From Bottle Ecosystem to the Earth Ecosystem

The carbon cycle on earth is complicated since there are more types of plants, animals, microorganisms, habitats, and so on. But the basic idea is the same as in our model ecosystem.

Bottle Ecosystem


Photosynthesis: Plants use CO2 to make food and grow. They give off O2. Same but there are many more plants.
Respiration: Fish, snails, and microorganisms use O2 and give off CO2. Same but there are many more animals and microorganisms.
Atmosphere: You may have a bit of air at the top of your ecosystem. This will contain oxygen and carbon dioxide along other gases. Atmosphere is a much, much larger part of the earth ecosystem.
Soil: After a while you'll likely see some matter at the bottom of your ecosystem. Microorganisms will be eating this matter and giving off CO2. Same but there are different types of soils in different ecosystems.
Water: The aquatic ecosystem shown here is mostly water. You can make other bottle ecosystems with only a little water. Water is found in rivers, lakes, the ocean, etc.
Amount of CO2: over time the amount of CO2 and O2 is relatively balanced (unless the ecosystem crashes and the fish, snails, and plants die). On earth the amount of CO2 in the atmosphere is becoming unbalanced with CO2 being added to system faster than it can be absorbed.
Human activity: None Humans and human activity (land use, transportation, generating electricity, etc.) are present.

In many ways the bottle ecosystem and the earth are very similar. Because of this we can conduct experiments to see how changes affect ecosystems. This can help us understand how the earth ecosystem might respond to the same change.

An example would be building two ecosystems—one with plants and one without. We could then compare the two systems and understand the role of plants in the carbon cycle. This could give us insights into the role of plants in the carbon cycle on earth.

The carbon cycle is all about how carbon moves around in ecosystems.

By now you should understand that:

  1. Carbon is present in all living things.
  2. The amount of carbon on earth doesn't change.
  3. Where carbon is found can change.
  4. Carbon can be bonded to different atoms at different times in the carbon cycle.
  5. There are many different chemical compounds that contain carbon.

If carbon moves around, how can it get from a polar bear to peanut butter?