B18 organisms and their environment

Question 1

what is the principal source of energy input into biological systems

Answer 1

sun

Question 2

describe the flow of energy thru living organisms

Answer 2

• light energy from sun converted by green plants and algae into chemical energy (carbs)
• plants use food from photosynthesis to grow
• eaten by animals, chemical energy of plant transferred to body of animal
• animal eaten by second animal, chemical energy transferred
• eventually all energy transferred to environment via heat loss

Question 3

describe what is meant by a food chain

Answer 3

• showing transfer of energy form one organism to next
• beginning with producer

Question 4

describe what is meant by a food web

Answer 4

network of interconnected food chains

Question 5

describe what is meant by a producer

Answer 5

• organism that makes its own organic nutrients
• usually using energy from sunlight thru photosynthesis

Question 6

describe what is meant by a consumer

Answer 6

organism that gets its energy by feeding on other organisms

Question 7

describe what is meant by a herbivore

Answer 7

animal that gets its energy by eating plants

Question 8

describe what is meant by a carnivore

Answer 8

animal that gets its energy by eating plants

Question 9

describe what is meant by a decomposer

Answer 9

an organism that gets its energy from dead or waste organic material

Question 10

describe what i smeant by a trophic level

Answer 10

position of organism in food chain and food web

Question 11

order of trophic levels

Answer 11

1. producers
2. primary consumers
3. secondary consumers
4. quaternary consumers

Question 12

why is the transfer of energy from one trophic level to another inefficient

Answer 12

• not all of plant is eaten
• energy used to build inedible tissue
• heat from respiration
• biological activities

Question 13

why do food chains usually have fewer than 5 trophic levels

Answer 13

• large amount of energy lost at each level
• energy transferred up less and less each level
• less energy available higher up

Question 14

why is it more energy efficient for humans to eat crop plants than livestock

Answer 14

• less energy is lost
• only around 10% transferred to livestock

Question 15

processes in carbon cycle

Answer 15

• photosynthesis
• respiration
• feeding
• decomposition
• formation of fossil fuels
• combustion