1. Biology Unit 7 Review Answers 

2. What are the 2 definitions of evolution?
Question #1 
What are the 2 definitions of evolution?
1- A change in a population over time.
2- A change in the allele frequency of a population over time.

3. What is natural selection?
Question #2 
What is natural selection?
The survival of certain organisms because they have the traits necessary to remain alive—healthy—and able to reproduce.

4. What does the term “adapt” mean?
Question #3 
What does the term “adapt” mean?
To ADAPT means to be able to use your “good” traits to remain alive-healthy-and reproducing during changing times.

5. What does “most fit” mean?
Question #4 
What does “most fit” mean?
“Most Fit” refers to organisms who have the traits necessary to remain living-healthy-and reproducing.

6. What is a population’s gene pool?
Question #5 
What is a population’s gene pool?
All of the different genes (and their variations) for the whole population.

7. Question #6  What is allele frequency?
How often an allele (or trait) shows up in the population.

8. The random (or “chance”) survival or death of organisms.
Question #7 
What is genetic drift?
The random (or “chance”) survival or death of organisms.

9. Describe an example of genetic drift.
Question #8 
Describe an example of genetic drift.
Certain types of organisms randomly dying or surviving, usually a catastrophic event (hurricane, earthquake, car running you over, etc.).

10. How does genetic drift drive evolution?
Question #9 
How does genetic drift drive evolution?
Randomly kill off certain types of organisms.
Change which types of traits are left over in the population.
Change the allele frequency.

11. Question #10  What is geographic isolation?
The separation of an existing population by some sort of barrier.

12. Describe an example of geographic isolation.
Question #11 
Describe an example of geographic isolation.
A group of organisms being separated by water / land / man-made structure.

13. How does geographic isolation drive evolution?
Question #12 
How does geographic isolation drive evolution?
Separate and Isolate groups of organisms.
In each area, certain traits will dominate.
Change the allele frequency.

14. What is genetic migration?
Question #13 
What is genetic migration?
The movement/traveling of certain types of organisms to another region and population.

15. Question #14  Describe an example of genetic migration.
A group of 1 type of animal travels to another region.

16. How does genetic migration drive evolution?
Question #15 
How does genetic migration drive evolution?
New traits coming into a population.
Change in the allele frequency.

17. What is a genetic mutation? Change in the DNA sequence of an organism.
Question #16 
What is a genetic mutation?
Change in the DNA sequence of an organism.

18. How does a genetic mutation drive evolution?
Question #17 
How does a genetic mutation drive evolution?
Change in DNA = New trait in the population.
Change in the allele frequency.

19. Which trait was most advantageous in 1990?
4 Wings
Question #18a 
Which trait was most advantageous in 1990?

20. Which trait was most advantageous in 2000?
4 Wings
Question #18b 
Which trait was most advantageous in 2000?

21. 4 Wings
It is advantageous to have 4 wings instead of 2…. Those organisms are living longer and reproducing more .
Question #18c 
Which trait had the lowest frequency in 1950? What might this tell you?

22. When were the 2 traits equally advantageous? How do you know?
Question #18d 
When were the 2 traits equally advantageous? How do you know?
They were never equally advantageous.
Equal = 50% each
This never shows up on the graph.

23. The study of the evolutionary relationships between all living things.
Question #19 
What is phylogenetics?
The study of the evolutionary relationships between all living things.

24. Question #20  What is a cladogram?
A diagram that shows how organisms are evolutionarily related by specific types of traits.

25. Where on the cladogram is the common ancestor?
Question #21 
Where on the cladogram is the common ancestor?
The very bottom of the “tree”.

26. Question #22 
How can you tell in a cladogram which organisms are most closely related?
Close Branches =
Closely Related

27. Question #23 
How can you tell in a cladogram which organisms are most distantly related?
Far Apart Branches =
Distantly Related

28. List from the BOTTOM  TOP.
Question #24 
How do you know the order in which traits or organisms evolved, using a cladogram?
List from the BOTTOM  TOP.

29. Which organism/s are most closely related to the common ancestor?
Question #25a 
Which organism/s are most closely related to the common ancestor?
Organisms A and B.

30. Which organism/s are most distantly related to the common ancestor?
Question #25b 
Which organism/s are most distantly related to the common ancestor?
Organism E

31. List the evolution of 4 traits in order.
Question #25c 
List the evolution of 4 traits in order.
Bottom  Top Right
1 , 2, 3, 4

32. Question #25d  Bottom  Top Right
List the evolution of the 5 organisms beginning with the common ancestor.
Bottom  Top Right
A/B , C , D , E

33. Which organism has traits 1, 5 and 6?
Question #25e 
Which organism has traits 1, 5 and 6?
Organism B

34. Which organisms have traits 1 and 2, but not 4?
Question #25f 
Which organisms have traits 1 and 2, but not 4?
Organisms C and D.

35. What did Darwin discover?
Question #26 
What did Darwin discover?
Natural Selection.
Some organisms are more fit for their environment than others.

36. What did Lamarck believe regarding evolution?
Question #27 
What did Lamarck believe regarding evolution?
Organisms pass on their acquired traits.
Organisms choose to change their bodies to evolve.

37. What did Malthus discover?
Question #28 
What did Malthus discover?
Organisms rely on resources and living area to survive.
Populations are regulated by famine, disease, and conflict.

38. Question #29  What did Hutton & Lyell discover?
The earth has changed several times over millions of years.

39. What is a homologous structure?
Question #30 
What is a homologous structure?
A body part which is similar between different animals because they have similar genetics + a relationship to a common ancestor.

40. Give examples of homologous structures.
Question #31 
Give examples of homologous structures.
Arm bones between humans, cats, dogs, birds, whales.
Skull bones between humans, chimps, gorillas.

41. What is an analogous structure?
Question #32 
What is an analogous structure?
Body parts which are similar because their environments are similar, not because they are genetically similar.

42. Give examples of analogous structures.
Question #33 
Give examples of analogous structures.
Insects, Birds, and Bats all have wings… but only because they all need to fly.
Whales, sharks, and mudpuppies all have fins…. But only because they all need to swim.

43. What is a vestigial structure?
Question #34 
What is a vestigial structure?
Body part which is similar to other organisms, but no longer has a function.
Shows relationship to common ancestry.

44. Give examples of vestigial structures.
Question #35 
Give examples of vestigial structures.
In Humans…. Appendix, wisdom teeth, wiggling ears, tailbone….
These are all parts other mammals have, showing our relationship to them and our common ancestor.