1. Notes: Speciation (pg 12)
• What is a species?

2. 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

3. 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

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

5. Types of Speciation
1. 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.

6. 2. Sympatric speciation: occurs without
geographic barriers

7. 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

8. 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

9. 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

10. 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.

11. 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