definitions Flashcards
gene pool
all the alleles of all the genes in a population
allele frequency
how often different alleles occur in the gene pool of a population
phenotype frequency
total individuals with phenotype
over
total individuals in population
x100
what does hardy Weinberg predict?
allele frequency in a population won’t change between from one generation to the next
assumptions of hardy Weinberg
conditions needed to correctly apply:
- large population
- random mating
- no migration/mutation/selection
- diploid
- no overlap between generations
if frequencies do change
- one of these present
HW for allele frequency
p + q = 1
p = dominant allele
q = recessive allele
HW for genotype frequency
p2 + q2 +2pq = 1
p2 = homozygous dominant
q2 = heterozygous genotype
2qp = homozygous recessive
population
all organisms of one species in a habitat at a given time
community
populations of different societies in a habitat
ecosystem
community + abiotic factors in an area
niche
role a species plays in its habitat
involves biotic and abiotic interactions
each species has different niche
- otherwise would compete, until only one species left
speculation
development of a new species from an existing one
- when populations become reproductively isolated
- changes in allele frequency = changes in phenotype (separate)
- allopatric (geographical isolation)
- sympatric (reproductively isolated without isolation)
natural selection
change in allele frequency overtime
- organisms become better adapted
stabilising, directional or disruptive
= increase in beneficial allele
evolution
change in allele frequency overtime
occurs due to nature selection or genetic drift
= great diversity of organisms
populations divided and evolved into separate species
