Species Interactions

Species Interactions When organisms live together in a

community, they interact constantly.

These interactions help shape the ecosystem they live in.

These interactions include:

Predation

Competition

Symbiosis

Predation

Predation – Interaction in which one organism captures and eats another organism.

The organism that does the killing and eating →predator.

The organism that is the food → prey.

Predation determines relationships in a food web and regulates population size.

Competition Competition: struggle between 2 or more species

to survive in a habitat with limited resources (food, water, shelter, etc.)

Occurs when 2 or more species' niches overlap

A niche is an organism’s way of life, or its role in an ecosystem

An organism’s habitat, what it eats, how it obtains its food, etc.

Competitive Exclusion Principle: If two species attempt to occupy the same niche in the same habitat at the same time, one species will be better at competing for limited resources.

The other species will eventually become extinct from the community.

What is Symbiosis? Symbiosis( “life together”): is when organisms live together

in close association over an extended period of time

At least one organism benefits from the relationship

There are 3 kinds of symbiotic relationships:

1. Parasitism

2. Commensalism

3. Mutualism

Parasitism Species interaction in which one

organism benefits from the relationship, and the other is harmed.

One species (the parasite) feeds on, but does not always kill, another species (the host)

Example: Humans and ticks

Tick gets food from the blood of human and human experiences pain, discomfort and infection

Commensalism

Species interaction in which one species benefits from the relationship, and the other is unaffected (neither benefited or harmed)

Example: Cattle egret and cattle

Cattle stirs up insects as it moves through the grass, and egrets hang around and eat the insects

Mutualism

Species interaction in which both organisms benefit from the relationship

Example: Bees and flowers

The bee gets food from the flower [nectar] and the flower gets pollinated

May 4, 2011

Objective: Describe the interactions among species

Drill: The birds in the picture are eating insects that are located on the rhino. What type of relationship (species interaction) exists between the birds and the rhino? Explain.

IR- pg. 32 In the ocean, the clownfish lives among the

stinging tentacles of the sea anemone, protected from predators that cannot tolerate the anemone’s sting. The clownfish also chases away certain anemone eating fish that can damage or kill the anemone. Because of the popularity of an animated movie about clownfish, Finding Nemo, there has been a sharp increase in the demand for the clownfish in pet stores. This has resulted in a substantial increase in the capture of these clownfish by companies that sell tropical fish.

Write a letter to a tropical fish company, explaining why it is important to limit the number of clownfish they are capturing and how the anemone population may be affected if the clownfish disappears.

Examples of Human Symbiosis

Mutualism- getting a service, paying for the service

Parasitism- Robbing

Communalism- sharing food, or giving someone a free ride

Review Population: A group of organisms, all

of the same species, which interbreed and live in the same place at the same time

Community: All the populations of different species that live in the same place at the same time

There are many different interactions among species.