Bell Ringer

1. Can a food web or food chain ever show

abiotic factors?2. A food web shows life at the [population,

community, ecosystem] level. (Pick one.)3. Can an energy pyramid ever be inverted?4. How much energy passes from one trophic

level to the next?5. Can a biomass pyramid ever be inverted?

Bell Ringer

What Shapes an Ecosystem?

So, how do all those organisms live together?

Ecosystems are defined by the

interactions among the biotic and abiotic factors that exist within.

The two major factors that these interactions influence are: How organisms survive and thrive. The overall productivity of the

ecosystem.

What shapes an Ecosystem?

The area where an organism lives is called

its habitat. An organism’s habitat can also include a host body, in the case of parasites.

The “role” that an organism plays in its habitat is called a niche. An organism’s niche includes: The conditions in which an organism lives. The means by which an organism survives.

What shapes an Ecosystem?

For example, a bullfrog’s habitat would

be a pond, lake or stream, as well as the land nearby.

A bullfrog’s niche would be: The food it eats, and is eaten by. The cold, watery environment it lives in. The means by which it maintains body

temp. The means by which it reproduces.

What shapes an Ecosystem?

Community Interactions

Organisms that live within the same ecosystem interact with each other on a constant basis.

These interactions may or may not be beneficial, to either party.

Community Interactions

Competition: This interaction occurs when two organisms fight over the use of one resource at the same time. The organisms may

OR may not be of the same species!

The competitive exclusion principle states

that no two species can occupy the same niche in the same habitat at the same time.

This principle means that different species will go out of their way to avoid competing with one another. This is because competition might lead to death

for the loser!

Community Interactions

Community Interactions

Community Interactions

Predation: An interaction in which one organism ACTIVELY hunts and eats another.

Both predator and prey evolve adaptations to help them survive.

Community Interactions

Symbiosis: ANY relationship where two organisms live closely together. This means the two

organisms are NOT trying to kill each other…

Although there may still be negative effects!

There are three possible symbiotic

relationships: Mutualism, where both organisms

benefit. Commensalism, where one organism

benefits, and the other is unaffected. Parasitism, where one organism

benefits, and the other is harmed.

Community Interactions

Symbiotic Relationship

What happens to organism 1?

What happens to organism 2?

Mutualism Benefits (+) Benefits (+)

Commensalism Benefits (+) Unaffected (=)

Parasitism Benefits (+) Harmed (-)

Community Interactions

1. The role that an organism plays in its

environment is its _______.2. Can two different species occupy the same

ecological niche? Why or why not?3. Two male deer are butting heads over

territory. What is this an example of?4. Barnacles attach themselves to a whale to

move around, and the whale is neither helped or harmed. What is this an example of?

Exit Ticket

Ecosystems do NOT stay constant over time.

They will change in response to both abrupt and gradual changes in the environment.

As an ecosystem changes, older inhabitants die out, and new ones replace them. This causes the local community to continually evolve.

We call this process ecological succession.

Ecological Succession

The type of succession that occurs depends

on whether soil already exists or not. If NO soil exists, primary succession

occurs. This happens right after a volcanic eruption,

or after glaciers melt. If soil already exists, secondary succession

occurs. This happens when farmland is abandoned, or

after a wildfire.

Ecological Succession

In primary succession, there is no soil to

start; just ash and rock.1. First, pioneer species (often lichens)

populate the area. They break up the rocks to form soil.

2. These species die, which provides nutrients to the soil. They are eventually replaced with new plants.

Ecological Succession

In secondary succession, good soil

already exists. Only the wildlife is replaced.

1. First, small shrubs and grasses appear.2. Small bushes and evergreen trees

develop first.3. Eventually, the evergreens are

overtaken by larger deciduous trees.

Ecological Succession

Marine ecosystems are also prone to

ecological succession. This can take the form of tectonic

upheaval, of temperature changes, or of the addition of new communities or habitats.

Ecological Succession

1. A dog is infested with fleas, which feed

of the skin and blood of the dog. What is this an example of?

2. What type of succession will occur after:a. a wildfire?b. a glacier melts?c. a swarm of locusts eats most of the

vegetation?

Exit Ticket

Answer true or false to all statements.1. Competition only occurs between members of the

same species.2. Symbiosis includes mutualism, commensalism and

parasitism.3. Ants move aphids to new leaves, while aphids produce

food the ants like. This is an example of mutualism.4. The appearance of pioneer species is the first step of

primary succession.5. Secondary succession only occurs when there is no

soil.

Exit Ticket