Coevolution Flashcards
What is coevolution?
Reciprocal evolutionary changes across species interactions
Why should we expect that it’s important in nature?
Links ecology and evolutionary biology, leads to the development of interspecies relationships
Victim/exploiter interactions
Predators and parasites
Why is specialization an important concept for coevolution?
Coevolution is a stronger force in more specialized systems
How can the concept of coevolution be framed in terms of adaptive topographies?
Unlinke shifting balance, coevolution does not shift the position of a species on a fitness peak but instead changes the peaks and valleys themselves
Why are ecological population models of species interactions useful in the context of understanding what traits are likely to be shaped by coevolution?
Predation is an ecological process, this shapes predator/prey evolution in a reciprocal fashion
What are some important constraints on coevolution (what did the snake/newt story tell us about this)?
Antagonistic pleiotropy, meaning that despite the usefulness of a trait, it may be selected against due to fitness cost
Why is the coevolutionary process difficult to study in practice?
Time is a limiting factor, as evolution occurs over a span of generations
What is the geographic mosaic theory of coevolution? What predictions does it make? How does it provide a framework for empirical studies of coevolution?
Interspecific interactions vary among populations, and a single population differ to a degree that no one population serves as an appropriate model. Only on a species-wide scale does it make sense.
How do parasitic relationships fundamentally differ from predation, and how does that affect the potential outcomes of coevolution?
Parasites do not always kill their host while predators by definition kill their prey. They can therefore evolve to coexist in positive ways
Why is there potential evolutionary tension between the within-host and among-hosts parts of parasites lifecycles? What are some possible outcomes resolving within/among host parasite lifecycles?
Parasites that are too successful WITHIN hosts are not successful in transmission AMONG hosts, as they kill their hosts before they can do so.
What are some possible outcomes resolving within/among host parasite lifecycles?
Extended phenotypes- effects of the gene impact the host in addition to the parasite, selection acts on host behavior/physiology
Attenuation of virulence- parasites evolve exploitative restraint to maximize between host transmission and minimize evolution of host defensive traits
How are mutual and parasitism related?
They exist on a spectrum, from highly lethal to highly beneficial
Are switches between the two likely to evolve in nature? What did the Jeon amoeba example tell us about this?
Cases have been studied where parasitism shifted to mutualism. Jeon’s amoeba showed an example where the parasite and host not only evolved to tolerate each other, but needed each other
