Interactions between species Coevolution when two species evolve

Interactions between species

Coevolution: when two species evolve in responses to changes in one another. Leads to close associations between species, like the fig being only pollinated by the fig wasp.

Symbiosis: • A close relationship between two organisms – Mutualism – both organisms benefit (+, +) -ants guard the nectar-producing aphids

mycorrhizae Left: same age and type of tree with no mycorrhizae Hairy fungus projections on roots increase surface area, allowing more minerals to be taken up from the soil. The fungus gets carbs from the plant

• Clownfish: messy eater. Drops food, has mucus layer to prevent stings • Anemone: provides protection, gains food

Lichen: a mutualism between a fungus (anchor) and algae (photosynthesiz er)

–Commensalism – one benefits and the other is NOT harmed (+, neutral) • Remora fish hitch rides on sharks, eat its leftovers, sharks are unharmed

Barnacles hitch rides by living on whale skin. Whales take them to fertile water where food is plentiful, but no harm comes to the whale, so it is a commensalism

Orchids, spanish moss, and pitcher plants are examples of epiphytes: plants that live above the ground on the branches of trees. They do no harm to the tree, but gain access to sunlight and a platform to grow on: commensalism

– Parasitism – one benefits and the other IS harmed. (+, -) This wasp is a parasitoid (a fatal parasite): It lays its eggs on a host (the caterpillar) and the larvae feed on its guts until they emerge (after pupation) as adults. the bottom image shows a tomato hornworm caterpillar covered in parasitoid wasp larvae

Ticks and tapeworms are clearly parasites who feed on living hosts

Predation: a relationship where one organism feeds (the predator) on another (prey)

Prey adaptations and defenses • • Coevolution Camouflage Disruptive coloration Ruffle feathers Make hair stand up Spray chemicals Play dead Killdeer • Warning Coloration • Mimicry • Mullerian mimicry – Poisonous species mimic each other • Batesian mimicry – Non-poisonous mimic poisonous