Evolution Flashcards
what is a scientific theory
is a well sustained explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through experiment
what is evolution
the genetic changes in a population over a very long period of time
what are five key mechanisms for evolution
mutations, sexual reproduction, gene flow, genetic drift and natural selection
what are mutations relating to the mechanisms for evolution
new alleles rise, increase in genetic variation if mutation is advantageous so harmful mutation aren’t often passed on
what are sexual reproduction relating to the mechanisms for evolution
Meiosis creates new combination of alleles, non random mating and increases variation in population
what are gene flows relating to the mechanisms for evolution
movement of genetic info from one population to another of the same species, increases genetic variation
what are genetic drift relating to the mechanisms for evolution
random change in an allele frequency in a population, survival is by chance
what are natural selection relating to the mechanisms for evolution
is the survival of the fittest, relies on variation in the gene pool of population and a selection pressure action on it
what does variation mean
individuals have the same number of genes but different alleles
define gene pool
all the different types of genes in a population
what are the types of selection pressure
predators, availability of resources, nutrient supply, disease, accumulation of waste, phenomena, abiotic factors and weather conditions
what are the steps of natural selection
Variation natural exist in population, the alleles in some organisms are expressed in favourable traits and better adapted, those with the favourable traits are more likely to survive and reproduce and over time the favourable traits are pass on their alleles and become more numerous
define adaptions
characteristics determined by genes that make an individual suited to its environment and way of life which may be passed down
define species
a population that can breed and produce fertile offspring
define biological fitness
the ability of a particular genotype to contribute to subsequent generations
what is directional selection
the process of natural selection favouring a particular phenotype - camouflage and antibiotic resistance
what is artificial selection
intentional breeding of plants and animals to produce desirable traits - aesthetics, increase in food production, improve flavour and drought resistance
