Ecosystems

• Species - Any group of similar organisms that are able to breed together and produce fertile offspring.
• A habitat is the place where an

  organism lives.
• A population is all the members of one

  species in an ecosystem.
• Community is all of the organisms

  living together within an ecosystem.
• Depending on how they obtain food, organisms are divided into 2 groups – PRODUCERS and CONSUMERS
• Producers are organisms that are able to produce their own food through the process of photosynthesis
• Consumers are organisms that eat other organisms to obtain energy.
• A predator is an animal that hunts and eats other animals to gain energy.
• Prey are animals that are hunted and eaten by other animals.
• Energy is transferred in the form of chemical

  energy in food from plants to animals and then to

  other animals. This feeding relationship is called a FOOD CHAIN.
• A food web is a complex relationship composed of

  several inter-related food chains.
• An ecosystem is composed of:

  
  

  -the entire community of living organisms

  (plants, animals and micro-organisms) that

  inhabit a particular area

  
  

  -the abiotic/non living factors present in that

  habitat with which the living things interact.
• Ecosystem = community + habitat
• A niche is the role that an organism plays

  within a community.
• A niche relates to how the organism:

  
  

  -makes use of resources in its ecosystem

  such as light and nutrient availability.

  
  

  -interacts with other organisms in the

  community including competition and

  predation.

  
  

  -tolerates conditions such as temperature.
• A food chain is a relationship where one organism

  feeds on the previous one in the series and in

  turn provides food for the next one.
• The interconnection of food chains is called a

  food web.
• If one organism in a food web is affected

  (disease etc) then it has a knock on

  effect on the others
• Competition between organisms occurs when resources are in short supply.
• What will animals living in the same

  habitat compete for?

  
  

  -Water

  
  

  -Shelter

  
  

  Shelter

  
  

  -Mates (only intraspecific)
• Interspecific competition - Individuals of different species compete for the same resource in an ecosystem.
• Intraspecific competition - Individuals of the same

  species compete for exactly the same resources.
• Intraspecific competition:

  
  

  -is the most intense because

  the organisms require

  exactly the same resources

  
  

  -regulates the size of the

  population affected

  
  

  -weaker members will be

  weeded out by natural

  selection.
• Competition can be reduced by:

  
  

  -eating different foods

  
  

  -looking for food at different times of the

  day

  
  

  -nesting in slightly different habitats