Species Interactions in

Biological Communities

Community

• Several different species interacting in the same geographic area

• Types of Interactions• Competition• Predation• Symbiosis

Interactions

• 2 Types of Competition• Intra-specific Competition

• Competition between organisms of the same species

• Inter-specific Competition• Competition between organisms of

different species

Competition

• Example of Inter-specific Competition• Competitive Exclusion

• Two species so similar in requirements that the same resource limits both species’ growth & 1 species may succeed over the other• Paramecium Study

Interactions

• Predation• Interaction in which 1 organism eats

another• Predator = Hunter• Prey = Hunted

• Predator/Prey Adaptations* Camouflage* Hunt in pack* Acute senses* Mimicry * Body Modifications:

• Claws, teeth, fangs, stingers* Chemical Defenses- Thorns, venom

Physical adaptations

Body structures that allow an animal to find and consume food, defend itself,

and to reproduce its species.

Physical adaptations help an animal survive in its environment.

Hey! I’m a walking stick. I look just like a stick you’d find on the ground.

© A. Weinberg

Physical adaptation

Camouflage (use of color in a surrounding)

The chameleon can change its color to match its surroundings.

Mimicry (looking or sounding like another living organism)

The Viceroy butterfly uses mimicry to look like the Monarch butterfly. Can you tell them apart?

Poisonous

Not poisonous

Physical adaptation

I’m the Monarch!

I’m the Viceroy!

Chemical defenses (like venom, ink, sprays)

Physical adaptation

Body coverings & parts (claws, beaks, feet, armor plates, skulls, teeth)

Physical adaptations

The elephant’s trunk is a physical adaptation that helps it to clean itself, eat, drink, and to pick things up.

Interactions

• Symbiotic Relationships• Close interaction between species in which 1

of the species lives in or on the other• 3 Main Types

• Parasitism• Parasite obtains its food at the expense of a host

• Mutualism• Both organisms benefit from the relationship

• Commensalism• 1 organism benefits while the other organism is

neither harmed nor helped