Tag Archives: Convergent Evolution

News

Science Daily reports on genetic convergence in bats and whales

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We have to start this post with the definition of convergence in biology.

In evolutionary biology, convergent evolution is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.

It is the opposite of divergent evolution, where related species evolve different traits.

On a molecular level, this can happen due to random mutation unrelated to adaptive changes; see long branch attraction. In cultural evolution, convergent evolution is the development of similar cultural adaptations to similar environmental conditions by different peoples with different ancestral cultures. An example of convergent evolution is the similar nature of the flight/wings of insects, birds, pterosaurs, and bats.

All four serve the same function and are similar in structure, but each evolved independently.

Jonathan Wells explains the problem that convergence poses for naturalistic evolution:

Human designers reuse designs that work well. Life forms also reuse certain structures (the camera eye, for example, appears in humans and octopuses). How well does this evidence support Darwinian evolution? Does it support intelligent design more strongly?

Evolutionary biologists attribute similar biological structures to either common descent or convergence. Structures are said to result from convergence if they evolved independently from distinct lines of organisms. Darwinian explanations of convergence strain credulity because they must account for how trial-and-error tinkering (natural selection acting on random variations) could produce strikingly similar structures in widely different organisms and environments. It’s one thing for evolution to explain similarity by common descent—the same structure is then just carried along in different lineages. It’s another to explain it as the result of blind tinkering that happened to hit on the same structure multiple times. Design proponents attribute such similar structures to common design (just as an engineer may use the same parts in different machines). If human designers frequently reuse successful designs, the designer of nature can surely do the same.

I’m a software engineer, and we re-use components all the time for different programs that have no “common ancestor”. E.g. – I can dump develop my String function library and use it in my web application and my Eclipse IDE plug-in, and those two Java programs have nothing in common. So you find the same bits in two different programs because I am the developer of both programs. But the two programs don’t extend from a common program that was used for some other purpose – they have no “common ancestor” program.

Now with that in mind, take a look at this post from Evolution News.

Excerpt:

Earlier this year I wrote about how convergent genetic evolution is highly unlikely under neo-Darwinism, but makes perfect sense if you allow common design. An article in ScienceDaily titled “In Bats and Whales, Convergence in Echolocation Ability Runs Deep,” points to evidence that, in my opinion, might be best explained by common design.

According to the standard mammalian phylogeny, the common ancestor of bats and whales was not capable of echolocation. Thus, the ability to echolocate must have evolved independently, and bat and whale echolocation is often cited by evolutionists as a textbook example of convergent evolution. However, the ScienceDaily article reports that these similarities are not just phenotypic but extend down into the level of the gene sequences:

two new studies in the January 26th issue of Current Biology, a Cell Press publication, show that bats’ and whales’ remarkable ability and the high-frequency hearing it depends on are shared at a much deeper level than anyone would have anticipated — all the way down to the molecular level

Just as I noted that convergent genetic evolution was said to be “surprising” under neo-Darwinian thinking, this article reports, “The discovery represents an unprecedented example of adaptive sequence convergence between two highly divergent groups and suggests that such convergence at the sequence level might be more common than scientists had suspected.”

The typical Darwinist tack is to call similar structures “superficially similar”. I.e. – the appearance (phenotypes) are similar, but at the genotype (code) level, there is nothing in common. They have to say that because there is no common ancestor who shares the structure, so the biological information CANNOT be similar. A naturalistic theory can’t accommodate similarities at the genetic level unless there is a shared common ancestor who has those instructions. But guess what? When you actually take a closer look at the evidence… the biological information IS similar between bats and whales – AND THEY DON’T SHARE A COMMON ANCESTOR. So it exactly like the software design scenario, where the designer has put the same bits into two programs that were developed independently and don’t extend from a common program.

The Science Daily article explains more:

“The natural world is full of examples of species that have evolved similar characteristics independently, such as the tusks of elephants and walruses,” said Stephen Rossiter of the University of London, an author on one of the studies. “However, it is generally assumed that most of these so-called convergent traits have arisen by different genes or different mutations. Our study shows that a complex trait — echolocation — has in fact evolved by identical genetic changes in bats and dolphins.”

[…]”We were surprised by the strength of support for convergence between these two groups of mammals and, related to this, by the sheer number of convergent changes in the coding DNA that we found,” Rossiter said.

Read the whole thing at Evolution News. This is quality work by Casey Luskin.

Commentary

Is universal common ancestry based on established facts?

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Casey Luskin wrote a wonderful article called “A Primer on the Tree of Life” that will help you to consider whether universal common ancestry is true.

Excerpt:

Evolutionists often claim that universal common ancestry and the “tree of life” are established facts. One recent opinion article argued, “The evidence that all life, plants and animals, humans and fruit flies, evolved from a common ancestor by mutation and natural selection is beyond theory. It is a fact. Anyone who takes the time to read the evidence with an open mind will join scientists and the well-educated.”1 The take-home message is that if you doubt Darwin’s tree of life, you’re ignorant. No one wants to be ridiculed, so it’s a lot easier to buy the rhetoric and “join scientists and the well-educated.”

But what is the evidence for their claim, and how much of it is based upon assumptions? The truth is that common ancestry is merely an assumption that governs interpretation of the data, not an undeniable conclusion, and whenever data contradicts expectations of common descent, evolutionists resort to a variety of different ad hoc rationalizations to save common descent from being falsified.

Here are two of the four evidences he looks at:

Molecular phylogenies

…the cover story of the journal New Scientist… titled, “Why Darwin was wrong about the tree of life.” …reported that “The problem was that different genes told contradictory evolutionary stories.” The article observed that with the sequencing of the genes and proteins of various living organisms, the tree of life fell apart…

You get completely different molecular phylogenies depending on which gene or protein you analyze from the organism. If UCA were true, all the genes and proteins would have to give similar molecular phylogenies. Casey also addresses horizontal gene transfer.

Convergent evolution

One data-point that might suggest common design rather than common descent is the gene “pax-6.” Pax-6 is one of those pesky instances where extreme genetic similarity popped up in a place totally unexpected and unpredicted by evolutionary biology. In short, scientists have discovered that organisms as diverse as jellyfish, arthropods, mollusks, and vertebrates all use pax-6 to control development of their very distinct types of eyes. Because their eye-types are so different, it previously hadn’t been thought that these organisms even shared a common ancestor with an eye.

Here, you have the same gene being used for the same function in different organisms that do not share a common ancestor.

Homologies and Morphological phylogenies

Casey goes on to look at the evidence from homologies and the disparities between molecular phylogenies and morphological phylogenies, (e.g. – Cytochrome B). Casey’s article is worth looking at, especially if you have never considered the case against universal common ancestry.

News

Round-up of stories about intelligent design, from the Discovery Institute

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The Discovery Institute is the headquarters for ID research and advocacy in the United States. They send out a newsletter by e-mail and I though this week’s hit on all cylinders. Below are some of their stories from the newsletter. Thanks to commenter ECM for an earlier tip on the Junk DNA story.

When “Junk DNA” Isn’t Junk: Farewell to a Darwinist Standard Response

Richard Sternberg, research scientist at the Biologic Institute supported by the Center for Science and Culture, is now blogging at Evolution News & Views, weighing in on the latest research showing that so-called “Junk DNA,” which Darwinists have discounted as “rubbish,” are actually “anything but that.”

Sternberg writes:

In the Darwinist repertoire, a standard response to evidence of design in the genome is to point to the existence of “junk DNA.” What is it doing there, if purposeful design really is detectable in the history of life’s development? Of course this assumes that the “junk” really is junk. That assumption has been cast increasingly into doubt. New research just out in the journal Nature Genetics finds evidence that genetic elements previously thought of as rubbish are anything but that. The research describes tiny strands of RNA, previously thought to be junk, that now turn out to play a role in gene expression. Another finding by Dr. Geoff Faulkner shows that “retrotransposons,” a further variety of “junk” as the dogma previously taught, play a similar role.

Also at ENV, Dr. Sternberg takes a look at the old Darwinian tripe that biological systems couldn’t possibly have been designed because they exhibit “shoddy engineering”:

We often hear from Darwinians that the biological world is replete with examples of shoddy engineering, or, as they prefer to put it, bad design. One such case of really poor construction is the inverted retina of the vertebrate eye. As we all know, the retina of our eyes is configured all wrong because the cells that gather photons, the rod photoreceptors, are behind two other tissue layers. Light first strikes the ganglion cells and then passes by or through the bipolar cells before reaching the rod photoreceptors. Surely, a child could have arranged the system better — so they tell us.

The problem with this story of supposed unintelligent design is that it is long on anthropomorphisms and short on evidence. Consider nocturnal mammals. Night vision for, say, a mouse is no small feat. Light intensities during night can be a million times less than those of the day, so the rod cells must be optimized — yes, optimized — to capture even the few stray photons that strike them. Given the backwards organization of the mouse’s retina, how is this scavenging of light accomplished? Part of the solution is that the ganglion and bipolar cell layers are thinner in mammals that are nocturnal. But other optimizations must also occur. Enter the cell nucleus and “junk” DNA.

Jerry Coyne Recycles: Why Darwinism Is False

Jonathan Wells is reviewing Jerry Coyne’s Why Evolution Is True over at ENV, and already the list of problems with Coyne’s book is mounting:

On Earth Day 2009, we are reminded of the ecological importance of recycling. As a professor in the Department of Ecology and Evolution at The University of Chicago, Jerry A. Coyne must be keen on recycling: He even recycles worn-out arguments for Darwinism.

If “evolution” meant simply that existing species can undergo minor changes over time, or that many species alive today did not exist in the past, then evolution would undeniably be true. But “evolution” for Coyne means Darwinism — the theory that all living things are descendants of a common ancestor, modified by unguided natural processes such as DNA mutations and natural selection.

Coyne discusses the fossil record, embryos, vestigial structures, the geographic distribution of species, artificial and natural selection, and the origin of species. In the process, (1) he ignores the Cambrian explosion — which Darwin considered a “serious” problem — and he rearranges the fossil record to fit Darwin’s theory; (2) he defends Ernst Haeckel — who faked some drawings of vertebrate embryos to provide support for Darwinism — and he dredges up the doctrine that ontogeny recapitulates phylogeny; (3) he claims that much human DNA is useless junk — despite abundant recent evidence that this is not true — and he relies on theological arguments that have no legitimate place in natural science; (4) he invokes “the well-known process called convergent evolution” to explain many cases of the geographic distribution of species — even though the “well-known process” is merely speculation — and he again falls back on theology to justify a supposedly scientific theory; and (5) he describes examples of natural and artificial selection — none of which show anything more than minor changes within existing species — and he misrepresents experimental evidence to make it sound as though the origin of species by natural selection has been directly observed.

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Other stuff

The newsletter also discussed historian A.N. Wilson’s return to faith from atheism, which is really interesting because he seems to be well-rounded in his reasons for rejecting atheism. And the newsletter mentions that Jay Richards’ forthcoming book, “Money, Greed, and God: Why Capitalism Is the Solution and Not the Problem” is out May 6th! Jay gave a great lecture on basic economics for Christians and another great lecture on what Christians should think about global warming.