biology. lawrence 1310 ex4
Terms
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- the main point in Fitness
- is that it's not that survival alone is so important. It's that it's able to survive and produce offspring
- gene frequency
- frequency of occurence of proportions of different alleles of a particular gene in a given population
- genotypic frequency
- proportion or frequency of any particular genotype among individuals
-
p^2=
2pq=
q^2=
-
=BB
=Bb
=bb - HW equation
-
calculates allele and genotype frequenciesin a population
-estimate frequencies of disease-causing alleles. - gene/genotypic frequency is
- change due to natural selection, genetic drift, and gene flow
- genetic drift
- change in gene pool of a population due to chance; most pronounced in small populations
- bottle neck
-
drastic reduction in population's size due to catastrophy.
-a rare allele is not so rare anymore. (instead of being 1/400 its now 1/20) - founder effect
- occurs when a few individuals become isolated from a larger populations, with the result that the composition of the new population's gene pool is not reflective of that original population.
- mutation
- change in nucleotide sequence of an organism's dna
- natural selection
- process in which organisms with certain inherited characteristics are more likely to survive and reproduce than are organisms with other characteristics
- species
- group whose members possess similar anatomical characteristics and have ability to interbreedand produce viable, fertile offspring
- Speciation
- emergence of a new species
- non-interbreeding population
- deme (in allopatric)
- Modes of Speciation
- allopatric, sympatric, parapatric
- allopatric
- species are seperated by a barrier
- sympatric
- (mostly in plants) formation of new species in populations that live in the same geographic area; vent occurs that isolates members
- parapatric
- individuals in a population adapt to some environmental change then develop reproductive isolation.(individual from a population become reproductive isolation within population)
- Mechanisms of Reproductive isolation
- prezygotic and post-zygotic
- prezygotic
- mechanism that prevents zygote from forming
- post-zygotic
- egg has been fertilized
- types of prezygotic mechanisms
- spatial, temporal, biochemical,mechanical, behavioral,character displcement
- spatial
- in different places
- temporal
- mate at different times of the year
- biochemical
- compatible receptors
- mechanical
- physical differences prevent intercourse
- behavioral
- little or no sexual attraction (rituals, signals, songs, etc)
- character displacement
- ex: east and west narrow mouth toad
- post-zygotic mechanisms
- hybrid inviabilty, hybrid sterility, hybrid breakdown
- hybrid inviabilty
- most hybrids dont survive (reduced hybrid viabilty)
- hybrid sterility
- hybrid offspring reach maturity (reduced hybrid fertility)
- hybrid breakdown
- first generation of hybrid offspring are viable and fertile, but wheen they mate with one another or with either parent species, the offspring are feeble or sterile
- oro
- discovered amino acids could be made from hydrogen cyanide (HCN)and ammonia in an aqueous solution