2.2 - Communities And Ecosystems

Question 1

Define respiration

Answer 1

Respiration is the conversion of organic matter into carbon dioxide and water in all living organisms releasing energy. Can be aerobic and anaerobic

Question 2

Respiration releases energy. State the form that this energy will eventually become

Answer 2

Stored energy —> kinetic energy —> heat

Question 3

Write the word equation for respiration

Answer 3

Glucose + oxygen —> carbon dioxide + water

Question 4

Define photosynthesis

Answer 4

Photosynthesis is the process by which green plants convert light energy into useable chemical energy stored stored in organic matter

Question 5

Write the word equation for photosynthesis

Answer 5

Carbon dioxide + water —> glucose + oxygen

Question 6

What are the type of organisms which can occupy the first trophies level but not perform photosynthesis

Answer 6

Chemosythetic bacteria

Question 7

Explain how the transfer of energy and matter throguh photosynthesis supports the first and second law off thermodynamics

Answer 7

First law : energy can nether be created nor destroyed, it can only change form
Solar energy enters the ecosystems as light energy. Photosynthesis converts light energy to stored chemical energy

Second law : energy goes from a concentrated form into a dispersed form. The availability of energy to do work therefore decreases and the system becomes increasingly disordered
The solar energy that falls on plant is dispersed in that;
- some reflects
- some is lost through respiration
- some is stored as biomass

Question 8

Compare and contarse pyramids of biomass and pyramids of productivity

Answer 8

Pyramids of biomass represents the biological mass of the standing stock at each tropic level at a particular point in time
Pyramids of productivity show the flow of energy through each trophies level over a period of time

Question 9

State the units of storage of biomass as represented in pyramids of biomass

Answer 9

Grams of biomass per square meter (gm^-2) or Jm^-2

Question 10

State the units for energy f;ow as represented in the pyramids of productivity

Answer 10

Gm^-2 Jm^-2 yr^-1

Question 11

Define bioaccumulation

Answer 11

Bioaccumulation is the build up of persistent/non biodegradable pollutants within a organism or trophies level because they cannot be broken down

Question 12

Define bio magnification

Answer 12

The increase in concentration of persistent/ non biodegradable pollutants along a food chain. This makes the pollutant more toxic in higher levels

Question 13

Explain how the emissions of elemental and methyl mercury into minamata bay resulted in local people suffering from mercury poisoning

Answer 13

Waste water containing mercury and methyl mercury were released into minimata bay. Methylmercuty is easily absorbed into the bodies of small organisms such as shrimp.
When shrimp are eaten by the fish the methyl mercury enters the fish. As the fish eat more and more shrimp the amount increased. The same happened to humans that were eating shrimp and fish from the bay.

Question 14

DDT is used as pesticide. The material is persistent, explain what this means

Answer 14

DDT cannot be broken down naturally. They will remain in the enviromental until they are physically removed by clean up

Question 15

According to a study in Long Island estuary, concentrations of less than 0.1 ppm of DDT in plankton lead to concentrations of up to 25ppm in sea birds. Explain why the concentration is higher in sea birds

Answer 15

Bioaccumulation - the concentration of DDDT builds up over time within each trophies level

Bio magnification - the concentration of a chemical substance increases at each tropic level with results in a top prediction potentially having an accumulation as stated above