Sunday, April 13, 2014
Bonus Letter: A is for Amoeba
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.