Unit 10 (7A, 7B) & Unit 11 (7F) Exam Review

7A Analyze and evaluate how evidence of common ancestry among groups is provided by the fossil record,

biogeography, and homologies, including anatomical, molecular, and developmental.

5. What is common ancestry? The concept that a group of closely related species are all descended with some

modifications from the same ancestor

6. According Figure 2 in the folder, what does the evolution of the animal on the right tell us about the environment the

top organism lived in versus the environment the bottom organism lived in? The picture shows that the top animal

(whale ancestor) lived on land and the bottom animal (current whale) lives in water. Note the lengthening of the

tail, the thickening of the spines, the hind legs dissolve, and the front legs shorten & become flat and wide.

7. Describe a homologous structure between a bat, cat, and human. All have forelimbs, common structures that

provide evidence that they are closely related and had a common ancestor. Their forelimbs are all used in

movement.

8. What is a vestigial structure? A structure that has little or no function in a species. Example: appendix in humans,

hind leg in whale

Sample Questions:

9. Analyze Why are homologous arm bones evidence for common ancestry among vertebrate groups?

a. because the common ancestor likely passed the traits for arm bones to its descendants

b. because the arm bones show how two closely related organisms can have different structures

c. because the arm bones show how ancient organisms were more complex than modern organisms

d. because the arm bones show that fossil record is true and accurate

10. Evaluate Scientists have observed many close similarities in the DNA sequences of whales and dolphins. This

observation is evidence for which idea?

a. Whales are ancestors of modern dolphins.

b. Whales and dolphins both evolved from a relatively recent common ancestor.

c. Whales and dolphins are members of the same species.

d. Whales and dolphins can breed with one another to produce a new species.

11. Apply concepts A scientists studies two organisms with many similar traits. He hypothesizes that they are closely

related, although they lived in different areas of the world. But a comparison of their DNA sequences reveals that they are

actually distantly related. How could biogeography explain these findings? It’s possible that the organisms lived in

similar environments with similar selection pressures. By chance, the same adaptations evolved in the distantly

related species.

7B Analyze and evaluate scientific explanations concerning any data of sudden appearance, stasis, and sequential

nature of groups in the fossil record.

12. Why is the fossil record considered incomplete? Not all organisms die and become fossils and processes like

erosion and mountain building can change or reorder rock layers. This can cause the fossils to become jumbled or

even destroyed.

13. What is stasis? Name an organism that has remained static for thousands of years. Stasis is a period of no change.

When referring to the fossil record, stasis occurs when the structure of a species in the fossil record does not

change over a long period of time.

14. Label the organisms below as examples of either gradualism or punctuated equilibrium.

Sample Questions:

15. Analyze How do scientists explain the incompleteness of the fossil record?

a. Geological events such as erosion might confuse or even destroy parts of the fossil record.

b. Evolution occurs only after a species has existed for millions of years so many fossils have been lost.

c. The fossil record contains only animals and no plants.

d. Fossils are the remains of organisms that have recently died.

16. Explain Sixty-five million years ago, all the dinosaurs and many other species went extinct. The adaptive radiation of

mammals helps explain which observation of the fossil record after that mass extinction?

a. a rapid increase in mammal diversity

b. stasis among certain mammal species

c. a gradual decrease in mammal diversity

d. a rapid decrease in the size of mammals

17. Evaluate How do scientists use stasis in the fossil record as evidence for evolution of species? Periods of stasis may

be followed by the appearance of many new species in the fossil record. These periods can be evidence for the

punctuated equilibrium model of evolution.

18. Contrast Gradualism and punctuated equilibrium are two models that explain the appearance of new species in the

fossil record. Describe how these models are different. Gradualism suggests that evolution is constant, and that it

[Type a quote from the document or the

summary of an interesting point. You can

position the text box anywhere in the

document. Use the Drawing Tools tab to

change the formatting of the pull quote text

box.]

Gradualism

Punctuated

Equilibrium

occurs at a constant but slow rate. Punctuated equilibrium suggests that evolution occurs very rapidly in specific

relatively short time intervals, preceded and followed by longer periods with few changes.

7F Analyze and evaluate the effects of other evolutionary mechanisms, including genetic drift, gene flow, mutation,

and recombination.

19. Match the vocabulary word with the correct example below:

20. Which of the following mechanisms will cause the gene pool of two populations to become similar?

a. gene flow c. mutation

b. genetic drift d. natural selection

Natural Selection

Non-random mating

Mutation

Genetic Drift

Gene Flow

I will see more of the dark feet with white tail feathers and less of

the light feet with dark tail feathers.

Founder effect… the diversity of the new population will decrease

compared to the original population.

Sample Questions:

26. Infer A plant breeder mates two pea plants from the same strain, and then plants the seeds they produce. Which

observation of the offspring suggests that a mutation occurred in the genes of one of the parent plants?

a. plants that produce orange peas, a color never before observed in this strain

b. plants that produce peas that are green and wrinkled, a combination that is rare in this strain

c. several plants that have a combination of the traits of the two parents

d. a plant that is nearly identical to one of its parents

27. Analyze Which of the following mechanisms of evolution usually causes an increase in genetic diversity within a

species?

a. competition

b. genetic drift

c. mutation

d. gene flow

28. Evaluate Explain how mutations can be mechanisms of evolution. A mutation in a gene can give an individual an

adaptation that allows it to better survive and reproduce. If the mutation is passed on from generation to

generation, it likely will become more common in the population.

29. Infer Why might a species that has 94 chromosomes per cell be able to evolve more quickly than a species that has 12

chromosomes per cell, even if both species depend on about the same number of genes? A greater number of

chromosomes allows for the genes to recombine in more ways in the offspring, producing a wider variety of genetic

traits in a species.

I will see more of the beetles with half their abdomen dark. I will

see less of the light colored beetles.

Bottleneck effect. The diversity of the new population will decrease

compared to the original population.

7A Analyze and evaluate how evidence of common ancestry among groups is provided by the fossil record,

biogeography, and homologies, including anatomical, molecular, and developmental.

Figure 2

7B Analyze and evaluate scientific explanations concerning any data of sudden appearance, stasis, and sequential

nature of groups in the fossil record.

7F Analyze and evaluate the effects of other evolutionary mechanisms, including genetic drift, gene flow, mutation,

and recombination.