Notes: Speciation (pg 12)

• What is a species?

Notes: Speciation (pg 12)

• What is a species?• Biological species concept = a species is a

group of organisms that can interbreed and produce fertile offspring

Notes: Speciation (pg 12)

• What is a species?• Biological species concept = a species is a

group of organisms that can interbreed and produce fertile offspring

• Speciation = the origin of new species in evolution

Types of Speciation

1. Allopatric speciation: occurs when a population becomes segregated by a geographic barrier (mountain, river, etc.)

Types of Speciation1. Allopatric speciation: occurs when a population

becomes segregated by a geographic barrier (mountain, river, etc.)

Example: Squirrels in Arizona: were one species until the grand canyon formed. Squirrels on the south rim were isolated from those on the north rim. Each population changed due to genetic drift and natural selection. Now if brought together they are not able to interbreed.

2. Sympatric speciation: occurs without geographic barriers

2. Sympatric speciation: occurs without geographic barriers

• Habitat isolation: species live in the same area, but in different habitats so they rarely encounter one another

2. Sympatric speciation: occurs without geographic barriers

• Habitat isolation: species live in the same area, but in different habitats so they rarely encounter one another

• Behavioral isolation: species have different signals to attract mates

2. Sympatric speciation: occurs without geographic barriers

• Habitat isolation: species live in the same area, but in different habitats so they rarely encounter one another

• Behavioral isolation: species have different signals to attract mates

• Temporal isolation: species breed during different times of day or different seasons

2. Sympatric speciation: occurs without geographic barriers

• Habitat isolation: species live in the same area, but in different habitats so they rarely encounter one another

• Behavioral isolation: species have different signals to attract mates

• Temporal isolation: species breed during different times of day or different seasons

• Polyploidy: Due to a mistake during meiosis, an individual ends up with more than 2 copies of each chromosome, so it can’t mate with parent population. Common in plants.

Speciation Skits

Working in groups, you will make up a skit about one type of speciation (choose allopatric, habitat isolation, behavioral isolation, temporal isolation, or polyploidy)

• Skits should be 1-2 minutes long • Must have a written script. Write it on page 13• All group members must have a speaking role