Evolution and Selection Flashcards
within evolution what is a pattern
the change we see in the fossil records through time
what does an evolutionary pattern infer
a relationship between different fossil organisms and their living descendants as well as an assumption that all organisms are related in some way
why has the natural selection model for evolution been widely accepted
since the model best fits the evidence of evolution contained: within our genes, within the homologies between living organisms or within fossil records
give 6 other principles of natural selection that have been proposed
-lamarckianism (lose characters you dont need)
-catastrophism (catastrophic events define fossil records)
-scalae naturae (a march towards perfection)
-theistic evolution (devine creation, god)
-orthogenesis (directional force driving evolution)
-mutationalism (species emerge in large jumps)
when was Darwins ‘On the Origin of Species’ published
1859
Give the 4 statements that define Darwins theory
-individuals less suited to an environment are less likely to survive and reproduce
-every species is fertile enough that is all offspring survived to reproduce the population would grow
-despite periodic fluctuations populations remain roughly the same
-resources such as food are limited and relatively stable over them
what did Mendel study
the inheritance of seven phenotypic traits (described genes as factors)
what are the 6 things that have created modern synthesis
-mutation
-genetic variation
-mendellian inheritance
-natural selection
-variation
-malthusian competition
what does a stabilising graph look like
selection against extreme trait values
what does a directional selection graph look like
mean trait value moves in response to the direction and intensity of selection
what does a disruptive selection graph look like
selection against the mean trait creating a multimodel trait distribution
what is the heritability of any given trait
the ratio of the genetic variation to the toal phenotypic variation (h2=Vg/Vp)
what is phenotypic plasticity
variability againsst the same genetic background
give the breeders equation
R=h2S
(R= evolutionary response
h= heritability
S= selection differential)
what are the two mechanisms of sexual selection
- intrasexual selection, competition between members of the same sex for access to mates
- intersexual selection, members of one sex choose members of the opposite sex
