Amplify Natural Selection Unit Review

Why would the distribution of traits in a population change dramatically over time?

A big changes in the distribution of traits is probably due to a change in the environment which caused new traits to be adaptive. The environment might change because a new predator was introduced, the climate changed, or perhaps a new plant spreads that changes the common "background color."

True or False: Offspring inherit traits from their parents.

False(technically), offspring inherit genes from their parents. Genes are instructions for building proteins, and proteins combine to form traits.

True or False: For Ostrilopes, thick fur is an adaptive trait.

False, fur is adaptive in a cold environment, but not in a hot one. Whether or not a trait is adaptive depends on the environment.

True or False: Mutations are super powers.

False, mutation are random changes in genes that sometimes lead to a new trait. The new trait is random and it will only spread if it happens to be useful (adaptive).

True or False: Individuals of a species can change so they have adaptive traits.

False, over many generation adaptive traits can become more common in the population of a species but individuals cannot change.

True or False: If a population lacks an adaptive trait it will just appear.

False, the trait must exist in the population in the beginning and then it can become more common. In rare cases, a mutation can cause a new trait. Usually, if the necessary adaptive trait is not present the population will go extinct.

How do new traits appear in a population?

New traits come from random genetic mutations.

How do adaptive traits spread in a population?

The individuals with adaptive traits survive longer and reproduce more, so the adaptive trait becomes more common in each generation.

How can you describe an entire population of a species?

You could use histograms to show the distribution of different traits.

feature

a characteristic that all members of a species have

mutation

a random change to a gene that sometimes results in a new trait

trait

a specific characteristic of an individual

non-adaptive trait

a trait that makes it less likely that an individual will survive in a specific environment

adaptive trait

a trait that makes it more likely that an individual will survive in a specific environment

variation

any difference in traits between individual organisms

selection pressure

something in the environment that affects an individual's chances of surviving

distribution

the number of individuals with each trait in a population

natural selection

the process by which the distribution of traits in a population changes over many generations