Anthro7:Week 2

-the study of the processes that change the gene frequencies

a = freq aa + .5(freq Aa)

A = freq AA + .5(freq Aa)

# of individuals/total population 

A2 + 2Aa + a2 = 1

-calculates mating in one generation and allows the calculation of allele frequencies in the next generation

• -Height
• -Weight

• -finger number
• -tongue rolling

• • Benefit = prevent other males from mating with female and sharing paternity of eggs
• • Cost = Can’t mate with other females while mate guarding
• -When females outnumber males,
• costs>benefits of mate guarding
• -When males outnumber females,
• benefits>costs of mate guarding

• • Correlated characters
• • Disequilibrium
• • Genetic drift
• • Local vs global optima
• • External force

-refers to a difference between the observed and the expected ratios of genotypes within a given population

• -Traits that influence the presence of other traits are correlated, either positively or negatively.
• -If selection acts on a trait that is correlated with another, it is possible that the second trait may become maladaptive

-random changes in allele frequencies

• -Organisms are classified in the same species if they are potentially capable of interbreeding and producing fertile offspring.
• -Reproductive isolation maintains species boundaries

• -organisms adapted to a particular set of resources, called a niche, in the environment.
• -Natural selection maintains species boundaries

-The formation of a new species as a result of an ancestral population's becoming isolated by a geographic barrier or reproductive isolation 

• -populations are not isolated by a physical barrier and are instead "beside" each other
• -Individuals are more likely to mate with their geographic neighbors than with individuals in a different part of the population’s range. 
• -population must be continuous
• -partial isolation
• -selection leads to speciation 

• -the individuals in the population are not separated at all and all live in the "same place"
• -no isolation
• -selection leads to speciation 

-An outcome of competition in which two species living in the same area have evolved differences in morphology or other characteristics that lessen competition for food resources.

• 1. Humans evolved from knuckle-walker
• 2. knuckle-walking evolved independently in chimps and gorillas

How things are related to one another

what we call things

• 1. Ancestral traits are those that two species share because of common ancestry.
• Ex. All birds have wings because their common ancestor did. They are ancestral traits.
• 2. Derived traits evolved in one species after it branched off from others.
• Ex. bats' evolved separately from birds' wings. They are derived traits
• -most useful when comparing very similar species to determine taxonomic relationships. (How closely they are related)

• -process whereby organisms not closely related, independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.
• Ex. Birds and bats wings

• -when two species share a structure that arises from the same origin but may have a different function.
• -For example, hair on mammals is homologous. Porcupine spikes are used for defense and sea otter fur is used for insulation. 

• -when species share a structure that has evolved independently and may have the same function.
• -For example, birds and bats’ ability to fly is analogous