What do the bone structures indicate about the ancestor of humans whales and bats?
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Is this evidence of evolution? Take a close look at this gorilla hand. The similarities
to a human hand are remarkable. Comparing anatomy, and characterizing the similarities and differences, provides evidence of evolution. Evidence from Living SpeciesJust as Darwin did many years ago, today’s scientists study living species to learn about evolution. They compare the anatomy, embryos, and DNA of modern organisms to understand how they evolved. Comparative AnatomyComparative anatomy is the study of the similarities and differences in the structures of different species. Similar body parts may be homologies or analogies. Both provide evidence for evolution. Homologous structures are structures that are similar in related organisms because they were inherited from a common ancestor. These structures may or may not have the same function in the descendants. Figure below shows the hands of several different mammals. They all have the same basic pattern of bones. They inherited this pattern from a common ancestor. However, their forelimbs now have different functions. The forelimbs of all mammals have the same basic bone structure. Analogous structures are structures that are similar in unrelated organisms. The structures are similar because they evolved to do the same job, not because they were inherited from a common ancestor. For example, the wings of bats and birds, shown in Figure below, look similar on the outside. They also have the same function. However, wings evolved independently in the two groups of animals. This is apparent when you compare the pattern of bones inside the wings. Wings of bats and birds serve the same function. Look closely at the bones inside the wings. The differences show they developed from different ancestors. Comparative EmbryologyComparative embryology is the study of the similarities and differences in the embryos of different species. Similarities in embryos are evidence of common ancestry. All vertebrate embryos, for example, have gill slits and tails. Most vertebrates, except for fish, lose their gill slits by adulthood. Some of them also lose their tail. In humans, the tail is reduced to the tail bone. Thus, similarities organisms share as embryos may be gone by adulthood. This is why it is valuable to compare organisms in the embryonic stage. Seehttp://www.pbs.org/wgbh/evolution/library/04/2/pdf/l_042_03.pdf for additional information and a comparative diagram of human, monkey, pig, chicken and salamander embryos.
Vestigial StructuresStructures like the human tail bone and whale pelvis are called vestigial structures. Evolution has reduced their size because the structures are no longer used. The human appendix is another example of a vestigial structure. It is a tiny remnant of a once-larger organ. In a distant ancestor, it was needed to digest food. It serves no purpose in humans today. Why do you think structures that are no longer used shrink in size? Why might a full-sized, unused structure reduce an organism’s fitness? KQED: The Reverse Evolution MachineIn search of the common ancestor of all mammals, University of California Santa Cruz scientist David Haussler is pulling a complete reversal. Instead of studying fossils, he's comparing the genomes of living mammals to construct a map of our common ancestors' DNA. He also specializes in studying the DNA of extinct animals, asking how the DNA has changed over millions of years to create today's species. His technique, referred to as computational genomics, holds promise for providing a better picture of how life evolved. Seehttp://www.kqed.org/quest/televis...lution-machine for more information. Summary
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What type of evidence is humans chimpanzees whales and bats all have the same bones in their arms fins or wings?Humans, chimpanzees, whales, and bats all have the same bones in their arms, fins, or wings. b. Why is this evidence of evolution? This is evidence of evolution because if all these animals have the same bones, they probably all evolved from one creature that had those bones a very long time ago.
What evidence suggests that humans and bats have a common ancestor?Previous studies on mammal DNA indicated that the common ancestor of these species lived 80 million years ago. The analysis showed that this common ancestor had DNA much more like our own than some of its other descendants, judging by the reconstruction.
What does the bone similarity between whales lions and humans suggest?Homologous structures are structures that have a common function and suggest common ancestry. For example, homologous structures include the limbs of mammals, such as bats, lions, whales, and humans, which all have a common ancestor.
What is the structure of the human whale bat?Whales, bats, cheetah and human share similarities in the pattern of bones of forelimbs. Though these forelimbs perform different functions in these animals, they have similar anatomical structure – all of them have humerus, radius, ulna, carpals, metacarpals and phalanges in their forelimbs.
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