ESS 2.2.1-2

• Ecosystem is a community of interdependent organisms and the physical environment they interact with. 

  A community is a group of populations living and interacting with each other in a common habitat 
•  Producers convert inorganic compounds into food. Hence they are known as autotrophs or self-feeders, they obtain their food by making it for themselves. Producers are at the base of the food chain and so they are referred to as primary producers.
• Plants have a number of important roles in the ecosystem:

  • They provide food for all other life on earth, herbivores eat plants and then carnivores and omnivores eat the herbivores. 
  • Plants regulate the hydrological cycle by taking water in and releasing it in to the atmosphere through transpiration.
  • They maintain the balance of gases in the atmosphere by absorbing CO2 and releasing oxygen. This may also help redress global warming.
  • Plants provide habitats for many animals.
  • The roots of plants help bind the soil and reduce erosion.
• Consumers are referred to as heterotrophs, meaning other-feeders, and cannot manufacture their own food, obtaining it by consuming other organisms.
• Herbivores are a type of consumer that eat just plants, including leaves, flowers, fruits, and nuts or stems and wood.
• Capybara, a large South American rodent, is an example of a herbivore that eats grasses, aquatic plants, fruit, and tree bark.
• Carnivores are a type of consumer that eat only meat or other animals and are the predators.
• African lions are an example of carnivores that eat wildebeest, zebras, buffalo, and warthogs.
• Omnivores are a type of consumer that eat both plants and other animals.
• Red panda is an example of an omnivore that eats bamboo, small mammals, birds, eggs, flowers, and berries.
• Decomposers such as bacteria and fungi absorb and metabolise waste and dead matter on a molecular level then release it as inorganic chemicals that can be recycled through the ecosystem via plants. 
• Decomposers and detritivores are vital because they:

  • Clear ecosystems of dead bodies.
  • Prevent the spread of disease by disposing of dead bodies. 
  • Facilitate the continued functioning of ecosystems by releasing the nutrients that were locked up in the organic matter and making them available again
• Animals eat plants (or other animals) the process of photosynthesis is reversed in respiration.
• Photosynthesis is green plants are able to take light energy from the sun and use it to make chemical energy – which is just as well for us as we cannot make our own energy we have to take it in when we eat. In fact all life on earth (including plants) need to take the chemical energy and use it for life processes.

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