Quiz 12 Flashcards
What is Speciation?
Evolution of one or more species from a parent species.
What is the Biological Species Concept?
A species is a group of actually/potentially interbreeding populations that is reproductively isolated from other such group.
What are the two steps of Speciation?
Extrinsic and Intrinsic Isolation
Define Extrinsic Isolation
Something happens to stop gene flow between 2 populations of the same species.
What is Intrinsic Isolation?
Over time, the 2 isolated populations evolve differently from each other to the point that they could no longer interbreed should the extrinsic barrier break down.
What does Extrinsic Isolation prevent?
Interbreeding
What does Intrinsic Isolation remove?
Potential for interbreeding
What are the Intrinsic Isolation Mechanisms?
Pre-zygotic Mechanisms and Post-zygotes Mechanisms
What does Pre-zygotes Mechanism prevent?
Fertalization
What are the five pre-zygotic mechanisms?
Mechanical, Temperate, Habitat, Behavioral, and Gametic
Define Mechanical Mechanisms
Physical difference in reproductive structures. Common in Anthropods & Flowering Plants
Define Temporal Mechanisms
Differences in the timing of reproduction
Define Habitat Mechanisms
differences in reproduction habitats
What is an example of Habitat Mechanisms?
Salmon: Spawning in pleasant point in WA. In the river, the females are bigger while the males are smalled. In the lake, the males are bigger and the females are smaller.
Define Behavioral Mechanisms
differences in reproductive behavior
What is an example of behavioral mechanisms?
Birds have differences in courtship behaviors. Fireflies have different flight patterns/altitudes and flashing patterns.
Define Gametic Mechanisms
Changes in surface proteins on the eggs & sperm
When/what does Post-zygotic Mechanisms occur/do?
After fertilization - prevents viability
What are the two types of Extrinsic Isolation?
Allopatric Speciation and Sympathetic Speciation
Define Allopatric Speciation
Some physical barrier that separates the populations and blocks gene flow
What are the two ways Allopatric Speciation occurs?
Vicariance (physical barrier “arises” (geological)) and through Dispersal to Unoccupied Habitats
Define Sympathetic Speciation
Gene flow is halted between two segments of the same population
What are the two ways Sympathetic Speciation occurs?
Disruptive Selections and Polyploidy
Where is Disruptive Selection common in?
Phytophageous Insects. They feed and breed on one species of plants