natural selection Flashcards
main ideas put forward by darwin
- living organisms that reproduce sexually are different apperance wise
-organisms produce excess offspring
-organisms that inherit best features more likely to survive
-organisms that are trash die
natural selection
process of survivial of the fittest where fitness the ability of organism to survive and reproduce in its home
whats evolution
change in genetic makeup of generations of organisms as a result of natural selection
neo D on change of genetic material
states that change doesnr have to be bad and can be good. might mean less good at reproducing and surviving.
anatomical adaptations
form and structure of a organism
-thick layer of blubber on seals and whales
physiological adaptations
the way the body works and biochemical differences
-difference of diving and non diving mammals
behavioural adaptations
changes to programmed behaviour to make species survive better
-huddling when cold
benefits of successful adaptations
enables species to exploit every possible habitat and different niches within each habitat
how can change to species or new species be made
natural selection makes organisms adapt to give organisms advantage or some niche
-if conditions change those adaptations might not be useful or good and selection pressure changes
selection pressure
pressure by change in enviormnent or niche on one or whole organisms causing changes in population
industrial melanism
soot and smoke out of factories
moths with betularia melanin advantage so amount of light moths fell and darker ones increased
how did frequency of moth colour change
anti pollution legislation means selection pressure on light moths again
pale allele in population increased
selection pressure in mating
some animals have features that dont benefit their niche but helps mate quicker
directional selection
change in major phenotype to another because of change in enviorment.
one phenotype selected over other
gene pool
all of alleles of all the genes of a population
