Natural Selection Study Guide

Natural Selection Study Guide

1. List and describe out the 4 principles of natural selection

Overproduction- Produce more offspring than can survive.

Variation- Differences within species

Adaptation-Ones that are adapted survive and reproduce. Have a favorable trait.

Change over time- Individuals with the best traits will survive and pass on those traits causing a shift in the population to all with the favorable trait.

2. Describe what happens to a population over time as natural selection occurs.

Those with favorable traits survive and reproduce, spreading that trait.

3. Apply the 4 principles of natural selection and describe the population shift to explain how wolves got the ability to grow and shed a winter coat.

Overproduction- more wolves are born than survive.

Variation- Wolves had different fur thickness.

Adaptation- Those who had thick fur in winter survived.

Change over time- Those that survived were able to reproduce and the population will wolves with thick fur.

4. Define adaptation and then describe how a population gets an adaptation.

An adaptation is an inherited trait that increases an organism’s chance of survival. Can be attained through mutations.

5. What determines which adaptation a species will need and develop?

An environmental factor- predators, seasons, disasters

6. Snowy owls are beautiful white owls that live in the arctic. They are able to withstand the frigid temps of the arctic. They usually migrate south to southern Canada during the middle of the arctic winter, but soon return far north. Explain how the population would respond in the following scenarios:

a. The snowy owls usually return to the north after migrating, but a group of then do not return and stay farther south. They end up isolated from the others for several years in an area that has more forests throughout the year.

Those that did not return will develop into their own species.

b. The snowy owls environment is warming up very quickly and going from very frigid temperatures to very warm. This change is happening so quickly that the snowy owls are too visible to their prey since there is less snow. They have started having a hard time finding food and many are starving. The warmth has also messed up their migration/breeding patterns.

They will go extinct if there is not enough time to adapt.

c. The snowy owls environment has been warming slowly over the last 70 years. The forests do not stay as snow covered throughout the year. The owls have a harder not being seen by prey for a few months out of the year. There is a mutation that allows the owls feathers to change to brown during