4.3 & 4 Flashcards
What do plants need to survive?
Light, water, CO2, minerals and space
What do animals need to survive?
Food, water, breeding partners, space, shelter
Define interdependance.
How different organisms depend on each other within a community.
What are three types of ecological relationships?
Predation, mutualism, parasitism
What is predation?
Predator-prey relationship, if prey population increases, so does predator as there is food for the predator.
As the prey is eaten their population decreases and so does the predator population - lack of food. Prey then can reproduce and cycle starts again.
What is mutualism?
Both organisms benefit from the relationship.
E.g. oxpecker-buffalo, oxpecker gets food (ticks and fleas) on buffalo, and buffalo is free from disease and irritation.
What is parasitism?
Only one organism benefits (the parasite)
The host suffers
E.g. tapeworms in animal digestive system or fleas on animals (e.g. cat’s blood is sucked)
What does a pyramid of number show?
The population at each trophic level, producer at the base, then primary consumer, secondary etc.
DOESN’T SHOW BIOMASS - pyramid can be inverted
What do pyramids of biomass show?
Biomass at each trophic level taking into account the number and size of organisms present.
How is biomass calculated?
Sample of organisms from each trophic level weighed, and then multiplied by the number of organisms (DRY WEIGHT)