Can the Hadza, a group of hunters and gatherers, help us understand how to maintain cardiovascular health? A recent study claims that the answer is yes, in two ways. First, we can correlate their health to their levels of activity. Second, we can extrapolate from these present-day hunters and gatherers to the thousands of generations in which the common ancestors of all humans lived similarly. That is, we can say that humanity evolved to thrive under certain levels of activity. Continue reading
Did you know that one kind of sea slug (an animal like us) can photosynthesize nutrients like algae (which are plants, more or less)? Along with being able to eat like any other self-respecting animal, the elysia chlorotica has chloroplasts and the requisite DNA to use them. If something as lowly as a slug can do this, why not us? Let’s make this happen.
Then there’s the question of whether a photosynthesizing animal is still merely an animal, rather than a planimal©. Continue reading
Posted in Evolution
As an article from the Daily Mail points out, early Homo sapiens had bigger brains than we do. Cro-Magnons, living in Europe perhaps as early as 45,000 years ago, had 10 percent more brain than the average human today. (Neanderthals had bigger brains, too, but, unlike those of Cro-Magnons, theirs grew in a differently shaped skull.)
So does this mean that Cro-Magnons and other big-brained earlier humans were smarter than us? Not necessarily, but it also doesn’t mean that they weren’t smarter. Continue reading
Recent research regarding two long-extinct hominin species has received a lot of press lately. Much of it has ridiculously over-interpreted or misinterpreted the published findings. What Sandi Copeland and her collaborators argue officially (article here) is that these species preferred for females to move into new groups after childhood, much like “chimpanzees, bonobos and many human groups”; males, in contrast, mostly remained part of the band into which they were born.
Maybe so – but this impressive research is preliminary. It represents only an initial step in demonstrating that this pattern occurred. And, despite some fun headlines, the species involved are not necessarily our ancestors. So here’s a list of concerns to temper the fanfare: Continue reading
On March 23, 2010, I gave a presentation at Nerd Nite in Washington, DC. The promo read: “No matter how funky Justin Timberlake is, races are not genetic categories. As the great sociologists Rodgers and Hammerstein averred, ‘You’ve got to be carefully taught.’ Hurray for education in the USA! Racial stereotypes seem to be one of the few things that almost every American learns, making race socially but not genetically ‘real.’ We’ll consider all that, including who can jump.” Continue reading
A recent article by Nicholas Wade of the New York Times focuses on a new hypothesis regarding the evolutionary divergence of humans from the phylogenetic branch resulting in chimps and bonobos. Much of it is based on suspect assumptions, which I’ll tackle at the end. But the research contains a fascinating observation regarding hunter-gatherers that illustrates just how flexible human behavior is.
The research, headed by Kim S. Hill and Robert S. Walker, compared different present-day bands of hunters and gatherers to test, in part, whether they consisted mostly of close relatives. Then they compared their observations to chimpanzees. Among other findings, sometimes male humans leave their home band to marry and sometimes females do, whereas chimps have a clear pattern of females moving to new bands.
And here, for me, is the highlight, which I’ve italicized: “the human pattern of residency is so variable that it counts as a pattern in itself.” That is, the researchers found the lack of a hard-wired ‘human nature’ (unless flexibility can be said to be hard-wired’). Continue reading
The answer is yes. Many roundups of this year’s scientific developments have highlighted the discovery that, as Science News. puts it, “people of European and Asian descent really have inherited a small percentage of their DNA from” Neanderthals. More recently a second ‘extinct’ group, the Denisovans, has been identified as the partial ancestors of Melanesians. Many of these stories refer to Neanderthals and Denisovans as separate species from Homo sapiens. National Geographic’s headline, for example, reads “Neanderthals, Humans Interbred,” and the Los Angeles Times refers to the Denisovans as “a previously unknown hominid species.” Since no universally applicable definition of species exists, I guess that we can call anything a separate species. But, by biologists’ most common definitions, we, our Homo sapien ancestors, Neanderthals, and Denisovans are all part of the same species. Continue reading