April 23, 2021 | David F. Coppedge

Fun in Evolutionary Wonderland

Unconstrained by competition, the Darwin Party’s science storytelling industry comes up with some wacky scenarios.

Where’s my horse-sized rabbit? (Phys.org). There are some pretty big fossil rodents, but no big fossil rabbits. Leave it to Darwinists to explain anything and everything.

So why don’t we see rabbits rivaling the sizes of horses?

To answer this question, a research team led by Kyoto University’s Primate Research Institute investigated the fossil record and evolutionary history of lagomorphs. In a study in the journal Evolution, the team reports that larger herbivore competitors were one evolutionary constraint limiting rabbits’ size.

The only horse-sized rabbits are botanical in nature.

Why didn’t rodents have larger herbivore competitors that kept them small? The evolutionary explanations given in this article for keeping rabbits from growing as big as horses could be asked about rodents, but the storytellers are silent on that. What they do, instead, is bring in Wonderland characters – complete with illustrations!

An ongoing debate in evolutionary biology concerns whether biological or environmental processes are more important in shaping biological diversity,” states Tomiya, “as characterized by the ‘red queen‘ and ‘court jester‘ hypotheses.”

“For some time, the court jester model—ascribing diversity to abiotic forces such as the climate—has been dominant, due to the difficulty of studying biological interactions in the fossil record.

The answer must have been that evolution constrained the size of carrots when rabbits were evolving. Eh, what’s up, Doc?

Tarantula’s ubiquity traced back to the cretaceous (Phys.org). Problem: tarantulas don’t travel far from home, but are found on almost every continent. If they evolved in one place, how did they get all over the globe? Call the Darwin Party help line:

They found that tarantulas are ancient, first emerging in the piece of land now considered the Americas about 120 million years ago during the Cretaceous period. At that time South America would have been attached to Africa, India and Australia as part of the Gondwana supercontinent. The spiders ultimately reached their present destinations due to continental drift, with a few interesting departures.

Tarantula (credit: Illustra Media)

This explanation doesn’t cover all cases: for instance, tarantulas in Asia are found on both sides of the Wallace Line that usually separates ecosystems. Some theory rescue is needed: look for auxiliary hypotheses to cover the bases. Maybe early tarantulas were better travelers than thought.

“Previously, we did not consider tarantulas to be good dispersers. While continental drift certainly played its part in their history, the two Asian colonization events encourage us to reconsider this narrative. The microhabitat differences between those two lineages also suggest that tarantulas are experts at exploiting ecological niches, while simultaneously displaying signs of niche conservation,” said Foley.

As long as King Charles is happy, it doesn’t matter what kind of stuff happens. Over at Live Science, Mindy Waisgerber put it this way: “Tarantulas conquered Earth by spreading over a supercontinent, then riding its broken pieces across the ocean.” Those tarantulas are so clever. They are stationary except when they are cosmopolitan. The dispersal into Asia “suggests that the spiders were able to fill ecological niches and adapt to new habitats more effectively than once thought.” Thought by whom, you ask? By the Darwin Party, of course. Changes to the narrative are not threatening; they’re fun, when nobody outside the Party is allowed to speak.

What does the study of domesticated birds tell us about the evolution of human language? (University of Barcelona via Phys.org). Unless this press release was written by a bot or a hoaxer, it’s hard to believe it is serious.

For the researchers, these differences between domestic and wild animals are “the central pieces in the puzzle of the evolution of human language”, since our species shares with other domestic animals particular physical changes related to their closest wild species. Modern humans have a plain face, a round skull and a reduced size of teeth compared to our extinct archaic relatives, Neanderthals. Domestic animals have comparable changes in facial and cranial bone structures, often accompanied by the development of other traits such as skin depigmentation, floppy ears and curly tails. Last, modern humans have marked reductions in the response measures to stress and reactive aggression compared to other living apes. These similarities do not stop with physical since, according to researchers, the genomes of modern humans and multiple domesticated species show changes focused on the same genes.

In particular, a disproportionate number of these genes would negatively regulate the activity of the glutamate neurotransmitter system, which drives the brain’s response to stressful experiences. Authors note that “glutamate, the brain’s main excitatory neurotransmitter, dopamine, in learning birdsong, aggressive behaviour, and the repetitive vocal tics of Tourette syndrome”.

So this is how human language evolved? Have some more glutamate, Shakespeare.

How the Zebra got its Rump Stripes: Salience at Distance and in Motion (Muhl-Richardson et al., bioRxiv, 16 April 2021). This preprint, written in Kipling Just-So Story Form, tries to answer a conundrum about zebra patterning. Darwin is on the line, seeing what his disciples will come up with. He loves hearing how creative scenarios can rescue his theory from falsification.

Zebras’ stripes cannot protect them from predators, Darwin concluded, and current consensus tends to support his view. In principle, stripes could support crypsis or aposematism, could dazzle, confuse or disrupt predators’ perception, yet no such effects are manifest in predator-prey interactions. Instead, narrow stripes covering zebras’ head, neck, limbs and flanks are an effective deterrent to tabanids, vectors for equine disease. Accordingly, while other potential benefits, e.g., thermoregulation and intraspecific communication, cannot be excluded, zebra stripes likely evolved primarily to deter parasites. Rump stripes, however, do not fit this, or any extant view.

The plot thickens. What will Darwin’s Wonderland Wizards do?

What are you looking at?

Typically horizontal and broader in sub-species with width variation, they are ill-suited to crypsis or parasite-deterrence and vary with hyaena threat, perhaps shaped by an additional selective pressure. We observed that rump (and rear-flank) stripes remain highly conspicuous when viewed in motion or at distance, while other stripes do not. To study this striking effect, we filtered images of zebra to simulate acuity limitations in lion and hyaena photopic and mesopic vision. For mountain zebra and plains zebra without shadow striping, rump stripes were the most conspicuous image regions according to computational salience models, corroborated by human observers’ judgements of maximally attention-capturing image locations, which were strongly biased toward the rear. By hijacking exogenous attention mechanisms to force predator attention to the rear, salient rump stripes confer benefits to zebra, estimated here in pursuit simulations. Benefits of rump stripe salience may counteract anti-parasite benefits and costs of conspicuity to shape rump and shadow stripe variation.

Bravo. Multiple examples of the Stuff Happens Law at work. The zebra herd must have thought about this trade-off strategy a lot: “Keep the lion looking at your rear end and gallop to outrun the flies.” It works. Human observers couldn’t get their eyes off the zebra’s butt.

We hope you enjoyed the wild ride through these adventures in Darwin’s alternate reality. If it weren’t so serious, it would be funny. Actually, Darwin’s story is full of mistakes that require continual revisions. And the theory causes a great deal of harm to society, including eugenics, two world wars and human experimentation. Don’t lose sight of the fact that Darwinism is a theory of Malice in Blunderland.

 

 

 

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