Next time someone tells you evolution isn’t true, ask them why there are microbes living off radioactive material in Chernobyl or why there are microbes able to digest nylon, a material not in existence 100 years ago.
About 50 million years ago, the area that is now known as Egypt was covered with an ancient sea. At the bottom of this sea were nummulites, a genus of small seashells made of calcium and carbon. Over millions of years, these creatures would die and stack up on the ocean floor, eventually creating limestone. Fast forward to human civilization and we see this:
This image comes from a limestone quarry near Cairo – the same sort of quarry that the ancient Egyptians used to build the pyramids and other structures of that great civilization. In other words, there is a homogenous mix of fossils that can be found all throughout one of the 7 Great Wonders of the World; the Egyptians owe much of their incredible accomplishments to deposits laid down by dying marine creatures over 50 million years ago.
I was reading about the Canada lynx on Why Evolution is True and that got me thinking about all the weird pets people have.
First up are skunks. It’s unfortunately illegal to keep them as pets in some states (including Maine), but where it is legal, an owner can have their skunk’s scent glands removed so they don’t spray all over the place. They’re expensive to keep (needing a weird diet consisting of food better than what a lot of humans eat) and they’re apt to get into everything, but they’re known to be very friendly.
The closest I’ve come to a pet squirrel was one that used to come up to the porch for peanuts. Unlike all the other squirrels, he (or maybe she) wouldn’t run away when someone opened the door. He’d stick around, knowing food was likely coming his way. He stuck around for a few seasons, presumably dying two or three winters ago. (Squirrels can live up to 10 years in captivity, but tend towards 4 years in the wild.)
I don’t know much about raccoons, but the fact that they make me think of little train robbers when I see them forces me to include them.
The red fox is relatively commonly tamed. In fact, one well known experiment in Russia has consisted of researchers grouping individual red foxes by how friendly they are towards humans and then selectively breeding those individuals who display the most friendly tendencies. It has resulted in very dog-like animals; the foxes (now called the domesticated silver fox) wag their tails in excitement, whimper when left alone, and have lost their normal coloring pattern (the researchers did not select for color). Just like with all artificial selection, it’s a good example of evolution in action.
But even when decades of selection haven’t been taking place, the red fox still manages to be a decent, tamable pet.
My least favorite so far, but here it is.
In my post about microsatellites and mitochondria there were a few errors. Fortunately, the author of the paper that formed the basis for a large portion of what I wrote also happens to be my professor. I petitioned him for review:
I stated that mtDNA is powerful as a tool for determining relations within a species. It should have read that mtDNA is useful for determining certain evolutionary patterns. There’s little excuse for this mistake.
I said genetic variation as determined by microsatellites is an indicator for population health. This may be true, but it isn’t possible to really be sure. If natural selection is acting upon these points, then populations with more variation may have better fitness.
I stated that populations are managed via arbitrary geographical lines. I actually meant political lines, but it’s unclear if that is true. This depends upon the level of coordination in management and conservation between the U.S. and Canada, and precisely where the borders fall. More on this later. Update: The political lines largely follow the geographical divides. There is some overlap, but it is minor.
I’ve also corrected some minor language here and there, as well as a citation (the paper I used was from 2004, not 2003). All the updates can be reviewed on the original post.
Thanks to Chris for his help.
With musical talent like this, I don’t know what he was doing with all that science-y stuff.
We’ve had an abundance of rain in the past month in my area. As such, we have a lot of standing water. To make matters worse, I live near a lake, which often means there’s standing water nearby anyway (and that’s definitely the case here). This all adds up to mean a deluge of mosquitos. Fortunately, there are also a lot of bats around here. But it isn’t all gum drops and soda. Sometimes having a lot of something means things will start showing up where you don’t want them to show up.
In the past two days, I’ve encountered three bats in my apartment. The first was dead. I’m not sure if a cat killed it or if it died naturally or if it was white nose syndrome (though there was no visible fungus). The second was among a series of shirts I have layed over a large change bottle. I got that guy downstairs before he decided to take a quick aerial tour of the area. I eventually got him out the door. The third one, which showed up tonight, almost victimized by the hungry mouths of several cats, decided to go for the extended stay with optional aerial tour of the living room. It was fascinating watching it flying back and forth and back and forth and back and forth. After waking some sleeping roommates, we got it sequestered in the sun room/porch. Unfortunately, there’s no light in that small room, so there was a lot of fast ducking and thrown blankets in response to the constant dives and erratic motions of the bat. With time and a little help from an empty Yahtzee box, we got it out one of the windows.
So, in honor of this story (which I don’t think is over – we have little idea of where these things are originating), I am reposting some bits from a Carl Zimmer piece on bats. Be sure to click “Bat in wind tunnel” and “Vampires running!” to watch the videos. For whatever reason, I cannot embed any better than that.
Bats evolved about 50 million years ago from squirrel-like ancestors. They probably made their first forays into the air as gliders. Like living gliders, they used flaps of skin to increase their surface area, letting them glide further. Their hands evolved long spindly fingers that were joined by membranes. Some early bat fossils suggest that they may have shifted from gliding to alternating between gliding and bursts of fluttering. Eventually bats evolved sustained powered flight.
Bats evolved a way to take advantage of the same laws of physics birds use to fly. And many scientists who have studied bat flight in the past have basically treated bats like leathery birds. Yet there’s no reason to assume that this should be so. After all, it would not be surprising to find that the way the feathers on a bird’s wing react to air pushing against them are different from the way the stretchy membranes on a bat react. Birds don’t have wing surfaces connecting their front and back legs, like bats do. And while birds only have a couple joints in their wing skeleton, such as at the elbow and wrists, bats have lots of knuckles they could, in theory, bend selectively to alter their wing surface. Bats also have lots of sensitive hair cells on their wings that appear to track the speed and direction of the air flow, and the information they get from the hairs may help them make fine adjustments to their wings many times a second.
I think the creepiest thing about this whole event, other than the possible rabies, was the way I watched the third bat walk. It landed on the floor a couple times and crawled around a bit. I wish I could have had more light to really observe it.
The intelligent beings in these regions should therefore not be surprised if they observe that their locality in the universe satisfies the conditions that are necessary for their existence. It is a bit like a rich person living in a wealthy neighborhood not seeing any poverty.
I have yet to read this article, but it looks interesting. I figured I’d offer something up until I can get to it, what with my lack of posting recently.