Ecosystem

Unit 5 Lesson 1 What Is an Ecosystem?

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What Is an Ecosystem?


• An organism’s environment is all the living and nonliving things that surround and affect the organism.

• Environments include biotic and abiotic parts. Biotic parts are living things in an environment, such as plants, animals, and other organisms.

• Abiotic parts are nonliving things in an environment, such as climate, water, soil, light, air, and nutrients.


What Is an Ecosystem?


• Abiotic parts of an environment have an important role. Temperature and amount of water affect which plants and animals can live in a place.

• An ecosystem is all the organisms living in a place together with their environment. Each ecosystem has its own living and nonliving things.

• An ecosystem can be huge, such as a large forest or desert, or it can be small, such as a mud puddle or a single bush.


• A group of organisms of the same species in an ecosystem is called a population.

• Each ecosystem contains different groups of living things. A savanna ecosystem may contain populations of zebras as well as grasses and trees.


Populations and Communities


• The different populations that share an ecosystem make up a community.

• A community consists of all the populations that live and interact in an area.




• Populations in every ecosystem need food, water, shelter, and space to live.

• The interaction between populations to meet these needs is called competition.




• Populations that compete and obtain enough resources will survive, while those that cannot compete will not survive.

• These resources are called limiting factors, because there is only enough food, water, shelter, and space to support a certain number of organisms.

• Competition also occurs within populations. Stronger individuals get the most food and best shelter. Thus, weaker individuals may not survive.




• An organism’s habitat is the place where it lives within an ecosystem. Several populations share the same habitat.

• An organism’s niche is its complete role or function in its ecosystem. A niche includes all the ways the organism survives.

• An organism’s niche includes how it finds food, as well as the climate in which it thrives.


Find Your Niche


• Every organism has a niche. Having different niches allows different organisms to survive in the same habitat.

• Organisms with a specific way of living have a narrow niche. For example, an animal that eats only one type of food cannot survive without that food.

• Organisms with narrow niches tend to live in specific places, while those with broad niches often move around large areas.


Find Your Niche


• Populations can share a habitat but not the same niche.

• For example, red-shouldered hawks and barred owls share a habitat, but have different niches. They both hunt different prey at different times of the day.

• If two populations of organisms share a niche, they must compete for resources.


Find Your Niche


• Diverse means different in kind. Diversity is the variety of different species that live in an ecosystem.

• An ecosystem that is very diverse contains many species. Ecosystems without much diversity may be inhabited by only a few species.

• Organisms are connected in a large, complex web. The more types of organisms in an ecosystem, the larger the web, and the more resources available.


Diversity

• Climate and location affect the amount and types of resources that are available for organisms.

• Generally, very diverse ecosystems, such as coral reefs and rain forests, are near the equator. Less diverse ecosystems are farther from the equator.



Diversity



• Humans can damage ecosystems and affect diversity by reducing the number of species living in the ecosystem.

• Activities such as overhunting or destroying forests to build may lower the numbers of important species.

• Species in those environments have lost their habitats, and diversity has decreased.

Diversity

Technology

Ecosystem