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Remember: In science, one line of evidence in and of itself is not sufficient. All evidence must work together and support a theory. Lines of Evidence.

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Presentation on theme: "Remember: In science, one line of evidence in and of itself is not sufficient. All evidence must work together and support a theory. Lines of Evidence."— Presentation transcript:

1 Remember: In science, one line of evidence in and of itself is not sufficient. All evidence must work together and support a theory. Lines of Evidence for Evolution:

2 1. Biogeography: geographic distribution of species *closely related species tend to be found in the same geographic region, whereas the same ecological niches in distant regions are occupied by very different (though sometimes similar-looking) species *this is what 1st suggested evolution to Darwin

3 -Example: Australia is home to a group of mammals (marsupials)that are distinct from another group of mammals (eutherians) that live elsewhere on Earth  Australia: sugar glider is superficially similar to flying squirrel (N. America)  sugar glider has characteristics that define it as distinctly marsupial *These external superficial similarities are an example of CONVERGENT EVOLUTION (not homologous structures & therefore, not evidence of evolution)

4 Because the continents drifted over time the mammal distribution has changed dramatically –Monotremes and marsupials developed in Gondwanaland 165 million years ago before the three southern continents were separated. –Placental mammals (developed life young) developed later 135 million years ago and replaced almost all of the monotremes (egg laying mammals) and marsupials (undeveloped young born into pouches) in the other continents. –Australia was separated from the other continents. This is why marsupials and monotremes are now found only on Australia. Monotremes and marsupials have evolved to fit the niches within the Australian environment and there are no placental mammals. This is simply because of geography not because Australia is unfit for placental mammals.

5 In order for an organism to have a high level of fitness, what must be true? A.It must be really strong B.It must be really fast C.It must have a lot of offspring D.It must be smarter than others in the population

6 What is the difference between common descent and a direct descendant? A.Common descent: parents children; direct descendant: having a common ancestor B.Common descent: having a common ancestor; direct descendant: parents children C.There isn’t a difference; both mean the same thing

7 In Darwin’s Theory of Natural Selection, evolution is acting on A.a population B.a species C.an individual D.a community

8 What are vestigial structures? A.Structures that are essential for survival B.Structures that have never served a useful purpose C.Structures that are similar in function but not in internal form D.Structures that no longer serve a purpose but did at one time

9 Which of the following is not a homologous structure? A.Fin of a goldfish and the fin of a whale B.The hemoglobin protein in humans & chimps C.A cat’s leg and a bat’s wing D. They are all homologous structures

10 What are analogous structures? A.Structures that are formed using the same DNA instructions B.Structures that seem to serve a similar purpose C.Structures that are similar in function but not in internal form D.Structures that no longer serve a purpose but did at one time


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