Adaptation & Speciation Flashcards
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.
Operational Sex Ratio
ratio of sexually competing males that are ready to mate to sexually competing females that are ready to mate
How are miscarriages anything good for the woman?
They are a way for the female body to reject embryos that have abnormalities and reduce body’s waste in resources
Do females ever leave their parental offspring role?
Yes, sometimes more females are ready to mate than males, and females abandon their eggs with the expectation that males protect them. This is true for wattled jacanas.
Why do some species manipulate the ratio of offspring sex?
Seychelles warblers do so because females stay behind to help the mothers raise more offspring. If there is more help in the nest, more offspring will survive. However, sometimes, too many females cause problems, so the mother will have more males next season who will leave and clear out the nest.
Do males treat females differently based on size? Why or why not?
Males give more resources to offspring of bigger females and less for small females. This ensures that only the offspring that are likely to survive (those from the bigger females) will be given all necessary to reproduce themselves.
What is parental conflict and how does it affect the offspring?
?
What is parental offspring conflict?
This strategy allows parents to benefit from withholding care or resources from some offspring and invest in other offspring.
What are consequences of parental offspring conflict?
Deprived offspring could benefit more if they received the withheld care or resources. Chicks often manipulate the intensity of their begging for food to get most possible. Some bird offspring fight siblings to the death to ensure that they receive all the resources.
What is behavior? Can it evolve, and if so, what is an example?
Behavior is an internally generated response to external stimulus. It evolves through natural selection, and an example are the foxes and their changes in aggression based on selective breeding.
How can behavior affect fitness?
Different behaviors affect fitness because they change the amount of food animals find, mating success, and the ability to avoid accidents.
What is an example of behavior changing based on cross breeding?
Oldfield mice were crossbred, with one creating long tunnels and another creating small/short tunnels. The new offspring creates a variety of tunnels.
How are individual selection and group selection different?
Individual selection helps traits of individuals that perform well be spread. Group selection favors behaviors that contribute to the better performance of the group.
What is individual selection?
occurs when behaviors that cause particular individuals within a population to perform well relative to other individuals are favored and spread
What is group selection?
favors behaviors that contribute to the performance of that group, so that groups performing these behaviors fare better than groups lacking them
What causes a particular behavior to increase in frequency?
If the behavior is successful, then selection should make the behavior more common.
Are some species selfish individuals? In such a case, what happens to behavior?
Species can be selfish, and this causes the behavior to depend on whether individual or group is stronger.
Is selection stronger for differences in fitness of individuals within a group or for the success of the group?
Selection is stronger for the differences in relative fitness of individuals within a group than the success of the group relative to other groups.
What does it mean for a new behavior to “invade” a population?
A new behavior can “invade” a population and spread to fixation, eliminating earlier behavior.
Can behavior resist invasions of new behaviors?
Yes, behavior that resists all possible invasions is evolutionary stable strategy.
How can fitness strategies change in their stability?
Fitness of particular strategies change depending on frequencies of other strategies, so that no one strategy is stable. One example is the competition between lizards with orange, blue and yellow throats.
What is the dilution effect? When does it occur?
It occurs in group living, and essentially each group member faces a smaller risk of being the target of an attack.
When do individuals choose group living over living alone?
When the gains brought to the individual outweigh the costs.
Name 5 benefits of living in a group.
Increased vigilance, dilution effect, enhanced defense capability, cooperative hunting, improved defense of resources
