Year 11 Term 1 continued Flashcards
(40 cards)
Biomass
Amount of biological matter measure as dry mass in kg
Carnivore
An organism that eats meat
Herbivore
An organism which eats producers (green plants)
Predator
An organism which hunts for food (a carnivore)
Producer
A green plant
Prey
An organism which is hunted by predators. can be carnivore or herbivore
What is a trophic level
This is a feeding level in the food chain. can be represented using numbers, starting at level 1
Further trophic levels are numbered subsequently according to how far the organism is along the food chain
Level 1 on the trophic level
Plants and algae make their own food and are called producers
Level 2 on the trophic level
Herbivores eat plants/ algae and are called primary consumers
Level 3 on the trophic level
Carnivores that eat herbivores are called secondary consumers
Level 4 on the trophic level
Carnivores that eat other carnivores are called tertiary consumers
What’s an apex predator
Carnivores with no predators
What’s a a decomposer
Break down dead plant and animal matter by secreting enzymes into the environment. Small soluble food molecules then diffuse into the microorganism
What happens to the amount of biomass and energy contained in living things as you progress up the food chain
It decreases as only 10% of the biomass from each trophic level gets transferred to level above it
Energy lost in waste
Meat is easier to digest than vegetarian so carnivores produce less waste but there are still undigestible materials (hair, teeth etc.) which become faeces. Protein is broken down to urea and passed as urine
Energy lost due to movement
Some biomass is used for respiration i.e. movement
Movement uses lots of energy, muscles become hot, the more the animal moves the more energy is tranferred
Why do mammals need to eat more food than other types of animals
Because lots of heat energy lost through respiration and so these large animals need to eat lots of food to maintain a body temp which is higher than its surroundings and get the same increase in biomass
Pyramids of biomass
The amount of biomass at each stage of the food chain is less than at previous stage.
We can draw total amount of biomass at each stage to scale in a pyramid
Interpreting pyramids of biomas
At each stage the amount of energy passed on gets less
A large amount of energy in the biomass of plants supports as smaller amount and so on this is why the numbers of each organism at each level gets smaller too
How to calculate the efficiency of a biomass transfer
efficiency= biomass transferred to next level/ biomass available at previous level x 100
What is cyclic fluctuation
The number of predators and prey affect each other and tend to go up and down in a regular pattern e.g rabbits and foxes
Describe how cyclic fluctuation works
Because of extra food, the no. of rabbits increase
As more food, no. of foxes also increases
More foxes= more rabbits eaten so no. of rabbits decreases
Now foxes have less food so decreases
this goes on and on
What is food security
Having enough food to feed a population. Sustainable methods must be found to feed all people on earth
Biological factors which are threatening food security
Increasing birth rate Changing diets in developed countries means scarce food resources are transported around world new pathogens affecting farming environmental changes cost of agricultural inputs
