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# 10.4: Macroevolution and the Origin of Species

Difficulty Level: At Grade Created by: CK-12

## Lesson 10.4: True or False

Name___________________ Class______________ Date________

Write true if the statement is true or false if the statement is false.

_____ 1. The process by which a new species evolves is called speciation.

_____ 2. For a new species to arise, members of a species must no longer be able to breed with each other.

_____ 3. Coevolution occurs when members of one species evolve independently of a symbiotic species.

_____ 4. Darwin believed evolution occurred both through gradualism and punctuated equilibrium.

_____ 5. Geographic separation usually leads to sympatric speciation.

_____ 6. A new river separating a population can result in allopatric speciation.

_____ 7. When geologic and climatic conditions are stable, punctuated equilibrium occurs.

_____ 8. The hummingbird and the flower it pollinates have coevolved.

_____ 9. When geologic and climatic conditions are changing, evolution may occur more quickly. This is known as gradualism.

_____ 10. Hawthorn flies are undergoing geographic separation.

_____ 11. During coevolution, as one species changes, the other species goes extinct.

_____ 12. The Kaibab squirrel is in the process of allopatric speciation.

_____ 13. A new mountain range or canyon separating a population can result in sympatric speciation.

_____ 14. A species is a group of organisms that can breed and produce fertile offspring.

_____ 15. Punctuated equilibrium is a relatively slow process.

Name___________________ Class______________ Date________

Read these passages from the text and answer the questions that follow.

Introduction

Macroevolution is evolution over geologic time above the level of the species. One of the main topics in macroevolution is how new species arise. The process by which a new species evolves is called speciation. How does speciation occur? How does one species evolve into two or more new species?

Origin of Species

To understand how a new species forms, it’s important to review what a species is. A species is a group of organisms that can breed and produce fertile offspring together in nature. For a new species to arise, some members of a species must become reproductively isolated from the rest of the species. This means they can no longer interbreed with other members of the species. How does this happen? Usually they become geographically isolated first.

Allopatric Speciation

Assume that some members of a species become geographically separated from the rest of the species. If they remain separated long enough, they may evolve genetic differences. If the differences prevent them from interbreeding with members of the original species, they have evolved into a new species. Speciation that occurs in this way is called allopatric speciation.

Sympatric Speciation

Less often, a new species arises without geographic separation. This is called sympatric speciation. The following example shows one way this can occur.

1. Hawthorn flies lay eggs in hawthorn trees. The eggs hatch into larvae that feed on hawthorn fruits. Both the flies and trees are native to the U.S.
2. Apple trees were introduced to the U.S. and often grow near hawthorn trees. Some hawthorn flies started to lay eggs in nearby apple trees. When the eggs hatched, the larvae fed on apples.
3. Over time, the two fly populations — those that fed on hawthorn trees and those that preferred apple trees — evolved reproductive isolation. Now they are reproductively isolated because they breed at different times. Their breeding season matches the season when the apple or hawthorn fruits mature.
4. Because they rarely interbreed, the two populations of flies are evolving other genetic differences. They appear to be in the process of becoming separate species.

Questions

1. What is a species?

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2. What is speciation?

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3. How do new species arise?

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4. Describe allopatric speciation.

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5. Describe sympatric speciation. Provide an example.

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## Lesson 10.4: Multiple Choice

Name___________________ Class______________ Date________

Circle the letter of the correct choice.

1. Which statement best describes allopatric speciation?
1. Speciation that occurs without reproductive separation.
2. Speciation that occurs without geographic separation.
3. Speciation that occurs when some members of a species become geographically separated from the rest of the species.
4. Speciation that occurs when some members of a species become reproductively separated from the rest of the species.
2. Which statement best describes sympatric speciation?
1. Speciation that occurs without reproductive separation.
2. Speciation that occurs without geographic separation.
3. Speciation that occurs when some members of a species become geographically separated from the rest of the species.
4. Speciation that occurs when some members of a species become reproductively separated from the rest of the species.
3. Which is the best definition of a “species”?
1. A group of organisms that can breed and produce fertile offspring together.
2. A group of organisms that can breed and produce infertile offspring together.
3. A group of organisms that can breed together.
4. A group of organisms that look and act similar.
4. An example of coevolution would be
1. the evolution of wings in bats and birds.
2. the toad and the flies they eat.
3. the hummingbird and the tubular flower it pollinates.
4. all of the above
5. Which statement is true concerning gradualism? (1) Gradualism occurs when geologic and climatic conditions are stable. (2) Darwin thought evolution occurred this way. (3) This type of evolution may result in long periods of little change.
1. 1 only
2. 1 and 2
3. 1 and 3
4. 1, 2, and 3
6. Punctuated equilibrium is
1. well supported by the fossil record.
2. a slow form of evolution.
3. how Darwin proposed evolution occurs.
4. none of the above
7. The hawthorn fly
1. is undergoing allopatric speciation.
2. can live on either hawthorn trees or apple trees.
3. has been geographically separated by the planting of new tree species.
4. all of the above
8. The Kaibab squirrel
1. is undergoing allopatric speciation.
2. is undergoing sympatric speciation.
3. were geographically separated from Abert's squirrels by the formation of the Grand Canyon.
4. both a and c

## Lesson 10.4: Vocabulary I

Name___________________ Class______________ Date________

Match the vocabulary word with the proper definition.

Definitions

_____ 1. a group of organisms that can breed and produce fertile offspring

_____ 2. when a new species arises without geographic separation

_____ 3. the process by which a new species evolves

_____ 4. when some members of a species become geographically separated from the rest of the species

_____ 5. evolution over geologic time above the level of the species

_____ 6. when species in symbiotic relationships evolve together

_____ 7. evolution that occurs gradually

_____ 8. evolution that occurs quickly

Terms

a. allopatric speciation

b. coevolution

d. macroevolution

e. punctuated equilibrium

f. speciation

g. species

h. sympatric speciation

## Lesson 10.4: Vocabulary II

Name___________________ Class______________ Date________

Fill in the blank with the appropriate term.

1. ____________ is slow, gradual evolution.

2. ____________ equilibrium is illustrated by bursts of rapid change.

3. The very long mouth part of the hummingbird has ____________ with the tubular flower it pollinates.

4. ____________ speciation is speciation without geographic separation.

5. ____________ speciation may occur when some members of a species become geographically separated from the rest of the species.

6. Evolution occurs in response to a change in the ____________.

7. A ____________ is a group of organisms that can breed and produce fertile offspring.

8. New species arise in the process of ____________.

9. In coevolution, as one species changes, the other species must also change in order to _________.

10. Macroevolution is evolution over ____________ time.

## Lesson 10.4: Critical Writing

Name___________________ Class______________ Date________

Thoroughly answer the question below. Use appropriate academic vocabulary and clear and complete sentences.

Describe two ways that new species may evolve.

Feb 23, 2012

Feb 20, 2015