4.2.5 what affects biodiversity?

Question 1

climate change

Answer 1

significant, long-lasting changes in weather patterns

Question 2

monoculture

Answer 2

crop consisting of 1 strain of 1 species

Question 3

how has human population growth impacted biodiversity due to increased demand for food/consumer goods

Answer 3

• learned to use environment to our advantage
• alter ecosystems to provide ourselves with food
• destroy & fragment habitats
• using more of earths resources
• pollute atmosphere

Question 4

how does human population growth lead to extinction

Answer 4

our activities harm species directly/indirectly which can lead to extinction

Question 5

how does agriculture impact biodiversity

Answer 5

• clear natural vegetation & reduce size of habitats/population size of any species living in habitat = reduces genetic diversity
• reduced genetic diversity = less capacity to adapt to changing conditions via evolution
• clearing natural vegetation may leave isolated/fragmented populations to small to survive
• modern agriculture relies on monoculture/selective breeding

Question 6

(agriculture) how does monoculture impact biodiversity

Answer 6

• very limited genetic diversity
• planted as easier to harvest
• rainforests with huge biodiversity are cut down (rate of 150 hectares an hour) which are replaced by huge stands of a single strain of 1 species

Question 7

(agriculture) how does selective breeding impact biodiversity

Answer 7

• reduces genetic diversity of species = genetic erosion
• farmers select particular traits & concentrating on these means other characteristics may be ignored altogether
• other breeds may become rare & die out

Question 8

how does climate change impact biodiversity

Answer 8

• species which have lost genetic diversity show less variation between them & are less able to adapt to changing environment
• alternative for them = slow migration of populations, communities & ecosystems to suited conditions (eg. towards poles)
• domesticated plants/animals at more risk as they’re selectively bred to provide best yield in specific conditions & have little variation = unlikely to be able to adapt/vulnerable to disease
  –> efficiency of agriculture declines & less food available

Question 9

obstructions to slow migration (result of climate change)

Answer 9

• major human developments
• agricultural land
• large bodies of water
• mountain ranges

Question 10

when does extinction occur

Answer 10

when last living member of species dies & species ceases to exist