Unit 2 KA2 Flashcards
absolute fitness
the ratio between the number of individuals of a particuar genotype after selection to those before selection
bottleneck effect
a sharp reduction in the size of a population due to enviromental events or human activities
co-evolution
the process by which 2 or more species evolve in response to selection pressures imposed by eachother
commensalism
symbiosis in which only one of the species benefits (+/0)
evolution
the chang eover time in the proportion of individuals in a population differing in one or more inherited traits
female choice
a mechanism of sexual selection in which females assess ales’ fitness and choose the ales with which they will mate
fitness
a measure of the tendency of some organisms to produce more surviving than competing members of the same species
founder effects
when the gene pool of a new population is not representative of that in the original gene pool,
occurs through isolation of a few members of a population from a larger popuation
gene pool
the total number of genes and their alleles in a population of one species
genetic drift
the random increase or decrease in the fequency of DNA sequences from one generation
Hardy-Weinberg (HW) principle
in the absence of evolutionary influences, allele and genotype frequencies in a population will remain constant over generatation
Male-male rivalry
a mechanism of sexual selection in which maless fight for females
often use weponary such as antlers or tusks
mutualism
both species in the interaction are interdependent on eachother for resources or other services
both gain from relationship (+/+)
natural selection
non-random increase in the prequency of advantageous alleles and the non-random decrease in the frequency of deleterious alleles
Parasitism
symbiosis in which the parasite benefits in terms of energy or nutrients and the host is harmed as the result of the loss of resources
(+/-)
Red Queen Hypothesis
in a co-evolutionary relationship, change in traits of one species can act as a selection pressure on the other species
Relative Fitness
The ratio of the number of offspring that survive per induvidual to the number of surviving offspring per induvidual of the most successful geneotype
Selection pressures
the enviromental factors that influence which individuals in a population pass on their alleles
Sexual dimorphism
females are generally inconspicuous, males usually have conspicuous markings, structures or behaviours
Sexual selection
the non-random process involving the selection of alleles that increase the individuals chances of mating and producing offspring
Symbiosis
co-evolved initimate relationships between members of 2 different species
What may sexual selection lead to?
Sexual dimorphism
When does genetic drift occur
when chance events occur and cause unpredictable fluctuations in allele frequency
