chapter 24 Flashcards
Process by which one species splits into 2 or more species
ecological species concept
views a species based on its ecological niche
biological species concept and its limit
Defines a species as 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
limits include the grolar bears species can mate? but are still different
morphological species concept
characterization f a species based on bod type
phylogenetic species concept
smallest group of individuals that share a common ancestor
List the three steps of speciation
Isolation of the gene pools of 2 or more populations of a species
Evolutionary change in the gene pools of 1 or both of the isolated populations
Reproductive isolation of 2 or more populations preventing gene flow
Distinguish between prezygotic and postzygotic isolating mechanisms.
Prezygotic (pre-fertilization) Barrier
Preventing an attempted mating
Or, fertilization is prevented if mating is attempted
Postzygotic (post-fertilization) Barrier
Mating does occur but offspring either do not survive or are sterile
Describe 5 prezygotic barriers and give an example for each.
Habitat Isolation - garter snakes one in water other on land rarely interact
temporal- mating times eastern and western spotted skunks
behavioral - boobie dance
mechanical- snail spiral cant mate...
gametic - sea urchins varying gametes making diffrent fusion hard
Explain and give examples of reduced hybrid viability, fertility, and hybrid breakdown
hybrids are frail slamanders
hybrids are sterile donkeys
hybrids can mate second gen but the third are crap
Distinguish between allopatric and sympatric speciation.examples
In allopatric speciation, a population is physically isolated into subpopulations – habitat isolation. mosquito fish for example
Explain how polyploidy can cause reproductive isolation
polyploudy individuals can not produce offspring because of problems in meiosis
Distinguish between an autopolyploid and an allopolyploid species and describe examples.
An autopolyploid individual is one that has more than 2 chromosome sets that are all from a single species.
alloploid has the correct number of chromosomes
Describe how cichlid fishes may have speciated in sympatry in Lake Victoria.
breeding color was a major barrier that effected breeding patterns so two distinct species evoloved in one lake
Explain how North American apple maggot flies exemplify sympatric speciation
they mate with like organsims mostly
Explain the gradualism model and the punctuated equilibrium model
Punctuated equilibrium statis followed by rapid change
while gradualism is slow changes
Give examples that illustrate the amount of genetic change necessary to give rise to a new species.
japanese land snail only needed one gene to change
or dune sunflower only needed a hybrid change
large scale changes creating new species