KEY to Unit 4 Qs - Q Are invertebrates monophyletic...

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1 Unit 4 Questions and Answers Q: Are invertebrates monophyletic, polyphyletic or paraphyletic? No, they are para phyletic. Why? Because invertebrate lineages and vertebrates share a common ancestor. The taxon “invertebrates” excludes the “vertebrates”, one of the descendants of the common ancestor. Q: The transition from gill arches to jaws is complex. Would intermediate stages in the evolution of the jaw have any function? Yes, even a crude jaw could have been useful to better hold prey or change the size or shape of the mouth. Individuals with these intermediate jaws would have had higher fitness and natural selection would increase the frequencies of the alleles that make crude jaws. Q: According to the fossil record of vertebrates , when bone first evolved, what structure did it form? 1. endoskeleton 2. exoskeleton 3. vertebrae 4. skull 5. jaw Answer = 2 NOTE: phylogeny does not include most of the fossil fish groups Q: Using your knowledge of chordate evolution, which came first, the chicken or the amniotic egg? The amniotic eggs first evolved in reptiles and shows up in the fossil record in the Carboniferous (~320 MYA), way before first birds show up in the fossil record. Q: Researchers agree that modern Homo sapiens originated in Africa and then spread throughout Europe, Asia and eventually the Americas. What do they disagree about? 1. whether the African population of H. sapiens left any descendants 2. whether early H. sapiens used tools 3. whether Neanderthals and H. sapiens interbred 4. whether H. neanderthalensis and Paranthropus went extinct at same time 5. whether Homo erectus and H. sapiens interbred Answer = 5
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2 Q: A shared derived trait of mammals is ______________ and a shared ancestral trait of mammals is ______________. 1. skull/ bipedalism 2. placenta/ amniotic egg 3. mammary glands/ lungs 4. parental care/ fur 5. amniotic egg/ lactation Answer = 3 Q: Mammals and another group of vertebrates both have an amniotic egg, a derived trait. What is this other group? In species with an amniotic egg, is fertilization internal or external? Why? Reptiles The sperm must fertilize the egg before the egg shell is made and egg is laid. Thus, fertilization must be internal , otherwise the egg could not become fertilized after shell is formed.
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KEY to Unit 4 Qs - Q Are invertebrates monophyletic...

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