Lecture 2 Flashcards
Examples of natural selection
Darwin finches (selective pressure).
Beetles (green vs red) due to which one was eaten less.
Associations with Darwin (Lamark, Lyell’s and Hutton)
1) a slow but continuous change over time. This led to Darwin’s idea of descent of inheritance.
2) Lyell’s principles of geology ^
Conditions for natural selection (4 - V.I.S.T)
1) Variation - individuals in a population vary from each other.
2) Inheritance - parents pass on their traits to their offspring genetically.
3) Selection - some variants reproduce more than others.
4) Time - successful variations accumulate over many generations.
Describe the importance of Wallace
Pushed Darwin to publish his theory of evolution paper as he had come up with the same idea.
“on the whole the best fitted lives”
“animals could be modified”
“Explains for definite characters and clear isolation of new species”
Sexual selection (2)
Subset of natural selection. Mode of natural selection where some individuals out-reproduce others of a population BECAUSE they are better at securing mates.
1) results in competition having little or no offspring.
2) sexual selection can drive against the natural
selection.
//Results in a specie becoming more dominant over another due to the fact that they are able to pass on their genes more readily than those whom aren’t able to secure partners for reproduction - a clear form of natural selection.//
Modern Studies (1)
1) molecular level - DNA heritability shows evolution
Allan Wilson
More change = more distance
1) showed molecules descended from common ancestor
2) number of changes in molecule is related to time
3) human & chimps = 99% similar in genetic sequence
Origins of humans
All living humans descend from common ancestor 60,000 years ago.
