2.2

• evolution

  is the change over time in the proportion of individuals in a population differing in one or more inherited traits
• genetic drift

  is a chance event that causes unpredictable fluctuations in allele frequencies from one generation to the next
• population bottleneck

  occur when a population size is randomly reduced for at least one generation, so lowering the range of alleles upon which any subsequent selection pressure may then act
• founder effect

  occurs through the isolation of a few random members of a larger generation, so the gene pool of the new population, is not representative of the original gene pool
• sexual dimorphism

  the appearance and behaviour of males and females is different
• sexual selection

  a non-random process involving the selection of alleles that increases the individuals chances of mating and producing offspring
• male-male rivalry

  increases a males access to females through successful conflict with other competing males, using things like large size and weaponry
• female choice

  involves a female assessing the fitness of a male through the observation of honest signals
• hardy weinburg principle

  in the absence of evolutionary influences, allele and genotype frequencies in a population will remain constant over generations
• fitness

  an indication of an individuals ability to be successful at surviving and reproducing
• absolute fitness

  the ratio between the frequency of individuals of a particular genotype after selection, to those before selection
• relative fitness

  ratio of the number of surviving offspring per individual of a particular genotype to the number of surviving offspring per individual of the most successful genotype
• co-evolution

  the process in which two or more species evolve in response to selection pressures imposed by each other
• symbiosis

  co-evolved intimate relationships between members of two different species
• red queen hypothesis

  in a co-evolutionary relationship the change in traits in one species acts as a selection pressure on the other species, therefore, the species in these relationships much adapt to avoid extinction