Theories of Evolution Lesson Objectives 1 Define Evolution

Theories of Evolution

Lesson Objectives 1. Define Evolution 2. Understand the process of evolution including: Sexual Reproduction Mutation Adaptation Natural Selection

Definition of Evolution? . . .

Jean Baptiste’s first theory…. He acknowledged that animals needed to adapt to their environment… But how did they do this…. . ? He stated… “Throughout it’s life an organism would come across situations where it may have needed to change to survive. ”

He thought that…. . So…. . Is this the case?

Mutation Term used to describe when there is a change in the gene. What would cause mutation?

Types of Mutation 1. Morphological mutations 2. Lethal mutations 3. Biochemical mutations 4. Loss of function 5. Gain of function

Effects of Mutation Morphological Affected the visible properties of an organism Lethal Can affect the survival of an organism Biochemical Affects how the cell works Loss of function e. g. blindness Gain of function The mutation could help an animal adapt to the environment, e. g. camouflage

Why are mutations important to Evolution? . . Less favourable mutations are lost through natural selection. Desired mutations will often accumulate through generations.

When a Mutation becomes an Adaptation Mutations are a ‘mistake’ in the copying of DNA when a cell replicates. If a mutation favours an animal, that animal will survive to reproduce and pass those genes on (Natural Selection). Eventually, if those animals carry on being more successful, over years that mutation will become ‘normal’ within the species. It is then classed as an adaptation.

Some examples of adaptation… Shape of a birds beak Number of digits Thickness of fur Shape/size of nose ears

Peppered Moths https: //askabiologist. asu. edu/sites/default/files/Pepper. Moth /pepper-moths. swf

Task: Start at question 1 – see how far you get in 10 minutes. After 10 minutes move to the back page and complete.

Chameleon

Camel

Giraffes