Healthy Ecosystem A healthy ecosystem is composed of: Producers Consumers Decomposers

Biodiversity Biodiversity maintains the health of the earth and its people. It provides us with food and medicine and contributes to our economy. It tells us a lot about the health of the biosphere. The greater the variety of species, the healthier the biosphere. SPEAKER’S NOTES: Biodiversity maintains the health of the earth (fill in the next blank) and its people. It provides us with food and medicine and contributes to our economy. For example, we use plants and animals for food and medicine and we can harvest plants and animals and sell them to make money. In Manitoba, the fishing industry contributes $150 million annually to our economy. Biodiversity tells us a lot about the health of the biosphere. The greater the variety of species, the healthier the biosphere is. Why is this? (pause, have students brainstorm answers). [Possible answers] more species = more links in food chains/webs = more stable more plants = more food for other animals (more oxygen too) more genes = better chances for survival through adaptation a variety of ecosystems = more habitat for different species.]

Sustainable Ecosystems

Sustaining an Ecosystem If you are healthy, you will probably live a long life. The same thing applies to ecosystems. A healthy ecosystem can sustain itself and stay intact (or stable) for a long time.

People have a responsibility to regulate their impact on the sustainability of ecosystems in order to preserve them for future generations

Ecosystems are dynamic and have the ability to respond to change, within limits, while maintaining their ecological balance.

Food Web A pictorial representation of the feeding relationships among organisms in an ecosystem Consists of various food chains

The more links in a food web, the more stable it is. SPEAKER’S NOTES: Removing one link from a food web that has many links does not affect it as much as if there were very few links. The more links in a food web, the more stable it is.

The Niche A niche is the full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions

NICHE No two species can share the same niche in the same habitat. Different species can occupy niches that are very similar.

Community Interactions When organisms live together in ecological communities, they interact constantly. Community interactions, such as competition, predation, and various forms of symbiosis, can affect an ecosystem.

Community Interactions/ Competition

Other factors that affect population growth Limiting factor- any biotic or abiotic factor that restricts the existence of organisms in a specific environment. EX.- Amount of water Amount of food Temperature

What is a Limiting Factor? Populations would continue to increase if they had all of the resources they require in unlimited amounts, but there are always factors that limit their increase. Limiting factors control population growth.

What is Carrying Capacity? Because of these limiting factors, each ecosystem has a finite capacity for growth connected to its carrying capacity.

What is Carrying Capacity? Carrying capacity is the number of individuals of a species that an ecosystem can support.

Ecological Succession Ecosystems are constantly changing in response to natural and human disturbances. As an ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further changes in the community.

This series of predictable changes that occurs in a community over time is called ecological succession. Sometimes, an ecosystem changes in response to an abrupt disturbance. At other times, change occurs as a more gradual response to natural fluctuations in the environment.

Primary Succession On land, succession that occurs on surfaces where no soil exists is called primary succession. For example, primary succession occurs on rock surfaces formed after volcanoes erupt. The first species to populate the area are called pioneer species

Primary Succession

Secondary Succession Components of an ecosystem can be changed by natural events, such as fires. When the disturbance is over, community interactions tend to restore the ecosystem to its original condition through secondary succession