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Question 1

1. What is the definition of a species?

Answer 1

a group of organisms that can breed together to produce fertile offspring

Question 2

2. Why do species adapt to their environments?

Answer 2

-to increase their chance of survival

=more likely that the organism will survive to reproduce.

Question 3

4. What are plants’ dependant on for their survival?

Answer 3

The environment:
Light 
minerals 
Oxygen 
Carbon dioxide
Water

Question 4

4. What happens if one factor an organism is dependant on is in short supply?

Answer 4

species will compete=not all will survive= population limited in that particular habitat

Question 5

5. What is there for resources in a habitat between different species of animals or plants?

Answer 5

-competition

Question 6

6. What changes in environment can impact species in a food web?

Answer 6

-if one species in a food chain is killed=effect rest of web (increase/decrease other populations)

Question 7

7. What is it called when species in a food web are reliant upon each other?

Answer 7

-interdependence

Question 8

8. What are 3 changes in the environment that can cause extinction of a species?

Answer 8

• the environmental conditions change beyond its ability to adapt (e.g. destruction of a habitat)
• A new species that is a competitor, predator or disease organism of that species is introduced (this includes humans hunting them)
• Another species (animal, plant or microorganism) in its food web becomes extinct (that it relied upon)

Question 9

9. What are nearly all animals ultimately dependant on?

Answer 9

energy from the Sun

Question 10

10. What do plants do to the Sun’s energy?

Answer 10

photosynthesis.

Question 11

11. What happens to the Sun’s energy in the plants?

Answer 11

The absorbed energy is stored in the chemicals which make up the plants’ cells

Question 12

12. When is energy transferred between organisms in an ecosystem?

Answer 12

• when organisms are eaten

- when dead organisms and waste materials are fed on by decay organisms (decomposers and detritivores)

Question 13

13. What happens to energy at each stage of the food chain?

Answer 13

Energy is lost

Question 14

13. How is the energy lost at each stage of the food chain?

Answer 14

• heat: mammals/ birds for example have to have a constant body temperature that is often higher than their surroundings
• waste products: e.g. droppings and urine
• uneaten parts: e.g. bones

Question 15

13. What does the loss of energy at each stage of food chains do to food chains?

Answer 15

-limits the length of food chains

not enough energy to support life after a certain number of stages

Question 16

14. What is the equation for percentage efficiency of energy transfer at different stages of a food chain?

Answer 16

efficiency= (energy available to the next stage/ energy that was available to the previous stage) x100

Question 17

15. How is carbon recycled through the environment? (what puts carbon in/out atmosphere)

Answer 17

Puts carbon into atmosphere:

• Combustion : the burning of fossil fuels releases carbon dioxide into the air
• Respiration : organisms release carbon dioxide when respiring
• Decomposition : microorganisms that break down decomposing plants and animals release carbon dioxide through respiration

Takes carbon out of atmosphere
-Photosynthesis : plants convert carbon into sugars as well as carbs, fats and proteins

Question 18

16. What is the importance of the role of microorganisms in the carbon cycle?

Answer 18

Microorganisms in the soil decompose carbon compounds from dead plants and animals

Question 19

17. How is nitrogen recycled through the environment?

Answer 19

• nitrogen fixation to form nitrogen compounds including nitrates
• conversion of nitrogen compounds to protein in plants and animals
• transfer of nitrogen compounds through food chains
• excretion, death and decay of plants and animals resulting in release of nitrates into the soil
• uptake of nitrates by plants
• denitrification

Question 20

18. What is the importance of the role of microorganisms in the nitrogen cycle?

Answer 20

• Decomposers : Decompose proteins and urea and turn them into ammonia
• Nitrifying bacteria : Turn ammonia in decaying matter into nitrates (nitrification)
• Nitrogen-fixing bacteria : Turn atmospheric N2 in the atmosphere into nitrogen compounds for plants to use
• Denitrifying bacteria : Turns nitrates back into N2 gas. This doesn’t benefit living organisms.

Question 21

20. How can environmental change be measured using non-living indicators?

Answer 21

• Temperature : The temperature will vary all the time however temperature measurements (taken by thermometers) over a long period of time can indicate climate change (e.g. global warming)
• Nitrate level : Can indicate environmental change in a body of water. Increase in nitrate level could be caused by sewage/fertilisers in water which shows water is polluted.
• Carbon dioxide level : Can indicate environmental change in air. Increase in carbon dioxide could be caused by burning fossil fuels. Increase in carbon dioxide= increase rate of global warming.

Question 22

21. How can environmental change be measured using living indicators?

Answer 22

-Lichen : Sulphur dioxide (Level of pollution from cars, power stations etc.)
Sensitive to sulphur dioxide
Number and type of lichen will indicate how clean the air is
Lots of lichen= clean air

-Mayfly nymphs : Oxygen (water pollution like raw sewage)
Sensitive too oxygen levels in water
If they are they- clean water
If raw sewage= increase bacteria population= decreases oxygen in water

-Phytoplankton (microscopic algae): Nitrates and phosphates (fertilisers and sewage) Population increases when levels of nitrates and phosphorus increase (algal bloom) = water pollution

Question 23

4. What are animals’ dependant on for their survival?

Answer 23

Food
Oxygen
Water
Other species