evolution 1.7 Flashcards
what is evolution
the result of changes of an organism over generations due to genomic variations
what is natural selection
the non random increase in frequency of DNA thet increase the chances of survival and the non random reduction of delerious sequences
changes in phenotype frequency come as a result of … selection
stabilising
directional
disruptive
what happens in stabalising selection
an average phenotype is selected for and extremes of phenotypes are selected against
describe directional selection
one extreme of the phenotype range is selected for
describe disruptive selection
two or more phenotypes are selected for
which type of cell is natural selection more rapid in and why
prokaryotes
can exchange genetic info horizontally
whats horizontal gene transfer
where genes are transferred between induviduals in the same generation
whats verticle gene transfer
where genes are transferred from parents to offspring as a result of sexual or asexual reproduction
what is a species
a gropu of organisms capable of interbreeding and producing fertile offspring and which does not normally breed with other groups
whats speciation
the generation of new biological species by evolution
stages if speciation
isolation
mutation
selection
speciation
what do isolation barriers do
prevent gene flow between sub populations in speciation
describe geographical barriers
prevent gene flow to lead to allopatric speciation
what do behavioral and ecocogical barriers do
prevent gene flow leading to sympatric speciation
