Question about last week: why talk about introduced and invasive species?
(food plants, rubber, chocolate, oil palm; weeds: environmental modification, control expenses)
"Survival of the fittest" doesn't necessarily mean the biggest, most aggressive, most voracious, etc. Cooperation can be an evolutionary adaptation.
Five types of interactions among species:
All of these interactions provide opportunities for coevolution (but coevolution does not always occur)
Interactions can be diffuse (among groups of species, e.g. plants and herbivorous insects) or specific (among two or a few species)
Competition: Ecological -> competitive exclusion (Gause) -> niche partitioning
Evolutionary (involves genetic change over time) -> niche differentiation
Predation, parasitism, pathogens:
Ecological -> population regulation, local extinction
Evolutionary -> "evolutionary arms race"
Mutualism: Ecological -> distribution and abundance may be linked (strict)
Evolutionary -> may evolve physiological interdependence (e.g. mitochondria, chloroplasts, gut flora e.g. humans, termites, algae/coral, lichens)
Examples of Coevolution
Diffuse: fruit colors and avian dispersers,
Diffuse or specific: herbivores and plant defensive compounds
Specific: numerous plant-pollinator relationships (e.g. orchid/hawkmoth, wasp/orchid, weevils/seeds); ant/acacia
Specific: many host/parasite relationships, ant/lycaenid larvae, ant/aphid
Multiple trophic levels
Figs, fig wasps, nematodes - specificity, congruent phylogenetic trees
Batesian - palatable sp. mimics noxious sp. e.g. viceroy/monarch, moths that mimic wasps
Müllerian - convergence in appearance of noxious species, e.g. Heliconius butterflies, various bees and wasps.