Download Unit 10: Natural Selection Study Guide

Name: __________________________________________________ Period: ________
Unit 10: Natural Selection Study Guide
1. What would happen if there was limited genetic variation in a tortoise population of
today compared to an earlier tortoise population with more variation?
a. The current tortoise populations are less likely to be able to adapt to environmental
changes.
2. In the 1940’s DDT was sprayed on mosquitoes. Over time some of the mosquitoes were
surviving the spraying of the pesticide, and eventually the whole population was showing
resistance to the spray. How would resistance to DDT spread in the mosquito population?
a. The mosquitos with a resistance gene survived the first DDT sprayings and passed that
gene to their offspring.
3. A population of beetles initially consists of dark colored and light colored members. After
several generations, the beetle population consists almost entirely of dark colored
beetles. Why would this happen?
a. This occurred because of natural selection. The dark beetles were able to blend in with
their surroundings; therefore predators did not see them. Over time the surviving dark
colored beetles were able to survive and reproduce.
4. What animal adaptations are observed to scare away potential predators?
a. Large false eyes – to scare away potential predators.
b. Standing on hind legs to look larger
c. Making threatening sounds
d. Rattle snake rattle noises
5. What animal adaptations are observed to provide protection from potential predators or
to hide from potential prey?
a. Spikes or quills – to penetrate predator skin
b. Bright colors – to ward off predators because of poison skin
c. Camouflage to blend in with the environment
6. Name some structural adaptations that help a plant survive in rough environmental
conditions.
a. Broad leaves that float in water.
b. Roots that reduce salt absorption in the ocean.
c. Leaves and stems that conserve water in the desert.
7. Describe natural selection.
a. An organism with genetic variations that help it survive and reproduce in its
environment.
8. Why do you think that life on Earth continued even though there has been numerous
catastrophes?
a. Life on Earth continued because there is a wide diversity of species.
9. Why did giraffes with longer necks survive over giraffes with shorter necks?
a. Giraffes with longer necks survived (were the most fit) because they were better suited
to their environment than giraffes with shorter necks.
10. What leads to evolutionary changes in organisms?
a. Evolutionary changes are a result of variations among offspring, followed by natural
selection.
11. Why would the finches that live on the Galapagos Islands not look or act like any other
finches in the world?
a. The finches on the Galapagos Islands don’t look or act like any other finches in the
world because they were geographically isolated to inherit advantageous genetic
variations to help them survive and reproduce.
12. Why would a geographically isolated population of organisms run the risk of possibly
becoming extinct?
a. The geographically isolated population of organisms run the risk of becoming extinct
because there is decreased genetic variation.
13. Antibiotic resistance results in stronger bacteria that do not respond to antibiotic
treatment. Why does this happen?
a. Antibiotic resistance occurs because the antibiotic, leaving behind strong resistant
bacteria, kills the weaker bacteria. The resistant bacteria in turn survive and are able
to reproduce more resistant bacteria. This is an example of natural selection.
14. Why did the peppered moths change over a short period of time?
a. The darker moths blended in with the soot colored vegetation, making it harder for the
birds to see them. The darker moths were able to survive and reproduce. The lighter
moths didn’t blend in with the darker vegetation, and were easily spotted by the birds.
Therefore the population of light colored moths eventually decreased.
15. Why would some bacteria survive medicine treatments?
a. Some bacteria have adaptations to help them stay alive and reproduce more medicine
resistant bacteria.
16. Look at the diagram to the right. What does the diagram suggest about the structures?
a. The diagram suggests that all of the species once
shared a common ancestor.
17. What are the structures pictured in the diagram?
a. The structures pictured in the diagram are called
homologous structures
18. What two organisms from figure 5.3 most likely share an
evolutionary relationship?
a. The bird and the bat because they have similar bone
structures.
19. What are vestigial structures?
a. Vestigial structures aer structures that
are not highly beneficial to the
organism. (For example: hip bones on
whales, appendixes in humans)
20. Why would a whale have a hip bone?
a. Whales have hip bones because they
had evolved from four-legged animals.
21. What are four types of evidence of
evolution?
a. Fossil evidence
b. Geographic evidence
c. Embryology
d. Anatomy
22. What does the fossil record show?
a. The fossil record shows how organisms have changed over long periods of time.
Usually from a simple organism to a more complex organism.
23. How did the horse change over time?
a. The horse changed by small structural changes in each species that were passed on to
offspring over many generations.
24. What does embryology show?
a. Embryology shows that many organisms all start out the same way in the earliest
stages of development. This is a clue that these embryos share a common ancestor.
25. What two structures on the earliest stage of embryo development are present?
a. The two structures that are located on an embryo in its earliest stage of
development are gills and a tail.
Constructed Response Study Guide – ANSWER KEY
There are two different color variations in the jaguar species. One variation results in
dark black coloration, the other variation results in spotted coloration. Scientists
observed the hunting success of the two groups of jaguars. The graph below shows the
scientists’ data.
Amount of prey killed per week
Average prey captured per week
5%
4%
4%
3%
3%
2%
2%
1%
1%
0%
Dark colored Cat
Spotted Cat
A. Explain what the data shows about the advantage of having spots for the jaguar
species.
The advantage of having spots on the jaguar lets it hunt prey more easily. The
females see that the spotted jaguars are successful hunters. This is called sexual
selection. The females choose the best hunters and reproduce with them to have
offspring with spots.
B. Identify one disadvantage that dark colored fur may have for jaguars.
The one disadvantage to having dark colored fur is that the jaguars stick out in the
light brown grass. The prey easily detects the dark colored jaguars.
C. Explain in detail how the dark colored fur evolved in jaguars despite causing
disadvantages for catching prey.
The dark colored fur evolved in jaguars despite causing disadvantages for catching
prey, because the dark furred jaguars changed their hunting behavior over time.
They started to hunt at night. This proved to be better and the dark jaguars were
able to be more successful at hunting and they were able to mate with females
(sexual selection by the females) to produce offspring.