Download Chapter 24 - Origin of Species

Chapter 24 - Origin of Species
Macroevolution
Macroevolution refers to any evolutionary change at or above the species level.
What is speciation?
What prevents cross-species mating in the flycatcher?
What would happen if two birds from different species did mate?
A. What is a Species?
- a group of actually or potentially interbreeding populations
- a hybrid is an offspring of two distinct species, example: Liger, Mule
Several similar species can live in the same area, but interbreeding is not
advantageous. Hybrids are often infertile. There are mechanisms that prevent this
type of mating.
B. Reproductive Isolating Mechanisms
Prezygotic ("before formation of a zygote")
a. Habitat isolation b. Temporal isolation c. Behavioral isolation d. Mechanical isolation e. Gamete isolation (incompatibility) Postzygotic ("after formation of a zygote")
a. Zygote mortality b. Hybrid sterility c. F2 fitness C. Modes of Speciation
1. Allopatric speciation:
2. Sympatric speciation:
3. Divergent Speciation occurs when species form, existing at the same time, likely in
different locations
4. Phyletic Speciation occurs when a new species completely replaces an older
species.
D. Adaptive Radiation
1. Adaptive radiation is a rapid development from a single ancestral species of many
new species.
Example:
WORD ATTACK!.........Compare and Contrast the terms in each set.
Prepare an illustration to share with the class for the set you are assigned to.
1. Phyletic Speciation / Divergent Speciation
2. Zygote mortality / Hybrid Sterility
3. Behavioral / Temporal / Habitat / Geographic Isolation
4. Adaptive Radiation / Polymorphism / Dimorphism
5. Species / Subspecies / Hybrid
6. Premating Isolation / Post-mating Isolation
7. Allopatric / Sympatric Speciation
8. Disruptive / Directional / Stabilizing Selection
9. Sexual Selection / Nonrandom Mating / Assortative Mating
10. Gene Pool / Gene Flow / Genetic Drift
11. Microevolution / Macroevolution
12. Founder Effect / Bottleneck Effect