Humans and the Ecosystem

• A producer is an organism that makes its own food, usually by photosynthesis.
• A food chain is a representation of the feeding relationships within a community.
• A consumer is an organism that eats other organisms for food.
• A herbivore is an organism that only eats producers (plants/algae).
• A predator is an organism that kills and eats other organisms.
• A prey organism is an organism that is killed and eaten by other organisms.
• An apex predator is a carnivore with no predators.
• The carbon cycle is process that returns carbon from organisms to the atmosphere as carbon dioxide, which can then be used by plants.
• The water cycle is the process that provides fresh water for plants and animals on land before draining into seas and rivers.
• Biodiversity is the variety of all the different species of organisms on Earth , or within an ecosystem.
• The advantage of high biodiversity is that it ensures stability of ecosystems by reducing the dependence of one species on another.
• Humans are trying to maintain biodiversity by:

  • Breeding programmes.
  • Protection of rare habitats.
  • Reintroduction of hedgerows.
  • Reduction of deforestation and carbon dioxide emissions.
  • Recycling resources.
• Due to a rapid growth in human population and increase in the standard of living, more resources are being used and more waste is being produced.
• Humans are reducing the land available for other organisms by: building, quarrying, farming and dumping waste.
• Negative impacts of destruction of peat bogs:

  • Reduces the amount of available habitat, causing decreases in biodiversity.
  • Burning or decay of peat releases carbon dioxide into the atmosphere.
• Large-scale deforestation has been carried out in tropical areas:

  • To provide land for cattle and rice fields.
  • To grow crops for biofuels.
• Carbon dioxide and methane are increasing in atmospheric levels and contributing to global warming.