6.5 - Ecosystems

Question 1

what is a niche?

Answer 1

the role of an organism within an ecosystem

Question 2

what is a habitat?

Answer 2

The place where an Organism lives.

Question 3

What is the population?

Answer 3

All the organisms of one species in a habitat.

Question 4

What is a producer?

Answer 4

An Organism that produces organic materials using sunlight energy.

Question 5

What is a consumer?

Answer 5

An Organism that eats other organisms.

Question 6

What is a decomposer?

Answer 6

An Organism that breaks down dead or undigested organic material.

Question 7

What is a trophic level?

Answer 7

a stage in a food chain occupied by a particular group of organisms.

Question 8

What is an ecosystem?

Answer 8

All the organisms living in a certain area and all the non living conditions found them.

Question 9

What are biotic factors?

Answer 9

The living features of an ecosystem.

Question 10

What are abiotic factors?

Answer 10

For non living features of any.

Question 11

What are examples of biotic factors?

Answer 11

• food
• competition
• territory
• predation
• disease

Question 12

What are examples of abiotic factors?

Answer 12

• temperature
• rainfall
• soil
• pH
• salinity

Question 13

What are examples of ecosystems?

Answer 13

• rock pool
• playing field
• tree

Question 14

How is energy stored within an ecosystem?

Answer 14

as biomass

Question 15

What happens to energy and biomass locked up in things that can’t be eaten?

Answer 15

They are broken down by decomposers and recycled back into the ecosystem.

Question 16

What is a food chain?

Answer 16

A single line showing energy transfer.

Question 17

What is a food web?

Answer 17

Multiple food chains connected together.

Question 18

Why is not all energy/biomass transferred to the next trophic level?

Answer 18

• some is never taken in in the first place as plants cant absorb all wavelengths
• some is lost to the environment during respiration or body heat
• some is used for growth or stored as biomass

Question 19

What is the equation for energy efficiency?

Answer 19

(energy
transferred/ energy intake) X 100

Question 20

How would you calculate the energy transfer between trophic levels?

Answer 20

calculate the difference between the amount of energy in each level

Question 21

How can you calculate the amount of energy in a trophic level?

Answer 21

• measuring dry mass of organisms

Question 22

What human activities can increase for transfer of energy through an ecosystem?

Answer 22

• herbicides
• fungicides
• insecticides
• natural predators
• fertilisers

Question 23

What are the features of waterlogged soil?

Answer 23

little oxygen

Question 24

What is the function of soil?

Answer 24

PROVIDES:
- water
- nutrients
- anchorage

Question 25

what are the features of clay soil?

Answer 25

- few air spaces - retains water - floods easily

Question 26

What are the features of sandy soil?

Answer 26

- lots of air spaces - doesnt store water

Question 27

What is Loam Soil?

Answer 27

A mix of clay and sandy soil.

Question 28

Why do plant roots need oxygen?

Answer 28

For respiration so there is enough ATP produced for active transport so minerals can be pumped into the plant.

Question 29

what is biomass?

Answer 29

the mass of living material present in a particular place or in particular organisms

Question 30

what are the 2 methods for measuring biomass?

Answer 30

- mass of fresh material present - dry mass

Question 31

why may measuring biomass by recording mass of fresh material present be used?

Answer 31

- easiest method BUT unreliable as mass of water varies greatly

Question 32

why may measuring biomass by recording dry mass be used?

Answer 32

- most accurate BUT organism must be killed and baked in an oven at 80 degrees

Question 33

what units are used for measure biomass in areas of land?

Answer 33

g m^-2

Question 34

what units are used for measure biomass in areas of water?

Answer 34

g m^-3

Question 35

what units are used for measure biomass in each trophic level?

Answer 35

KJ m^-2 yr^-1

Question 36

why is biomass measured at each trophic level per year?

Answer 36

it allows for seasonal changes in photosynthesis and feeding patterns

Question 37

what is the equation for ecological efficiency?

Answer 37

(biomass at higher trophic level) / ( biomass at lower trophic level) X100

Question 38

what is gross primary productivity?

Answer 38

the rate that plants convert light energy into chemical energy through photosynthesis

Question 39

what is net primary productivity?

Answer 39

the proportion of energy from the sun which remains to enter the food chain (1-8%)

Question 40

why do producers only convert 1-3% of the sunlight absorbed into chemical energy?

Answer 40

- not all solar energy is used for photosynthesis - limiting factors for photosynthesis - some is lost through photosynthetic reactions

Question 41

what is the equation for net production?

Answer 41

gross production - respiratory losses

Question 42

what are methods for improving primary productivity?

Answer 42

- greenhouses - irrigation - pesticides/ herbicides/ fungicides - crop rotation - fertilisers

Question 43

how do greenhouses and irrigation improve primary productivity?

Answer 43

increase rate of photosynthesis as limiting factors are reduced

Question 44

how do pesticides/ herbicides/ fungicides improve primary productivity?

Answer 44

- reduce loss of biomass

Question 45

how do crop rotation and fertilisers improve primary productivity?

Answer 45

increase nutrient in soil so yields are improved

Question 46

what is secondary productivity?

Answer 46

the amount of biomass produced by the primary consumer

Question 47

what are methods for improving secondary productivity?

Answer 47

- harvesting young animals - limiting movement - maintain a warm environment - treatment with antibiotics - selective breeding

Question 48

why does limiting movement and maintaining a warm environment improving secondary productivity?

Answer 48

maximises energy used for growth BUT disease can spread quickly

Question 49

why does treating organisms with antibiotics improve secondary productivity?

Answer 49

prevents sickness which uses energy BUT it could cause antibiotic resistance

Question 50

what are examples of carbon stores?

Answer 50

- atmosphere - sedimentary rock - fossil fuels - soil - vegetation - dissolved in oceans

Question 51

outline the carbon cycle

Answer 51

- carbon is removed from the atmosphere by autotrophs during photosynthesis - carbon stored in sedimentation - repsiration releases carbon into atmosphere - carbon passed between organisms in feeding - combustion releases carbon

Question 52

what is succession?

Answer 52

the process of ecosystems changing over time

Question 53

what are the features of a pioneer species?

Answer 53

- produce large quantities of easily dispersible seeds or spores - rapid germination of seeds - ability to photosynthesise - ability to fix nitrogen - withstand extreme conditions

Question 54

what is the process of primary succession?

Answer 54

1. pioneer species colonises bare ground, they dies and release minerals 2. as plants die + decompose soil deepens, larger plants survive 3. diversity increases, smaller plants are outcompeted 4. climax vegetation

Question 55

what is primary succession?

Answer 55

where species colonise somewhere that didnt use to be a habitat (bare ground)

Question 56

what is secondary succession?

Answer 56

where succesion takes place on a previously colonised but disturbed or damaged habitat such as after a forest fire

Question 57

what is deflected succession?

Answer 57

when human activity prevents succession from running its course e.g. sheep grazing to prevent grassland from developing into woodland

Question 58

what does deflected succession form?

Answer 58

a plagioclimax community if repeatedly managed