4. Ecology And The Evironment

Question 1

Pollution

Answer 1

Releasing harmful substances into the environment in amounts that cause harmful effects and which biological processes cannot easily remove

Question 2

Greenhouse gases

Answer 2

• methane (generated by bacteria in anaerobic/low oxygen conditions e.g. cattle)
• water vapour
• nitrous oxide (burning fossil fuels)
• carbon dioxide (burning fossil fuels)
• CFCs (used as a solvent for aerosols like deodorant)

Question 3

Sulphur dioxide

Answer 3

• formed when fossil fuels are burnt since they contain sulphur
• sulphur dioxide reacts with oxygen in the air and dissolves in rain water to produce sulphuric acid
• creates acid rain
  + nitric acid

Question 4

What does acid rain cause

Answer 4

• death of confir trees -> loss of habitat, loss of species diversion, more CO2 less photosynthesis
• damage of leaves/flowers
• acidification of soil -> leaching of ions onto lakes kills fish or acidifies them directly, killing fish which results in change of ecosystem

Question 5

Carbon monoxide in humans

Answer 5

CO binds irreversibly to haemogoblin
-> less oxygen transported to repairing cells
-> less energy released
-> loose consciousness/death from lack of CO2

Question 6

Deforestation

Answer 6

Clearing of trees, usually on a large scale
-> done for land farming, palm oil production, new homes
-> removal of habitat decreases biodiversity

Question 7

Greenhouse gas effect

Answer 7

Sun emits radiation -> some is reflected by earths atmosphere but some pass through and is absorbed by earths surface

Question 8

Effects of global warming

Answer 8

• melting of polar ice caps -> leads to sea level rising, causing flooding in some regions
• destruction of habitats -> leads to extinction of species
• increased extreme weather events -> more energy present due to global warming
• increase in heat related illness/death

Question 9

Population

Answer 9

Group of organisms of the same species in the same area at the same time

Question 10

Community

Answer 10

ALL of a population living in the same area at same time

Question 11

Independence

Answer 11

Species depend on other species for food/shelter
-> one species removed would affect whole community

Question 12

Habitat

Answer 12

Where an organism lives

Question 13

Ecosystem

Answer 13

Interaction of a community -> biotic and abiotic factors interacting at same time

Question 14

Quadrants - investigate population size

Answer 14

Equipment: Quadrat (square frame), measuring tape, results table.
• Choose an area to study (e.g. school field) and place tape
• Place the quadrat randomly to avoid bias (random generate coordinates).
• Count the number of chosen plant species inside the quadrat.
• Repeat this in multiple random spots (usually at least 10 times).
• Calculate the average number per quadrat.
Estimated population = average per quadrat × total area / quadrat area

Question 15

Abiotic

Answer 15

Non living

Question 16

Abiotic factors

Answer 16

Light intensity for photosynthesis and rate of growth
Temperature for photosynthesis
Moisture levels for water levels
Soil pH and mineral content which affects rate of decay

Question 17

Biotic

Answer 17

Living

Question 18

Biotic factors

Answer 18

Food availability for more breeding and greater population
New predators
New pathogens, population would be wiped out with no resistance to it
Competition, outcompeting other species and reducing population of less adapted (to environments) species

Question 19

Producers

Answer 19

Make own food via photosynthesis

Question 20

Primary consumers

Answer 20

Herbivores

Question 21

Tertiary consumer

Answer 21

Apex predator

Question 22

Decomposers

Answer 22

Bacteria and fungi that breaks down dead animals body/waste for energy using enzymes

Question 23

Food chain shows

Answer 23

Feeding relationship btwn organisms

Question 24

Food web

Answer 24

Shows interdependence of organisms

Question 25

Energy transfer in food chain

Answer 25

Transfers 1% of incident energy from ligh for photosynthesis since not all light lands on green of leaf

Question 26

Energy transfers for biomass pyramids

Answer 26

10% of biomass transferred each trophic level

Question 27

Reason for not all biomass converted

Answer 27

- not all can be eaten (bones/claws) - not all eaten is converted -> glucose in respiration produces CO2 waste product -> urea waste product -> faeces since not all enzymes can digest so its egested

Question 28

Combustion

Answer 28

Plant + fossil fuels/remains are burnt and CO2 is released

Question 29

Respiration

Answer 29

Glucose + oxygen —> carbon dioxide + water

Question 30

Pollution of water by sewage

Answer 30

- sewage is rich in minerals and nutrients that allow algae and decomposers to thrive - decomposers respire aorebically to break down sewage using O2 - algae bloom -> stops light reaching aquatic plants so they die - oxygen depletion means other aquatic organisms also die

Question 31

How is eutrophication caused

Answer 31

Fertilisers are washed off land into nearby rivers and lakes by rain Excess nutrients washed into lake increase rapid growth of algae Algae blocks sunlight reaching aquatic plants No photosynthesis => oxygen depletion => higher biological oxygen demand Organisms die