bio unit 1: natural selection

What is natural selection?

Phenomena where organisms with traits suited to their environment have greater chances of survival and reproducing.

What did Aristotle believe about the origin of species?

He believed all plants and animals existed on Earth since the beginning and none have changed.

What were Lamarck's and Darwin's theories on the origin of species?

Life has changed over time.

What was Lamarck's first law?

Law of Use and Disuse.

Body parts that are used more often are more developed.

What was Darwin's theory of Evolution?

Evolution happens because of natural selection.

What was Lamarck's second law?

Inheritance of Acquired Characteristics.

The more developed/underdeveloped traits are passed on.

What are the four key conditions for natural selection?

1. Struggle for survival

2. Inheritance variation

3. Variation of fitness

4. Lots of time

Describe the condition: struggle for survival

Competition between organisms to survive.

Limited food and resources in the environment, so not all animals can survive.

Describe the condition: inheritable variation

Organisms within a population exhibit differences due to variance in the genes.

Traits caused by differences in DNA can be passed onto the offspring.

Describe the condition: variation of fitness

Fitness = ability to produce offspring

Alive to have offspring → pass of genes

Describe the condition: Lots of time

Natural selection causes gradual changes in population

Results in all organisms acquiring the trait