Ecosystems

Question 1

Define ecosystem

Answer 1

A living system of plants and animals which interacts with the physical environment

Question 2

Define biome

Answer 2

An ecosystem on a global scale, with a climax community of plans and animals which has reached equilibrium with its environment

Question 3

What is an ecosystem made up of?

Answer 3

Biotic factors (living organisms) and abiotic factors (the physical environment)

Question 4

Give examples of biotic factors

Answer 4

Vegetation

Mammals, insects, birds, microorganisms

Question 5

Give examples of abiotic factors

Answer 5

Soil characteristics, underlying parent rock, relief of land, drainage characteristics, climate

Question 6

What are the inputs of an ecosystem?

Answer 6

Energy from the sun
Animals
Water- precipitation or rivers

Question 7

What are the outputs of an ecosystem?

Answer 7

Nutrients transferred out
Animals move
Water can move out- rivers, evapotranspiration, through flow, ground water flow

Question 8

What are the 3 main stores of an ecosystem?

Answer 8

The 3 main stores of nutrients are in the vegetation, plant litter and soils

Question 9

Name the 4 trophic levels

Answer 9

1. Producers (plants)
2. Primary consumers (herbivore)
3. Secondary consumer (carnivore)
4. Tertiary consumer (top predator)

Question 10

How much energy is available at the next trophic level?

Answer 10

10%

Question 11

Explain how energy flows operate within an ecosystem

Answer 11

• Firstly energy from the sun allows photosynthesis to take plant (autotrophs)
• There are 2 types of organisms that have direct access to the energy in plan tissues which are herbivores and decomposers
• In most ecosystems, the majority of the energy goes to the decomposers
• Herbivores use most of their energy intake on respiration and maintaining their bodies
• Much of the energy in herbivore biomes is taken by carnivores and decomposers
• Ultimately all of the energy originally captured by plants is transferred and lost as heat
• Energy is not recycled

Question 12

Define nutrients

Answer 12

The chemical elements and compounds needed for organisms to grow and function

Question 13

Define soil

Answer 13

The unconsolidated mineral material on the immediate surface of the earth that serves as a natural medium for the growth of land plants

Question 14

Define litter

Answer 14

The organic matter above the soil (compost)

Question 15

Define biomass

Answer 15

The total mass of living organisms mainly plant material

Question 16

What is leaching?

Answer 16

When nutrients are washed out of the soil

Question 17

Describe the nitrogen cycle

Answer 17

• Nitrogen is necessary for the construction of plant and animal matter
• Nitrogen is present in the atmosphere and can be fixed in the soil by some plants
• It is then taken up by the roots of other plants, passes through the ecosystem and is retuned to the soil by decomposition

Question 18

Describe the carbon cycle

Answer 18

• All life is based on the element carbon
• In recent years, there has been a growing concern that human activity is disrupting the carbon cycle
• Large amounts of carbon are in temporary stores in plans, animals and the soil
• The burning of fossil fuels and destruction of forests are peat deposits has released much of this carbon back into the atmosphere as carbon dioxide

Question 19

Describe the Gersmehl diagram for a tropical rainforest cycle

Answer 19

• Hot, wet all year
• Large proportion of nutrients stored in biomass store. Climate ideal for plant growth
• Small litter store as litter is broken down quickly in hot, humid conditions
• Small soil stores as nutrients are taken up so quickly by plant growth
• High temperatures and high humidity lead to rapid weathering of rock releasing nutrients into soil
• Trees are every green with no autumn season of leaf fall
• Rapid release of nutrients from litter into soil due to rapid decomposition
• Relatively low loss in runoff as most rainfall is taken up by vegetation
• Can be a high loss by leaching as heavy rainfall can wash nutrients out of the soil and carry away

Question 20

Describe the Gersmehl diagram for a temperate deciduous woodland

Answer 20

• Wet all year, cold and warm season
• Biomass store- the forest cover isn’t as dense or high as rainforest so fewer nutrients
• Large little store as autumn leaf fall decay slowly in low temperatures
• Large soil store due to nutrients from litter carried down by decomposers
• Low temp leads to low weathering
• Rapid uptake of nutrients by plans in spring and summer
• Fertile soil= leave decompose
• Some loss by leaching