Unit 1.3-1.4 Toth Science 10
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Define mutation
A permanent change in the genetic material of an organism; a source of new genetic variation.
What’s a selective advantage
a genetic advantage that improves an organism’s chance of survival, usually in a changing environment
What is natural selection
the process by which characteristics of a population change over many generations as organisms with heritable traits survive and reproduce
what do mutations provide
new alleles
do mutations happen spontaneously
yes
when di mutations happen
they occur spontaneously when DNA is copied before a cell divides
what other factors can cause mutations
UV radiation, mutagens etc
what is the effect of mutations in DNA
a cell may exhibit new characteristics
what are possible negative effects of mutations
can die, malfunction, multiply more than normal
what cases do mutations show
when the mutation occurs in a gamete, not a somatic cell
what’s a selective advantage
a genetic advantage that improves an organism’s chance of survival, usually in a changing enviorment
what does a selective advantage mean for a species
it helps the organism survive and reproduce, meaning that more organism’s in the species will have the mutation.
what is natural selection
The process by which organisms with traits better suited to their enviorment will survive to reporoduce and pass these traits on.
What is the prerequisite for natural selection
There must already be genetic diversity within the species.
what is adaptation
a strhctrular or behavioral process that helps an organism survive and reproduce in a particular enviorment
what is selective pressure
a factor in an organisms enviorment that may influence survival and reproduction. they favour some more than others
what are examples of selective pressures
predators, parasites, competition
define species
a population or group of populations in nature whose members can interbreed to produce fertile offspring that can also interbreed
define speciation
the formation of new species from existing species
what’s adaptive radiation
the diversification of a common ancestral species into a variety of differently adapted species
wyat are reasns for adaptive radiaton
mostly geographical barriers such as glacier, lava flow, fluctuation ocean levels, a few individuals finding new lnad
what is an effect of adaptive radiation
the gene pools of a split population become so distinct that the two groups are unable to interbreed even if brought back together
explain what happened galapagos ilsand wuth the finches
the ancestral finch population may have been blown off course during a tropical storm. the finches were the only land birds around, so they could move in. They were subjected to many selective pressures in different ecosystems, so the ancestral species divided into different populations with different adaptations for different uses.
what is extinction
when a species completely disappears off Earth