ECOSYSTEMS.

Transcription

1 ECOSYSTEMS

2 Cycles, Balance, And Life For hundreds of millions of years the chemicals and elements found on Earth have remained relatively constant, or in other words, they have changed very little. The amount of one element or chemical in the Earth s surface is practically the same as it was many millions of years ago. This consistency is one of the things that makes life on Earth possible.

3 This balance is maintained via complex interactions or cycles between the Earth, and its organisms, or life forms. The elements of the Earth are taken into life forms, used to sustain the organism, and later released in the form of waste, or through decomposition upon the death of the organism. Most of these cycles only take a few months, or a few years to complete. However, some can take many millions of years.

4 THE ENERGY CYCLE Each day as the Sun rises, our world is showered with heat and light. This energy from the Sun is very important to all life on Earth. Without it, life could not exist. While most of the heat and light that reaches the Earth is either reflected, or radiated back into space, some of it is captured by plant life through the process of photosynthesis.

5 Photosynthesis takes place when plants use sunlight in order to produce sugars. These sugars can than be used by the plant as food, in order to sustain the functions of life. Animals do not have the ability to produce our own food. Thus we must obtain our energy by eating plants, or by eating other animals that have eaten plants.

6 At some point as plants, or animals die, or release waste into the environment, the heat from the Sun is released back into the environment.

7 Water/Hydrologic Cycle The water found within your body has been used, and re-used by organisms throughout the history of Earth. It is quite possible that there is water found in your body, that was once inside of a tyrannosaurus rex.

8 The Carbon Cycle

9 The Carbon Cycle and Fossil Fuels Every so often, a plant or animal does not decompose right away. Their bodies are trapped, in locations where decomposition can simply not take place. Instead of returning to the atmosphere, the carbon from these life forms is trapped within the Earth. Over millions of years more and more of the carbon on Earth has been trapped in this manner. Today, almost 99% of all the carbon on Earth has been locked up deep within the Earth.

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11 This important balance has been altered significantly in the past century, as humans have begun using fossil fuels to produce energy. By burning the Earth s store of carbon, mankind is able to create the energy needed to operate our communities. However, we must be careful as we do so. By releasing more carbon into the atmosphere than is being locked up, we risk causing damage to the delicate carbon cycle.

12 The Oxygen Cycle

13 The Nitrogen Cycle

14 Ecosystems and Biomes

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16 What is an ecosystem? All living and non-living things in a given area that interact with one other, make up an ecosystem. All the different organisms that live together in an ecosystem is called a community The community is organized into relationships called food webs or chains The non-living part of an ecosystem includes water, rocks, air, light, and soil.

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18 Ecosystems The plants and animals depend on each other and the non-living environment to survive. Each organism has its own niche, or role, to play. Disruptions to any part of an ecosystem can be disastrous to all organisms within it.

19 What is a Biome? A biome is a large area with similar plants, animals, and microorganisms. Each of these large communities contain species that are adapted to its varying conditions of water, heat, and soil.

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21 What is the difference between an ecosystem and a biome?? An ecosystem is much smaller than a biome. Conversely, a biome can be thought of many similar ecosystems throughout the world grouped together. An ecosystem can be as large as the Sahara Desert, or as small as a puddle.

22 Ecosystem Issues Ecosystems will fail if they do not remain in balance. No community can carry more organisms than its food, water, and shelter can accomodate. Food and territory are often balanced by natural factors such as fire, disease, and the number of predators.

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24 Humans and Ecosystems Most natural ecosystems are constantly changing. The types and abundance of organisms in the ecosystem change because the living and non-living factors change. For example, changed weather conditions, such as heavy rain or prolonged dry weather, change the availability of food or the presence of disease-causing organisms.

25 Natural Changes in Ecosystems However these changes are rarely permanent, and the ecosystem usually recovers over a period of time. Human activity, on the other hand, can dramatically change the type and composition of an ecosystem. In many cases, the activity can change the ecosystem permanently.

26 Humans and Ecosystems Humans can change both the living and nonliving factors in an ecosystem. They can alter the food source through the clearing of vegetation and introduce predators such as cats and dogs to food webs. Clearing the natural vegetation also alters soil fertility, and household and industrial wastes can change the quality of the air and water.

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