Evolution Concept Questions Answers

1. What is evolution? Why is evolution referred to as a theory? (change over time is the way that organisms have descended from ancient ones; theory because it is a well-supported explanation of observed evidence)

2. How would you summarize the main ideas in Darwin’s theory? (variations occur in populations and some are favorable. Offspring that have favorable variations have a survival advantage and, over time, favorable traits accumulate)

3. How did his visit to the Galapagos Islands influence Darwin’s thinking? (the distribution of species convinced him that new species might be arising from existing species over time)

4. How did artificial selection influence Darwin’s thinking? (huge changes can be made in thousands of years so could happen naturally over longer periods of time)

5. What two ideas in geology were important for Darwin’s thinking? (Earth is very old and the same processes that shaped Earth millions of years ago continue today; allowed time for living things to change)

6. What does the fossil record tell us about evolution? (species have become more complex over time; not all species lived at the same time; some species are no longer present)

7. Why are fossils of many species not found in the fossil record? (have to have just the right conditions for fossils to form; some organisms are soft-bodied and don’t fossilize well)

8. What evidence for evolution can be found in biogeography? (unrelated organisms share traits because they evolved to a similar habitat; organisms in nearby locations are more closely related than organisms in similar but distant environments)

9. What can we learn from looking at the embryos of vertebrates? (all are similar early in development; more closely related species are more similar later in development)

10. What is artificial selection? How does it differ from natural selection? (humans selecting traits instead of nature)

11. How does natural variation affect evolution? (provides the raw material for natural selection which, in turn, leads to evolution)

12. What role do mutations play in evolution? (create the original differences between individuals)

13. How is the process of natural selection related to a population’s environment? (those best suited to their environment survive and reproduce most successfully)

14. How does the process of natural selection account for the diversity of organisms that have appeared over time? What is being selected in the process? What is selecting it? (traits that are advantageous are selected by the environment; this leads to changes in organisms over time)

15. Distinguish between fitness and adaptation. Give an example of each. (fitness is the ability for an organism to survive and reproduce in its environment and increases through ongoing adaptation. For example camouflage. An adaptation is any inherited characteristic that increases an organism’s chance of survival. For example quills or claws)

16. How does the concept of descent with modification explain the variety of species observed today? (species change over time by inheriting traits from their ancestors but those traits are modified over time as natural selection favors different things)

17. What is meant by the term vestigial structure? How do they provide evidence of evolution? (reduced or no function; evidence because suggests was present in an ancestor - why else would they be present)

18. How is the general understanding of survival of the fittest misleading? (fitness does not mean strongest)

19. What do we mean when we describe an organism as “more fit” than some other organism? (better suited to survive in its environment)

20. How might natural selection have produced the modern giraffe from short-necked ancestors? (a slightly longer neck would give an advantage for reaching food)

21. How does sexual reproduction benefit a species? (parent genes mix in new combinations creating variety)

22. Explain the difference between homologous and analogous. Give examples of each. (homologous are similar because of shared ancestry; analogous are similar because of convergent evolution)

23. How could two unrelated structures become analogous? (similar selective pressure)

24. If you looked at the DNA of two closely related species, what would you expect to find? (should be more similar the more closely related)

25. What can be learned through protein comparisons of two different species? Give an example. (proteins change by mutation; proteins in distantly related species would have more time to become more different from one another)

26. Although wild turkeys can fly, domesticated turkeys cannot. Imagine a population of domesticated turkeys escaped from a farm into a new environment. Give some examples of conditions that would determine if the birds could survive or not. (avoidance of predators and food supply)

27. Is protecting endangered species upsetting the process of natural selection? (species are usually endangered because of human activity. Protecting them may restore the balance)

28. How can two species that look very different from each other be more closely related than two species that look similar to each other? (regardless of appearance, two species are closely related when they share a common ancestry; if one evolved to suit an environment it might look similar to some unrelated species in a similar environment somewhere else)

29. What term describes each of the following?

a) Two species may live in the same area but in different habitats. Since there is little if any contact the possibility of successfully mating is drastically reduced. (geographic isolation)

b) Since the breeding times of similar organisms are different there is no chance of reproductive contact. (temporal isolation)

c) Birds, mammals, and insects have pre-mating rituals that attract the proper mate. (behavioral isolation)

d) A physical barrier separates a species into two separate areas and does not allow any further contact. (geographic isolation)

30. How did the breakup of Pangea and then of Gondwana contribute to the variety of species? (as species became isolated they began to diverge)

31. Predict what may eventually happen to two snail populations living on either side of a road. (geographic isolation may lead to speciation)

32. What causes allopatric speciation? (when species become separated)