8th Grade Science Review 4 (Survival of the Fittest)

A cat’s leg, a dolphin’s flipper, and a bat’s wing contain similar bones. What does this suggest?

• These species developed at the same time.
  
• These structures perform the same function.
• These species share a common ancestor.
  
• The cat is the most advanced of these species.

A group of birds become separated from its original population. Over a period of time, the new population of birds adapted to its new environment. If this new population returned to the environment it originated from, which of the following would most likely determine its ability to survive as a species?

• its beak size
  
• its ability to fly
  
• its common ancestry
• its ability to reproduce

Variation happens as a result of the exchange of genetic information as it is passed from parent to offspring. Which of the following is true about inherited variation?

• Variation can influence separation.
• Variation can influence selective breeding.
• Variation can influence the resources that are available to an organism.
• Variation can influence whether organisms are more likely to survive to reproduce.

Ahmed had a bronchial infection. His doctor gave him an antibiotic that made him feel better for a week. Then, he got sick again. When Ahmed went back to the doctor he was given a different antibiotic. This time, the infection went away. What survival characteristic explains why the first antibiotic did not cure Ahmed’s infection?

• division
  
• resistance
  
• overproduction
• selective breeding

Which of the following is an example of selective breeding?

• Populations of lizards with a certain trait become more numerous after a change in climate.
• Farmers allow only sheep that produce the best wool to breed.
• A population of bacteria develops resistance to an antibiotic.
• Female birds prefer to mate with colorful males rather than noncolorful males.

A farmer uses a new insecticide to treat his crop plants. In the first year, the insecticide kills almost all of the insect pests. In the second year, the insecticide kills few insect pests. Which of the following is an unintended consequence of using the insecticide?

• The farmer will grow crops that are larger in size.
  
• The farmer can raise more kinds of crops.
  
• The farmer will have insecticide resistant pests on his crops.
• The farmer will make more money.

There are three species of birds on an island. These three species are shown below. Bird A has a heavy bill for eating big seeds. Bird B has a sharply pointed bill for eating insects. Bird C has a sharp bill for eating insects and small seeds. If the insect populations suddenly disappeared one season, which bird or birds would probably be the least affected that season?

• A
• B
• C
• A and B

The diagram below shows the layers of sedimentary rock exposed during an archaeological dig. These layers of rock have formed over hundreds of millions of years. Archaeologists discovered the fossil of a Pakicetus, a mammal that lived around 50 million years ago. They uncovered these remains from layer 2 in the diagram.

In what layer would you expect to find the remains of an Ambulocetus, which existed after the Pakicetus?

• 1
• 2
• 3
• 4