Friday, August 2, 13 AWS
Evolution and Biodiversity
Friday, August 2, 13
Evolution Term Review • natural selection - inherited traits that enhance survival and reproduction are passed on more often, changing the population over time • adaptation - traits that improve an individual’s chances of surviving to reproduce
Friday, August 2, 13
The Biodiversity Connection • Natural selection can increase or decrease biodiversity. • When natural selection favors multiple variations within a species, biodiversity increases. • Natural selection can influence 1.) diversity within a species and 2.) diversity of species.
Friday, August 2, 13
Evolution Influences Biodiversity • 1. Diversity within a species (genetic diversity). • Example: rock pocket mouse - the diverse environmental conditions (dark and light backgrounds) favors a diverse population (dark and light mice) Friday, August 2, 13
Evolution Influences Biodiversity • 2. Diversity of species (species diversity) • Example: Darwin’s finches different food sources on each of the island favored different beak shapes; over time, this finch population evolved into many different species who share a common ancestor Friday, August 2, 13
Types of Speciation •
Allopatric Speciation - different place
•
Occurs when: geographic isolation between members of a population results in a new species
•
Example: Galapagos finches
•
Sympatric Speciation - “same place”
•
Occurs when: reproductive isolation between members of a population results in a new species
•
Example: cichlid fish (for more information, see “Ciclid Fish” in the “Ecosystem Diversity” playlist)
Friday, August 2, 13
Friday, August 2, 13
Evolution Term Review • natural selection - inherited traits that enhance survival and reproduction are passed on more often, changing the population over time • adaptation - traits that improve an individual’s chances of surviving to reproduce
Friday, August 2, 13
The Biodiversity Connection • Natural selection can increase or decrease biodiversity. • When natural selection favors multiple variations within a species, biodiversity increases. • Natural selection can influence 1.) diversity within a species and 2.) diversity of species.
Friday, August 2, 13
Evolution Influences Biodiversity • 1. Diversity within a species (genetic diversity). • Example: rock pocket mouse - the diverse environmental conditions (dark and light backgrounds) favors a diverse population (dark and light mice) Friday, August 2, 13
Evolution Influences Biodiversity • 2. Diversity of species (species diversity) • Example: Darwin’s finches different food sources on each of the island favored different beak shapes; over time, this finch population evolved into many different species who share a common ancestor Friday, August 2, 13
Types of Speciation •
Allopatric Speciation - different place
•
Occurs when: geographic isolation between members of a population results in a new species
•
Example: Galapagos finches
•
Sympatric Speciation - “same place”
•
Occurs when: reproductive isolation between members of a population results in a new species
•
Example: cichlid fish (for more information, see “Ciclid Fish” in the “Ecosystem Diversity” playlist)
Friday, August 2, 13
