B18.8 Trophic levels and biomass Flashcards
What is a trophic level?
The positions of organism within a food chain are known as trophic levels
What is in Trophic level 1?
The producers that make their own food by photosynthesis - Plants and algae
What is in Trophic Level 2?
Primary consumers - Herbivores that eat plants or algae
What is in Trophic Level 3?
Secondary consumers - carnivores that eat herbivores
What is in Trophic Level 4?
Tertiary consumers - carnivores that eat other carnivores
At the top of the food cahin
What are the roles of decomposers?
Break down dead plant and animal matter by secreting enzymes into the environment
Small soluble food molecules then diffuse back into the microorganism down a concentration gradient
What is biomass?
The mass of material in living organisms
What is Biomass often measures as?
Dry mass of biological organisms
What are the main problems of using dry biomass?
You have to kill the organisms to dry them out
It is less useful because the amount of water in living organisms can vary throughout the day and depending on conditions
What is the purpose of measuring the biomass?
Useful way of looking at the feeding relationships between the different organisms
Why is the amount of biomass at each trophic level less than it was at the previous level?
Not all organisms or parts of organisms ar eaten by the stage above
Some of the biomass taken in is passed out and lost in the waste materials of the organism
Large amounts f biomass taken in at each trophic level are used in respiration to transfer energy for the organisms
Where is Trophic level one usually found?
At the bottom of the pyramid
