Co-evolution

Co-evolution

• Def – interactions among species that result in reciprocal adaptation.– Two species evolve in response to long-term

interactions with each other.– Escalation – Predators evolve better equipped

to catch prey items• Pray evolve adaptations to help get away from

predators

• Like during the “cold war” US and Soviet Union

• Acacia eaters – if you are a plant how might you defend yourself?

• Animals that cannot eat acacia trees and bushes – wildebeests, hippos, rhino, zebra, buffalo, birds, squirrels, turtles, mice, rats

• Orchid have developed a spur. The spur holds nectar. – The nectar is a reward for

animal and insect visitors. • Why would the plant

reward the visitors?

• This particular bee can get the nectar only by buzzing.

• Some bugs have a tongue to get the nectar.

• Orchid and moth – a particular orchid in Madagascar has a spur 40 cm long– At the end of the spur it stores it’s nectar– Knowing what you know now about coevolution

what prediction can you make about a moth that might feed on the nectar?

– Show Pirjin’s hawk moth– What benefit would there be to having a spur

that long?– Darwin predicted there should be a moth with a

“tongue” long enough to get the nectar.• 50 years later a moth was discovered that fit the

prediction.

Slid the moth over and you will see the tongue fits perfectly

How could this evolve like this?

• Other place we can see co-evolution– Pronghorns

• Can run up to 60 mph for short distances and 45 mph or miles and miles.

• Why would the prong horn be able to run that fast?

• 10,000 years ago there were cheetahs and long legged hyenas

• http://query.nytimes.com/gst/fullpage.html?res=9502E0D71031F937A15751C1A960958260&sec=&spon=&pagewanted=all

– Hummingbirds• 1

• 2

– Plant poisons

• Bacteria– antibiotic resistance. when you don’t finish your

medicine what happens?– if you don’t finish, some of the bacteria remain.

The ones that remain have a little resistance.