B19 human influences on ecosystems

Question 1

describe what is meant by an ecosystem

Answer 1

• a unit containing the community of organisms
• and their environment
• interacting together

Question 2

describe what is meant by biodiversity

Answer 2

number of diff species that live in an area

Question 3

reasons for habitat destruction

Answer 3

• increase area for housing, crop plant production, livestock production
• extraction of natural resources
• freshwater and marine pollution

Question 4

undesirable effects of deforation

Answer 4

• reducing biodiversity
• extinction
• loss of soil
• flooding
• increase co2 in atmosphere

Question 5

explain why deforestation would reduce biodiversity

Answer 5

• primary producers in food web
• provide habitat

Question 6

explain why deforestation would cause extinction

Answer 6

• struggle to find food, mates, shelter
• in small, fragmented habitat
• some may not be able to spread seeds far

Question 7

explain why deforestation would cause a loss of soil

Answer 7

• trees and vegetation help keep soil in place, reduce erosion by wind and rain
• protective layer lost
• soil blown away by wind or washed away by rain

Question 8

explain why deforestation would cause flooding

Answer 8

• hold soil together, hold water in ground
• no vegetation to restrict flow, rain flow quickly into rivers and lakes
• washes more soil away
• flooding

Question 9

explain why deforestation would case an increase of co2 in atmosphere

Answer 9

• less photosynthesis
• some vegetation then burned, release more co2

Question 10

reasons for endangerment/extinction of organisms

Answer 10

• climate change
• habitat destruction
• hunting
• overharvesting
• pollution
• introduced species

Question 11

how does climate change cause the endangerment/extinction of organisms

Answer 11

• affect local conditions
• affect organisms in area
• cannot adapt

Question 12

how does habitat destruction cause the endangerment/extinction of organisms

Question 13

how does hunting cause the endangerment/extinction of organisms

Answer 13

• too many killed
• for sport etc

Question 14

how does overharvesting cause the endangerment/extinction of organisms

Answer 14

• not enough left in area for viable breeding population

Question 15

how does pollution cause the endangerment/extinction of organisms

Question 16

how does introduced species cause the endangerment/extinction of organisms

Answer 16

• disrupt balance of ecosystem
• cause competition, lack of resources, etc

Question 17

methods of conservation of endangered species

Answer 17

• monitoring and protecting species and habitats
• education
• captive breeding programmes
• seed banks