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, this new article on convergence in birds and humans, from Evolution News.
Everyone is familiar with the striking ability of certain birds (such as parrots) to vocalize speech, much as humans do. Well, according to the new papers published in Science that I wrote about earlier, confirming that birds arose explosively, those vocalization abilities are the result of “convergent evolution” at both the morphological and genetic levels.
Nature News reports, “The authors also conclude that vocal learning may have evolved independently in the ancestors of parrots, hummingbirds and songbirds.” But this is about more than just birds. According to a Science Daily article about the technical papers, the genetic “convergent evolution” extends to birds and humans:
“We’ve known for many years that the singing behavior of birds is similar to speech in humans — not identical, but similar — and that the brain circuitry is similar, too,” said Jarvis, an associate professor of neurobiology at the Duke University Medical School and an investigator at the Howard Hughes Medical Institute. “But we didn’t know whether or not those features were the same because the genes were also the same.”Now scientists do know, and the answer is yes — birds and humans use essentially the same genes to speak.
After a massive international effort to sequence and compare the entire genomes of 48 species of birds representing every major order of the bird family tree, Jarvis and his colleagues found that vocal learning evolved twice or maybe three times among songbirds, parrots and hummingbirds.
Even more striking is that the set of genes involved in each of those song innovations is remarkably similar to the genes involved in human speaking ability.
If you’re already thinking “This isn’t ‘convergent evolution,’ it’s common design,” you haven’t seen the best part yet. Science Daily goes on:
One of the Dec. 12 papers in Science found there is a consistent set of just over 50 genes that show higher or lower activity in the brains of vocal learning birds and humans. These changes were not found in the brains of birds that do not have vocal learning and of non-human primates that do not speak, according to this Duke team, which was led by Jarvis; Andreas Pfenning, a graduate of the PhD program in computational biology and bioinformatics (CBB); and Alexander Hartemink, professor of computer science, statistical science and biology.”This means that vocal learning birds and humans are more similar to each other for these genes in song and speech brain areas than other birds and primates are to them,” Jarvis said.
These genes are involved in forming new connections between neurons of the motor cortex and neurons that control the muscles that produce sound.
The Science paper puts it this way:
More than 50 genes contributed to their convergent specialization and were enriched in motor control and neural connectivity functions. These patterns were not found in vocal nonlearners, but songbird RA was similar to layer 5 of primate motor cortex for another set of genes, supporting previous hypotheses about the similarity of these cell types between bird and mammal brains.(Pfenning et al., “Convergent transcriptional specializations in the brains of humans and song-learning birds,” Science, Vol. 346: 1256846-1 – 1256846-13 (December 12, 2014). )
So certain birds and humans use the same genes for vocalization — but those genetic abilities are absent in non-human primates and birds without vocal learning? If not derived from a common ancestor, as they clearly were not, how did the genes get there? This kind of extreme convergent genetic evolution points strongly to intelligent design.
The rest of the article talks about the conclusions of the study authors – they think it’s a huge problem – and it is.
I hope you’re all beginning to see why I love birds so much. I just adore them. In fact, I am excited about them right now, and will probably appear silly by gushing about how great they are. Fortunately, my editorette is not hear to stop me!
Birds are not just a living disproof of naturalistic evolution. They are also loveable and adorable. (Especially parrots, of course) If you guys are considering a pet, go out and get yourself a cockatiel, if it’s your first bird, or a green-cheek conure, if you’ve had birds before. Just remember that they live 20-25 years, so you have to be ready to face responsibilities, expectations and obligations if you make a commitment like that. And you know what? That is totally awesome, to have someone to care about. It’s good stewardship to care for animals. And if you can’t commit to a parrot of your own over the long haul, then put out an additional bird feeder this winter, and vote against wind power. Wind power kills birds, and I hate it.
Also, that bird in the Evolution News post is an Indian ringneck parrot. And they are awesome!!!!
More posts on convergence
- New study: how the hummingbird performs stunning feats of aerobatics
- Another example of convergence found in human and squid eye genes
- Convergence detected in the genetic structure of bats and dolphins
- How biological convergence falsifies Darwinian evolution
- Science Daily reports on genetic convergence in bats and whales
- What kinds of predictions does intelligent design make?
- Is universal common ancestry based on established facts?