Population Evolution and Speciation Flashcards
What is Anagenesis?
One species is transformed into another as it continues to adapt to a changing environment
New species evolve from older ones through 2 ways:
- Anagenesis
2. Cladogenesis
What is Cladogenesis?
One species is transformed into 2 or more new species over time
What counteracts cladogenesis?
Gene Flow
What is Allopatric Speciation?
Geographic barriers separate populations into different ranges. These barriers prevent organisms from crossing without great difficulty.
When a small population is separated by Allopatric Speciation, this causes the ______ effect to take place
The Founder Effect
What is the founder effect?
A small population is broken away from the main population by Allopatric Speciation and is introduced into a different environment then they were previously in. This population will then grow and go on its own evolutionary sequence.
What is Sympatric Speciation?
The formation of new species within the range of the parent species
What is Reproductive Isolation?
2 different populations of the same species don’t breed for a period of time, if they try to breed after this period of time, you will only get a hybrid, not one of the parent species.
What is geographic seperation?
Organisms live in different places so they never meet to breed. (Same thing as Allopatric Speciation!!!)
What are Temporal Mechanisms?
Organisms are active at different times of the day or year so never come in contact.
What are behavioral mechanisms?
Sexual attraction is lacking between members of the same species
What are mechanical mechanisms?
Different genital morphology prevents copulation
What are Chemical Mechanisms?
Male and Female gametes are incompatible
What is Hybrid inviability?
Hybrid zygotes cannot develop due to genetic difficulties
