9 - Ecosystems

Question 1

What are the different levels of ecosystem organisation?

Answer 1

• Individual
• Population
• Community
• Ecosystem

Question 2

What are the definitions for individual and population ecosystem levels?

Answer 2

I: A single organism
P: All the organisms of one species in a habitat

Question 3

What are the definitions for community and ecosystem ecosystem levels?

Answer 3

C: All the organisms of different species living in a habitat
E: A community of organisms along with all the non-living (abiotic) conditions

Question 4

What abiotic factors affect communities?

Answer 4

• Temperature
• Amount of water
• Light Intensity
• Levels of pollutants

Question 5

How can communities be affected by temperature and light levels?

Answer 5

• Temperature can affect distribution of species, if a country suddenly got hotter there could be an increase of variety of species
• Things like trees can block sunlight, letting grass die and fungi grow

Question 6

How can communities be affected by water amount and pollutant levels?

Answer 6

• If a plant grew best in dry conditions, too much water will decrease it’s population and vice versa
• Some plants are unable to survive if there is too high/low a concentration of something like a pollutant in the air

Question 7

What biotic factors affect communities?

Answer 7

• Competition
• Predation

Question 8

How can communities be affected by biotic factors?

Answer 8

• Competition - Organisms can compete with each other for the same resources, like food
• Predation - If the number of predators suddenly decreases, their pray might increase due to the fact less of them will be eaten

Question 9

Why is interdependence so important in communities?

Answer 9

• Organisms can depend on each other for things like food and shelter in order for survival
• If there is a change in population of one species can greatly impact the other species in the same community

Question 10

What is mutualism?

Answer 10

A relationship between two organisms where they both benefit, like bees and flowers

Question 11

What is parasitism?

Answer 11

Parasites live closely, on or in their host species
The parasites take what they need to survive, but the host doesn’t benefit, like fleas taking blood from dogs

Question 12

Why is energy lost as its transferred through trophic levels? How does this affect the organisms?

Answer 12

• Energy is used by organisms at each stage to stay alive, like respiration and movement
• This energy isn’t stored as biomass, therefore it isn’t transferred to the next trophic level and is lost
• Not all the energy stored as biomass will get transferred either, like bones or indigestible parts

Question 13

How does the loss of energy in food chains affect the organisms in it?

Answer 13

• So much energy gets lost at each stage there isn’t enough left to support more organisms after about 4 or 5 levels
• There can also be fewer organisms at each trophic level due to this

Question 14

How do you calculate efficiency of energy transfer/biomass lost through the trophic levels?

Answer 14

efficiency = (energy transferred to next level/energy available at previous level) x100

to calculate biomass - replace ‘energy’ with biomass