Natural selection!

Which of the following must be present for natural selection to occur?

• Genetic variation of traits

• Small population size

• Genetic similarities in a population

• Variation in the number of species present

What is natural selection?

• Inherited characteristic that increases chances of survival

• Organisms well-suited to their environment survive and reproduce at a greater rate

• A growing population causes a scarcity of resources

• Differences in the DNA sequence of individuals

Characteristics that an individual acquires in their lifetime, in general, are:

• Able to pass to the next generation

• Are not able to pass to the next generation

Adaptations are characteristics that:

• Arise from deliberate choice by the organism

• Support an individual to alter its environment

• Serve to maintain similarities between species

• Make an individual better-suited to its environment and way of life

In response to environmental pressure, individuals...

• that are less well adapted produce more offspring.

• that are less well adapted tend to survive.

• in the population survive at random.

• that are better adapted tend to survive and reproduce.

Individuals that are better adapted to environmental change are able to:

• select specific characteristics to pass to their offspring

• pass on heritable characteristics to their offspring

• remove heritable characteristics from their offspring

• all of the above

Natural selection increases the frequency of:

• Random mutations within a species

• Characteristics that make individuals less well adapted

• Change within a species

• Characteristics that make individuals better adapted

A population of crickets are green and yellow and move into an area that is lush and green most of the year and has a high number of predators. What do you expect will happen to this population?

• Over time, more green crickets will survive and reproduce, making more of the crickets green than yellow

• Over time, more yellow crickets will survive and reproduce, making more of the crickets yellow than green

• Yellow crickets will become green to match their envrionment

• Green crickets will die out because they won't be able to find mates

A population that has always had all-white bunnies now has two baby bunnies that are brown. What is the best explanation for why this might have happened?

• The bunnies chose to be brown to blend in with their environment

• A random mutation in the gene for fur color changed that trait

• A brown bunny snuck in at night with his brother

• All of the above

A mutation occurs in a population of birds that increases the length of its bill. This allows birds with the mutation to access new food sources that other birds and animals cannot access. What do you expect will happen over time?

• More birds will have this adaptation in future generations because it increases fitness

• Fewer birds will have this adaptation in future generations because it increases fitness

• Other birds will choose to copy the new trait, increasing competition for the food source

• It is impossible to tell what will happen, because natural selection is completely random