Sustainable Ecosystems

Concept of Sustainability Ecosystems: all the interacting parts of a biological community and its environment Sustainable Ecosystem: An ecosystem that is capable of withstanding pressure and giving support to a variety of organisms

The Case of Easter Island Is thought to be a once thriving island People built statues and lived in forested area People cut down trees to grow crops, to burn as a heat source, until there were no more trees This lead to erosion, loss of plants as a food source, no extra materials to make houses, boats The island could no longer support the human population and society began to die off Only the statues remain

Parts of an Ecosystem Biotic Factors: living parts such as plants, animals, and microorganisms Abiotic Factors: non-living parts such as water, oxygen, light levels, nutrients

Biotic Interaction The interaction between members of two different species that live together in a close association. You may not see any interaction from the surface, the sea anemone and the clown fish. The clown fish eats animals that are attracted to the sea anemone and the fecal matter from the fish feeds the sea anemone There are three main types of symbiotic relationships: 1. Mutualism- both organisms benefit from the relationship 2. Commensalism- one organism benefits while the other is unaffected 3. Parasitism- one organism benefits at the cost of the host

Predation When one organism consumes another organism for food The consumed organism is called prey eaten by the predator This lady bug is the predator for aphids a bug that destroys many crops.

Competition Occurs when two or more organisms compete for the same resource such as food in the same location at the same time. Dandelions compete with the grass for same resources, water, nutrients and light

Abiotic Characteristics Key factors are: their importance and role on ecosystems Water –cells are mostly made up of water, wastes are disposed of with water, many animals and plants live in water –Water availability, desertification, water quality and pollution Oxygen –Essential for cell processes, animals breath it where it is absorbed into blood to the cells. Aquatic animals get oxygen through water –Human activities can lower oxygen levels in water depleting fish populations, pollution

Abiotic continued Light –Photosynthesis requires light. Plants and algae need light to undergo this process. All energy for ecosystems comes from light energy converted to other forms of energy –Amount of light is affected by ecosystems, forest trees block light from plants underneath, sediment in water blocks light for algae Nutrients –All organisms need nutrients, key ones are nitrogen and phosphorous –Human activities can alter nutrient levels, clear cutting, fertilizer run off etc. Soil –Provides structure for growth in plants, provides nutrients to plants –Top soil contains most of nutrients can be washed away from heavy rains

Homework Pg 9 # 1-4 Pg 20 # 1-3