Category Archives: evolution

Monday mites: the evolution of human hair mites (you have them!)

There are two species of “face mites,” Demodex, that live on humans. One, D. folliculorum, lives mostly on the hair follicles, and mostly on the face. It’s small (0.1-0.4 mm), has a transparent body with four pair of anterior legs (remember, mites are arachnids), and nearly all of us harbor them. They’re harmless, although in large numbers they […]

Twelve days of evolution. #2: Is evolution random?

We continue with the PBS/”It’s ok to be smart” collaboration that’s produced twelve videos on evolution for the holiday season. Here’s #2: “Is evolution random?” It’s better than yesterday’s video on what evolution is, but of course the petulant PCC(E) has two beefs—though they’re trivial. First, the DNA sequence of an organism isn’t really like […]

Twelve Days of Evolution: #1: What’s evolution?

I’ve just noticed that this is post #12,002 since we began nearly six years ago. That’s a lot of posts! “It’s okay to be smart” and PBS are producing a series of short videos, “Twelve days of evolution.” I’ll put up one a day, which should ultimately take us close to the end of Coynezaa. This first one explains what […]

The irony of natural selection

Although most mutations in the DNA that affect fitness are harmful, without mutations there would be no evolution. Evolution depends on the genetic variation created by mutation, and although there are other ways to change DNA beyond conventional mutations (horizontal gene transfer is one, though in effect it acts like a big mutation), in general evolution would […]

Hold the presses: maybe tardigrades don’t have so much horizontal gene transfer after all

About a week ago I discussed a new paper by Boothby et al. in the Proceedings of the National Academy of Sciences (US) with a stunning finding: the sequenced DNA of the tardigrade species Hypsibius dujardini showed that about 17% of its genome comprised sequences taken from distantly-related species—mostly bacteria. This was the most pervasive example of horizontal gene […]

Darwin’s primate tree

by Matthew Cobb This sketch of human origins was made by Darwin in 1868, and reflects the knowledge of the time. Humans are on the left, with our closest relatives, gorillas and chimps, grouped together. Darwin seems to mistakenly suggest that the gibbons (Hylobatus) are more closely related to the other apes – gorillas, chimps […]

Evolution: theory, fact, or both?

I’ve long been uncomfortable with explaining, in public lectures, why evolution is both a theory and a fact. To do that properly, you have to explain what a scientists really mean by the word “theory” and why it’s not just an idle guess or speculation. But that can be confusing, because I always say that a […]

An unusual fishlike sea slug

Nudibranchs, or sea slugs, are in the phylum Mollusca and the class Gastropoda, which means that they’re snails. But they’ve lost their shell during the course of evolution, though a vestigial shell is retained in the early larval stage. They’re also often toxic or venomous, and have therefore adopted aposematic (warning) coloration (note: because many […]

Nature to launch new ecology and evolution journal

This hasn’t been officially announced yet, but I learned about it last week and it’s not really a secret given that Nature is already advertising for editors (here and here) for a new journal whose description is in the second ad: Nature Ecology and Evolution — the latest member of the Nature family — will […]

Wrongheaded anthropologist claims that humans aren’t apes

It’s time to affirm once and for all that humans are apes, and to educate those who say otherwise. To deny that is to deny a palpable fact of biology and evolution: our close ancestry with other primates. One of those who need education is Jonathan Marks, a cultural anthropologist at the University of North Carolina […]

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