Movement of energy and matter in ecosystems

Question 1

first law of thermodynamics

Answer 1

energy can be converted from one form to another but cannot be created or destroyed

Question 2

second law

Answer 2

Transformations of energy always result in some loss or dissipation of energy

Question 3

Amount of energy at higher levels

Answer 3

smaller than in producers

also a number of ecological constraints that make the transfer even less efficient

Question 4

as energy from one trophic level to next is must be transferred via

Answer 4

consumption assimilation and production

Question 5

What does the energy between trophic levels depends on

Answer 5

efficiency of each step

Question 6

consumption efficiency

Answer 6

Proportion of the net production of the lower trophic level that is consumed

Question 7

consumption efficiency =

Answer 7

consumed energy/ net production of the lower trophic level

Not all plant material consumed

Question 8

assimilation

Answer 8

percent of the consumed energy that becomes available for work or growth
Don’t assimilate all of what you consume- excrete/regurgitate

Question 9

assimilation efficiency =

Answer 9

assimilated energy/consumed energy

Question 10

net production efficiency

Answer 10

percentage of assimilated energy that is incorporated into new biomass
Lower in highly active animals

Question 11

net production efficiency

Answer 11

net production energy/assimilated energy

Question 12

ecological effiency

Answer 12

percentage of net production from one level compared to the next lower level

Question 13

ecological efficiency

Answer 13

net production of energy of a trophic level/ net production energy of a lower trophic level
Equivalent to product of 3 steps previously

Question 14

ecological efficiency explain number of trophic levels

Answer 14

plants avoid being consumed by defences
Less energy moving up trophic levels because of low consumption efficiency
Less transferred supports lower trophic levels

Question 15

aquatic ecoystems

Answer 15

algae consumed more efficiently leading to support for more trophic levels

Question 16

standing crop

Answer 16

amount of biomass present at a particular at a particular time in a system

Question 17

low consumption efficiency by higher trophic level means

Answer 17

biomass residence high
Means energy and standing crop may differ
consumers not eating all the plants

Question 18

movement of matter through the ecosystem

Answer 18

matter moves between abiotic and biotic

Question 19

exchange from ocean to atmosphere

Answer 19

relatively fast

Question 20

exchange from mantle to lithosphere

Answer 20

relatively slow

Question 21

Rate of exchange between pools

Answer 21

depends on types of biota

Question 22

flow of matter

Answer 22

no new matter, all recycled

Question 23

water cycle

Answer 23

water availability affects rates of primary productivity and decomp

Question 24

human impact on the water cycle

Answer 24

over-abstraction from lakes and rivers
vegetation loss 
soil erosion
pollution of surface water and ground aquifers
drainage of wetlands
climate impacts

Question 25

What do man made impervious surfaces do

Answer 25

incr runoff and affect groundwater supply- less infiltration of water so decr evapotranspiration

Question 26

take carbon out of the atmosphere

Answer 26

assimilation by plants and animals
assimilation into soil
organic decomp (animal waste/dead animals and plants)
assimilation by phytoplankton

Question 27

releasing carbon

Answer 27

fossil fuel

respiration

Question 28

human impacts on carbon cycle

Answer 28

by burning fossil fuels intoducing carbon back into the cycle that has been out of it for many years eg carbon in form of oil and peat

Question 29

solutions to high CO2

Answer 29

plant trees
incr phytoplankton
reduce fossil fuel output, renewable energy

Question 30

nitrogen cycle

Answer 30

most nitrogen is in the atmosphere

Question 31

How is nitrogen fixed

Answer 31

bacterial fixation, lightning fixation

Burning material releases some material that precipitates into nitrates

Question 32

Industrial fixation

Answer 32

revolutionised agriculture but incr eutrophication

Question 33

Increased nitrogen

Answer 33

dominant species get more dominant

decr diversity due to loss of other species

Question 34

eutrophication

Answer 34

results in incr primary productivity but -ve effects incl species loss, changes in community structure and toxicity

Question 35

What is the main environmental form of phosphorous

Answer 35

PO4

Question 36

Phos cycle

Answer 36

v little in the atmosphere

Question 37

main source of phosphorous

Answer 37

rocks of maritime origin

Question 38

Human impacts on Phos cycle

Answer 38

livestock waste and P used in inorganic fertilisers both contribute to eutrophication

Over harvesting crops

Question 39

3 steps of decomp

Answer 39

leaching, partitioning and micropartitioning

Question 40

key players in decomp

Answer 40

invertebrates and microbes

Question 41

decomp rates depend on

Answer 41

temp- colder = litter accumulating (because warmer= faster decomp= less accumulation) and more variation in types of soil affects composition of forest

Precip, and groups of organisms

Question 42

deforestation

Answer 42

incr volume of water runoffs

Incr loss of nutrients

Question 43

Mining

Answer 43

causes deforestation, physical damage, contamination
Deep disturbance of soil
Heavy machinery compacts soil
Bringing toxic substances to the surface- contamination

Question 44

fire

Answer 44

important in many ecosystems eg savanas, grasslands:

• germination of seeds
• regeneration of nutrients locked in biomass
• control of pests

Incr temp,water usage, precip and drought due to climate change incr incedence of fire
Habitat fragmentation makes habitats vulnerable to fire

Question 45

Fire affects nutrient cycling

Answer 45

loss of N and C
Transfer of nutrients to ash
Warmer soil profiles which alter microbial growth and decomp rates
Devastating for ecosystems not adapted to fires

Question 46

restoration ecology

Answer 46

speed up recovery of degraded ecosystems using knowledge of nutrient cycles
2 strategies: bioremediation and augmentation of ecosystem processes

Question 47

bioremediation

Answer 47

use organisms to detoxify ecosystems
use plants, bacteria and fungi
These organisms can: absorb and conc toxic compounds facilitating removal from environment
Metabolise toxic molecules into inorganic or non toxic

Question 48

augmentation

Answer 48

use organisms to add essential materials to a degraded ecosystem
eg nitrogen fixing bacteria to incr available nitrogen in the soil