Nature Of Ecocststems

Question 1

Define an ecosystem

Answer 1

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

Question 2

Main points of an ecosystem

Answer 2

• self regulating
• where living things interact
• can be considered at any scale
• like any other system with inputs and outputs
• open system- energy and living matter can enter and leave

Question 3

Define a biome

Answer 3

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

Question 4

What does biotic mean

Answer 4

The living environment

• vegetation
• mammals, insects, birds and microorganism

Question 5

What does abiotic mean

Answer 5

The non-living, chemical and physical components

• soil characteristics
• underlying parent rock
• relief of the land
• drainage characteristics

Question 6

What are the inputs of an ecosystem

Answer 6

• most important is energy from the sun- this drives photosynthesis and enables plants to grow
• animals that arrive from other places
• water

Question 7

What are the outputs

Answer 7

• nutrients- from animals moving, water

Question 8

What are the flows within a ecosystem

Answer 8

Within a ecosystem nutrients can be transferred from one store to another
- from the soil to the vegetation through capillary uptake by plant roots

Question 9

What are the stores in a ecosystem

Answer 9

• vegetation
• plant litter
• soil

Question 10

What is the word for the different levels in a energy flow diagram

Answer 10

Trophic level

Question 11

What are the trophic levels

Answer 11

1) producers- autotrophs- plants
2) primary consumers- herbivores
3) secondary consumers- carnivores
4) tertiary consumers- top predators

Question 12

What happens during photosynthesis

Answer 12

• plants capture the Suns light energy
• use this to make carbohydrates from carbon Dioxide and water
• increase their biomass
• less than 4% of the Suns light is captured
• more than half of this energy is lost by heat

Question 13

What does each trophic level feed on

Answer 13

• primary consumers feed on plants and insects birds
• secondary consumers feed on the herbivores
• top predictors feed on everything

Question 14

What are energy transfers

Answer 14

• can be illustrated by a pyramid diagram
• some of the energy contained is available as food for the next level
• each layer from the bottom up decreases in size because around 90% of the energy contained within is lost through life processes
• only 10% is available for the next level

Question 15

An energy pyramid

Answer 15

• 90% energy lost- respiration, movement and excretion
• majority of energy goes to the decomposes
• detritivores and decomposes operate at each level

Question 16

What is a detritivores

Answer 16

• is an animal that feeds on dead material or waste products

Question 17

What is a decomposers

Answer 17

• an organism that breaks down dead plants , animals and waste matter
• fungi and bacteria

Question 18

Nutrient cycle

What are nutrients

Answer 18

• the chemical elements and compounds needed for organisms to grow and function

Question 19

Nutrients cycle

What are the three compartments stores

Answer 19

• soil
• litter
• biomass

Question 20

Define soil

Answer 20

A mixture of weathered rock, air, water and decomposed organic matter on the surface of the earth

Question 21

Define litter

Answer 21

The amount of dead organic matter on top of the soil

Question 22

Define biomass

Answer 22

The total of plant and animal life in an ecosystem

Question 23

What is the diagram in the nutrient cycle

Answer 23

Gersmehl diagram

Question 24

What are the three biomes for the nutrients cycle

Answer 24

• tropical rainforest
• tropical grasslands
• temperate deciduous woodlands

Question 25

Tropical rainforest cycle Describe the biomass store and explain why

Answer 25

- growth is rapid so the biomass store is huge | - the equatorial climate Is ideal for plant growth

Question 26

Tropical rainforest cycle Describe the litter circle and why it's like that

Answer 26

- when litter falls it is broken down quickly in the hot and humid conditions - litter store is very small

Question 27

Tropical rainforests Describe the soil circle and explain why

Answer 27

- soil is little | - any nutrients in the soil is taken up quickly by plant growth

Question 28

Tropical rainforest cycle Other factors (leaching...)

Answer 28

- heavy rainfall means that nutrients can also be leached out of the soil and carried away - so if the forest cover is destroyed by burning, most of the nutrients is lost from the ecosystem - soil soon becomes infertile

Question 29

Temperate deciduous woodlands Biomass store

Answer 29

- Fewer nutrients stored in vegetation than rainforest | - the forest cover is neither so dense or as high as the rainforest

Question 30

Temperate deciduous woodland Litter layer

Answer 30

- autumn leaf decays fairly slowly in the lowest temperatures - litter layer is large

Question 31

Temperate deciduous woodlands Soil stores

Answer 31

- nutrients from litter layer is then carried down by decomposers (worms) - so the soil store is still quite important and still pretty big

Question 32

Savanna grasslands cycle Biomass

Answer 32

- much less biomass - grasses die back in the dry season - no possibility of huge accumulation like in the rainforest

Question 33

Savanna grasslands cycle Litter layer

Answer 33

- the dead grass roots more slowly because the area lacks moisture to speed up decomposers - grasses are really tough as well - proportion of litter layer is higher than in the rainforest

Question 34

Savanna grasslands cycle Soil

Answer 34

- plant growth is seasonal and does not occur all year round - greater accumulation of nutrients in the soil than in the rainforest

Question 35

Nitrogen cycle What if is and the cycle

Answer 35

- nitrogen is necessary for the construction of plant and animal matter - present in the atmosphere and can be fixed in the soil by some plants - taken up by the roots of other plants and passes around the ecosystem - then returned to the soil by the decomposition - this cycle can operate over land or over sea or In the atmosphere

Question 36

Nitrogen cycle What are the possible inputs and out puts

Answer 36

Inputs- volcanic eruptions | Outputs- loss to deep sea sediment

Question 37

Carbon cycle What are the concerns

Answer 37

- recent years there has been a growing concern that human activity is disrupting the carbon cycle - over millions of years large amounts of carbon have been extracted from the environment and sorted In The ground as coal oil and gas

Question 38

Carbon cycle What is carbon stored as

Answer 38

- coal, oil and gas | - temporary stores- plants animals and the soil

Question 39

Carbon cycle What is releasing the carbon back into the atmosphere as carbon dioxide

Answer 39

- burning of fossil fuels | - destruction of forests

Question 40

Carbon cycle Why is it bad that carbon dioxide is being released into the atmosphere

Answer 40

- carbon dioxide is a greenhouse gas that is believed to be responsible for global warming and climate change

Question 41

Food chains Define

Answer 41

Shows the flow of energy through an ecosystem

Question 42

Food chains main points

Answer 42

- four flows because of the four levels - each link feeds on and obtains energy from the preceding link and in turn is consumed by and provides energy for the following link - illustrates how trophic levels work - most are interconnected - consume a varied diet which results in a complex food web

Question 43

Example of a food chain

Answer 43

Grass --> grasshopper --> frog --> heron