biomass and food security

Question 1

how do decomposers work?

Answer 1

they break down dead plant and animal matter by secreting enzymes into the environment
small soluble food molecule then diffuse into the microorganism

Question 2

trophic levels?

Answer 2

level 1: plants and algae make their own food - producers
level 2: herbivores eat the plants/algae - primary consumers
level 3: carnivores eat these herbivores - secondary consumers
level 4: carnivores which eat other carnivores - tertiary consumers
if a carnivore has no predators, they are known as an apex predator

Question 3

biomass transfer and how is it lost?

Answer 3

only 10% is transferred to the trophic level above in a pyramid of biomass
lost as a result of not all the ingested material being absorbed such as egested as faeces
lost as waste such as carbon dioxide and water in respiration as well as water and urea in urine

Question 4

what threatens food security? (give three factors)

Answer 4

• the increasing birth rate has threatened food security in some countries
• changing diets in developed countries means scarce food resources are transported around the world
• new pests and pathogens that affect farming
• environmental changes that affect food production, such as widespread famine occurring in some countries if rains fail
• the cost of agricultural inputs
• conflicts that have arisen in some parts of the world which affect the availability of water or food.