Tag Archives: Tree of Life

News

New study: another example of convergence, this time for geomagnetic navigation

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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.

And now, Evolution News has a story about a new discovery.

Turtles have the ability to navigate by sensing magnetic isolines:

Science Magazine gives a brief review of the findings:

Much like shifting sand, magnetic fields slide slightly over time, and their strength also increases as one moves away from the equator, akin to latitude.This property gives each stretch of coast a unique geographic marker, known as an isoline. The team found that in years when these magnetic isolines moved apart, the turtle nests spread out over a larger area — by 1 or 2 kilometers. Conversely, when isolines converged, the nests squeezed into a smaller patch of beach, suggesting the turtles follow shifting magnetic tracks to their favorite nests. The findings also argue that a magnetic address is imprinted on loggerhead turtles at birth to point the way home.

But so do salmon, and other birds, fishes and mammals:

Remarkably, salmon show this same ability. Brothers and Lohman write:

In a previous study, the migratory route of salmon approaching their natal river was shown to vary with subtle changes in the Earth’s field. Whereas the endpoint of the salmon spawning migration was presumably the same regardless of route, our findings demonstrate for the first time a relationship between changes in Earth’s magnetic field and the locations where long-distance migrants return to reproduce.

Joining the contenders for this skill set are more unrelated animal types:

… our results provide the strongest evidence to date that sea turtles find their nesting areas at least in part by navigating to unique magnetic signatures along the coast. In addition, our results are consistent with the hypothesis that turtles accomplish natal homing largely on the basis of magnetic navigation and geomagnetic imprinting. These findings, in combination with recent studies on Pacific salmon, suggest that similar mechanisms might underlie natal homing in diverse long-distance migrants such as fishes, birds, and mammals.

So here we have a highly-precise navigational ability, able to cue on very faint properties in the earth’s magnetic field, then on olfaction, and possibly on “other supplemental local cues” to find home across thousands of miles. The sensory “instruments” involved are integrated so that they are able to coordinate their functions for the same goal. Furthermore, the baby turtles, with their tiny brains, must have the ability to memorize the natal signatures of odors and magnetic field properties at birth, then recall those memories years later as large adults. (Sea turtles return about every two years to lay eggs.)

That would be a conundrum enough to explain by unguided processes like natural selection. But then, adding to the difficulty for Darwinism, similar abilities are found in distantly related animals like fish, birds, and mammals. Even if a Darwinian could show a possible line of descent from fish to mammal, the abilities involved would have been lost and regained multiple times, because not all fish, birds, and mammals use magnetic navigation. Given the complexities of the sensory systems involved, this would represent a case of “convergent evolution” on steroids. If the origin of this capability in one type of animal is highly implausible by mutation and selection, how about four times or more?

A design perspective, by contrast, would expect that unrelated animals on a common planet would share similar capabilities for their needs. The earth’s magnetic field is global. It isn’t surprising that very different animals would be designed to use that feature of the earth.

How can it be that animals that have no recent common ancestor can have evolved this remarkable ability independently? The best explanation of this convergence is common design, not common descent.

More posts on convergence

News

New PNAS study: maximum animal diversity exists at the beginning of the fossil record

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From Phys.org – news of a study that is lethal to orthodox Darwinian belief. This is huge.

Excerpt:

Our understanding of how animals on the planet evolved may be wrong, according to scientists at the University.

In a new paper, recently published in the Proceedings of the National Academy of Sciences, evolutionary biologists from the Department of Biology & Biochemistry looked at nearly one hundred fossil groups to test the notion that it takes groups of animals many millions of years to reach their maximum diversity of form.

Contrary to popular belief, not all animal groups continued to evolve fundamentally new morphologies through time. The majority actually achieved their greatest diversity of form (disparity) relatively early in their histories.

Lead researcher from the Department of Biology & Biochemistry, Dr Matthew Wills said: “This pattern, known as ‘early high disparity’, turns the traditional V-shaped cone model of evolution on its head. What is equally surprising in our findings is that groups of animals are likely to show early-high disparity regardless of when they originated over the last half a billion years. This isn’t a phenomenon particularly associated with the first radiation of animals, or periods in the immediate wake of mass extinctions.”

The team used published descriptions of extinct groups in order to construct ‘morphospaces’; empirical spaces in which anatomically similar species plotted close together, and more dissimilar species plotted further apart. By looking at the manner in which the occupied ‘volume’ of space changed through time, they were able to track changes in morphological disparity.

Evolution News analyzes how the authors of the study explain away their findings to keep faith with Darwin.

Excerpt:

Why did 20 or more separate animal phyla suddenly appear in the geological blink of an eye? Because “Clades reach highest morphological disparity early in their evolution,” answer Martin Hughes, Sylvain Gerber, and Matthew Albion Will… The Cambrian animals exploded onto the scene because evolution works fast sometimes. It seems to be a pattern that high disparity occurs early on. Must be a law of nature. What, you’ve got a problem with that?

These three biologists from the University of Bath took a bath in their own assumptions. They don’t deny that the animals appear suddenly. They just believe that when opportunity arises, evolution works fast to fill up the landscape with endless forms most beautiful. Under the section, “Why Do Clades Have Early High Disparity?” they say:

What might explain the prevailing pattern of early high disparity in clade evolution? Both ecological and developmental explanations have been proposed, and our results remain consistent with both. The “empty ecospace” modelpredicts that clades will radiate and diversify more rapidly when colonizing a new environment. This colonization may occur because ecospace has been vacated by other occupants (e.g., in the wake of some other extinction, typically the result of external, physical factors) or because a hitherto inaccessible environment or other resource has been rendered viable by the acquisition of some novel, “key” adaptation or series of characters (an intrinsic, biological trigger). Morphological change under these circumstances may be rapid eitherbecause transitions are unusually large or because rates of cladogenesis areunusually high (even with “normal” step sizes at each splitting event). (Emphasis added, reference numbers omitted.)

Jaws should drop at that “explanation.” If Hughes, Gerber and Wills were simply describing what is found in the fossil record — the sudden appearance of complex animals — it would be one thing. But they attempted to explain how these complex animals appeared, so suddenly as Jonathan Wells described in the film Darwin’s Dilemma, that it’s comparable to less than two minutes on a twenty-four-hour clock.

[…]As Stephen Meyer shows in Darwin’s Doubt, prior to the Cambrian explosion there were only microbes, sponges and the enigmatic Ediacaran fauna that most paleontologists do not consider related to the Cambrian animals. There were no jointed appendages, eyes, guts, nervous systems or any of the other organs, tissue types and body plans that characterize Cambrian phyla. What kind of Darwinian “miracle” would it take to get all those complex traits in blink of an eye? Calling it “cladogenesis” is like calling the simultaneous chance appearance of cars, boats, and airplanes “vehicle-o-genesis.”

The model has striking similarities to the old notion of Punctuated Equilibrium discussed in Chapter 7 of Darwin’s Doubt. In fact, the PNAS paper was edited by Steven Stanley, “an early advocate of the punctuated equilibrium model” according to Meyer (p. 137). As such, this new model is really a throwback to the old “punk eek,” and suffers from the same drawbacks: it’s an attempt to explain away the absence of evidence for evolution by claiming, without any mechanism better than old-fashioned neo-Darwinism, why the fossil record shows a discontinuous pattern, not a record of a gradually branching tree.

There’s a lot more in that Evolution News article.

Now, I’m pretty sure I read about this upside-down tree of life years ago in a little book by biologist Jonathan Wells entitled “Icons of Evolution“. Dr. Wells made the case that Darwin’s iconic picture of “the tree of life” should really be inverted. Darwin thought that the root came early in the fossil record, and the branches came later – by mutation and selection. The truth is that the branches come first. The diversity is all at the beginning of the fossil record. This falsifies evolution (again).

Is this new study going to make the naturalists change their religion? Probably not. Because science has nothing to do with the presupposition of naturalism. Darwinists presuppose naturalism for other reasons that are insulated from experimental science. It’s a faith commitment – and they don’t care about revising their faith when the progress of science reveals new facts.

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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.