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Flashcards in Energy Transfers Deck (22):
1

Environmental problems with deforestation

Soil erosion/mud slides/flooding/leaching of minerals- trees no longer protect from rain
Increased co2- global warming
Less diversity/loss of species/loss of habitats/niches/ecosystem
Changed rainfall patterns/drought-less transpiration from trees

2

What is biological control

Using a predator/pathogen to control a pest organism
Give example

3

Advantages/disadvantages of biological control

Advantages
- if well screened a biological control agent only attacks pest/maintains low level of pest
Forms self perpetuating population (only one application required/does not need repeated treatment)
Cheaper e.g. saves cost of using chemicals
Safer because does not leave chemical in environment/no chemical residue
Organisms do not become resistant

Disadvantages
- doesn’t completely eradicate pest
- cost of research/setting up a biological control system
- must be well screened/ biological control may turn a pest
- Slower to get rid of pest than chemicals
More subject to environmental factors

4

Process of genetic engineering and benefits over selective breeding

Use of restriction endonuclease
Cuts dna at specific base sequence/recognition site
Vector
Same endonuclease to cut vector/host dna
Use of Lucas’s enzyme to join dna strands

It is much quicker/more efficient/several genes can be inserted at once compared to selective breeding

5

Effective pest management schemes include..

Use of insecticide
Selective breeding of resistant palms
Release sterile males/females
Introduce a virus

6

Benefits of an integrated pest management scheme(biological control and artificial methods)

If one method fails, other still partially effective
Reduces amount of pesticide needed/less chemicals used
Increased yield/ less chance of resistant species
Less effect on food webs
Biological control gives longer term control of pests

7

Limitations of biological control

Effect on non target species
Population explosion/lack of natural predators
Not all pests killed
Difficulty in maintaining population of control organism

8

Concerns of leaching

Increased growth of algae
Results in eutrophication
Increase in microoorganisms feeding on dead organisms
Deoxygenatiin
Increased nitrate in drinking water
Causing human illness

9

Productivity on farmland v woodland

Plants smaller/ less vegetation/grazing
Less area for phs
removed in harvesting

10

Advantages/limitations of using inorganic fertilisers

Advantage:
Ions in readily available form
Effects relatively rapid
Easy to apply
Quantities applied can be controlled

Disadvantage
Quickly leached
More likely to cause pollution
Relatively expensive

11

What is monoculture

Cultivation of single species/ variety of crop: named crop/one crop grown over a large area

12

Two benefits of hedge removal

More space for crop
Easier to use machines
Removes habitat for pests
Lower labour costs in maintenance
Less competition with crop plants

13

How can pesticides lead to the death of animals that are not pests

Food source killed by pesticides
Insufficient food for survival/ lack of alternative sources
Or
Pesticide passed through food chain
Bio accumulation(organisms at higher trophies levels eat large numbers of organisms at lower trophies levels)
Or
Stored in fat/released over time
Or
Leached into rivers
Kills aquatic life

14

How selective breeding can reduce the unwanted part of the crop

Use plants with smallest amount of unwanted material
Cross pollination/select and repeat cross

15

Measurements needed to measure rate of phs

Oxygen produced/co2 used
Per unit time

16

How to measure Effect of temp on crop yield

RANGE OF TEMPS used
OTHER FACTORS kept same
Measure MASS OF GIVEN PRODUCT in given TIME

17

Describe and explain the effects of monoculture on the environment

Loss of hedgerows
Since small fields impractical for large machines
Soup more exposed to wind (soil erosion)
Reduced diversity
Smaller variety of niches/habitats
Smaller variety of producers
Deport rooted plants removed
Increase in soil erosion
Increased risk of large scale crop failure/increased disease/increased number of pests
Increased use of fertiliser- eutrophication/damage to gene pool/soil structure

18

Why are some pesticides non biodegradable

Different shapes molecules
Do not fit active sites of enzymes produced by decomposers

19

Features of predator in biological control

Only feeds on pest/ does not affect non target population
Can live in environment of the host
Can reproduce under conditions of use/active during the season

20

Farmed v wild salmon

Faster rate of growth
Reduced movement/low respiratory losses
More sustained/plentiful supply of food
High survival rate e.g. due to protection from predators
Reduced fishing effort

21

Why not all food is converted to biomass

Not all digestible
Used in respiration
Synthesis of biomass inefficient/ involves energy or heat loss

22

Insecticide caused reduction in the population size of the peregrine, a bird which feeds on seed eating birds. Explain how this caused death of peregrines

Accumulation of insecticide within individual tissue
Peregrine eat large number of birds
Biomagnification/ high concentration of insecticide kills peregrine
Or
Seed eating birds eat a lot of seed
Biomagnification/ high conc insecticide in seed eating bird kills them
Kills them
No/less food for peregrine