Ecology Notes – Part 3:

Interactions

Ecology Notes – Part 3:

InteractionsBiology

Spring 2012Biology

Spring 2012

Interactions

• Types of Interactions among organisms

• Symbiosis (3 types)

• Competition

• Predator/Prey (Predation)

Interactions – Symbiosis

Symbiosis: the relationship between two organisms in which at least one benefits, but the other does not die

Sym – = with / together

-biosis = mode of life

Ex: bird on hippos, fleas on dogs

Symbiosis

3 Types of Symbiosis:

Commensalism

Mutualism

Parasitism

SymbiosisCommensalism: one organism benefits and the other is not harmed (+/0)

Ex: Lichen on a tree branch

Maggots decomposing a rotting carcass

Symbiosis

Mutualism:

both organisms benefit from the relationship (+/+)

Ex: Clown fish and sea anemone

Insect pollination of flowers

SymbiosisParasitism:

One organism benefits and the other is harmed, but not killed (+/-)

Ex: mosquito and human

Interactions – Competition

• Competition:

• When different species struggle over the same resource

• Resources are limited by supply

• Water, food, shelter

Interactions – Competition

• Revisiting the niche…

• Niche: the role of an organism in its environment, “how it makes a living”

• How it gets food

• Habitat conditions for survival

• Is it used for food?

• All its biotic and abiotic resources

Interactions – Competition

• Niche Example

Competition, cont.•Competition can happen in two

ways:

•Between two different species (interspecies)

•Cheetahs & lions competing for antelopes.

•Between members of the same species (intraspecies).

•Mountain goat rams butting heads to “win” the females.

Interactions – Competition

• Competitive Exclusion Principle:

• If two species compete for the same resource(s), one will win and one will lose

• The “winner” gets the territory / resource(s)

• The “loser” will either move to another location or get killed

Why are they in different regions of the

tree??

Interactions – Predator/Prey

Interactions – Predator/Prey• Predation: where one organism

kills another for its food

• Organism getting the food is the predator

• Organism that is the food is the prey

• 1 lives & 1 dies

Which is which?

http://www.msnbc.msn.com/id/9600151/ns/technology_and_science-science/t/gator-guzzling-python-comes-messy-end/

To succeed...

•Both predators and prey adapt to better survive

•Predators get better at catching prey

•Prey get better at avoiding being caught.

What do they need?

• Think of a predator/prey relationship

• Generate a list of characteristics that are helpful for each to survive…

• Predators:

• Prey:

Predator adaptations

•Speed & agility or power & strength

•Acute senses

•“Weaponry:” claws, fangs, poison

•Camouflage

Prey Adaptations•Avoid:

•Speed, senses, hide, mimic

Prey Adaptations•Warn:

•Coloring, smell, cry

Prey Adaptations•Defend:

•Shell, needle, fight back, taste, smell...

Interactions – Overview

Write a general description of what happens to each organism in the following types of interactions among organisms:

• Symbiosis:

• Describe each of the 3 types of symbiosis

• Competition:

• Predator/Prey (Predation):

Interactions – Overview Types of

InteractionOne

organismThe other

organism…Symbiosis Doesn’t die

1.

2.

3.

Competition

Predator / Prey

Predator-Prey Simulation

“Queen of Trees”

Interactions