Adaptation & Speciation Flashcards
(119 cards)
How did the Galapagos Finches change by the drought?
The birds who were able to eat the harder seeds survived compared to those who ate the smaller seeds
What finch is the medium ground finch? What type of beak do they have?
Geospiza fortis, and a larger beak for larger seeds
What finch is the small ground finch?
Geospiza fuliginosa, and smaller beak for small seeds
How did the beak size of finches change after the drought?
Average beak size grew larger
How do oldfield mice change their coat color based on their surroundings?
Dark coat color mice match the dark soil while mice on beaches have light coats to match sand
What are the benefits of the coat color for the mice?
Coat colors prevent predators from finding the mice. More offspring because of higher survival rate.
How does high gene flow affect populations?
It makes speciation more difficult since it will recombine the gene pools of groups of species
What is the definition of gene flow?
How quickly alleles move between populations
What does the amount of gene flow movement depend upon?
How far individual organisms move and how far their gametes move
Alleles don’t affect the ____ of populations, but rather the ___ traits
selection; phenotypic
What is aposematism?
anti-predator strategy used by potential prey to signal danger or lack of palatability (ex. coloration)
How is lactose intolerance part of natural selection?
feeding on milk was once rare, but as it became more popular and a way to get nutrients, the people able to drink milk survived for longer…milk tolerance more common in cattle herding cultures
What is sweep?
sweep is: reduction or elimination of variation among the nucleotides in neighboring DNA of a mutation as the result of recent and strong positive natural selection
What is selective sweep?
when sweep occurs faster than recombination can separate the allele from the nearby regions of the genome, leaves a fingerprint of natural selection
How have humans impacted selection?
Artificial selection for dogs/domestic animals, picking wheat for seeds that don’t shatter, pesticides, hunting and fishing
Do deleterious mutations always affect an individual?
It may have no effect on fitness if the mutation is deleterious in old age, since the animal is likely to die from external causes
Do deleterious mutations that appear early in life affect individuals?
They tend to have a stronger effect on fitness because the odds of an animal being alive is much higher.
What are the consequences of having an unbalanced number of litters on the mother?
Too many litters can be hard on the mother, because the offspring require many resources, while too little can prevent enough genes from being passed on in the population. Selection would want the best strategy to maximize the number of offspring that survive to maturity to pass on the genes. Therefore, the mother must find the right balance.
How do the island opossums and the mainland opossums differ from one another, in terms of predation, likelihood to survive, and number of offspring?
On the mainland, there are more predators and selection favors earlier sexual maturity and large litters to ensure that genes as passed on as much as possible. On the island, there is no predation, so opossums are likely to survive till old age, and therefore don’t have to expend resources to produce large litters. Mainland opossums deteriorate faster than the island ones.
In the guppy case study, how does the offspring growth rate change based on their surroundings?
In areas that don’t face predators, the offspring would grow up slowly. Females will produce fewer offspring at a time because of longer period of time to reproduce. Areas with predators have smaller offspring, and males mate often to spread their genes.
What is the cost of parental investment?
There is the expense of other reproductive options, such as producing additional young later or seeking other mating opportunities.
Why are females more likely to care for their offspring?
Females want to increase probability of their offspring’s survival, since they are the definite parent. Males have less certainty on whether the partner’s offspring are his.
Why are males less involved in the raising of offspring?
They have less certainty about the paternity of the offspring. Males are only adding cheap sperm and invest less because they have less to lose.
What sets up the sexual selection traits found on male species today?
The excess of males to mate causes males to look for something that makes them look unique to females. The males are expected to outcompete rivals and gain access to females.