B17 - Biodiveristy And Ecosystems

Question 1

Carbon sinks - trapping of carbon

Answer 1

Forests - absorb CO2 via photosynthesis
Oceans - CO2 dissolved in water
- phytoplankton use carbon for their skeleton and shells
Peat bogs - lock away CO2, when burnt CO2 released back into the atmosphere

Question 2

Peat bogs

Answer 2

• incompletely decomposed plant remains
• formed by waterlogging and lack of oxygen which effect the natural processes of decay
• preservation of matter due to limited oxygen to the matter as they have been water logged
• therefore microorganisms cannot fully decompose (lack of bacteria breaking down)
• bodies found
• when oxygen is removed, bacteria is no longer able to respire therefore reducing the rate of decomposition

Question 3

Why does deforestation happen?

Answer 3

• population explosion - 8 billion people on Earth
• more people = more resources
• global warming = Earth gradually heating up because of increasing levels of greenhouse gases

Question 4

Biodiversity

Answer 4

• 8.7 million species
• destruction of habitats (fishing, agriculture, manufacturing)
• exploitation of species - fishing, bogging, harvesting - population collapses due to high demand
• pollution - eutrophication
• alien species introduced
• rapid climate change - mass extinction events
• loss of sea ice
• alters weather patterns

Question 5

3 ways biodiversity is reduced

Answer 5

• deforestation reduces biodiversity
• using peat bogs decreases biodiversity
• landfill destroys habitats - less biodiversity

Question 6

What is global warming?

Answer 6

• result of the greenhouse effect
• solar radiation is infrared/ultraviolet

Infrared radiation can:
• emit
• absorb heat

Question 7

Effects of climate change on biodiversity:

Answer 7

• loss of habitat
• rising sea levels destroy habits and reduce biodiversity in that area
• another effect is a change in the distribution of organisms
• as temperatures and rainfall patterns change, organisms may find that their range shrinks or completely disappears
• organisms migration patterns may also change due to a change in seasons

Question 8

Breeding programmes for endangered species

Answer 8

• animals are bred in captivity to ensure a species survives
• individuals can sometimes be released into the wild to boost a population
• eg white rhinos/snow tigers
• RSPCA and WWF work to support animals

Question 9

Protection and regeneration of rare habitats

Answer 9

• protecting habitats like mangroves in coastal regions, heathland and coral reefs
• helps preserve ecosystems and biodiversity in the area

Question 10

Reintroduction of field margins and hedgerows

Answer 10

• introduce this on farms where only a single type of crop is grown
• field margins are where wild flowers/grasses grow
• provide habitat for wider variety of organisms that could survive
• arable

Question 11

Reduction of deforestation and carbon dioxide emissions

Answer 11

• gov introduced regulations to reduce deforestation, especially for businesses
• reduce global warming
• CO2 is released by buisnesses
• in the Amazon

Question 12

Recycling resources

Answer 12

• people are encouraged to recycle to reduce the amount of waste that gets dumped in landfill sites
• leaving ecosystems in place because less land is needed for landfill
• recycling plastic
• Different bins

Question 13

Land pollution examples

Answer 13

• land fill
• deforestation

Question 14

Water pollution examples

Answer 14

• oil spills
• eutrophication
• sewage/commerical waste

Question 15

Air pollution

Answer 15

• combustion of fossil fuels

Question 16

What is meant by abiotic/biotic factors?

Answer 16

The environment in which organisms live changes all the time. The things that change are either abiotic (non living) or biotic (living) factors. These can effect the community.

Question 17

Examples of abiotic factors

Answer 17

Moisture level
Light intensity
Temperature
Carbon dioxide level for plants
Wind intensity and direction
Oxygen level for aquatic animals
Soil pH and mineral content

Question 18

Example of how a change in an abiotic factor effects the community

Answer 18

• a decrease in light intensity, temperature or level of carbon dioxide could decrease the rate of photosynthesis in a plant species. This can affect plant growth and cause a decrease in the population size.
• a decrease in the mineral content of the soil. For example, a lack of nitrates could cause nutrient deficiencies. This could also affect plant growth and cause a decrease in the population size.

Question 19

Examples of biotic factors

Answer 19

New predators arriving
Competition – one species may outcompete another, so that numbers are too low to breed
New pathogens
Availability of food

Question 20

Examples of how changing biotic factors could affect the community

Answer 20

• a new predator could cause a decrease in the prey population
• red and grey squirrels live in the same habitat and eat the same food. Grey squirrels outcompete the red squirrels so the population of red squirrels is decreasing.