bio final ch24.txt
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What is speciation?
The process by which one species splits into two or more species.
What is the biological species concept?
A species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable, fertile offspring with members of other such groups.
What is reprodictive isolation?
The existence of biological factors (barriers) that impede members of two species from interbreeding and producing viable, fertile offspring.
What are hybrids?
Offspring that result from an interspecific mating.
What are the prezygotic barriers ("before the zygote")?
- Prezygotic barriers block fertilization from occurring. Barriers are:
- 1. Habitat Isolation
- 2. Temporal Isolation3. Behavorial Isolation
- AFTER MATING ATTEMPT
- 4. Mechanical Isolation
- 5. Gametic Isolation
What are the postzygotic barriers ("after the zygote")?
- Postzygotic barriers prevent a hybrid zygote from developing into a viable, fertile adult. Barriers are:
- 1. Reduced Hybrid Viability
- 2. Reduced Hybrid Fertitlity
- 3. Hybrid Breakdown
What is the morphological species concept?
The morphological species concept characterizes a species by body shape and other structural features.
What is the ecological species concept?
The ecological species concept views a species in terms of its ecological niche, the sum of how member of the species interact with the nonliving and living parts of their environment.
What is the phylogenetic species concept?
The phylogenetic species concept defines a species as the smallest group of individuals that share a common ancestor, forming one branch on the tree of life.
What is allopatric speciation?
In allopatric speciation (latin for "other country"), gene flow is interrupted when a population is divided into geographically isolated subpopulations. Remember the fish in different ponds graphic.
What is sympatric speciation?
In sympatric speciation (latin in "same country"), speciation occurs in populations that live in the same geographic area. Remember the fish in different ponds graphic.
A species may originate from an accident during cell division that results in extra sets of chromosomes.
An autopolyploid (from the Greek autos, self) is anindividual that has more than two chromososme sets that are al derived from a single species.
What is allopolyploidy?
In subsequent generations, various mechanisms can change a sterile hybrid into a fertile polyploid.
What basic ways do species respond to natural selection?
- - Extinction
- - Speciation
- 1. Anagenesis
- 2. Cladogenesis
What are the two rates of evolutionary change?
- Gradualism - change of time
- Puntuated Equilibrium - change at a specific point in time
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