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?
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