Chapter 33 - Energy Flow, Food Webs & Pyramids Of Biomass

Question 1

What is ecology?

Answer 1

The study of living organisms in relation to one another and to their environment.

Question 2

What is an ecosystem?

Answer 2

A self-contained area which includes all living organisms (biotic) and their physical non-living (abiotic) environment.

Question 3

What is a carnivore?

Answer 3

An animal that gets its energy by eating other animals.

Question 4

What is a food web?

Answer 4

A network of interconnected food chains which shows feeding relationships in an ecosystem.

Question 5

What is a community?

Answer 5

All the different populations living in the same place or habitat.

Question 6

What is a producer?

Answer 6

An organism that makes its own organic nutrients by photosynthesis.

Question 7

What is a trophic level?

Answer 7

The position of an organism in a food chain or food web.

Question 8

What is a pyramid of numbers?

Answer 8

A diagram which shows the quantities of organisms involved in a set of feeding relationships.

Question 9

What is a herbivore?

Answer 9

An animals that gets its energy by eating green photosynthesising plants.

Question 10

What is a population?

Answer 10

A group organisms of one species, living in the same area at the same time.

Question 11

Describe the flow of energy through living organisms.

Answer 11

• The sun is the principal source of all energy
• chlorophyll in the chloroplasts traps light energy and uses it during photosynthesis
• during photosynthesis, light energy is changed into chemical energy in plants
• chemical energy is stored in organic food molecules
• animals eat the plants and obtain the organic molecules during nutrition
• during respiration, the energy is released for the use of living ogranisms

Question 12

Describe the non-cyclic flow of energy.

Answer 12

• energy flows only in one direction through the ecosystem
• each organism uses or loses energy
• energy does not flow back to the sun (source)
• energy is therefore not recycled within the ecosystem

Question 13

What is an omnivore?

Answer 13

An animal that gets its energy by eating other plants and animals.

Question 14

What is a decomposer?

Answer 14

An organism that gets its energy from dead or organic waste materials.

Question 15

Explain why energy is lost from the food chain at each stage.

Answer 15

• energy is lost through respiration/excretion/movement
• not all of an organism from the lower trophic level is consumed and edible.

Question 16

Explain why it is possible to feed a greater number of people if an area of land is used to farm crops rather than to farm animals.

Answer 16

• energy transfer is only 10% to next trophic level
• eating plants involves short food chains, and thus more energy is efficiently transferred as fewer trophic levels are involved
• more energy is available, so more humans can be fed

Question 17

Why can eating a plant diet be inefficient?

Answer 17

Humans cannot digest cellulose, so a plant diet alone is not necessarily more efficient.