M6 C23 Ecosystems PMT QP1

Question 1

The efficiency of energy transfer between trophic levels limits the number of organisms in a particular ecosystem.
(a) Outline how the percentage efficiency of energy transfer between producers and herbivores can be estimated.

Answer 1

herbivore NRG/producer NRG x100

• collect sample of herbivores
• collect sample of producers
• calculate NRG content of herbivores and producers

Question 2

Name the specific type of innate or learned behaviour described… Sparrows initially fly away from fruit bushes on which shiny CDs are hung, particularly when the CDs move in the wind.

Answer 2

escape reflex

Question 3

Name the specific type of innate or learned behaviour described…After a few days the sparrows start visiting the fruit bushes again, and do not fly away even when the CDs move.

Answer 3

habituation

Question 4

Name the specific type of innate or learned behaviour described…Carrot flies move towards chemicals released by carrot plants.

Answer 4

positive chemotaxis

Question 5

Name the specific type of innate or learned behaviour described…Raccoons learn to remove lids from containers of grain in a barn.

Answer 5

operant conditioning

Question 6

Name the specific type of innate or learned behaviour described…A line of young chicks follow their mother into a cornfield.

Answer 6

imprinting

Question 7

Name a biological process that is slowed down or stopped by each procedure.
storing apples at a low temperature of 5° C

Answer 7

ripening

Question 8

Name a biological process that is slowed down or stopped by each procedure.
removing weeds from a vegetable garden

Answer 8

interspecific completion

Question 9

Name a biological process that is slowed down or stopped by each procedure.
placing seedlings so they are lit from all sides equally

Answer 9

positive phototropism

Question 10

Name a biological process that is slowed down or stopped by each procedure.
removing elm suckers and self-sown tree seedlings from farmland

Answer 10

succession

Question 11

Suggest three ways that farmers can maximise the efficiency of the transfer of energy up
food chains from primary consumers to humans.

Answer 11

• by reducing animals movement, keep in a small area
• keeping animals warm
• feed animals high NRG foods
• selective breeding

Question 12

define… producer

Answer 12

photosynthesises CO2 into organic molecules

Question 13

list two abiotic factors that play a role in determining what species of plant can grow in an area.

Answer 13

• pH
• mineral content
• water depth

Question 14

Name a process that changes a lake community into a peat bog community.

Answer 14

succession

Question 15

Most of the minerals in a peat bog are held within the living plants at all times, not in the soil.
• Plants like bog cotton and bog asphodel recycle the minerals they contain.
• The leaves of these plants turn orange as the chlorophyll within them is broken down.
• Minerals such as magnesium ions are transported from the leaves to the plants’ roots for storage.

Describe one similarity and two differences in mineral recycling in a peat bog and in a deciduous forest.

Answer 15

similarity: chlorophyll breaks down / leaves change colour
difference: (bog) minerals stay in plant / (forest) minerals in soil