co-evolutionCo-evolution is frequently seen in pairs of species that interact frequently or closely. A change in the traits of one species acts as a selection pressure on the other species.

activity 1 - co-evolutionYour task is to research the examples of co-evolution shown on the following slides.Be prepared to discuss your findings at the next lesson.

pollinators and plantsmutualistic co-evolution

Darwin’s orchid

Morgan’s sphinx moth

mutualism

Pseudonyrmex antBullshorn acacia

mutualistic co-evolution

herbivores and plantscompetitive co-evolution

tobacco hornworm

tobacco

red crossbilllodgepole pine

seed-eater and plantcompetitive co-evolution

predators and their preycompetitive co-evolution

common garter snake

rough skinned newt

parasites and their hostscompetitive co-evolution

human

Plasmodium falciparum

the ‘arms race’

activity 2 – the ‘arms race’

You will now read and discuss an article on the ‘arms race’ between the human host and the parasite Plasmodium falciparum.

malaria’s evolutionary arms race

the red queen hypothesis The co-evolutionary ‘arms race’ between a parasite and host is known

as the Red Queen Hypothesis as both organisms must ‘keep running in order to stay still’.

At the top of the hill, the Red Queen begins to run, faster and faster. Alice runs after the Red Queen, but is further perplexed to find that neither one seems to be moving. When they stop running, they are in exactly the same place. Alice remarks on this, to which the Red Queen responds: "Now, here, you see, it takes all the running you can do to keep in the same place".

malice in wonderland

the red queen hypothesis

Hosts better able to resist and tolerate parasitism have greater fitness. Parasites better able to feed, reproduce and find new hosts have

greater fitness.

parasitic wasp / housefly PPQ