Chp.16 - Evolution of Populations

Chp.16 - Evolution of Populations

16-1 Genes and Variation16-2 Evolution as Genetic Change16-3 The Process of Speciation

By: Ramtin N. & Dassel Pak

16-1 Genes and Variation16-2 Evolution as Genetic Change16-3 The Process of Speciation

By: Ramtin N. & Dassel Pak

Darwin’s IdeasDarwin’s Ideas

• 1910 Biologists began to realize that genes carry information that determines traits

• Now biologists are able to explain how evolution takes place

• 1910 Biologists began to realize that genes carry information that determines traits

• Now biologists are able to explain how evolution takes place

Dassel

Gene Pool & Relative Frequency

Gene Pool & Relative Frequency

• Gene Pool - Combined genetic information of all the members of a particular population

• Relative Frequency - Number of times that an allele occurs in a gene pool other than others

• Gene Pool - Combined genetic information of all the members of a particular population

• Relative Frequency - Number of times that an allele occurs in a gene pool other than others

Ramtin

Sources of Genetic Variation

Sources of Genetic Variation

• Mutations• Gene Shuffling

• Mutations• Gene Shuffling

Ramtin

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Single-Gene and Polygenic Traits

Single-Gene and Polygenic Traits

• Single-Gene Trait• Polygenic Trait

• Single-Gene Trait• Polygenic Trait

Dassel

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Natural SelectionNatural Selection

• Natural Selection on single-gene traits can lead to changes in allele frequencies and thus to evolution

• Directional Selection • Stabilizing Selection• Disruptive Selection

• Natural Selection on single-gene traits can lead to changes in allele frequencies and thus to evolution

• Directional Selection • Stabilizing Selection• Disruptive Selection

Dassel

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Genetic Drift & Genetic Equilibrium

Genetic Drift & Genetic Equilibrium

• Genetic Drift• Genetic Equilibrium - Random mating - Large population - No movement into or out of the

population - No mutations - No Natural Selection

• Genetic Drift• Genetic Equilibrium - Random mating - Large population - No movement into or out of the

population - No mutations - No Natural Selection

Ramtin

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Reproductive IsolationReproductive Isolation

• Reproductive Isolation - when the members of two populations cannot interbreed and produce fertile offspring

• Behavioral Isolation • Geographic Isolation • Temporal Isolation

• Reproductive Isolation - when the members of two populations cannot interbreed and produce fertile offspring

• Behavioral Isolation • Geographic Isolation • Temporal Isolation

Dassel

Speciation Speciation

• Founders arrive • Separation of populations• Changes in gene pool• Reproductive Isolation• Ecological Competition • Continued Evolution

• Founders arrive • Separation of populations• Changes in gene pool• Reproductive Isolation• Ecological Competition • Continued Evolution

Ramtin

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.