Bio I&J: Ecosystems and Global warming (PAPER 2)

Question 1

Required random sampling practical:

Answer 1

Use two tape measures to measure out a 10m x 10m area.
Using a random number generator, generate 2 random numbers on the x and y axis.
Go to where the two points meet and place down a quadrat, counting the number of plants in each square.
Repeat this process in multiple coordinates and compare results.

Question 2

Three main greenhouse gases

Answer 2

Carbon dioxide
Methane
Nitrous oxide

Question 3

How does increased CO2 levels cause global warming

Answer 3

The CO2 traps sunlight in the atmosphere which heats the earth.
An increase in CO2 will increase the rate in which this reaction occurs.

Question 4

Ecosystem

Answer 4

A geographic area where biotic and abiotic components come together to form a bubble of life.

Question 5

Est. population size formula

Answer 5

(area sampled / total area) x 100

Question 6

Investigation for number of organisms in different locations along the coast

Answer 6

Lay a transect line from the edge of the sea up to the stony beach.
Place a quadrat at regular intervals.
Count number of each species present or estimate cover of plants.
Repeat with different transect lines.
Calculate means for each distance up the shore.

Question 7

How does sulphur dioxide and nitrous oxide form acid rain?

Answer 7

Acid rain occurs when nitrous oxide and sulphur dioxide are emitted into the atmosphere by wind and air currents. They react with water, oxygen and other chemicals to form sulphuric and nitric acids. These then mix with water and other materials before falling to the ground.

Question 8

Effect of fertilisers on biodiversities (Eutrophication)

Answer 8

1. ) Excess fertiliser leaches into waterways
2. ) Nitrates released stimulate growth of algae
3. ) Algal bloom on ocean surface prevents sunlight reaching parts of the ocean.
4. ) Lack of sunlight reduces photosynthesis leading to dying plants and animals as respiration requires oxygen.
5. ) Organisms decompose on ocean bed by microorganisms which need oxygen to respond, decreasing oxygen levels
6. ) Overall biodiversity decreases.

Question 9

How materials are cycled

Answer 9

Microorganisms like bacteria and fungi decompose dead animals, helping recycle minerals and nutrients to the environment which can be used by other organisms.

As they decompose dead matter, microorganisms respire releasing carbon dioxide into the environment.

Question 10

Maintaining biodiversity

Answer 10

Field margins and hedgerows between crops and field boundaries provides a vital habitat for species.
Captive breeding saves animals from extinction, disease, and other threats.
Recycling reduces the need for raw materials so rainforests can be preserved.
Government schemes put limits on deforestation and CO2 limits