Evolution Flashcards
Name non-random processes of evolution
natural selection
sexual selection
random processes
genetic drift
What is natural selection
MUTATIONS
-harmful or neutral, creates novel alleles which result in VARIATION
What happens as a result natural selection
population produces more individuals than environment can support
better alleles = higher survival rate
What is sexual selection
selection of alleles that increases mating chances
- SEXUAL DIMORPHISM
examples of sexual dimorphism
males are bigger and have armour
male to male rivalry
female choice
What happens as a result of genetic drift and where is it most likely to occur
gene pool altered as alleles are over/under represented
More likely in small populations
What is genetic drift
random fluctuations in allele frequency
What is the bottleneck effect
population size reduced for at least one generation ( natural disasters)WH
What is the founder effect
isolation of a few members of a population causing inbreeding
-new gene pool is not representative of original gene pool
Examples of BIOTIC selection pressures
competition
predation
disease
parasitism
Examples of ABIOTIC selection pressures
temperature
light intensity
humidity
pH
salinity (salt levels)
What is the Hardy Weinberg principle?
allele and genotype frequencies remain constant within generations with no evolutionary influences
What does the Hardy Weinberg principle assume?
random mating
large population size
no natural selection
no mutation
no gene flow
HW principle eq
P^2 + 2pq + Q^2 = 1
How to calculate absolute fitness
Frequency after selection / frequency before selection
1 = stable
<1 genotype decreasing
>1 genotype increasing
How to calculate relative fitness
particular / most successful
ratio of surviving offspring to surviving offspring w most successful genotype
What is co evolution
two or ore species evolve in response to selection pressures
describe mutual symbiosis
relationship of organisms are dependant on eachother for survival
describe commensal symbiosis
only 1 organism benefits
describe parasitic symbiosis
host is harmed while symbiote benefits
What is the red queen hypothesis
hosts have better defense mechanisms and have greater fitness
parasites overcome defences
host-parasite relationship becomes specific and parasites only infect 1 host
