Tag Archives: Mutation

Polemics

Is there a smooth pathway from micro-evolution to macro-evolution?

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From Luke Nix. (H/T Apologetics 315)

Excerpt:

Macroevolutionary changes are a lot of microevolutionary changes, but they are in a specific series that follow a specific pathway. The missing premise in this argument is that the pathway from ancestor to claimed offspring (many generations down the road) is clear of obstacles.

In his book, “The Edge of Evolution” Michael Behe shows that scientists have observed such an obstacle in the lab. The obstacle was not time, it is in the genetic pathway that must be traversed if macroevolutionary changes are to take place in reality. Since an obstacle has been observed, we now have a false premise in the argument. Since there is a false premise, the argument fails. There is a difference between micro- and macro-evolutionary changes. A lot of microevolutionary changes are necessary for macroevolution, but they are not sufficient. The other sufficient condition (a clear genetic pathway) still has yet to be met. Since both sufficient conditions for macroevolution have not been met, it has not been demonstrated. And since changes over time has been demonstrated, there is a need to distinguish between the two. To prevent confusion about what we know to be true and what we don’t, this distinction must be made.

There is only one way that this can be overcome by the naturalist: find a pathway that would be clear by default in nature. Notice that I have added one more piece to the missing premise above: “…clear by default in nature“. I have to add that last qualification because as scientists are looking for a way to overcome this obstacle, they are introducing their own intelligence- fine-tuning the process, then “allowing nature to take its course”. Their conclusion of naturalistic macroevolution will depend on a premise that is founded on intelligence. That would undermine the whole argument for naturalistic (macro)evolution.

This is one of the ways to show that evolution is true – by showing a pathway to macro-evolutionary change in the lab. If people expect me to believe in the grandiose claims of fully naturalistic evolution through a stepwise process, then why can’t I see the pathway myself? Why do I have to take it on faith?

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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.

News

New peer-reviewed article argues for irreducible complexity in birds

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From Evolution News.

Excerpt:

In a peer-reviewed paper titled “Evidence of Design in Bird Feathers and Avian Respiration,” in International Journal of Design & Nature and Ecodynamics, Leeds University professor Andy McIntosh argues that two systems vital to bird flight–feathers and the avian respiratory system–exhibit “irreducible complexity.” The paper describes these systems using the exact sort of definitions that Michael Behe uses to describe irreducible complexity:

[F]unctional systems, in order to operate as working machines, must have all the required parts in place in order to be effective. If one part is missing, then the whole system is useless. The inference of design is the most natural step when presented with evidence such as in this paper, that is evidence concerning avian feathers and respiration.

He further notes that many evolutionary authors “look for evidence that true feathers developed first in small non-flying dinosaurs before the advent of flight, possibly as a means of increasing insulation for the warm-blooded species that were emerging.” However, he finds that when it comes to fossil evidence for the evolution of feathers, “[n]one of the fossil evidence shows any evidence of such transitions.”

Regarding the avian respiratory system, McIntosh contends that a functional transition from a purported reptilian respiratory system to the avian design would lead to non-functional intermediate stages. He quotes John Ruben stating, “The earliest stages in the derivation of the avian abdominal air sac system from a diaphragm-ventilating ancestor would have necessitated selection for a diaphragmatic hernia in taxa transitional between theropods and birds. Such a debilitating condition would have immedi¬ately compromised the entire pulmonary ventilatory apparatus and seems unlikely to have been of any selective advantage.” With such unique constraints in mind, McIntosh argues that the “even if one does take the fossil evidence as the record of development, the evidence is in fact much more consistent with an ab initio design position – that the breathing mechanism of birds is in fact the product of intelligent design.”

Let’s take a step back and ask what counts as evidence for (macro) evolution for people who actually care about evidence.

Here’s what counts as evidence:

  1. A smooth sequence of fossils showing the gradual emergence of different body body features across a wide spectrum of body plans. Not just horses and whales, not just micro-evolution. Major changes in body structure, which properly dated fossils, from a wide range of body plans.
  2. A lab experiment that derives a new organ type or body plan from an unmodified organism, like the Lenski experiments tried to do on a smaller scale.
  3. A computer simulation that shows a string of mutations that occur on one organism that would give it a new feature or organ within a reasonable amount of time (less than 4 billion years). The mutations must be probable, and the organism must have improved functionality at each stage of its development. And a calculation would have to be done to show that each beneficial mutation would spread to the rest of the population and survive in the next generation, which is a separate question.

Do we have that evidence in the case of bird evolution (feathers and lungs)? Of course not.

Do we have that evidence in the case of evolution as a whole? Of course not.

People who embrace evolution embrace it on the basis of non-rational, non-evidential factors.