Community Ecology Ms. Klinkhachorn September 29, 2010 AP Biology

Interspecific Interactions “Inter” means between These are the interactions between species in the same community – Competition – Predation – Herbivory – Symbiosis

How to Represent the Effects Can show the effects of interactions on the survival and reproduction of a species using symbols + = positive effect, benefit - = negative effect, harm 0 = neutral, nothing gained or lost

Competition Interspecific competition – Competitive exclusion Resource partitioning – Ecological niche The role in the habitat – Character displacement Allopatric vs sympatric

DNA – September 30, In your own words, describe competitive exclusion. Give an example. 2.In your own words, describe character displacement. Give an example. 3.If N is large relative to K, will there be a big change in population size or a small one? Explain. What kind of growth model would we be talking about?

Predation Predator vs. Prey (+/-) Survival of the fittest – Adaptations perfected through natural selection – Example: hiding/fleeing behaviors, heat-sensing organs, poison

Example: Hawk and Rodent

Example: Lion and Hyena

Predator / Prey Adaptations Cryptic Coloration aka camouflage Aposematic Coloration – Apo = away, sematic = sign or meaning Batesian Mimicry – A harmless, palatable species mimics a dangerous, unpalatable species Mullerian Mimicry – Two dangerous, unpalatable species mimic each other Safety in numbers

Batesian Mimicry

Mullerian Mimicry

Mimicry doesn’t have to be in appearance only – can mimic behaviors, movements, and sounds

DNA – October 1, Explain how the mimic octopus uses mimicry to protect itself from predators. 2.What is the difference between mullerian and batesian mimicry? 3.What is the difference between cryptic and aposematic coloration? What is the advantage for having each kind of coloration?

What is Symbiosis? Long-term, close associations between organisms – Species interdependence 3 types of symbiosis: – Mutualism +/+ – Commensalism +/0 – Parasitism +/-

Mutualism Both organisms benefit from the relationship Both are able to survive better +/+

Example: Sharks and Remoras

Commensalism +/0 A relationship where only one of the organisms benefits, but the other is NOT harmed

Example: Large Animals and Birds

Parasitism +/- A relationship where one organism (the parasite) benefits and the other is harmed (the host). Do you think the parasite kills the host organism?

Example: Tape Worms and Humans

Example: Maggots and Baby Birds

Example: Damselfly and Mites

Example: Moray Eels and Cleaner Fish

Community Structure Species Diversity Feeding Relationships

Species Richness vs Relative Abundance Species richness: # of different species Relative abundance: proportion of species Example: – Community 1 – 25A, 25B, 25C, 25D – Community 2 – 80A, 5B, 5C, 10D

Shannon diversity Do NOT memorize the formula All you need to know is that it is an equation that scientists use to learn about the diversity of a community