5 Energy and ecosystems

Question 1

Producer

Answer 1

Photosynthetic organisms that produce organic substances using light energy, water, carbon dioxide and mineral ions

Question 2

Consumer

Answer 2

Organism that obtain their energy by feeding on other organisms

Question 3

Saprobionts

Answer 3

DECOMPOSERS
Break down complex materials in dead organisms into simple ones. When they do sp they realises the valuable minerals in a form that can be absorbed by plants.

Question 4

Saprobionts

Answer 4

DECOMPOSERS
Break down complex materials in dead organisms into simple ones. When they do sp they realises the valuable minerals in a form that can be absorbed by plants.

Question 5

What do arrows in a food chain represent?

Answer 5

Direction of energy flow

Question 6

Plants only use 1-3% of the suns energy to produce organic matter. State some reasons why?

Answer 6

1) 90% reflects back into the atmosphere from the earth
2) not all wavelengths of light are absorbed
3) not all lights falls on chlorophyll
4) low co2 levels limit rate of photosynthesis

Question 7

Identify 3 ways energy is lost between trophic levels

Answer 7

1) lost by heat
2) lost to the atmosphere
3) digested

Question 8

Equation for percentage efficiency

Answer 8

Percentage efficiency =

energy after transfer ÷ Energy before transfer

Question 9

Amonification

Answer 9

Production of ammonia from organic nitrogen containing compounds

Question 10

Nitrification

Answer 10

Oxidation of ammonia into nitrite no2- to nitrate no3-

Question 11

Nitrogen fixation

Answer 11

Nitrogen gas converted into nitrogen containing compounds

Question 12

What are the 2 main microorganisms that carry out nitrogen fixation?

Answer 12

1) free living nitrogen-fixing bacteria

2) mutalistic nitrogen-fixing bacteria

Question 13

Denitrification

Answer 13

Convertion of soil nitrates into gaseous nitrogen

Question 14

Why is it important to plough soil?

Answer 14

When soil isnt ploughed is reduces oxygen content in the soil. Fewer aerobic notifying bacteria and more anaerobic denitrifying bacteria - convert soil nitrates into gaseous nitrogen. Reduces availability of nitrogen containing compounds for plants

Question 15

Why do living organisms require nitrogen?

Answer 15

• protiens

- nucleic acid

Question 16

Why is phosphorus an important biological element?

Answer 16

It's a compound of
of
-ATP 
-phospholipds
-nucleic acid