c1.6 - human impact on the envrionment

Question 1

endangered species

Answer 1

species due to loss of habitat or rapid decrease in population numbers is at risk of extinction

Question 2

when is a species extinct

Answer 2

when all members of species dead

Question 3

potential causes for extinction

Answer 3

• natural selection
• loss of habitat (e.g: deforestation, removal of hedgerows)
• pollution (e.g: oil, PCBs)
• overhunting by humans
• introduction of new competitors (e.g: domesticated animals)
• non-contiguous populations

Question 4

conservation

Answer 4

maintenance of ecosystems + biodiversity through human action in order to preserve the earths resources

Question 5

how conservation can be achieved

Answer 5

• protection of habiats (e.g: nature reserves, national parks, SSIs)
• protection of endangered species (e.g: making hunting illegal, breeding programmes increase population size)
• international cooperation (e.g: restricting trade of endangered species + their parts)
• species reintroduction
• gene + sperm banks
• seed banks

Question 6

why is conservation of gene pools important

Answer 6

• many plant species are yet to be discovered + may contain chemical that could be used in medicine
• protection of potential food sources
• some allele a may provide selective advantages, preventing extinction
• each species + its genes are precious

Question 7

agricultural exploitation

Answer 7

increase in efficiency + intensity of food production in order to meet growing demands

Question 8

deforestation

Answer 8

removal of trees from land subsequently used to grow crops or provide space for cattle

Question 9

consequences of deforestation

Answer 9

• biodiversity loss
• climate change
• habitat loss
• soil erosion
• desertification
• lowland flooding

Question 10

what do managed forests involved

Answer 10

sustainable replanting + regeneration
e.g:
- coppicing
- selective cutting
- long rotation time

Question 11

overfishing

Answer 11

excessive fishing of an area at a rate which exceeds potential replenishment of the species

Question 12

methods of regulating fishing

Answer 12

• use lines rather than nets
• regulating net size
• fishing quotas + exclusion zones
• avoid overfished species, fishing non traditional species
• limiting fishing fleet sizes
• fish farming

Question 13

fish farming

Answer 13

breeding of fish commercially in enclosures for food to combat overfishing

Question 14

problems of fish farming

Answer 14

• rapid spread of disease
• escape of farmed fish
  ~ spread disease to wild populations
  ~ larger, outcompete wild populations
• bioaccumulation of pesticides
• farmed fish contain high concs of toxic chemicals (e.g: dioxins, PCBs)

Question 15

sustainability

Answer 15

using resources in a way that also maintains them for future generations

Question 16

environmental moniting requis for conservation, give examples of factors to be monitored

Answer 16

• air quality
• water quality
• soil quality

Question 17

planetary boundaries

Answer 17

set of nine limits proposed by a group of environmental + earth system sciences within which human active can operate without risk of irreversible damage t9 the planet

Question 18

planetary boundaries crossed

Answer 18

• climate change
  biosphere integrity
• land system change
• biogeochemical flows

Question 19

planetary boundaries avoidable

Answer 19

• ocean acidification
• fresh water use

Question 20

planetary boundary avoided

Answer 20

ozone depletion in stratosphere

Question 21

planetary boundaries not quantified

Answer 21

• atmospheric aerosols
• introduction of novel entities