Semester 2 Review

The trees that giraffes eat from are getting taller over the generations. How will the giraffe population most likely respond?

• It will drop under carrying capacity but then continue to rise and will shoot over it.

• the giraffes will stretch their necks out day after day in order to reach the tall trees, gaining a significantly longer neck in their lifetime.

• the shorter necked giraffes will not get enough food and will die, making it so the longer-necked giraffes of each generations will be the ones to survive and reproduce.

• giraffes will grow longer necks due to the need to reach taller trees and then will pass this trait onto their offspring

How much a specific trait increases an organism's chances of survival.

• adaptive value

• fitness

• natural selection

• alelle frequency

Variations within a species are most likely the result of

• genetic recombination and sexual reproduction

• natural selection and evolution

• over-reproduction and competition

• asexual reproduction and gene flow

A large population of houseflies was sprayed with a newly developed, fast-acting insecticide. Some flies survived the insecticide and reproduced. Which of the following explains the appearance of the resistant trait?

• organisms developed the trait in response to the insecticide

• the trait already existed in some organisms but was only made apparent once the insecticide was used

• the insecticide caused mutations in the DNA of the houseflies that made some of them resistant

• non-resistant houseflies mated with different fly species in order to gain the resistant trait so they could survive

Which of the following is not a result of natural selection?

• Giraffes have long necks, which help them feed from trees

• Pesticide-resistant insects

• Development of genetically modified organisms

• Rat snakes have different coloration depending on their habitat

The gene frequency for a particular trait in a population of insects was determined to be 80% A and 20% a. Fifty years later, the gene frequency was determined to be 50% A and 50% a. This is change is best explained by which of the following?

• The A and a alleles had the same adaptive value.

• The size of the insect population grew over time.

• An increase in the mutation rate of the A gene.

• An increase in the adaptive value of the a allele.

A certain species of lizard ranges from slimy to not slimy, with most lizards having a low amount of slime. A new predator moves in that captures its prey with its paws. It does eat lizards but is only able to hold onto the ones without much slime. Which of the following statements is true?

• The non-slimy trait is more likely to be passed on in the next few generations.

• The predator increased the value of slime.

• The slime is the selecting agent for the lizard population.

• Non-slimy lizards will start producing large amounts of slime to survive.

90% of a population has Trait X. Which will be the biggest factor in determining if Trait X will continue to have such a high frequency?

• The size of the population.

• How fast the organisms within the population reproduce.

• The amount of resources available for the population.

• The value of Trait X in helping organisms survive in their environment.

Where do the adaptations of most organisms come from?

• they are traits that have been passed down for generations

• the organism inherits the trait from its parents that developed it to survive in the environment

• they come from mutations caused by bioaccumulation

• they are traits the organism gains or loses in its lifetime due to use and disuse

Biological fitness is the ability of the individual to

• gain favorable mutations in response to the environment

• live to be the oldest in the population

• contribute genes to future generations

• outrun other organisms of the same species