September 10, 2018 | David F. Coppedge

Lizards Pre-Programmed to Adapt Their Coloration

Lizards put onto lava can change color within a week. Over time, the population blends into the darker environment.

“Plasticity precedes and facilitates adaptation” in side-blotched lizards. Behind this piece of jargon is an interesting story that flies in the face of Darwinian evolution, although Darwinists are trying to make the most of it.

There’s a volcano out in the California desert called Pisgah Crater. It sticks out like a solitary black mountain in a tan-colored environment, surrounded by black lava flows. Most of the side-blotched lizards that live in that part of the Mojave desert have tan-colored patterns, but their relatives living on the volcano are nearly jet black. How did that come about? Is this evolution in action?

Pisgah Crater (DFC)

Before proceeding, we should recognize that the two varieties of side-blotched lizards are interfertile, so this is not a case of the “origin of species” but rather of color adaptation to a new habitat. A press release from the University of California at Santa Cruz tries to make this a story of natural selection:

One explanation has been that many of an animal’s traits are not fixed, but can change during its lifetime. This “phenotypic plasticity” enables individual animals to alter their appearance or behavior enough to survive in a new environment. Eventually, new adaptations promoting survival arise in the population through genetic changes and natural selection, which acts on the population over generations. This is known as the “Baldwin effect” after the psychologist James Mark Baldwin, who presented the idea in a landmark paper published in 1896.

This cannot be a case of Darwinian evolution, because a single lizard can begin changing its color within a week. Zoologist Ammon Corl describes what they found:

When researchers move side-blotched lizards from one background to another (for example, from sand to lava rock), changes in coloration start to appear within a week, and gradual changes in coloration continue for months afterwards. “It seems like there’s a slow, gradual build-up of the dark melanin pigment,” Corl said.

In classic neo-Darwinism, only the offspring with chance mutations for darker color would be selected. The ‘Baldwin Effect’ implies a degree of plasticity (internal ability to adapt) that comes pre-programmed in the lizard genome. It can be expressed within the lifetime of a single individual, suggesting that adaptability is epigenetically regulated. It is not due to chance mutations.

A male lizard from the Pisgah Lava Flow photographed five days after collection in the field (left), and the same lizard (right) after being housed for four months in the lab on light-colored sand. (Image credit: Corl et al., Current Biology, 2018)

Mutations will continue within either population, however. Over generations—for the population living entirely on the volcano—the in-built plasticity can be reduced, just like the genes for eyes in blind cave fish are no longer needed. Mutations that do not prevent melanin production can become fixed in the population, giving the appearance of Darwinian natural selection. The paper in Current Biology explains:

Overall, our results suggest that ancestral plasticity for coloration facilitated initial survival in the lava environment and was followed by genetic changes that modified the phenotype in the direction of the induced plastic response, possibly through de novo mutations. These observations provide a detailed example supporting the hypothesis that plasticity aids in the initial colonization of a novel habitat, with natural selection subsequently refining the phenotype with genetic adaptations to the new environment.

But natural selection was not the cause of the adaptation in this closely-researched example. If anything, it was a johnny-come-lately artifact of the Stuff Happens Law that did not prevent the black lizards from keeping mutations that enhanced dark coloration. The potential to quickly adapt to dark background was already present in the plasticity of the lizard genome.

If pre-programmed adaptability explains lizard coloration, the possibility of “phenotypic plasticity” explaining many of the classic icons of evolution (e.g., peppered moths, Galapagos finches) cannot be dismissed.

Plasticity implies design. Imagine trying to design robots to operate on an alien planet. A good designer would include plenty of “if-then” routines to help it operate under a variety of circumstances. A bad designer would turn adaptation over to luck (the Stuff Happens Law), thinking, “Well, if I send out a million robots, the ones that just happen to continue operating will survive, and all the rest will die.” The former is adaptation by intelligent design. The latter expresses what neo-Darwinians believe happens in living organisms. Which view makes more sense? Which one matches the real world?

If the side-blotched lizards had to wait for neo-Darwinian mechanisms, they would never survive on the lava. It would take far too long for lucky mutations to show up in the offspring and be “selected” by the Stuff Happens Law. The observations published by this research team show that the plasticity to adapt to a novel habitat was built-in ahead of time.

Dr Randy Guliuzza at ICR has written extensively on pre-programmed adaptability, which he calls “engineered adaptability.” In his most recent entry in ICR’s Acts & Facts monthly magazine, he says,

The Institute for Creation Research is developing an engineering-based, organism-focused model called continuous environmental tracking (CET) to explain how organisms self-adjust to changing conditions. Our model anticipates that the adaptive solutions creatures express can also be characterized as directed, rapid, and highly targeted. As we’ve highlighted in this Engineered Adaptability article series, research results are aligning with this expectation.

While the evolutionists struggle to encompass their observations within neo-Darwinism, Guliuzza could celebrate the dark coloration of the Pisgah Crater lizard population as a recent confirmation of his model.

 

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