Unit 2 Flashcards
What is homologous structures
Structures in organisms that share the same basic form
Similar in structure but not function
What is analogous structures
Similar in function but not in structure (not mentioned in bio)
What is vestigial structures
Structures that exist in organisms that have no apparent function at all and appear to be residual parts from a past common ancestor.
Structures that no longer have any purpose (ex the human tailbone)
What is speciation
The formation of 2 species from 1 original species.
What is a definition of a speices
The organisms can have viable offspring that can reproduce.
What is natural selection? What are the three principles of it?
The theory that the animals best suited to the environment will survive and reproduce
1. Most characteristics of organisms are inherited
2. More offspring are than can survive which leads to competition
3. Offspring vary regarding characteristics
Survival of the Fittest
What is a prezygotic barrier?
Barrier before sex. A mechanism that stops reproduction from taking place ex: Mate different times of year
What is a postzyotic barrier
Barrier after sex. Occurs after zygote formation ex: offspring is infertile
What is temporal isolation
differences in breeding schedules
what is sympatric speciation?
when populations of a species that share the same habitat become reproductively isolated from each other
what is allopatric speciation
when organisms are seperated by a physical barrier
What are the 6 pieces of Evidence of Evolution? Get as many as you can!
- Fossils
- Homologous Structures (structures that share basic form)
- Vestigial Structures (Structures that have no apparent function)
- Embryology
- Biogeography (distribution of animals follows the moving of plate tectonics)
- Convergence in form of organisms living in similar environments
What is habitat isolation?
When populations of a species move or are moved to a new habitat and take up residence in a place that no longer overlaps with the other populations of the same species. Also if there is a river or physical barrier in between.
What is Behavioral Isolation?
The presence or absence of a specific behavior prevents reproduction from taking place. Ex) mating calls for birds
What is Gametic Barrier?
When differences in gamete cells prevent fertilization from taking place. OR reproductive structures don’t fit.
