Wednesday, April 16, 2014
Neanderthals dominated Europe for tens of thousands of years. Then, about 60,000 years ago, when humans emerged from Africa, the Neanderthals began to die out, which scientists find mysterious. (Hint: It has to do with humans emerging from Africa.)
Although there are traces of Neanderthal DNA among humans, the Neanderthal was not our ancestor but a whole nother species. It would be nice to believe that humans overwhelmed them with superior brainpower, but the reality is we probably just had a much faster reproduction rate. We weren't smarter, just hornier.
Contrary to what you might think, Neanderthals weren't hairy creatures that walked bent over and grunted at each other. They stood upright, had a language, and used tools. If you saw a Neanderthal walking by dressed in modern clothes, you would not notice anything particularly strange.
Neanderthals cared for their sick and buried their dead. On the other hand, at least one scientist says they raped and killed humans and weren't above eating human flesh. So all in all, they weren't all that different from us.
Tuesday, April 15, 2014
When a daddy donkey, or jack, and a mommy horse, mare, love each other very, very much, God gives them a little baby mule to take care of. A daddy horse, or stallion, can also love a mommy donkey, or jenny, very, very much, but God isn't nearly as likely to give them a baby if they do. Even better, zebras sometimes love horses or donkeys, creating sporty mules called zedonks. I am not making this up, so help me.
The mule, except in very rare instances, cannot have babies of its own. It is considered as sturdy, sure-footed, and patient as a donkey, but as fast and strong as a horse. Plus it never takes maternity leave, so it's pretty much a win-win unless you're a mule. Basically a mule is an animal with absolutely no purpose in life but to do what humans tell it.
The reason mules are sterile is that a horse has 64 chromosomes and a donkey 62. The mule compromises at 63 chromosomes which evidently is a bad number if you're looking for off-spring. A zebra has between 32 and 36 chromosomes. And since you're probably wondering, a human has 46, putting us closer to the zebra end of the spectrum than that horse. I have no idea what horses are doing with all those extra chromosomes.
A male mule might be sterile, but it's not impotent, and a stud mule - there is such a thing - is notoriously mean, and have to be fixed. The mules themselves do not feel they were broken in the first place.
Monday, April 14, 2014
The lemming lives in the arctic tundra. You probably already know that lemmings don't really commit mass suicide, but it sure looks that way. They have a very high reproduction rate but at the same time are surrounded by animals who like to eat lemmings. For these reasons, their population varies widely. One moment, it's like, hey, where did all the lemmings go? And the next, it's like, damn, enough with the lemmings already.
When lemmings get too numerous - and after all, how many lemmings do you really need anyway? - they set off for new places to live. Some of these new places are on the other sides of bodies of water, such as rivers. Fortunately, lemmings are excellent swimmers. Well, some of them are excellent swimmers, some of them are only so-so. Bottom line, the good swimmers make it, and the so-so swimmers don't. This is the source of the mass suicide myth. Bad thing is, if you're a lemming, you don't know what kind of swimmer you are until you jump in the river and give it a try.
That's pretty much a metaphor for life in general.
Sunday, April 13, 2014
Owing to the rules of the A-to-Z blogging challenge, I'm not required to post on Sundays; nevertheless, here's a bonus blog about my friend, the amoeba.
Even if you don't know a rotifer from a gastrotrich, you've heard of amoebas. They are the rock-stars of protozoans. The name amoeba means change, because their shape is so fluid.
Amoebas have a contractile vacuole, but that's kind of what you'd expect. No surprises there. Their genome has 290 billion base pairs, which contrasts to a measly 29 billion pairs in the human genome; it seems kind of insulting such a simple animal would have so much genetic information, but that's the way it is. Amoebas eat by phagocytosis, which is a fancy way of saying the amoeba just engulfs its food, surrounds it. Since the amoeba doesn't have a mouth, it's all mouth. If a great big amoeba tries to hug you, watch out.
Scientists used to think amoebas had always produced asexually, but it turns out a long time ago, there were mommy amoebas and daddy amoebas, and when they loved each other very, very much, you got little baby amoebas. After a few million years or so, however, the amoebas decided it just wasn't worth the effort and it made a lot more sense reproducing without getting into the whole, "You forgot our anniversary" and "do these vacuoles make my protist look fat?" thing. What this means is, while we used to believe that sexual reproduction represented an advance over asexual, in fact, it's the other way around. This news is disappointing to the rest of us who still view sex as at least mildly entertaining, but maybe when you've been on the planet as long as amoeba have, you start to see things differently.
Saturday, April 12, 2014
The Kakapo weighs nine pounds, fully grown, and is the world's only flightless parrot. And I say thank goodness. One thing we don't need is a bunch of nine-pound parrots flying overhead. They have a sweet, floral smell, which is not something I associate with parrots I have known.
The few kakapos we have left live in New Zealand - there are only about 150 or so. At night they come out - they are nocturnal - and root around for food. This system worked very well for the kakapo until sailors started bringing over cats and rats which are also nocturnal and also root around for food at night and for whom a flightless, nine-pound parrot is a dream come true.
When kakapos mate, the males gather around making enticing displays - enticing to a kakapo - and the females choose their favorites for a quickie and then they never see each other again. This sounds very sexy and daring, but think what they've ended up with. Nine-pound flightless parrots that smell like flowers. It probably didn't help matters that the females were making their selections at night.
One does not wish to blame the victim here, but we can't help but wonder how the kakapo managed to paint itself into such a corner, evolution-wise. Like the dodo, it found itself in an isolated island without predators and just let itself go. Then when the rats and cats showed up, it was a sitting duck, or sitting kakapo if you prefer.
Let that be a lesson to the rest of you.
Friday, April 11, 2014
Back in the Cambrian, 700 million years ago, before there were even plants, back when the only things around were trilobites and anomalocarises, there were jellyfish. All the arthropods were like, "You jellyfish are never going to make it, ha-ha, with your soft bodies. Good luck." But it turns out the jellyfish outlived them all. Way to go, jellyfish.
When a mommy and daddy jellyfish love each other very, very much, the daddy releases sperm into the mommy's mouth, which is not considered kinky if you're a jellyfish, and pretty soon there are a bunch of baby polyps anchored to the ocean floor, their tentacles waving upward like adorable baby birds, only not so adorable and capable of stinging. Several polyps may share a single stomach, and yet they never complain, unlike human offspring who can't even manage to share a bathroom. When they mature, they float off into the water, and soon are full-grown jellyfish, or medusa, and the whole beautiful cycle begins again.
Along with there being boy and girl jellyfish, which I bet you didn't know, there are also jellyfish with eyes. Do you find this as disturbing as I do? The box jellyfish, which is among the most venomous species on earth, has up to twenty-four eyes, is capable of fast directional swimming, and can even form memories. In other words, it can see you, chase you, and think about you.
Thursday, April 10, 2014
Alas, that story is about as true as the one where the elephant gets its trunk, but it's a good one, nevertheless.
The indri is a great big lemur and is also called babakoto, which means "ancestor" because somehow the Malagasies tumbled onto the notion they'd descended from lemur-like animals, which is pretty smart of the Malagasies. According to the myth, there were two brothers, one of whom decided to climb down from the tree and try his hand at farming, while the other stayed put. We're descended from the one who left the tree. The loud songs of the indri, which can last up to three minutes, are the indri calling for their lost brother.