Updated: May 20, 2019
The second barrier to life is the transformation of the single-cell living creature from a simple to a more complex form of a single-cell. Scientists have never observed the transformation of life from a bacterial cell, to a cell with a nucleus.
The two types of single cells that we are talking about are called prokaryotes and eukaryotes. One simple way to remember the difference is that prokaryote starts with the letter "p." Think of the word puny. The word eukaryote starts with the letter "e." A eukaryote is enormous compared to a puny prokaryote. Prokaryotes can be as small as 0.0002 milimeters, while the largest eukaryotes can be as large as 3 or 4 inches in length! Note, most eukaryotes are not measured in inches; they are much smaller.
This is a brief discussion of the second barrier to life. This topic is covered in much more depth with many more scientific sources in my book: Evolution Myths: A Critical View of neo-Darwinism.
Prokaryotes are extremely small. Encyclopedia Britannica online defined prokaryote as: “any organism that lacks a distinct nucleus and other organelles due to the absence of internal membranes. Bacteria are among the best-known prokaryotic organisms” (2013). The public refers to them in other terms such as bacteria. Some examples of prokaryotes are E-coli and streptococcus bacteria. The streptococcus bacterium is responsible for what doctors refer to as strep throat.
The average size of bacteria are 0.2–2.0 µm. For comparison, 0.2 micrometers are 0.0002 millimeters. Bacteria are invisible to the human eye.
The most abundant source of life on Earth are bacteria. Scientists believe that bacteria were formed on Earth about 3.5 billion years ago. Then, about 1 billion years later, the first single-celled eukaryote appeared on Earth. The problem is that there is no evolutionary explanation for the eukaryote, natural selection cannot explain it!
Encyclopedia Britannica online defines eukaryote as, “any cell or organism that possesses a clearly defined nucleus” (2018).
The famed evolutionary biologist Ernst Mayr (1999), the author of What Evolution Is, wrote, “The origin of the eukaryotes was arguable the most important event in the whole history of life on earth. It made the origin of all the more complex organisms, plants, fungi, and animals possible” (2001, p. 47).
Here is what Dr. Francis Crick (1981), the co-discoverer of DNA had to say about the development of eukaryotes.
“The most significant division [of life] is between organisms whose cells have a nucleus like ours, called eukaryotes, and humbler organisms which lack such a nucleus, known as prokaryotes . . . These could not have been studied effectively without the use of modern equipment, such as the electron microscope which allows us to visualize the components of cells in much finer detail than was ever possible before. For this reason the eukaryote-prokaryote classification is comparatively recent, dating only from about 1960.” (pp. 122-123)
The differences between eukaryotes and their predecessors, the prokaryotes are mind-blowing. Here is a passage from my book, Evolution Myths: A Critical View of neo-Darwinism:
“Eukaryotes differ from prokaryotes in over a dozen ways. Eukaryotes have a nucleus; prokaryotes do not. Eukaryotes reproduce sexually; prokaryotes do not. Eukaryotes organize DNA into chromosomes, prokaryotes do not. Eukaryotes have an energy plant [source] called mitochondria; prokaryotes do not.” (p. 150)
AN ENERGY PROBLEM
Evolutionary biochemist Nick Lane (2010) explains that the amount of energy required from a prokaryote (bacteria - no nucleus) to form a eukaryote (a cell with a nucleus) would be 200,000 times the energy level of the prokaryote! The question is where did the energy come from and how did the DNA get reprogrammed to create all the new structures (called organelles) inside the eukaryote?
“The eukaryote common ancestor increased its genetic repertoire by some 3,000 novel gene families. The invention of new protein folds in the eukaryotes was the most intense phase of gene invention since the origin of life". (p. 932).
As I state in my book, Evolution Myths, A Critical View of neo-Darwinism,
"This is a striking statement by an evolutionary biochemist. Lane states that new protein folds in eukaryotes were "invented." Clearly, Lane is at loss to explain what he observes and is limited by language. I do not mean to imply that Lane is suggeting that eukaryotes can think, and therefore eukaryotes invented gene complexity that is 3,000 times more complex than that of prokaryotes! Once again, it begs the question: Since a stunning new development in gene complexity took place in eukaryotes, where did the complexity and coding information come from? Lane offers us no theory to address this important research question." (p. 143)
An example of the size of a Eukaryote is an amoeba, which can be 1mm (1000 µ) in length. Some amoebas can be seen with the human eye. The largest single-cell life forms discovered are called xenophyophores. They have been observed as deep as 6.6 miles, in places like the Mariana Trench. Some were measured as long as 4 inches!
This is perhaps one of the most heated debates among microbiologists today. Something that the public is completely unaware of. We are told that evolution is a fact and that it explains life, but scientists have NO EVIDENCE for how life changed from bacteria (prokaryote) to an amoeba (eukaryote).
THEORY OF ENDOSYMBIOSIS
This theory was developed by the late biologist Lynn Margulis. It tries to explain the development of eukaryotes from prokaryotes. It was rejected soundly when first introduced back in the 1960s. Margulis self-published a book titled: Origin of eukaryotic cells (1970). Margulis was fascinated with symbionts that have been observed in nature. Symbionts are life forms that live inside of hosts, or other life forms. For example, certain types of bacteria have been found to life in hosts (McFall-Ngai, Margaret J, 1999).
Scientists have never observed the formation of a eukaryote. The theory of endosymbiosis tries to explain the development of eukaryotes as, one prokaryote bumping into another prokaryote, gobbling it up and then eventually creating a bigger eukaryote. The problem is that this is a nice story, but it has never been observed! It is only a story.
The topic of endosymbiosis is lengthy and will be the subject of a future blog post. It is sufficient to say that the theory has been accepted and is now prevalent in biological texts as an explanation for how eukaryotes evolved. The theory, in a nutshell suggests that two prokaryotes collided, combined over time and eventually produced a eukaryote.
When the theory was first proposed, the electron microscope had just been invented and little was known about the complexity of DNA or the internal structures (organelles) that exist in a eukaryote but are absent in a prokaryote.
Today, there is abundant criticism of endosymbiosis. Biologists Emberly and Martin (2006) write:
“There are no obvious precursor structures known that would guide a gradual evolutionary inference between the prokaryote and eukaryotic state known among prokaryotes from which such attributes could be derived, and no intermediate cell types.” (p. 626)
Crick, Francis. (1981). Life itself: its origin and nature. New York: Simon and Schuster. Emberly, T. M., & Martin, W. (2006). Eukaryotic evolution, changes and challenges. Nature, 440(7084), 623-630.
Lane, N., & Martin, W. (2010). the energetics of genome complexity. Nature, 467(7318), 929-934.
Mayr, E. (1999). What evolution is. New York: Basic Books
McFall-Ngai, Margaret J. (1999). Consequences of evolving with bacterial symbionts: Insights from the Squid-Vibrio Associations, 30, 235-256.