Evolution Flashcards
(20 cards)
Evolution is…
genetic variation in a line of descent over a certain period
the change in the characteristics of a species leading to genetic variation over several generations and a certain period.
Relies on the process of natural selection.
How does inheritance play a role in evolution
evolution is seen as a change in inherited characteristics
inherited genes = determines characteristics
Other than natural selection was can cause genetic diversity?
mutations - changes phenotypes in populations
genetic evidence shows…
humans share common ancestors with different life forms on earth
processes that promote evolution (3)
natural selection
adaptation
genetic drift
Speciation:
when a population cannot interbreed successfully due to acquisition of many genetic differences, 2 new species are made
inability to evolve leads to…
extinction
Natural selection was proposed by … and it means …
Charles Darwin
the ability to survive and reproduce based on advantageous traits that they pass on to offspring.
(dark peppered moths during industrial evolution)
Genetic drift// allelic drift
change in allele frequencies in a population from generation to generation that occurs due to chance events. To be more exact, genetic drift is change due to “sampling error”
(more brown that white rabbits as white ones are hunted for their colour)
a negative consequence of genetic drift
elimination of advantageous alleles
Adaptation
any heritable trait that helps an organism, such as a plant or animal, survive and reproduce in its environment.
during evolution some structures lose their original function and become…
vestigal structures - teeth, coccyx, vermiform appendix
extinction
the disappearance of an entire species
not an unusual event
extinction can occur due to: (4)
competition
inability to adapt
hunting
global warming
(human causes are primary causes)
extinction is proved by
palaeontology - study of fossils
fossils are?
preserved remains of a once living organism, usually obtained by digging
Homo sapiens
species of highly intelligent primates
living subtribe of hominid with chimpanzees, gorillas and orangutans
Homo sapiens are characterised by (5)
erect posture
high manual dexterity
complex language use
walking on twos
tool use in comparison to other animals
Homo sapiens come from?
homo erectus teeth larger and brains smaller )
homo neanderthals (primitive humans that lived 28000 - 300000)
disruptive and stabilising natural selection?
d - choosing extreme phenotypes
s - genetic diversity decreases as average phenotype is favoured
