food chains and food webs

Question 1

why do organisms need energy

Answer 1

organisms found in the ecosystem rely on energy to carry out all their activities

Question 2

source of energy

Answer 2

ultimate source of energy is sunlight which is then converted to chemical energy by plants and then passed as food between other organisms

Question 3

producers

Answer 3

• photosynthetic organisms that manufacture organic substances using:
  1) light energy
  2) water
  3) CO2
  it can be expressed in the equation:
  6CO2 + 6H2O + energy –> 6O2 + C6H12O6

Question 4

consumers

Answer 4

• organisms that obtain their energy by feeding on other organisms rather than by using light energy directly
• there are two types of consumers:
  1) primary consumers
  2) secondary consumers
  3) tertiary consumers

Question 5

primary consumers

Answer 5

organisms that directly eat producers, they are the first in the chain of consumers

Question 6

secondary consumers

Answer 6

organisms that eat primary consumers, they are the second in the chain of consumers

Question 7

tertiary consumers

Answer 7

organisms that eat secondary consumers, they are the third in the chain of consumers

Question 8

decomposers

Answer 8

group of organisms that break down complex materials such as dead consumers and producers into simple components - releasing minerals, energy and elements

Question 9

how do decomposers contribute to recycling

Answer 9

the process of decomposing which they perform will release necessary minerals, energy and elements that can be absorbed by plants

Question 10

saprophytes

Answer 10

organisms that feed on dead organic material through decomposition e.g. fungi, bacteria and earthworms

Question 11

autotrophs

Answer 11

organisms that are able to synthesise their own food using inorganic substances and chemical energy sourced from light energy

Question 12

heterotrophs

Answer 12

organisms that cannot manufacture their own food and instead obtain it from producers
this includes consumers and decomposers

Question 13

food chain

Answer 13

• describes the feeding relationship between organisms, starting from producers and ending at quaternary consumers and decomposers
• arrows represent the direction of energy flow

Question 14

trophic level

Answer 14

hierarchical levels in an ecosystem, starting from producers at the bottom to quaternary consumers at the top

Question 15

food webs

Answer 15

when many food chains are linked together within a single habitat to form a complex web
- because in reality most animals do not rely upon a single source of food