EI - Roles in an Ecosystem Lesson

Roles in an Ecosystem

What's my Role?

Look at these photos of these common animals found in the Savanna of Africa.
What comes to mind?

Image of Lions, bulls and Elephants

Can you identify all of the animals? There is the lion, the elephant, and the…wait what is the third one? A water buffalo? An African cow?

Mmmm, but without knowing exactly what it is we can infer its role among these other animals. Does it look to be a predator or prey? Will it eat the elephant or lion or be eaten?

Understanding fundamental interactions within an ecosystem is known as community ecology. Community ecology helps scientists apply rules to help ecosystems that are being affected by pollution, habitat loss, severe weather, or interactions with humans.

Let's Get Organized

Ecosystems are made up of several habitats. Habitats are the environment in which a particular species of an organism lives. Biotic and abiotic factors define habitats that are found within a specific space. There can be several habitats within an ecosystem, and within each habitat every living organism has a niche or a job. The niche includes all of the relationships that organisms have within their environment and affect the survival and reproduction of that organism. An animal’s niche includes how it behaves, what it eats, when it is active, and how it interacts with other organisms.

Essentially a habitat is an organism’s house and a niche is its' job!

Habitats are the environment in which a particular species of an organism lives. Biotic and abiotic factors define habitats that are found within a specific space. There can be several habitats within an ecosystem, and within each habitat every living organisms has a niche or a job.

A species’ niche must be specific to that species as no two species can fill the EXACT same niche. There can be overlapping among different species, but there must be a distinct difference. If there is not a difference then two species will compete for the same resources, forcing one to outcompete the other often causing the other species to adapt or risk extinction. This is an example of the competitive exclusion principle that states that if all other factors are constant, no two species that compete for the same resources can occupy the same niche at a constant population. Therefore resources in an ecosystem are often partitioned due to competition between two species with similar niches. If a niche is left vacant within an ecosystem, other organisms can expand their niche and fill that position. Organisms can do this because they are often tolerant, able to survive and reproduce under a range of conditions. If there is an organism that cannot fill the role, than often a species will adapt so that niche does not go unused.

There are two types of niches, fundamental and realized. The fundamental niche is the full potential range of the organism if there were no other interactions. In other words if there were no barriers. But there are barriers within an ecosystem, from limiting factors, such as food, water, and shelter; and interspecific competition. Interspecific competition is when the different species compete for the same resources in an ecosystem, food, shelter, etc. This competition limits an organism's role in an ecosystem. The niche that an organism actually fills in an ecosystem is much smaller than its fundamental niche. This is known as an organism's realized niche, which is the part of the potential niche that allows a species to survive and reproduce.

So there is this thing called competition. It plays a big role in the ecosystem.

Watch the video below to find out more.

Let's take a look at this example. It's a raccoon...

The raccoon can eat a variety of foods from plants, insects, and fish and can nest in a variety of places. The raccoons’ fundamental niche would include all of the things this species could eat and all of the places it could live. If given a chance raccoons would live in forests eating fresh plants and small animals. But, rarely in real-life does a species get an ecosystem all to itself; therefore the raccoon's niche is affected by the interactions with many different organisms - some of which may have similar fundamental niches. A raccoon's realized niche is in an urban setting in sewers and dumpsters.

Roles in an Ecosystem Challenge

Before You Go, You Need to Know

The following key points are from this explore section of the lesson. You must know the following information before moving to the next lesson. This is just a summary of the key points.

A habitat is the PLACE where and organism lives, and its niche is its job.
An organism's fundamental niche is the entire set of conditions under which an animal could survive and reproduce.
An organism's realized niche is the actual condition used by an organism to survive and reproduce, after all interactions with other organisms have been taken into account.
The competitive exclusion principal states that two organisms with the same realized niche cannot exist at constant population together within an ecosystem.
Interspecific competition is when organisms compete for the same ecological niche.

IMAGES CREATED BY GAVS OR OPEN SOURCE