➶ Human evolution and the role of our grandmothers

From the archives, this article from NPR sheds fascinating light on the role of our grandmothers in human evolution. For example, Dr. Kristen Hawkes at the University of Utah follows modern hunter-gatherer tribes to understand how our ancestors might have lived.

Over many extended field visits, Hawkes and her colleagues kept track of how much food a wide sample of Hadza community members were bringing home. She says that when they tracked the success rates of individual men, “they almost always failed to get a big animal.” They found that the average hunter went out pretty much every day and was successful on exactly 3.4 percent of those excursions. That meant that, in this society at least, the hunting hypothesis seemed way off the mark. If people here were depending on wild meat to survive, they would starve.

So if dad wasn’t bringing home the bacon, who was? After spending a lot of time with the women on their daily foraging trips, the researchers were surprised to discover that the women, both young and old, were providing the majority of calories to their families and group-mates.

A Hazda woman digs for tubers with a digging stick.

A Hazda woman digs for tubers with a digging stick. (copyright NPR/Nigel Pavitt/Getty Images/AWL Images).

As we learn more, we are coming to realize that our strong relations with our grandparents is not just a weird (and lucky!) quirk of our evolution, but quite necessary to our anthropological journey to our present.

For starters, not all animals have ‘grandparents’, i.e. ‘elders’ living long past their reproductive age, in the first place. Humans (and other great apes), whales and elephants are a small minority of those with societal grandparents. Even among humans, having grandparents may be a more recent development than we think.

This NPR article provides a great perspective from several researchers. We were surely hunter gatherers in our evolutionary past, but it turns out that how our hunting and gathering occurred is way more complex than the men hunted and fed their families.

If you’re following Dr. Hawkes’ work, you might be interested in this podcast that she appeared on at The Insight.

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➶ The climate change that helped the dinosaurs

The Atlantic has an excellent piece on a drastic climate change event about 230 million years ago, when vast quantities of carbon dioxide gas erupted from undersea volcanoes. We’ve all heard the story of how the dinosaurs disappeared; well, this one is a different story.

But perhaps the most extraordinary aspect of the Carnian Pluvial Episode was not the crisis itself, but the world that came after. Until then, dinosaurs had been a puny and obscure lineage confined to the furthest southern reaches of Pangaea. But by the time the crisis was over, they had spread all over the world—perhaps using the oddly humid pulse to hopscotch across the previously arid wastelands of Pangaea—and rapidly diversified, using the extinction of their competitors to experiment with new lifestyles. The planet would never be the same.

Speaking of climate change, living in the US makes it pretty clear that some of us haven’t yet gotten our head around the whys, the hows, and really, the necessity, of caring about climate change. This is the part that we must keep reminding ourselves: it’s not that climate change destroys the Earth; far from it. The Earth was, is and will be fine. It’s just that the species that inhabit the Earth has and will change with drastic climate change.

If we, humankind, as a species are destined to have the same fate as the dinosaurs, well, so be it. But hey, if there’s one thing us humans have done better than any other species, that’s to change our environment to suit ourselves. Let’s use that to keep Earth’s climate as we like it! A huge chunk of our civilization is based on proximity to water, including oceans; a huge chunk of us are used to certain weather patterns. We won’t like it if either of those factors change. We won’t; the Earth won’t care.

(Hopefully we won’t end up like the dinosaurs. Hopefully, we will (a) keep Earth’s climate under control, and (b) inhabit other planets, at least, by the time the Sun makes Earth uninhabitable.)

Anyway, go read this great article. This kind of story about the paths of life and evolution on Earth is always fascinating to read.

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More on the Naked Mole Rat

I’ve written about the naked mole rat before, about how it seems to be immune to acid.

Well, it turns out it has more tricks up its genetic sleeve.

To compare how the naked mole rat made their proteins, they inserted an engineered gene in the naked mole rat as well as in mice, which allowed them to compare the rate of errors in making proteins. And here’s what they found:

[The naked mole rat] built the engineered protein far more accurately, in other words. Naked mole rats, the scientists found, made anywhere from four to ten times fewer mistakes. Yet the naked mole rats can make their proteins as quickly as the sloppier mice.

This seems to be a fascinating creature the more we study it!

I wonder, though, why other species did not pick up this brilliant piece of evolution. Are there side effects to this that are detrimental, overall, to other species but which don’t affect the naked mole rat? As I said in my earlier post, intriguing.

(Original source, quoted by National Geographic: Jorge Azpurua et al.“Naked mole-rat has increased translational fidelity compared with the mouse, as well as a unique 28S ribosomal RNA cleavage.” PNAS 2013


Virgin births… in snakes!

Species that reproduce sexually usually need two partners to reproduce, right? Right. What I didn’t know was, females of some species (that usually reproduce sexually) have apparently been observed to be able to reproduce without a mate—rarely, and when they’re in captivity and away from potential mates.

But now, virgin births have been observed in snakes–in the wild, with males present nearby!

They captured pregnant copperhead and cottonmouth female pit-vipers from the field, where males were present.

The snakes gave birth, allowing the scientists to study the physical and genetic characteristics of the litters. […]

“That’s between 2.5 and 5% of litters produced in these populations may be resulting from parthenogenesis.

“That’s quite remarkable for something that has been considered an evolutionary novelty,” he said.

No insights yet on how and why this happens, though, or what implications it may have.

But this is fascinating, nonetheless.


➶ Rethinking Dinosaurs

The latest in paleontology:

[…] “a filamentous body covering obviously represents the plesiomorphic state for dinosaurs in general,” wrote Rauhut’s team.

Plesiomorphic is another way of saying “ancestrally typical.” In short, it was feathers all the way down.

What?! All two legged dinosaurs had feathers? What were we thinking all these years? Has this been verified?

Now they’ll have to make Jurassic Park all over again.

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