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The late zoologist Sidnic Manton acknowledged that arthropods一animals with jointed exoskeletons, such as flies, crabs, and spiders- are all descended from soft-bodied segmented worms. Yet he maintained that differences in limb form, musculature, and embryonic development indicate that these three arthropod groups一insects. crustaceans. and chelicerates, respectively- evolved independently from worms rather than from i common arthropod ancestor. Consequently. according to Manton. shared characteristics such as a jointed exoskeleton and large compound eyes represent cases of convergent evolution- similar yet independent developments in these organisms. But if they evolved convergently, then one would expect significant differences in the neurological systems supporting sight. In fact. however. many nerve cells play virtually identical roles in supporting complex visual responses in both insects and crustaceans, suggesting that their common ancestor already possessed highly developed eyes, and therefore was probably already in arthropod. Yet the compound eyes of chelicerates differ neurologically from those of insects and crustaceans. suggesting that the eyes of chelicerata did evolve independently and providing partial confirmation of Manton's views.
当前版本由去没人的岛更新于2023-07-13 15:21:21 感谢由去没人的岛对此题目的解答所做出的贡献。
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[数学 ]【新版】冲分救命题 -11989
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