Darwinism Intelligent Design Naturalism

Genomics is upsetting the classification of bird species

Spread the love
Phylogeny of birds. The five major, successive, neoavian sister clades are: Strisores (brown), Columbaves (purple), Gruiformes (yellow), Aequorlitornithes (blue), and Inopinaves (green). Background colors mark geological periods. Ma - million years ago; Ple - Pleistocene; Pli - Pliocene; Q. - Quaternary. Clade numbers refer to the plot of estimated divergence dates. Illustrations of representative bird species are depicted by their lineages. Figure continues below from the green arrow at the bottom of the top panel. Image credit: Richard O. Prum et al., doi: 10.1038/nature15697.
Current phylogeny of birds/Richard O. Prum et al

Further to “Nineteen new “species” of gecko? Or 19 new fundraising opportunities…?,” now and then we see people confronting the problem. From Rebecca Heismann at Living Bird,

What’s in a Name? How Genome Mapping Can Make It Harder to Tell Species Apart

The biological species concept remains the most widely accepted standard among ornithologists for classification decisions at the species level. But in the last five years, yet another revolution has rocked the world of avian classification. Gone are the days when ornithologists would labor for months to sequence just a few individual genes on their way to building an evolutionary tree. Today’s “high-throughput” or “next-generation” genome sequencing means a student in an evolutionary biology laboratory today can assemble an entire genome—all 1 billion or so units in a bird’s DNA—in just a few weeks.

Birds are apparently a good subject for genome mapping because they have comparatively small genomes.

All of this means that scientists have the ability to peer more deeply into the DNA of birds today than ever before. But in some ways the resulting picture for species classification isn’t getting clearer—rather, it’s getting blurrier. It seems that the more closely evolutionary biologists look into the genome, the more arbitrary the boundaries between some species appear to be. It’s a bit like stepping too close to a pointillist painting: instead of revealing tiny details on the picnickers’ faces, the whole thing dissolves into dots.

Well, if that’s the way it is, what does it mean for specific claims about evolutionary history?

“We didn’t see the kinds of genomic differences that we’d expect to see between birds that have been [reproductively] isolated for long periods of time,” says Taylor.

Instead, says Mason, the world’s three redpoll species seem to be “functioning as members of a single gene pool that wraps around the top of the globe.” Indeed, Hoary, Common, and Lesser Redpolls all have overlapping breeding ranges around the Arctic.

Instead of different genes, the morphological variation—or differences in how various redpolls look—seemed to stem from genetic expression. It’s kind of like how two humans might have the same gene for brown hair, but one person’s hair might be lighter than the other’s—that gene is being expressed differently. In the same way, Hoary and Common Redpolls have remarkably similar sets of genes, but those genes are expressed differently, causing plumage differences. More.

The researchers have proposed that the three groups of birds be treated as a single species.

Why is it taking so long to organize claims about speciation in a manner worthy of science? One possibility is that Darwinism largely depends on convincing people that natural selection acting on random mutation produces the “endless forms most beautiful” that make up the history of life. Any serious effort to reform the classification process would require such a case to be made much more rigorously than it is now. Which means that the few instances we see (as opposed to the many assertions we hear) might diminish further. This would put more pressure on the school textbook industry and for pop science in general to update their thinking as to how evolution works.

Note from Sci-News:

But the evolutionary history of 90 percent of contemporary birds in a group called Neoaves has remained unclear.

The early ancestors of thousands of these species appeared to have evolved suddenly within a few million years after the extinction the non-avian dinosaurs.

Sounds like some interesting projects lie ahead.

See also: Nineteen new “species” of gecko? Or 19 new fundraising opportunities…?

Nothing says “Darwin snob” like indifference to the mess that the entire concept of speciation is in

and

What the fossils told us in their own words

3 Replies to “Genomics is upsetting the classification of bird species

  1. 1
    awstar says:

    From the original article:

    “Our names for birds are partly motivated by our need to categorize the world in ways that are useful for humans, and sometimes that’s more simplistic than the actual biological reality that we’re trying to classify,” Lovette admits.

    But the checklist isn’t going the way of Dendroica just yet. The AOS’s Chesser puts it succinctly: “People need a standardized taxonomy in order to communicate.”

    We need to be able to give names to things. Whether it’s for the Endangered Species Act or for ecological studies of how many species of birds exist in a certain place, you have to have that organizing principle. You really can’t function without it,” says Lovette, who is also on the AOS Classification Committee.

    Well I guess that explains why God gave Adam the responsibility to give names to the newly created kinds of animals.

  2. 2
    Bob O'H says:

    Why is it taking so long to organize claims about speciation in a manner worthy of science?

    Because we now have better tools? Redpoll classification, for example, comes from the 18th century (from Linnaeus & Borkhausen). ET is happy to tell us that Linnaeus was a creationist, so can we claim that evolutionary biology is cleaning up a mess created by creationists? 🙂

  3. 3
    awstar says:

    That’s not how I interpret what the article says:

    1800s morphology: good

    In the 1800s, ornithologists classified birds based mostly on morphology, or how they looked.

    1942 biological species concept: better

    A pivotal point for ornithology, and for biology in general, was the publication of Ernst Mayr’s Systematics and the Origin of Species in 1942, which formalized the biological species concept.

    1980 phylogenetic species concept: not as good

    In the 1980s, a new idea known as the phylogenetic species concept began to gain prominence, partly owing to scientific advances in constructing the evolutionary trees (or phylogenies) that depict the evolutionary relationships among birds, from today’s species all the way back to the earliest avian origins.

    [BUT] The biological species concept remains the most widely accepted standard among ornithologists for classification decisions at the species level

    2012 phylo–genomics: even worse

    Lovette describes it as a shift from “genetics” to “genomics.”

    “Before, we did what I would call genetics, pulling out very, very small pieces of DNA,” he says. “With next-generation sequencing, we’ve moved from dealing with tiny fractions of the genome to all of it, and that’s expanded the amount of information we have by many orders of magnitude.

    It’s a bit like stepping too close to a pointillist painting: instead of revealing tiny details on the picnickers’ faces, the whole thing dissolves into dots.

    technology like an audio amplifier enhances the voice a good singer, but the effect in amplifying a poor singer is not good at all.

Leave a Reply