This week, rather than focus on a specific coevolutionary
interaction, I am going to go through the five different modes of coevolution
that have been suggested by various scientists so far.
I know, I know... not quite as interesting as my previous
blog! However, I think it’s necessary to chat about it so that we all know what
types of species interactions are likely to occur in each particular mode.
The five different modes of coevolution are as follows: Gene-for-gene,
Specific, Guild, Diversifying and Escape-and-radiation (Thompson, 1989).
Gene-for-gene coevolution is most likely seen in species
interactions of plants and pathogens with the perception that each gene
affecting resistance in the host population is matched by a specific gene
affecting virulence in the parasite population.
Specific coevolution is most likely seen in all interactions
with selection pressures that are reciprocal, however uncommon in competitive
interactions. This type of coevolution has an assortment of possible outcomes;
divergence, convergence and ‘evolutionary arms races’ being the main three.
Guild coevolution, or diffuse coevolution, is seen in all
species interactions and is a helpful experimental tool for discerning how groups
of species within communities link and change together; Showing that evolutionary
interactions could be more extensive than a pair of species.
Diversifying coevolution is most likely seen in
seed-parasitic pollinators & plants, hosts & symbionts that regulate
movement of host gametes, and maternally inherited symbionts & hosts. In
some cases this form of coevolution may result in reciprocal speciation.
Escape-and-radiation coevolution is most commonly seen in
species interactions involving hosts and parasites and is a more explicit form
of how guild coevolution could involve both speciation and adaptation.
As I mentioned earlier, not quite as interesting but
hopefully informative :)
I found this particularly interesting, as I wasn’t aware there were different types of coevolution! Many articles just talk about “coevolution” without making this distinction, so I think that it is useful to distinguish them. I find the gene-for-gene coevolution idea fascinating. You mentioned that this was common in plants, but do you think that this is also common in animals, particularly humans? Great blog!
ReplyDelete