Unit 3 Flashcards
(45 cards)
What is needed for evolution to occur?
The genetic material (that produce traits) in the population must change, resulting in in changes in the traits expressed by the population
What does evolution mean on a genetic level?
The frequencies of alleles of genotypes in the population must change.
Mutations
The ultimate source of new genes (alleles) and thus variation
What are something important to remember about mutations?
The can spread from one generation to the next, altering allele frequencies.
A specific mutation even it not influenced by natural selection?
What is gene flow?
an Individual with different alleles may disperse to a new population and affect the gene pool of the population, leading to hominization’s of said species.
What is non-random mating?
In some populations, individuals that tend to look alike mate more frequently that would be expected if mating was random.
What is sexual selection?
Selection of reproductive traits at the potential compromise of survival.
Genetic drift is…
A random process that is important in small populations
What 2 processes work under genetic drift?
The founder and bottle neck effects
What is the bottle neck effect?
A large population decreases into a smaller one, and then when it becomes a large population again, it can only have the traits of those who survived the bottle neck
What is the founder effect?
A small group of dispersers colonizes a area, which may or may not be representative of the parent population.
Evolution will not occur if all of these things are present
No mutations
no genes transferred to or from other sources
Random mating is occurring
The population size is so large, it offsets genetic drift
no natural selection occurs
What is genetic equalibrium?
Frequencies of genes or traits are the exact same year in year out.
What assumptions need to be made to mathematically equate evolution?
Random mating, no mutations, large population sizes, no gene flow in or out, and no natural selection. In other words, no evolution
Does evolution operate at the population or individual level?
Population
What is the Hardy-Weinberg equation?
It is the mathematical equation P^2 + 2pq + q^2 =1
What does p, q and 2pq represent?
P^2 is the frequencies of homozygous dominate individuals
2pq is the frequency of the hetrozygous genotype
q^2 is the frequency of homozygous recessive individuals.
Why isn’t the dominant allele also the most common?
Dominance doesn’t equate to commonality, and things like predation can contribute to that.
What is to be said about populations over time experiencing genetic equilibirum?
Over time, a populations will cease to exist in equilibrium because its darn near impossible to stop evolution.
What did early primates most likely look like?
They were small and arboral
What are the characteristics of primates?
Limber shoulder joints
Dexterous hands and opposable thumbs
Claws replaced by flat nails
Sensitive fingers for tactile perception
Good vision and hand eye coordination
Extensive parental care.
Why can’t we have definite answers on our primate ancestors?
There are still fossil gaps and degrees of relationships
What does it mean to be human?
Bi-pedal locomotion
Large brain to body size ratio
Culture or the transmission of accumulated knowledge over generations
Degree to which we manipulate our environment
Ability to acquire food.
What are some characteristics of Australopithocus afarensis?
They live in trees, are bi-pedal, climate change forces them to walk because of droughts, they walk upright to save energy in raising babies.
