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Notes

• biotic: concerning living things which an organism comes into contact with
• abiotic: includes light, water, oxygen, temperature, salinity and pH of water or soil
  

Some terms

• Habitat: a place where an organism lives
• Population: a group of individuals of the same species
• Niche: the role played or position occupied by an organism in the habitat
• Community: consists of populations of plants and animals living together and interacting with one another under the same environmental conditions
• Producers: green plants that can manufacture food materials by photosynthesis
• Consumers: obtain their energy from the organisms on which they feed
• Decomposers: break down organic matter, feeding on some of the remains and releasing the rest
  

Food chain and Food web

• Food chain:
  
• a series of organisms through which energy is transferred in material form constitutes a food chain
• A food chain is usually short because of the loss of much energy to the environment at each level
  

• A food web consists of two or more food chains interlinked together

Carbon cycle

• The carbon cycle consists of processes by which carbon dioxide is removed and restored to the atmosphere

Parasitism

• Parasitism is an association between 2 organisms such that one organism (the parasite) lives on or in the body of another organism (the host)
• The parasite usually does some harm to its host
  

Malaria

• The malaria parasite requires 2 hosts (man and anopheles mosquito) to complete its life cycle
• It is transmitted from an infected person to a healthy person by the female Anopheles mosquito (the vector)