March 23, 2017 Objective: Analyze and evaluate how natural selection produces change in populations, not individuals (TEKS 7C) WE WILL: Complete Isolation Notes YOU WILL: Isolation Activity

The Process of Speciation Isolation Notes

Vocabulary- Words to Know! Species – interbreeding populations of organisms that can produce fertile offspring Speciation – formation of a new species

Reproductive Isolation Reproductive Isolation – when members of two populations cannot interbreed and produce fertile offspring Horses and donkeys can mate and produce a mule. However, all mules are infertile females.

How do organisms become isolated? Behavioral isolation – when 2 populations are capable of interbreeding but have differences in courtship rituals or other reproductive strategies that involve behavior Blue footed boobies

How do organisms become isolated? (cont.) 2. Geographic isolation – when 2 populations are separated by geographic barriers such as rivers, mountains or bodies of water

How do organisms become isolated? (cont.) 3. Temporal Isolation- when 2 or more species reproduce at different times Different seasons or different times of the day. Example: 3 similar species of orchids live in the same rain forest. Each species has flowers that last only one day and must be pollinated (reproduce) on that day to produce seeds. Because the species bloom at different times of the year they cannot pollinate one another.

Speciation in Darwin’s Finches Darwin found over a dozen different species of finches on the Galapagos Islands that all evolved from a common ancestor How? Speciation in Galapagos finches by founding of a new population Geographical isolation Changes in the new populations gene pool Behavioral isolation and ecological competition Pg 496

PARTNER QUESTIONS What is Geographical Isolation? A newly formed lake divides a population of a beetle species into two groups. What other factors besides isolation might lead to the two groups becoming separate species?