Human impact on the environment.

Question 1

Extinction definition.

Answer 1

The total loss of a species.

Question 2

Endangered species meaning.

Answer 2

At risk of becoming extinct because of few breeding pairs remaining.

Question 3

Reasons for extinction.

Answer 3

Natural selection
Habitat destruction
Pollution
Hunting and collecting (e.g. rhino horns)
Competition from domestic animals.

Question 4

Conservation definition.

Answer 4

The planned management of ecosystems to enhance biodiversity and protect gene pools.

Question 5

Conservation methods.

Answer 5

-Nature reserves and SSSIs(sites of special scientific interest) are procted by law
-Restricting/limiting trade of endangered species
-Captive breeding programmes
-Sperm and seed banks reserve gene pools
-Reintroduction programmes.

Question 6

Agricultural exploitation meaning.

Answer 6

The need to increases efficiency and intensity of food production to meet increasing demands by a rapidly increasing human population.

Question 7

Methods of agricultural exploitation.

Answer 7

Removal of hedgerows
Mono cultures-reducing available niches
Use of insecticides, herbicides and pesticides
Ecosystem destruction to provide agricultural land.

Question 8

Reasons for conserving gene pools.

Answer 8

Plants may provide new medicines
Wilds genes of crop plants relatives may be useful to breed with to increase productivity
Unethical and long terms impacts not fully realised
Reduced gene pools make species more vulnerable to disease/extinction as less variation.

Question 9

Deforestation definition.

Answer 9

The removal of trees to use as timber or fuel or to repurpose the land use for agriculture or building.

Question 10

Consequences of deforestation.

Answer 10

Soil erosion- not protected by canopy or held together by roots
Flooding- less water removed from roots, denitrification, loses nitrates
Habitat loss reduces biodiversity
Less photosynthesis- less CO2 removed.

Question 11

Solutions for deforestation.

Answer 11

Selective felling
Replanting correct mix of species, correct distance apart, allowing to regenerate
Protecting certain areas.

Question 12

Overfishing definition.

Answer 12

Fish are caught at a higher rate than they reproduce and grow to the point where increased fishing efforts lead to declining catches.

Question 13

Overfishing consequences.

Answer 13

Reduced fish population sizes- lose genetic diversity
Size of fish caught reduced- no time to grow
Fewer individuals- can’t replace harvested fish.

Question 14

Overfishing solutions.

Answer 14

Quotas of mass of fish allowed to be caught
Restricted fishing seasons- allow to reproduce
Exclusion zones- prevent certain area’s use
Increased mesh size- smaller, younger fish escape and grow
Limiting size of fishing fleet.

Question 15

Fish farming definition.

Answer 15

Fish are intensively reared in ponds/tanks or nets
A solution to overfishing.

Question 16

Good consequences of fish farming.

Answer 16

Less fish need to be harvested wild
Fish have been selected for high growth rates=large size, increased yield.

Question 17

Negative consequences of fish farming.

Answer 17

Excess fish food, excretions can fall out of nets and cause habitat eutrophication
Parasites and disease spread quickly through overcrowded fish
Excess antibiotic uses may cause resistance
Pollution due to pesticide uses and could harm marine invertebrates
Farmed fish escaping could cause them to out compete wild fish or interbreed with them
The feed is often made from harvested wild fish.

Question 18

Planetary boundaries definition.

Answer 18

‘safe operating space for humanity’
If the impacts of human activities/actions breaches the thresholds, there is a risk of abrupt and irreversible change.

Question 19

The planetary boundaries description and current states.

Answer 19

Ocean acidification:
-Avoidable
-Increased CO2 dissolves into oceans
-Carbon shelled organisms can’t make shells in acid water
Climate change:
-Crossed
Aerosol boundary:
-Unquatified
-Air pollution by particulates
Fresh water boundary:
-Avoidable
-Desalination of sea water helps
-Caused by land use change and water body modification
Nitrogen boundary:
-Crossed
-From fertiliser/eutrophication
Chemical pollution boundary:
-Unquantified
-Air chemical pollution
-Reduced fertility and genetic damage
Biosphere integrity boundary:
-Crossed
-Loss of biodiversity and extinction
-From higher food demand
Ozone boundary:
-Avoided
-Actions against CFCs at Montreal Protocol means crossing avoided
Land use boundary:
-Crossed
-From agriculture/human use.

Question 20

Core boundaries definition.

Answer 20

Crossing would drive the earth into a new and unpredictable state with sever biosphere consequences
Climate change
Biosphere integrity.