Coevolution Flashcards
What two things are involved in coevolution?
Coadaptation and cospeciation
What is coadaptation?
When change in one organism causes the other to respond to that change
What is the difference between something being infected vs infested?
Infected refers to an internal parasite, infested refers to external parasite
What is the Red Queen hypothesis?
Hosts and parasites are constantly locked in an evolutionary arms race
What is cospeciation?
When an original host species diverges into two species, the parasite also undergoes speciation
What are the 3 options for a parasite once its host evolves?
- Go extinct
- Same parasite infects derived host
- Undergoes speciation
How can we tell if cospeciation has occurred?
Congruent phylogenies between parasite and host
What is host capture?
Two hosts sharing similar niches allow one to contract the parasites of the other
What is a parasite?
An organism living in or on another organism that causes damage to its host
What is the parasite life cycle?
Hatch, find a host, get inside the host, extract nutrients to grow, reproduce, get offspring out
What are the problems that parasites have during their life cycle?
Hard to find a mate, they tend to be R selected species and make tons of offspring
What selection pressures are the hosts under?
Avoiding parasitism
What selection pressures are the parasites under?
Evade host defences
Which host genotypes will parasites evolve to exploit?
The most common ones
Which genotypes will be selected for in the host?
The rare alleles that confer resistance to the parasite, so they become more common
What will happen to the parasite when the host genotype conferring resistance to the parasite becomes more common?
The parasite evolves to exploit that genotype
Despite all the problems associated with sexual reproduction, why is it advantageous?
Genetic variability
Will a population that is parasitized choose to reproduce sexually or asexually more often?
Sexually
What is toxoplasmosis?
A parasite that influences the behaviour of the host
What are the 3 types of lice found on humans?
Head lice, body lice, pubic lice
What phenomenon explains how body lice diverged off from head lice when we started wearing clothing?
Coadaptation
What phenomenon explains how we acquired head lice?
Cospeciation
How do we know that we acquired head lice through cospeciation?
Constructing phylogenies for the primates and lice lineages shows that head lice diverged off at the same time we diverged off from chimps, congruency
What phenomenon explains how we acquired pubic lice?
Host capture from gorillas
