why does a spider have 8 legs
was correct in citing the encyclopedia and Wikipedia about the definitions. To give a perhaps more digestible and cursory explanation, think of a millipede and a grasshopper. Metameres are simply a series of linear repeating segments. In a millipede, each segment with its pair of appendages is repeated, quite dramatically in number, but they don t differ from each other very much (homonomous). They all basically operate the same way for the same function in unison for the purpose of locomotion. Now think of a grasshopper. The grasshopper s thorax (middle section) has some repeating segments each with a pair of appendages just like the millipede. However specialization of metameric units allows the first pair to be specialized for grasping terrain or food or even a mate while the last pair of appendages are the strong jumping legs that are so easily recognized (heteronomous).
In this case of variation on a theme, the appendage-bearing segment is the theme that gets elaborated upon according to position in the thorax. The thorax, then, is a tagma used primarily for locomotion, but with local specialization. The number of tagmata are a major characteristic that differentiates between the major groups of anrthropods. For example arachnids like the spider in OP s question have 2 tagmata, a prosoma and opisthosoma, whereas insects have 3 tagmata, a head, thorax, and abdomen. And yes, even the head is a fused number of repeating segments! Unfortunately I don t think I m qualified to conjecture as to how tagmatization or specialization of repeated segmental units called metameres, might have influenced the evolution of appendage numbers between spiders and insects!
Hope this helps! Edit: spelling. Everything Shitty Meta ShittySFWporn Help/Advice Life, Culture The Arts Academics/Science Do you have a question that mainstream science refuses to answer? Are your theories and experiments so bizarre that sensible people tell you they will never be published? Do you need help building a doomsday machine, or shopping for a monstrous assistant? Then you ve come to the right place! The esteemed panelists at Shitty Ask Science might be the only people who are willing to help you! We reserve the right to remove all Dad Jokes and throw them in the pile of hazardous waste behind our laboratory.
THE FOLLOWING SUBJECTS HAVE BEEN THOROUGHLY RESEARCHED AND ARE NO LONGER CONSIDERED SCIENCE. PLEASE DON T USE THEM. Farts, poop, pee, and shit. Basic bitches. Homosexual Sapiens. The conversion rate of fuck-tons and shit-loads. Being what you eat, or a percentage of something. Genetic jeans. Space vacuum cleaners. Speed of heavy and/or dark. Sharp things that taste like blood. The fact that heat rises but mountains, the North Pole, and outer space are still cold. Making planes out of black boxes. Shaving with Occam s razor. Energy drink equations. The well-established relationship between autism and vaccines. Steel fuel. Jet memes. Steel memes.
Steal beams. God. Pokemon. Questioning dead people. Degrees of murder and other crimes in Celsius or Fahrenheit. Blurry Japanese genetalia. ISIS in space. The deadly youth in Asia. Solving global warming with air conditioners. Upside-down Australians, almond milk, gender fluids, and anything else we ve seen a million times already. Asking why meteors land in craters will result in a permanent ban! Asking what kind of thing is this when it s obviously not that kind of thing at all. And any other grossly willful misinterpretation of an image. Brand-name product placement. Scientists are on a budget. We can only afford generic products. Also, no one named Nagi allowed. He is almost as bad at memes as he is at L4D2 NO SCREENSHOTS, MEMES, OR MACROS!
- Views: 59
why do you want to work as an au pair
why do polar bears have short legs
why is nh3 more basic than ph3
why wont my phone connect to my car bluetooth
why is a spider not considered an insect
why do we use primers in pcr
why do we have 23 pairs of chromosomes