Exam 3 Flashcards
Species can have a range of relationships with each other, from _________ to ________.
antagonistic, mutualistic
What is reciprocal selection?
Selection that occurs in two species, due to their interactions with one another
The anemone and the clownfish is an example of a _______ relationship
mutualistic
Describe our relationship with our gut microbiome
- Mutualistic
- Positive frequency dependent selection
How is our relationship with our gut microbiome mutualistic?
- They (the bacteria) rely on our unused metabolic products for their own metabolism.
- Provide us with a myriad of benefits that are essential for optimal human health.
Scavengers partake in what type of relationship?
Commensalism
What are some examples of antagonistic interactions?
- Predator/prey
- Herbivore/plant
- Deceptive pollination
- Host/parasite
What food do you eat that has “evolved” to be eaten? (i.e. would go under mutualisms)
Fruits!
Describe deceptive pollination. What type of selection is it?
- Negative frequency dependence
- Insect is attracted by color, but is ultimately tricked
Describe commensalism
positive / neutral
Describe mutualisms
positive / positive
Describe antagonisms
negative / positive
What type of relationship is rarest?
Commensalism
Species in ecological relationships with other species produce ____________, and adapt to one another in a process known as ___________
reciprocal selection, coevolution
Humans and dogs have what type of relationship?
Mutualistic
How can we focus on how dogs have changed in relation to us?
By comparing with wolves
________ is an example of co-adaptations due to reciprocal selection
Pollination
Pollinators ______ on flowers to attract them
select
Flowers _______ colors, food rewards that attract
evolve
Flowers _______ on the pollinators to transfer pollen
select
Pollinators _______ hairiness, body shape, and behavior that effectively transfer pollen
evolve
What changes when evolution is interactive?
Co-adaptations due to reciprocal selection
Deceptive pollination is another example of
co-adaptations due to reciprocal selection
What kind of interaction is deceptive pollination?
Can be commensalism or antagonistic
What are some evolutionary changes due to deceptive pollination?
- Selection on insect to learn about deception
- Selection on plant to be more attractive and deceptive
What example of coevolutionary alteration did we learn about?
Cuckoo birds evolving to avoid the nests of birds that have evolved to recognize the cuckoo eggs
Mutualistic species exert _____________ on one another, and the rapid ________ that results can be similar to an “arms race” onlywithout the antagonism
positive frequency dependent selection, coevolution
Mutualistic interactions are vulnerable to the invasion of _________, that spread rapidly and lead to the collapse of the mutualism.
cheaters
Host and parasite (or pathogen) may generate _____________ on one another, maintaining genetic variation in both populations.
negative frequency dependent selection
Predators sometimes switch between prey, resulting in sequential bouts of __________.
pairwise coevolution
Define attenuated
weakened or thinned (reduced virulence)
Is it always beneficial for a virus to have high virulence?
No because if the host dies too quickly, the virus cannot move to another host and it will die too
Describe the use to the myxoma virus in Australia
- The virus was introduced in order to get the rabbit population under control
- The virus had a very high virulence at first
- Virulence went down after awhile
Two species of Joshua Tree diverged due to….
two sister species of pollinating moths specializing on trees in different areas
Coevolution can increase…
biodiversity
Coevolution can drive…
extinction
How/why does coevolution drive extinction?
Within coevolution, two species become more and more specialized for each other. If one organism disappears/dies, the other one is likely to as well
Coevolutionary relationships can increase biodiversity as…
genetic diversity among populations diverges
What are endosymbionts?
Mutualists that must live inside coevolutionary partners
________ = how two species become one
Endosymbiosis
Describe the relationship between leaf hoppers and the bacteria that live within them
- Bacteria in leaf hoppers help with digestion
- Bacteria have lost a large part of their genome – retain genes needed to help leaf hoppers with digestion
What two cell organelles are thought to have started as bacterial endosymbionts?
Chloroplasts and mitochondria
Mitochondria evolved from…
free-living bacteria
What was interesting about the gopher and lice populations?
- The lice are kind of considered endosymbionts
- When the gopher populations split, the lice populations living on them did as well
What are retroviruses?
Retroviruses create an RNA copy of their genome, turn it into DNA and insert into genome of a host cell (instructs cell to make viruses)
Retroviruses catalyze coevolution between…
different parts of a genome
How can genomic parasites be passed down from generation to generation?
If it infects sperm or egg cells, genes from virus can be passed down generation to generation via the genome
Endogenous retroviral DNA makes up about ____% of our genome
8
Endogenous retroviral DNA makes up ____ times more of the human genome than the 20,000 genes that encode proteins!
4
_________ can behave like genomic parasites
Transposons/mobile genetic elements
What are “domesticated” parasites?
Originally DNA hurt host, but then takes on function that benefits host
___________ are mutualistic organisms that live within the body or cells of another organism
Endosymbionts
_________ and _______ are endosymbiotic bacteria that coevolved with their hosts until they became “organelles”
Mitochondria, plastids
Endogenous retroviruses and mobile genetic elements have…
coevolved with their hosts genomes
What are some of the benefits (for animals) of living in a group?
- Increased vigilance
- Dilution effect
- Enhanced defense capability
- Cooperative foraging/hunting
- Improved defense of critical resources
What are some of the costs of living in a group?
- Increased conspicuousness to predators
- Increased competition for mates
- Increased competition for resources
- Decreased certainty of maternity/paternity
- Increased risk of transmission of disease/parasites
In the prisoner’s dilemma, describe what type of social interaction is occurring.
- Cooperative
- Selfish
- Spiteful
- Altruistic
- Cooperative: both actor and recipient benefit
- Selfish: actor benefits, recipient is harmed
- Spiteful: both the actor and recipient are harmed
- Altruistic: actor is harmed, recipient benefits
What is the problem of altruism?
What is good for the group is not always good for the individual
How are alarm calls considered altruistic?
- Alarm calls help all the individuals in the area as they notice the predator.
- Alarm calls attract the predator to the caller!
Why wouldn’t altruistic behaviors be removed by natural selection?
Because overall, it is good for the group/beneficial
Why do females give more alarm calls than males?
- Kinship!
- Females often stay put after sexual maturity and have more ties to those around them
What is Hamilton’s rule?
- A central theorem of inclusive fitness (kin selection) theory. It predicts that social behavior evolves under specific combinations of relatedness, benefit and cost
- An altruistic allele will spread if (Br – C > 0)
In Hamilton’s rule, what do B, r and C represent?
- B = = benefit to recipient
- r = coefficient of relatedness (between actor and recipient)
- C = cost to actor of behavior
How is the “r” in Hamilton’s rule calculated?
Genetics
What is r equal to for half siblings? Full siblings? Cousins?
- Half siblings = 1/4
- Full siblings = 1/2
- Cousins = 1/8
Based on coefficient of relatedness which of the following should you save (no cost to yourself) to increase your indirect fitness the most?
1) Both maternal and paternal grandmothers
2) One full sibling
3) 5 cousins
4) An aunt and her husband (uncle)
5 cousins
T / F : parents are more likely to care for genetically related children
T
What is inclusive fitness?
A theory in evolutionary biology in which an organism’s genetic success is believed to be derived from cooperation and altruistic behavior
How can adoption be considered an altruistic behavior?
If kin/relative is adopted
Kin selection makes the explicit prediction that…
animals should extend their help to relatives
What is the problem with kin selection?
Must be able to distinguish/recognize kin from unrelated individuals
What are some mechanisms of kin recognition?
- Physical proximity
- Odor
When might physical proximity might not be enough for recognizing kin?
If dispersal, multiple mating or inter-brood aggregation has occurred
Can cooperation evolve in non-kin groups?
Yes!
What is game theory?
- A theory developed by economists
- Assumes that “players” behave rationally and attempt to maximize some criterion (e.g. profit)
- In terms of evolution, natural selection replaces rationality and fitness replaces profit
Define strategy
a complete specification of what an individual will do in any situation (behavioral phenotype)
Define/describe Evolutionary Stable Strategy
a strategy that if adopted by all members of a population, it can not be invaded by an alternative strategy
What is the dominant strategy for the prisoners dilemma?
For both players, the dominant strategy is to confess
What is the “dilemma” of the prisoners dilemma?
The outcome is not efficient (there is no other outcome that pays all players more).
How is cooperation among non-kin possible?
- Repeated interactions with same individuals
- Many opportunities for altruism to occur
- Individuals have good memories
- Potential altruists interact in symmetrical situations
What are some examples of tit-for-tat in nature?
- Egg swapping in hermaphroditic fish
- Blood sharing in Vampire Bats
- Reciprocal grooming in Impala