(ECO) Community and Environment Lesson
Community and Environment Lesson
An ecosystem is made up of the living (biotic) community and its nonliving (abiotic) environment. A community is the biological (biotic) components of an ecosystem.
An ecosystem can exist on land, in water, and in air. The plants, animals, and microorganisms that live in a small body of freshwater are the biotic parts of a pond ecosystem, or the community. The plants and tiny organisms depend on sunlight to carry out photosynthesis.
Biodiversity
Some ecosystems are more stable than others. Stable ecosystems are able to maintain their balance because they have a great deal of biodiversity. Biodiversity is the amount of different types of organisms living in an ecosystem or community. Biodiversity is not spread evenly across the Earth; it is greatest in tropical areas where milder temperatures and rainfall allow for more species to coexist.
Biodiversity is a measure of how healthy the Earth is. If we lose biodiversity, it means that we are losing species. Humans rely on biodiversity because we use resources from the plants and animals for food, medicine, shelter, and fuel. Humans can cause biodiversity to decrease when we destroy habitat, over-consume resources, or change the climate (temperature or rainfall) as a result of pollution.
Take a look at this map that shows the Biodiversity hotspots on Earth. Read the caption. Do you live near or have you visited a biodiversity hotspot? What could humans do to help maintain biodiversity in these valuable areas?
See description of diagram Links to an external site.
Extinctions
Succession
The communities within ecosystems change over time. Succession is a term used to describe how the biotic (living) parts of that ecosystem change over long periods of time. You can see the stages of succession on one piece of land below.
Disturbances, such as disease and fire, may cause ecosystems to become unstable. When an ecosystem is disturbed, individual organisms as well as entire species can die out and succession may begin again.
Presentation Primary Succession
Primary succession, or a development of an ecosystem in an area where life did not exist before, occurs in the following stages:
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Lack of rain or a drought can change a pond ecosystem dramatically. The remains of dead organisms can accumulate at the bottom of the pond. Over time, the layers of soil and decomposing matter increase and change the habitat. Larger plants begin to grow along the edge of the disappearing pond. After many years, larger animals such as mice and rabbits begin to move into the area that has gradually been transformed. The pond ecosystem had changed over time into a forest ecosystem.
See description of diagram Links to an external site.
Watch the following video from Khan Academy that explains Succession. Answer the following questions while watching:
- What is ecological succession? What are the two types of succession?
- What is the difference between the two types of succession?
- What are pioneer species? Can you give some examples? What is their job in succession?
Succession is a transition in a community. Primary succession occurs if no previous organisms were present.
Biosphere
The biosphere is the highest level of the ecological organization of life. The biosphere is the part of Earth where organisms live. It extends from the crust and the ocean to the atmosphere. The biosphere includes all of the organisms living on Earth's surface as well as the nonliving things such as soil, water, and air. The abiotic factors of a biosphere are important for the flow of energy, nutrients, air, and water in an ecosystem. The biosphere consists of all of the ecosystems on Earth. An ecosystem found over a large geographical area is called a biome.
Now watch the video Learning About Ecology below. The video is approximately 13 minutes long and focuses on the characteristics of each of the levels of organization in ecology. Pause the video when necessary to make notes.
Complete the following review activity to test your new knowledge about ecosystems, their community and environment.
Key Terms
Complete the following activity to review your key terms.
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