Do Now What is a species’ ecological niche? What is the difference between a fundamental niche and a realized niche? What does the competitive exclusion principle state?

Interspecies Interactions Unit II, Subtopic VI

Interspecies Interactions When 2 species interact in some way, each species can experience one of 3 outcomes: –A species can benefit (+) –A species can be harmed (-) –A species can be unaffected (0) There are 6 combinations of outcomes that can occur

Mutualism (+/+) Species 1 and Species 2 both benefit Can be thought of as a “biological trade” of services or resources Ex: Birds/insects pollinating plants –Insects get food, plant gets pollinated

Birds that clean parasites off hippos Sea Anemonies provide protection for clown fish – clown fish defend anemonies from predators

Competition(-/-) Species 1 and Species 2 both harmed Because of the competitive exclusion principle, competition eventually leads to niche separation or local extinction

Trees competing for spots in the sun and nutrients in the soil Cheetahs and Lions competing for the same food

Neutralism (0/0) Species 1 and Species 2 both unaffected Rare and hard to prove – there are so many connections in ecosystems that few species are truly neutral to each other Ex: Trout and pine trees

Predation/Parasitism (+/-) Species 1 benefits and Species 2 harmed Ex: Lions kill buffalo to eat

Parasitism (+/-) Cordyceps fungus kills ants as it spreads

Commensalism (0/+) Species 1 unaffected and Species 2 benefits Ex: Remora fish attach themselves to sharks – they receive protection and eat scraps of food; sharks gain nothing

Commensalism (0/+) Cattle Egrets follow large animals around and eat the insects in the grass that become exposed; cattle gain nothing

Amensalism (0/-) Species 1 unaffected & Species 2 is harmed Often occurs when one organism produces a chemical that harms another organism Ex: The mold Penicillium produces chemicals which kill bacteria

Amensalism (0/-) Ex: Black Walnut Trees produce chemicals which prevent other trees from growing near them

Application Activity Using yourself as “Species 1”, come up with an example from your life for each of the 6 types of interactions Ex: Amensalism – my college roommate always had the Air Conditioning on high, making our room freezing cold – he was unaffected and I was harmed