year 9 autumn biology big test rev

• • Food chains show the flow of energy from one organism to another.
• • All organisms in an ecosystem depend on each other.
• • Food chains show the feeding relationships between organisms.
• • Food webs show how all the food chains in an ecosystem interact.
• carnivor- animals that only eat other animals
• herbivore- animal that inly eats plants
• A food chain is a list of organisms in a habitat that shows their feeding relationship, i.e what eats what.
• The organisms are joined by arrows which show the transfer of energy in food between them. The stages in food chains are called trophic levels.
• There are volcanic vents at the bottom of the oceans where it is so dark that no plant or algae could live. Places like this are the only food chains on Earth that don’t start with photosynthesis.
• The producers are bacteria which feed directly on the chemicals released from the vents and use a variety of chemical reactions to make glucose. This process is called chemosynthesis.
• if poison enters a food chain it is passed along and has knock on effects of all animals in a food chain
• DDT poison to kill pests and insects were taken in by plants and was passed along the food chain causing bird eggs to be thin and crack easily
• if there are too many of a certain animal it can cause damage to the habitat and other animals
• food web- all the food chains that make up an ecosystem
• decomposers in a food chain are organisms that break down dead organic material and waste products, returning nutrients to the soil and making them available for plants. They play a crucial role in the ecosystem by recycling nutrients and maintaining the balance of the food chain. Examples of simple decomposers include bacteria and fungi