1. Evolution and Speciation
Ms. Day
Honors Biology
LECTURE #31

2. REVIEW: What is a Population?
Populations evolve over MANY generations, individuals do NOT evolve
Populations are groups of interbreeding individuals that live in the same place at the same time
Individuals in a population compete for resources with each other

3. Types of Evolution 1. Convergent evolution
organisms that are NOT closely related independently evolve similar traits as a result of having to adapt to similar environments.
Ex: Dolphins & fishes
Ex: Wings of bees & bats

4. 2. Divergent evolution 2 species gradually become different
Often occurs when closely related species diversify to new habitats
responsible for the creation of the current diversity of life on earth from the first living cells
Ex: Darwin’s finches
Type: Adaptive radiation

5. Adaptive Radiation Example of divergent evolution
Adapted species from a common ancestor
Occurs when they are introduced to new environmental opportunities
Typically occurs when a few organisms make their way to new, usually distant areas OR mass extinctions occur, which open up new habitats to occupy

7. 3. Coevolution 2 organisms evolve (change) in response to each other
Insects and the flowers (ex: orchids) they pollinate

8. 4. Parallel Evolution
2 species evolve independently of each other, maintaining similar traits
Usually occurs between unrelated species that do NOT occupy the same or similar habitats
Ex: Eutherians (placental) and Marsupial mammals

9. What is a Species?
Species is a Latin word meaning “kind” or “appearance”
A population of organisms that produces viable fertile offspring in nature.
VIABLE = LIVING
FERTILE= CAN REPRODUCE
They can NOT interbreed with other populations

10. Similarity between different species  different behaviors and songs
Diversity within a species  defined by capacity to interbreed.

11. Speciation Speciation = the origin of new species
How is a species and a population different?
A population is a group of the same species LIVING IN THE SAME PLACE AT THE SAME TIME
A species is a group of organisms that can interbreed and produce offspring that lives and can reproduce too