Food Chains Flashcards
What are producers?
•Organisms at the first level of the food chain e.g. green plants or algae
•they make glucose by photosynthesis
•glucose is used to make other biological molecules in a plant which make up the biomass
What are primary consumers?
•organisms at the second level of the food chain
•these are herbivores that only eat plants
What are secondary consumers?
•Organisms at the third level of the food chain
•these are carnivores that eat herbivores
What are tertiary consumers?
•Organisms at the fourth level of the food chain
•these are carnivores that eat other carnivores
•they have no predators and are at the top of the food chain (apex predators)
What are decomposers?
Fungi and bacteria that break down dead plant or animal matter
How do decomposers break down matter?
•they secrete enzymes
•the matter is broken down into small soluble food molecules and they move into microorganisms by diffusion
What is biomass?
•The mass of living material (the “energy stored in a plant”)
•energy is transferred through living organisms in an ecosystem when they eat other organisms
Why is only around 10% of biomass transferred to the next levels of the food chain?
•not all biomass can be eaten e.g. carnivores cannot eat bone, claws and teeth
•not all biomass eaten is converted into biomass of the animal eating it e.g. it lost can be lost as faeces, urea or in plants lost due to respiration as carbon dioxide
•herbivores do not have all the enzymes to digest all the material they eat so it is egested instead
What are predators?
Consumers that hunt and kill other animals
What are prey?
Organisms that predators eat
In a stable community, what determines the population size of any species?
The population of any species is usually limited by the amount of food available
In a stable community what happens if the amount of prey increases?
The population of the predators increase
In a stable community what happens if the population of predators increases?
The number of prey decrease
Why are predator-prey cycles are always out of phase with each other?
It takes a while for one population to respond to changes in the other population e.g. in a community where foxes eat rabbits, when the number of rabbits increase, the number of foxes doesn’t increase immediately as it takes time for them to reproduce
