Evolution, Adaptations, Sexual Selection Flashcards Preview

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Flashcards in Evolution, Adaptations, Sexual Selection Deck (19):

What is descent with modification?


we all come from a common ancestor
disimilarities between species accumulate over time
we change through inheritance - blended characteristics

Mendel - pea plants


What is natural selection?

eg. Endler

within a population individuals vary on pheno- and geno- type and so some reproduce more successfully than others. natural selection is the slow, non-random process acting on the phenotype to make the genotype more common -- over time accumulations of features that make individuals more or less likely to reproduce will accumulate, and individuals with adaptive traits that enhance their reproduction success will be more frequent

guppies have colour patterns which are attractive to females and vary with predator pressure


What are mutations?

permanent change to DNA sequence of a cell's genetic material


What is gene flow?

changes due to moving from one place to another


What is non-random mating?

mating based on traits, sexual selection


What is gene re-shuffling?

new gene combinations brought into a population in any generation


Evolutionary mechanisms that reduce genetic variation?

natural selection - adaptive traits more reproduction
genetic drift - random changes in the frequency of occurrence of traits due to chance fators


Types of genetic drift

bottle necking event - something happens to drastically reduce population
founder effect - small part of population moves off to create new colony, allele frequency may be different from parent population (eg. Amish)


What is convergent evolution?

evolution of the same biological trait in unrelated lineages of species


What is the comparative method?

correlations between traits and selective pressures


Other ways to ID adaptations?

complexity of the trait
design of the trait - if it corresponds with engineering design this suggests there is a function
spandrel - is it an accidental by-product?


eg. of spandrel

language a by-product of a big brain?


eg. of con of sexual reproduction?

marsupials suicidal reproduction
in elephant seals, 20% male offspring don't reproduce in comparison to 80% female offspring


Pros of sexual reproduction?

Red Queen hypothesis with support from Lively's snails


Jones et al. 98

some sandflies were more successful in mating, but there were no benefits to mating with these flies other than their sons were more successful



only have an attractive trait if you have the viability to hold it - the cost is sufficient to stop it increasing across males


Barber et al. 01

sticklebacks - darker red patch, more resistant to parasties



female fish were more attracted to male fish with plastic swords attached - preference there before the trait develops in their species


Workman and Reader

female stags can do inter-sexual competition as well, exclude smaller stags from lushest parts of territory means they get the best food and their sons more likely to survive first winter and have more reproductive success