Exam 4 Flashcards
(33 cards)
What is population density
Number of organisms per area
Equation is # of organisms/area
What are the population distributions?
Clump
Uniform
Random
What is logistic growth and where does it increase and level off?
Carrying capacity is the limit for population (organisms die after curve drops) levels off when resources become limited.
Increases when there few individuals and ample resources available
What is density independent inhibition?
Example?
Flies die from something other than population density
What is density dependent?
Flies in a jar (too many flies and not enough resources)
What are the different evidences of evolution?
Fossil record
Comparative anatomy-homologous organs (similarities in bone structure)
Comparative embryology-embryos look alike
Biogeography-geography of species
Molecular biology-we are all formed of molecules
What is Micro evolution?
Evolution through a short period of time
What is genetic drift?
Change in genotypes of a small population owing to the chance disappearance of particular genes as individuals die or don’t reproduce
Gene flow
Migration so genotypes spread
What is Non random mating
Occurs when the probability that two individuals in a population will mate is not the same for all possible pairs of individuals.
What is the Hardy-Weinberg law?
P^2+2PQ+Q^2=1 P+q=1 P^2=dominant Q^2=Recessive PQ=Heterozygous Dominant
Examples of artificial examples
Dog breeds
Horses cats cattle and plants
What is stabilizing natural selection?
That intermediate trait is favored
What is directional selection?
One extreme favored at a time
Ex) peppered moth or resistant roach
What is disruptive or diversifying selection?
Both extremes favored at the same time
What does the Hardy-Weinber law assume?
1) large portions
2) no natural selection
3) no mutation
4) no gene flow (migration)
5) random mating
6) no genetic drift
What are prezygotic reproductive barriers?
Temporal isolation Habitat Mechanical Behavioral Gametic
What are postzygotic reproductive barriers?
Hybrid Inviability
Hybrid sterility
Hybrid breakdown
Examples of hybrids
Mule Liger Leo pon-male leopard Lama- male camel Zorse- make zebra Wholphin- make killer whale
Types of speciation
Allopatric-due to geography
Sympatric-due to complete nondisjunction no geographical movement
Adaptive radiation-organisms diversify from ancestral species because of new resources or challenges
What is polyploid
More chromosomes than other individuals and cannot mate and creates new species
What are gradualist and punctuated theories of evolution
Gradualist evolution happens through a long period of time
Punctuated evolution happens with a shorter time
What is mimicry-object
Prey looks like an object
What is Batesian mimicry?
Something harmless looks harmful like the moth looking like a wasp
