldquoorganic life . is eternal,&rdquo most realized it must have come &ldquointo existence at a certain period in the past&rdquo (Haeckel, 1905, p. 339). It now is acknowledged that the first living organism could not have arisen directly from inorganic matter (water, carbon dioxide, and other inorganic nutrients) even as a result of some extraordinary event. Before the explosive growth of our knowledge of the cell during the last 30 years, it was known that &ldquothe simplest bacteria are extremely complex, and the chances of their arising directly from inorganic materials, with no steps in between, are too remote to consider seriously.&rdquo (Newman, 1967, p. 662). Most major discoveries about cell biology and molecular biology have been made since then.

Search for the Evidence of Earliest Life

Theories abound, but no direct evidence for the beginning of the theoretical evolutionary climb of life up what Richard Dawkins and many evolutionists call &ldquomount improbable&rdquo ever has been discovered (Dawkins, 1996). Nor have researchers been able to develop a plausible theory to explain how life could evolve from non-life. Many equally implausible theories now exist, most of which are based primarily on speculation. The ancients believed life originated by spontaneous generation from inanimate matter or once living but now dead matter. Aristotle even believed that under the proper conditions putatively &ldquosimple&rdquo animals such as worms, fleas, mice, and dogs could spring to life spontaneously from moist &rdquoMother Earth."

The spontaneous generation of life theory eventually was proved false by hundreds of research studies such as the 1668 experiment by Italian physician Francesco Redi (1626�). In one of the first controlled biological experiments, Redi proved that maggots appeared in meat only after flies had deposited their eggs on it (Jenkens- Jones, 1997). Maggots do not spontaneously generate on their own as previously believed by less rigorous experimenters.

Despite Redi&rsquos evidence, however, the belief in spontaneous generation of life was so strong in the 1600s that even Redi continued to believe that spontaneous generation could occur in certain instances. After the microscope proved the existence of bacteria in l683, many scientists concluded that these &ldquosimple&rdquo microscopic organisms must have &ldquospontaneously generated,&rdquo thereby providing evolution with its beginning. Pasteur and other researchers, though, soon disproved this idea, and the fields of microbiology and biochemistry have since documented quite eloquently the enormous complexity of these compact living creatures (Black, 1998).

Nearly all biologists were convinced by the latter half of the nineteenth century that spontaneous generation of all types of living organisms was impossible (Bergman, 1993a). Now that naturalism dominates science, Darwinists reason that at least one spontaneous generation of life event must have occurred in the distant past because no other naturalistic origin-of-life method exists aside from panspermia, which only moves the spontaneous generation of life event elsewhere (Bergman, 1993b). As theism was filtered out of science, spontaneous generation gradually was resurrected in spite of its previous defeat. The solution was to add a large amount of time to the broth:

Although this view now is widely accepted among evolutionists, no one has been able to locate convincing fossil (or other) evidence to support it. The plausibility of abiogenesis has changed greatly in recent years due to research in molecular biology that has revealed exactly how complex life is, and how much evidence exists against the probability of spontaneous generation. In the 1870s and 1880s scientists believed that devising a plausible explanation for the origin of life

The German evolutionary biologist Ernst Haeckel (1925) even referred to monera cells as simple homogeneous globules of plasm. Haeckel believed that a living cell about as complex as a bowl of Jell-o ® could exist, and his origin of life theory reflected this completely erroneous view. He even concluded that cell &ldquoautogony&rdquo (the term he used to describe living things&rsquo ability to reproduce) was similar to the process of inorganic crystallization. In his words:

About the same time T. H. Huxley proposed a simple two-step method of chemical recombination that he thought could explain the origin of the first living cell. Both Haeckel and Huxley thought that just as salt could be produced spontaneously by mixing powered sodium metal and heated chlorine gas, a living cell could be produced by mixing the few chemicals they believed were required. Haeckel taught that the basis of life is a substance called &ldquoplasm,&rdquo and this plasm constitutes

Once the brew was mixed, eons of time allowed spontaneous chemical reactions to produce the simple &ldquoprotoplasmic substance&rdquo that scientists once assumed to be the essence of life (Meyer, 1996, p. 25). As late as 1928, the germ cell still was thought to be relatively simple and

Cytologists now realize that a living cell contains hundreds of thousands of different complex parts such as various motor proteins that are assembled to produce the most complex &ldquomachine&rdquo in the Universe—a machine far more complex than the most complex Cray super computer. We now also realize after a century of research that the eukaryote protozoa thought to be as simple as a bowl of gelatin in Darwin&rsquos day actually are enormously more complex than the prokaryote cell. Furthermore, molecular biology has demonstrated that the basic design of the cell is

This is a major problem for Darwinism because life at the cellular level generally does not reveal a gradual increase in complexity as it ascends the evolutionary ladder from protozoa to humans. The reason that all cells are basically alike is because the basic biochemical requirements and constraints for all life are the same:

The most critical gap that must be explained is that between life and non-life because

The belief that spontaneous regeneration, while admittedly very rare, is still attractive as illustrated by Sagan and Leonard&rsquos conclusion, &ldquoMost scientists agree that life will appear spontaneously in any place where conditions remain sufficiently favorable for a very long time&rdquo (1972, p. 9). This claim then is followed by an admission from Sagan and Leonard that raises doubts not only about abiogenesis, but about Darwinism generally, namely, &ldquothis conviction [about the origin of life] is based on inferences and extrapolations.&rdquo The many problems, inferences, and extrapolations needed to create abiogenesis just-so stories once were candidly admitted by Dawkins:

The method used in constructing these hypothetical replicators is not stated, nor has it ever been demonstrated to exist either in the laboratory or on paper. The difficulties of terrestrial abiogenesis are so great that some evolutionists have hypothesized that life could not have originated on earth but must have been transported here from another planet via star dust, meteors, comets, or spaceships (Bergman, 1993b)! As noted above, panspermia does not solve the origin of life problem though, but instead moves the abiogenesis problem elsewhere. Furthermore, since so far as we know no living organism can survive very long in space because of cosmic rays and other radiation, &ldquothis theory is . highly dubious, although it has not been disproved also, it does not answer the question of where or how life did originate&rdquo (Newman, 1967, p. 662).

Darwin evidentially recognized how serious the abiogenesis problem was for his theory, and once even conceded that all existing terrestrial life must have descended from some primitive life form that was called into life &ldquoby the Creator&rdquo (1900, p. 316). But to admit, as Darwin did, the possibility of one or a few creations is to open the door to the possibility of many or even thousands ! If God made one animal type, He also could have made two or many thousands of different types. No contemporary hypothesis today has provided a viable explanation as to how the abiogenesis origin of life could occur by naturalistic means. The problems are so serious that the majority of evolutionists today tend to shun the whole subject of abiogenesis.

History of Modern Abiogenesis Research

The &ldquowarm soup&rdquo theory, still the most widely held theory of abiogenesis among evolutionists, was developed most extensively by Russian scientist A.I. Oparin in the 1920s. The theory held that life evolved when organic molecules rained into the primitive oceans from an atmospheric soup of chemicals interacting with solar energy. Later Haldane (1928), Bernal (1947) and Urey (1952) published their research to try to support this model, all with little success. Then came what some felt was a breakthrough by Harold Urey and his graduate student Stanley Miller in the early 1950s.

The most famous origin of life experiment was completed in 1953 by Stanley Miller at the University of Chicago. At the time Miller was a 23-year-old graduate student working under Urey who was trying to recreate in his laboratory the conditions then thought to have preceded the origin of life. The Miller/Urey experiments involved filling a sealed glass apparatus with methane, ammonia, hydrogen gases (representing what they thought composed the early atmosphere) and water vapor (to simulate the ocean). Next, they used a spark-discharge device to strike the gases in the flask with simulated lightning while a heating coil kept the water boiling. Within a few days, the water and gas mix produced a reddish stain on the sides of the flask. After analyzing the substances that had been formed, they found several types of amino acids. Eventually Miller and other scientists were able to produce 10 of the 20 amino acids required for life by techniques similar to the original Miller/ Urey experiments.

Urey and Miller assumed that the results were significant because some of the organic compounds produced were the building blocks of proteins, the basic structure of all life (Horgan, 1996, p. 130). Although widely heralded by the press as &ldquoproving&rdquo the origin of life could have occurred on the early earth under natural conditions without intelligence, the experiment actually provided compelling evidence for exactly the opposite conclusion. For example, equal quantities of both right- and left-handed organic molecules always were produced by the Urey/Miller procedure. In real life, nearly all amino acids found in proteins are left handed, almost all polymers of carbohydrates are right handed, and the opposite type can be toxic to the cell. In a summary the famous Urey/Miller origin-of-life experiment, Horgan concluded:

The reasons why creating life in a test tube turned out to be far more difficult than Miller or anyone else expected are numerous and include the fact that scientists now know that the complexity of life is far greater than Miller or anyone else in pre-DNA revolution 1953 ever imagined. Actually life is far more complex and contains far more information than anyone in the 1980s believed possible. In an interview with Miller, now considered one of &ldquothe most diligent and respected origin-of-life researchers,&rdquo Horgan reported that after Miller completed his 1953 experiment, he

The major problem of Millers experiment is well put by Davies,

We now realize that the Urey/Miller experiments did not produce evidence for abiogenesis because, although amino acids are the building blocks of life, the key to life is information (Pigliucci, 1999 Dembski, 1998). Natural objects in forms resembling the English alphabet (circles, straight lines and similar) abound in nature, but this does not help us to understand the origin of information (such as that in Shakespear&rsquos plays) because this task requires intelligence both to create the information (the play) and then to translate that information into symbols. What must be explained is the source of the information in the text (the words and ideas), not the existence of circles and straight lines. Likewise, the information contained in the genome must be explained (Dembski, 1998). Complicating the situation is the fact that

Yet another difficulty is, even if the source of the amino acids and the many other compounds needed for life could be explained, it still must be explained as to how these many diverse elements became aggregated in the same area and then properly assembled themselves. This problem is a major stumbling block to any theory of abiogenesis:

Several recent discoveries have led some scientists to conclude that life may have arisen in submarine vents whose temperatures approach 350° C. Unfortunately for both warm pond and hydrothermal vent theorists, heat may be the downfall of their theory.

Heat and Biochemical Degradation Problems

Charles Darwin&rsquos hypothesis that life first originated on earth in a warm little pond somewhere on a primitive earth has been used widely by most nontheists for over a century in attempts to explain the origin of life. Several reasons exist for favoring a warm environment for the start of life on earth. A major reason is that the putative oldest known organisms on earth are alleged to be hyperthermophiles that require temperatures between 80° and 110° C in order to thrive (Levy and Miller, 1998). In addition some atmospheric models have concluded that the surface temperature of the early earth was much higher than it is today.

A major drawback of the &ldquowarm little pond&rdquo origin- of-life theory is its apparent ability to produce sufficient concentrations of the many complex compounds required to construct the first living organisms. These compounds must be sufficiently stable to insure that the balance between synthesis and degradation favors synthesis (Levy and Miller, 1998). The warm pond and hot vent theories also have been seriously disputed by experimental research that has found the half-lives of many critically important compounds needed for life to be far &ldquotoo short to allow for the adequate accumulation of these compounds&rdquo (Levy and Miller, 1998, p. 7933). Furthermore, research has documented that &ldquounless the origin of life took place extremely rapidly (in less than 100 years), we conclude that a high temperature origin of life. cannot involve adenine, uracil, guanine or cytosine&rdquo because these compounds break down far too fast in a warm environment. In a hydrothermal environment, most of these compounds could neither form in the first place, nor exist for a significant amount of time (Levy and Miller, p. 7933).

As Levy and Miller explain, &ldquothe rapid rates of hydrolysis of the nucleotide bases A,U,G and T at temperatures much above 0° Celsius would present a major problem in the accumulation of these presumed essential components on the early earth&rdquo (p. 7933). For this reason, Levy and Miller postulated that either a two-letter code or an alternative base pair was used instead. This requires the development of an entirely different kind of life, a conclusion that is not only highly speculative, but likely impossible because no other known compounds have the required properties for life that adenine, uracil, guanine and cytosine possess. Furthermore, this would require life to evolve based on a hypothetical two-letter code or alternative base pair system. Then life would have to re-evolve into a radically new form based on the present code, a change that appears to be impossible according to our current understanding of molecular biology.

Furthermore, the authors found that, given the minimal time perceived to be necessary for evolution to occur, cytosine is unstable even at temperatures as cold as 0º C. Without cytosine neither DNA or RNA can exist. One of the main problems with Miller&rsquos theory is that his experimental methodology has not been able to produce much more than a few amino acids which actually lend little or no insight into possible mechanisms of abiogenesis.

Postulating alternative codes for an origin-of-life event at temperatures close to the freezing point of water is a rationalization designed to overcome what appears to be a set of insurmountable problems for the abiogenesis theory. Given these problems, why do so many biologists believe that life on earth originated by spontaneous generation under favorable conditions? Yockey concludes that although Miller&rsquos paradigm was at one time

The many problems with the warm soup model have motivated the development of many other abiogenesis models. One is the cold temperature model that is gaining in acceptance as the flaws of the hot model become more obvious. As Vogel notes, many researchers still

Based on a geochemical assessment, Thaxton, Bradley, and Olsen (1984 p. 66) concluded that in the atmosphere the &ldquomany destructive interactions would have so vastly diminished, if not altogether consumed, essential precursor chemicals, that chemical evolution rates would have been negligible&rdquo in the various water basins on the primitive earth. They concluded that the &ldquosoup&rdquo would have been far too diluted for direct polymerization to occur. Even local ponds where some concentrating of soup ingredients may have occurred would have met with the same problem.

It also is theorized that life must have begun in clay because the &ldquoclay-life&rdquo explanation explains several problems not explained by the &ldquoprimordial soup&rdquo theory. Graham Cairns-Smith of the University of Scotland first proposed the clay-life theory about 40 years ago, and many scientists have since come to believe that life on earth must have began from clay rather than in the the warm little pond as proposed by Darwin. The clay-life theory holds that an accumulation of chemicals produced in clay by the sun eventually led to the hypothetical self-replicating molecules that evolved into cells and then eventually into all life forms on earth today.

The theory argues that only clay has the two essential properties necessary for life: the capacity to both store and transfer energy. Furthermore, because some clay components have the ability to act as catalysts, clay is capable of some of the same lifelike attributes as those exhibited by enzymes. Additionally the mineral structure of certain clays are almost as intricate as some organic molecules. However, the clay theory suffered from its own set of problems, and as a result has been discarded by most theorists. At the very least, the Stanley Miller experiments proved that amino acids can be formed under certain conditions. The clay theory has yet to achieve even this much. As a result, Miller&rsquos experiments continue to be cited because no other viable source exists for the production of amino acids. Now, the hot thermal vent theory is being discussed once again by many as an alternative although, as noted above, it too suffers from potentially lethal problems.

What is Needed to Produce Life

Naturalism requires enormously long periods of time to allow non-living matter to evolve into the hypothetical speck of viable protoplasm needed to start the process that results in life. Even more time is needed to evolve the protoplasm into the enormous variety of highly organized complex life forms that have been found in Cambrian rocks. Neo-Darwinism suggests that life originated over 3.5 billion years ago, yet a rich fossil record for less than roughly 600 million years commonly is claimed. Consequently, almost all the record is missing, and evidence for the most critical two billion years of evolution is sparse at best with what little actually exists being highly equivocal.

A major issue then, in abiogenesis is &ldquowhat is the minimum number of possible parts that allows something to live?&rdquo The number of parts needed is large, but how large is difficult to determine. In order to be considered &ldquoalive,&rdquo an organism must possess the ability to metabolize and assimilate food, to respirate, to grow, to reproduce and to respond to stimuli (a trait known as irritability). These criteria were developed by biologists who were trying to understand the process we call life. Although these criteria are not perfect, they are useful in spite of cases that seem to contradict our definition. A mule, for instance, cannot usually reproduce but clearly is alive, and a crystal can &ldquoreproduce&rdquo but clearly is not alive. One attempt by an evolutionist to determine what is needed in order to self-replicate produced the following conclusions:

The cell, then appears to be the only biological entity that self-reproduces and simultaneously possesses the other traits required for life. The question then becomes &ldquoWhat is the simplest cell that can exist?&rdquo

Many bacteria and all viruses possess less complexity than required for an organism normally defined as &ldquoliving,&rdquo and for this reason must live as parasites which require the existence of complex cells in order to reproduce. For this reason Trefil noted that the question of where viruses come from is an &ldquoenduring mystery&rdquo in evolution. Viruses usually are much smaller than parasitic bacteria and are not considered alive because they must rely on their host even more than bacteria do. Viruses consist primarily of a coat of proteins surrounding DNA or RNA that contains a handful of genes, and since they do not

In order to reproduce, a virus&rsquos genes must invade a living cell and take control of its much larger DNA. A bacterium is 400 times greater in size than the smallest known virus, while a typical human cell averages 200 times larger than the smallest known bacterium. The QB virus is only 24 nanometers long, contains only 3 genes and is almost 20 times smaller than Escherichia coli, billions of which inhabit the human intestines. E. coli is 1,000 nanometers long compared to a typical human cell that is about 10,000 nanometers long (1 nanometer equals 1 billionth of a meter, or about 1/25-millionths of an inch) and contains an estimated 100,000 genes. Researchers have detected microbes in human and bovine blood that are only 2-millionths of an inch in diameter, but these organisms cannot live on their own because they need more than simple inorganic, or common inorganic molecules to survive.

Since parasites lack many of the genes (and other biological machinery) required to survive on their own, in order to grow and reproduce they must obtain the nutrients and other services they require from the organisms that serve as their hosts. Independent free-living creatures such as people, mice and roses are far more complex than organisms like parasites and viruses that are dependent on these complex free-living organisms. Abiogenesis theory requires that the first life forms consisted of free-living autotrophs (i.e. organisms that are able to manufacture their own food) since the complex life forms needed to sustain heterotrophs (organisms that cannot manufacture their own food) did not exist until later.

Most extremely small organisms existing today are dependent on other, more complex organisms. Some organisms can overcome their lack of size and genes by borrowing genes from their hosts or by gorging on a rich broth of organic chemicals like blood. Some microbes live in colonies in which different members provide different services. Unless one postulates the unlikely scenario of the simultaneous spontaneous generation of many different organisms , one has to demonstrate the evolution of an organism that can survive on its own, or with others like itself, as a symbiont or cannibal. Consequently, the putative first life forms must have been much more complex than most examples of &ldquosimple&rdquo life known to exist today.

The simplest microorganisms, Chlamydia and Rickettsea, are the smallest living things known, but also are both parasites and thus too simple to be the first life. Only a few hundred atoms across, they are smaller than the largest virus and have about half as much DNA as do other species of bacteria. Although they are about as small as possible and still be living, these two forms of life still possess the millions of atomic parts necessary to carry out the biochemical functions required for life, yet they still are too simple to live on their own and thus must use the cellular machinery of a host in order to live (Trefil, 1992, p. 28). Many of the smaller bacteria are not free living, but are parasite like viruses that can live only with the help of more complex organisms (Galtier et al., 1999).

The gap between non-life and the simplest cell is illustrated by what is believed to be the organism with the smallest known genome of any free living organism Mycoplasma genitalium (Fraser et al., 1995). M. genitalium is 200 nanometers long and contains only 482 genes or over 0.5 million base pairs which compares to 4,253 genes for E. coli (about 4,720,000 nucleotide base pairs), with each gene producing an enormously complex protein machine (Fraser et al., 1995). M. genitalium also must live off other life because they are too simple to live on their own. They invade reproductive tract cells and live as parasites on organelles that are far larger and more complicated but which must first exist for the survival of parasitic organisms to be possible. The first life therefore must be much more complex than M. genitalium even though it is estimated to manufacture about 600 different proteins. A typical eukaryote cell consists of an estimated 40,000 different protein molecules and is so complex that to acknowledge that the &ldquocells exist at all is a marvel. even the simplest of the living cells is far more fascinating than any human- made object" (Alberts, 1992, pp. xii, xiv).

M. genitalium is one-fifth the size of E. coli but four times larger than the putative nanobacteria. Blood nanobacteria are only 50 nanometers long (which is smaller than some viruses), and possess a currently unknown number of genes. When Finnish biologist Olavi Kajander discovered nanobacteria in 1998, he called them a &ldquobizarre new form of life.&rdquo Nanobacteria now are speculated to resemble primitive life forms which presumably arose in the postulated chemical soup that existed when earth was young. Kajander concluded that nanobacteria may serve as a model for primordial life, and that their modern-day primordial soup is blood. Actually, nanobacteria cannot be the smallest form of life because they evidently are parasites and primordial life must be able to live independently. Like viruses they are not considered alive but are of intense medical interest because they may be one cause of kidney stones (Kajander and Ciftcioglu, 1998). Other researchers think these bacteria are only a degenerate form of larger bacteria.

For these reasons, when researching the minimum requirements needed to live the example of E. coli is more realistic. Most bacteria require several thousand genes to carry out the minimum functions necessary for life. Denton notes that even though the tiniest bacterial cells are incredibly small, weighing under 10 㪤 grams, each bacterium is a

The simplest form of life requires millions of parts at the atomic level, and the higher life forms require trillions. Furthermore, the many macromolecules necessary for life are constructed of even smaller parts called elements. That life requires a certain minimum number of parts is well documented the only debate now is how many millions of functionally integrated parts are necessary. The minimum number may not produce an organism that can survive long enough to effectively reproduce. Schopf notes that simple life without complex repair systems to fix damaged genes and their protein products stand little chance of surviving. When a mutation occurs

Therefore, the answer to our original question, &ldquoWhat is the smallest form of nonparasitic life?&rdquo probably is an organism close to size and complexity of E. Coli, possibly even larger. No answer is currently possible because we have much to learn about what is required for life. As researchers discover new exotic &ldquolife&rdquo forms thriving in rocks, ice, acid, boiling water and other extreme environments, they are finding the biological world to be much more complex than assumed merely a decade ago. The oceans now are known to be teeming with microscopic cells which form the base of the food chain on which fish and other larger animals depend. It now is estimated that small, free-living aquatic bacteria make up about one-half of the entire biomass of the oceans (MacAyeal, 1995).

Many highly complex animals appear very early in the fossil record and many &ldquosimple&rdquo animals thrive today. The earliest fossils known, which are believed to be those of cyanobacteria, are quite similar structurally and biochemically to bacteria living today. Yet it is claimed they thrived almost as soon as earth formed (Schopf, 1993 Galtier et al., 1999). Estimated at 3.5 billion years old, these earliest known forms of life are incredibly complex. Furthermore, remarkably diverse types of animals existed very early in earth history and no less than eleven different species have been found so far. A concern Corliss raises is &ldquowhy after such rapid diversification did these microorganisms remain essentially unchanged for the next 3.465 billion years? Such stasis, common in biology, is puzzling&rdquo (1993, p. 2). E. coli, as far as we can tell, is the same today as in the fossil record.

Probability Arguments

As Coppedge (1973) notes, even 1) postulating a primordial sea with every single component necessary for life, 2) speeding up the bonding rate so as to form different chemical combinations a trillion times more rapidly than hypothesized to have occurred, 3) allowing for a 4.6 billion- year-old earth and 4) using all atoms on the earth still leaves the probability of a single protein molecule being arranged by chance is 1 in 10,261. Using the lowest estimate made before the discoveries of the past two decades raised the number several fold. Coppedge estimates the probability of 1 in 10 119,879 is necessary to obtain the minimum set of the required estimate of 239 protein molecules for the smallest theoretical life form.

At this rate he estimates it would require 10 119,831 years on the average to obtain a set of these proteins by naturalistic evolution (1973, pp. 110, 114). The number he obtained is 10 119,831 greater than the current estimate for the age of the earth (4.6 billion years). In other words, this event is outside the range of probability. Natural selection cannot occur until an organism exists and is able to reproduce which requires that the first complex life form first exist as a functioning unit.

In spite of the overwhelming empirical and probabilistic evidence that life could not originate by natural processes, evolutionists possess an unwavering belief that some day they will have an answer to how life could spontaneously generate. Nobel laureate Christian de Duve (1995) argues that life is the product of law-driven chemical steps, each one of which must have been highly probable in the right circumstances. This reliance upon an unknown &ldquolaw&rdquo favoring life has been postulated to replace the view that life&rsquos origin was a freakish accident unlikely to occur anywhere, is now popular. Chance is now out of favor in part because it has become clear that even the simplest conceivable life form (still much simpler than any actual organism) would have to be so complex that accidental self-assembly would be nothing short of miraculous even in two billion years (Spetner, 1997). Furthermore, natural selection cannot operate until biological reproducing units exist. This hoped for &ldquolaw,&rdquo though, has no basis in fact nor does it even have a theoretical basis. It is a nebulous concept which results from a determination to continue the quest for a naturalistic explanation of life. In the words of Horgan:

The atheistic world view requires abiogenesis therefore scientists must try to deal with the probability arguments. The most common approach is similar to the attempt by Stenger, who does not refute the argument but tries to explain it by way analogy:

The major problem with this argument, as shown by Dembski, is that it is a gross misuse of statistics, one of the most important tools science has ever developed. Although change is involved, intelligence is critically important even in the events Stenger describes. The fallacy of his reasoning can be illustrated by comparing it to a court case using DNA. Stenger&rsquos analogy cannot negate the finding that the likelihood is 1 in 100 million that a blood sample found on the victim at the crime is the suspect&rsquos. For this reason, it is highly probable that the accused was at the crime scene the fact that his blood was mixed with the victim&rsquos, will no doubt be accepted by the court and an attempt to destroy this conclusion by use of an analogy such as Stenger&rsquos will likely be rejected.

Conclusions

It appears that the field of molecular biology will falsify Darwinism. An estimated 100,000 different proteins are used to construct humans alone. Furthermore, one million species are known, and as many as 10 million may exist. Although many proteins are used in most life forms, as many as 100 million or more protein variations may exist in all plant and animal life. According to Asimov:

Even using an unrealistically low estimate of 1,000 steps required to &ldquoevolve&rdquo the average protein (if this were possible) implies that many trillions of links were needed to evolve the proteins that once existed or that exist today. And not one clear transitional protein that is morphologically and chemically in between the ancient and modern form of the protein has been convincingly demonstrated. The same problem exists with fats, nucleic acids, carbohydrates and the other compounds that are produced by, and necessary for, life.

Scientists have yet to discover a single molecule that has &ldquolearned to make copies of itself&rdquo (Simpson, 1999, p. 26). Many scientists seem to be oblivious of this fact because

Some bacteria, specifically phototrophs and lithotrophs, contain all the metabolic machinery necessary to construct most of their growth factors (amino acids, vitamins, purines and pyrimidines) from raw materials (usually O 2 , light, a carbon source, nitrogen, phosphorus, sulfur and a dozen or so trace minerals). They can live in an environment with few needs but first must possess the complex functional metabolic machinery necessary to produce the compounds needed to live from a few types of raw materials. This requires more metabolic machinery in order to manufacture the many needed organic compounds necessary for life. Evolution was much more plausible when life was believed to be a relatively simple material similar to, in Haeckel&rsquos words, the &ldquotransparent viscous albumin that surrounds the yolk in the hen&rsquos egg&rdquo which evolved into all life today. Haeckel taught the process occurred as follows:

Abiogenesis is only one area of research which illustrates that the naturalistic origin of life hypothesis has become less and less probable as molecular biology has progressed, and is now at the point that its plausibility appears outside the realm of probability. Numerous origin-of-life researchers, have lamented the fact that molecular biology during the past half-a-century has not been very kind to any naturalistic origin-of-life theory. Perhaps this explains why researchers now are speculating that other events such as panspermia or an undiscovered &ldquolife law&rdquo are more probable than all existing terrestrial abiogenesis theories, and can better deal with the many seemingly insurmountable problems of abiogenesis.

Acknowledgements: I want to thank Bert Thompson, Ph.D., Wayne Frair, Ph.D., and John Woodmorappe, M.A., for their comments on an earlier draft of this article.

Jerry Bergman has seven degrees, including in biology, psychology, and evaluation and research, from Wayne State University, in Detroit, Bowling Green State University in Ohio, and Medical College of Ohio in Toledo. He has taught at Bowling Green State University, the University of Toledo, Medical College of Ohio and at other colleges and universities. He currently teaches biology, microbiology, biochemistry, and human anatomy at the college level and is a research associate involved in research in the area of cancer genetics. He has published widely in both popular and scientific journals. [RETURN TO TOP]

References

CRSQ: Creation Research Society Quarterly.

CENTJ: Creation Ex Nihilo Technical Journal.

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Asimov, Isaac. 1962. The genetic code. The Orion Press, New York.

Behe, Michael. 1996. Darwin&rsquos black box. Basic Books, New York.

Bergman, Jerry. 1993a. A brief history of the theory of spontaneous generation. CENTJ 7(1):73㫩.

———. 1993b. Panspermia—The theory that life came from outer space. CENTJ 7 (1):82㫯.

———. 1998. The transitional form problem. CRSQ 35(3):134𤪄.

Black Jacquelyn G. 1998. Microbiology principles and applications. Prentice Hall, Upper Saddle River, NJ.

Cairns-Smith, Alexander G. 1985. The first organisms. Scientific American 252(6):90𤩔.

Conklin, Edwin Grant. 1928. Embryology and evolution in Creation by evolution . Frances Mason (editor). Macmillan, New York.

Coppedge, James, F. 1973. Evolution: Possible or impossible? Zondervan, Grand Rapids, MI.

Corliss, William R. 1993. Early life surprisingly diverse. Science Frontiers . 88:2.

Darwin, Charles. 1900. Origin of species. Reprint of sixth edition PF Collier, New York.

Davies, Paul. 1999. Life force. New Scientist. 163(2204): 27㪶.

Dawkins, Richard. 1996. Climbing mount improbable. W.W. Norton, New York.

de Duve, Christian. 1995. Vital dust: Life as a cosmic imperative. Basic Books, New York.

Dembski, William A. 1998. The design inference: Eliminating chance through small probabilities. Cambridge University Press, Cambridge, England.

Denton, Michael. 1986. Evolution: A theory in crisis. Adler and Adler, Bethesda, MD.

———. 1998. Nature&rsquos destiny how the laws of biology reveal purpose in the universe. The Free Press, New York.

Dover, Gabby. 1999. Looping the evolutionary loop. Review of the origins of life: from the birth of life to the origin of language. Nature. 399:217𤫊.

Fraser, Claire M., Jeannine Gocayne and Owen White. 1995. The minimal gene complement of mycoplasma genitalium. Science 270(5235):397𤮃.

Galtier, Nicolas, Nicolas Tourasse and Manolo Gouy. 1999. A nonhyperthermophilic common ancestor to extant life forms. Science. 283 (5399):220𤫍.

Gish, Duane T. 1995. Evolution: The fossils still say no. Institute for Creation Research, El Cajon, CA.

Gould, Stephen. 1989. Wonderful life. W. W. Norton, New York.

Haeckel, Ernst. 1905. The wonders of life. Harper and Brothers, New York.

———. 1925. The history of creation : natürliche schöpfungsgeschte. D. Appleton, New York.

Hanegraaff, Hank. 1998. The face that demonstrates the farce of evolution. Word Publishing, Nashville, TN.

Horgan, John. 1996. The end of science. Addison-Wesley, Reading, MA.

Jenkins-Jones, Sara (editor). 1997. Random House Webster&rsquos dictionary of scientists. RandomHouse, New York.

Kajander, E.O. and Ciftcioglu, . 1998. Nanobacteria: An alternative mechanism for pathogenic intra- and extracellular calcification and stone formation. Proceedings of the National Academy of Sciences of the United States of America, 95(14):8274�.

Lahav, Noam. 1999. Biogenesis : Theories of life&rsquos origin. Oxford University, New York.

Levy, Matthew and Stanley L. Miller. 1998. The stability of the RNA bases: Implications for the origin of life. Proceedings of the National Academy of Science USA 95: 7933�.

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Moore, John. 1976. Documentation of absence of transitional forms. CRSQ, 13(2):110𤩟.

Newman, James (editor). 1967. The Harper encyclopedia of science. Harper and Row, New York.

Pigliucci, Massimo. 1999. Where do we come from? A humbling look at the biology of life&rsquos origin.&rdquo Skeptical Inquirer, 23(5):21㪳.

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Sagan, Carl and Jonathan Leonard. 1972. Planets. Time Life Books, New York.

Schopf, J. William. 1993. Microfossils of the early Archean, Apex chert new evidence of the antiquity of life. Science 260:640𤱶.

———. 1999. Cradle of life: The discovery of the earth&rsquos earliest fossils. Princeton University Press, Princeton, NJ.

Shapiro, Robert. 1986. Origins A skeptics guide to the creation of life on earth. Summit Books, New York.

Simpson, Sarah. 1999. Life&rsquos first scalding steps. Science News, 155(2):24㪲.

Spetner, Lee. 1997. Not a chance! Shattering the modern theory of evolution. Judaica Press, New York.

Standen, Anthony. 1950. Science is a sacred cow. E. P. Dutton, New York.

Stenger, Victor. 1998. Anthropic design and the laws of physics. Reports: National Center for Science Education, 18(3):8㪤.

Thaxton, Charles, Walter Bradley, and Roger Olsen. 1984. The mystery of life&rsquos origin reassessing current theories. Philosophical Library, New York.

Trefil, James. 1992. 1001 things everyone should know about science. Doubleday, New York.

Vogel, Gretchen. 1999. RNA study suggests cool cradle of life. Science. 283(5399):155𤪌.

Wynn, Charles M. and Arthur W. Wiggins. 1997. The five biggest ideas in science. John Wiley and Sons, New York.

Yockey, Hubert P. 1992. Information theory and molecular biology. Cambridge University Press, Cambridge, p. 336.

Editor&rsquos Note

The Quarterly has published numerous items on the same subject as Dr. Bergman&rsquos article. Readers should find the following references of interest.

Armstrong, H. 1964. The possibility of the artificial creation of life. CRSQ 1(3):11.

———. 1967. Is DNA only a material cause? CRSQ 4: 41㫅.

Butler, L. 1966. Meteorites, man and God&rsquos plan. CRSQ 2(4):33㪺.

Coppedge, J. F. 1971. Probability of left-handed molecules. CRSQ 8:163𤪞.

Frair, W. F. 1968. Life in a test tube. CRSQ 5:34㫁.

Gish, D. T. 1964. Critique of biochemical evolution. CRSQ 1(2):1㪤.

———. 1970. The nature of speculations concerning the origin of life. CRSQ 7:42㫅, 83.

Henning, W. L. 1971. Was the origin of life inevitable? CRSQ 8:58㫔.

Lammerts, W. E. 1969. Does the science of genetic and molecular biology really give evidence for evolution? CRSQ 6:5㪤, 26.

Nicholls, J. 1972. Bacterium E. Coli vs. evolution. CRSQ 9:23㪰.

Sharp, D. . 1977. Interdependence in macromolecular synthesis: Evidence for design. CRSQ 14:54㫕.

Trop, M. 1975. Was evolution really possible? CRSQ 11:183𤪫.

Williams, E. L. 1967. The evolution of complex organic compounds from simpler chemical compounds: Is it thermodynamically and kinetically possible? CRSQ 4:30㪻.

Zimmerman, P. A. 1964. The spontaneous generation of life. CRSQ 1 (Annual):13㪩.


Moving to a DNA world

Demonstration that biological molecules and membranes can arise in an abiotic environment is not a demonstration of the emergence of life. It shows only what might have happened in the transition from non-living chemistry to the eventual formation of life. It does, however, show that a necessary step in abiogenesis – the spontaneous emergence of complex organic molecules – is not only possible, but likely under the right conditions.

Theoretically, continuous rearrangement and construction of larger and larger organic molecules from chemical building blocks that would form on the early Earth should eventually lead to molecules that can copy themselves. That’s because the bigger an organic molecule gets, the more functional chemical groups it has. Functional groups are sections of molecules with atoms other than carbon, such as oxygen, nitrogen, and phosphorus, which like to hold onto electrons. This allows for electrons to be moved around between parts of the molecule and between the molecule and other molecules. Also, the bigger a molecule gets, the more it’s able to bend and twist around. This capability, together with the capability to move around a lot of electrons, &^means it’s possible, simply by luck, for any random, very large organic molecule with a lot of nitrogen, oxygen, and phosphorus atoms to have some enzymatic capability –that is, to be able to catalyze chemical reactions.

Certain sets of reactions catalyzed by a molecule can result in the molecule making a copy of itself. Thus, with plenty of building materials in a Haldane soup, as time goes on, it is likely that self-replicating molecules would emerge. The first self-replicating molecule would have only crude copying ability. But, since it would not copy itself exactly, each new “copy” would be a little different than the “parent” molecule. Randomly, a newly copied molecule might have the ability to copy slightly better than the molecule that made it. Natural selection would then work for non-living chemical molecules similar to how Darwin described it working for living organisms. Those molecules copying better would make more copies using building blocks taken from the breakdown of other molecules that could not copy themselves so well.

Self-copying molecules enclosed in membranes would fare even better because they would be held close together with other chemicals. But for life to really begin, there has to have been a molecule whose copying ability was extremely good. Today, there is such a molecule: DNA. However, DNA is incredibly complex and this makes for a chicken and egg kind of dilemma.

In the 1980s, scientists began to realize that not all enzymes are proteins. Scientists dissected some cell components called ribosomes and found that they are made of protein and RNA. What was strange was that some of the RNA molecules actually work as enzymes. They can catalyze chemical changes in themselves and in other RNA molecules.

Like DNA, RNA can hold genetic information, but RNA is less complex than DNA (Figure 8). Consequently, a hypothesis called the “RNA world” was proposed independently by three different researchers: Leslie Orgel, Francis Crick, and Carl Woese. It’s a keystone in origins of life research today. The idea is that RNA emerged on Earth prior to DNA and was the genetic material in the first cells (or in the first cells on a different world, if life began somewhere else).

Figure 8: A comparison of Ribonucleic acid (RNA) and Deoxyribonucleic acid (DNA).

Today, no known bacterial cell or other fully-fledged life form uses RNA the way that we use DNA, as the storage molecule for genetic information. But there are RNA viruses. Not all viruses are RNA viruses some use DNA to hold genetic instructions, just as our cells do. But if RNA is adequate as the only genetic material in some viruses, it’s easy to imagine RNA also being the only genetic material in an early bacterium, or other singled-celled creature that could have existed on the early Earth.

It’s not hard to image how the transition from RNA to DNA might have occurred. As with the evolution of everything else, there would have been mistakes. In living organisms today, DNA stores genetic information over the long term and DNA sequences are transcribed into RNA sequences, which then are used to put together sequences of amino acids into proteins (see our Gene Expression: An overview module). Essentially, DNA is an additional layer beyond RNA and the proteins that RNA makes. RNA sequences could have been the genes before a mistake created DNA. Being more stable chemically than RNA, DNA took over the job of storing genetic information. This gave RNA a chance to get better at translating genetic information into proteins.

That would have been an enormous step in life’s evolution. It also would mean that life was not here all at once. Rather, abiogenesis occurred in increments or steps during prebiotic, chemical evolution. Thus, entities must have existed along a spectrum from nonliving to living, just as viruses today have characteristics of both living and nonliving entities. We don’t know the precise abiogenesis pathway, but scientists have worked out each of the major steps necessary to go from nonliving chemistry to self-sustaining cells. Importantly, scientists also have conducted laboratory experiments demonstrating that each step is possible. Unlike the days of Anaximander, Darwin, or even Haldane, there are no big holes or theoretical barriers to abiogenesis. Scientists have a good idea of how it probably happened. Still, in terms of the details within each major step, that is where science is now focused on getting some answers.

Summary

Since prehistoric times, people have pondered how life came to exist. This module describes investigations into the origins of life through history, including Louis Pasteur’s experiments that disproved the long-held idea of spontaneous generation and and later research showing that the emergence of biological molecules from a nonliving environment – or abiogenesis – is not only possible, but likely under the right conditions.

Key Concepts

Theories about the origins of life are as ancient as human culture. Greek thinkers like Anaximander thought life originated with spontaneous generation, the idea that small organisms are spontaneously generated from nonliving matter.

The theory of spontaneous generation was challenged in the 18th and 19th centuries by scientists conducting experiments on the growth of microorganisms. Louis Pasteur, by conducting experiments that showed exposure to fresh air was the cause of microorganism growth, effectively disproved the spontaneous generation theory.

Abiogenesis, the theory that life evolved from nonliving chemical systems, replaced spontaneous generation as the leading theory for the origin of life.

Haldane and Oparin theorized that a "soup" of organic molecules on ancient Earth was the source of life's building blocks. Experiments by Miller and Urey showed that likely conditions on early Earth could create the needed organic molecules for life to appear.

RNA, and through evolutionary processes, DNA and the diversity of life as we know it, likely formed due to chemical reactions among the organic compounds in the "soup" of early Earth.


Watch the video: Abiogenese - Der Ursprung des Lebens I 2019 (August 2022).