Community Level Systems

Question 1

Define the term ecosystem

Answer 1

It is a specific area within Earth’s biosphere which supports live and living organisms that are interdependent on biotic and abiotic factors

Question 2

Give 2 examples of an ecosystem

Answer 2

• Deciduous forest
• River
• Coniferous forest

Question 3

Define population

Answer 3

A group of living organisms of the same species that occupy a habitat in an ecosystem

Question 4

Define community

Answer 4

A group of living organisms of different species occupying a habitat in an ecosystem

Question 5

Explain and name the biotic factors

Answer 5

• Competition: living organisms compete for food/territory/water and other natural resources
• Predation: Predator/prey interaction as predators prey on other living organisms for energy source
• New Pathogens: if a new pathogen is in an ecosystem this can lead to a rapid decline of a population

Question 6

Name abiotic factors

Answer 6

• Light intensity
• Temperature
• Soil pH
• Water availability
• Wind direction
• Oxygen concentration

Question 7

Why is nitrogen important

Answer 7

Nitrogen make up a living organism including amino acids, ATP, Nucleic acids, DNA, mRNA which determine genetic make up of an organism

Question 8

What are the 4 main stages in the NItrogen cycle?

Answer 8

• Nitrogen fixation
• Nitrification
• Decomposition by decomposers
• Dentrification

Question 9

Why is Nitrogen inert?

Answer 9

Nitrogen is a diatomic form which has triplet covalent bonds which is hard to break and needs a lot of energy to break so it is unreactive

Question 10

What is mutualistic interdependency?

Answer 10

Relationship in which the organisms involved benefit from each other. eg. Clownfish survive toxins so they can protect themselves from predators and in return clownfish eat parasites that harm sea anemones

Question 11

What is a parasitic relationship?

Answer 11

-Only the parasite benefit from the organism and they live inside a host organism and gets all the nutrients to survive but give back nothing. Mostly, the parasite harms the host

Question 12

Explain the process of feeding in the nitrogen cycle

Answer 12

Animals feed on other plants and animals so they obtain nitrogen containing molecules from the food

Question 13

Explain the process of Death and excretion in the nitrogen cycle

Answer 13

Animals excrete and die with lots of NItrogen molecules

Question 14

Explain the process of Decomposition in the nitrogen cycle

Answer 14

Decomposers release enzymes to break down large organic molecules like dead plants and in this process ammonia is released into the soil which then goes through nitrrification

Question 15

Explain the process of oxidation by nitrifying bacteria in the nitrogen cycle

Answer 15

Ammonium ions in the soil are oxidised by free living bacteria in the soil first to nitrate then to nitrate ions

Question 16

Explain the process of break-down by denitrifying bacteria in the nitrogen cycle

Answer 16

Certain types of bacteria in waterlogged conditions break down nitrate ions to use oxygen in respiration but release nitrogen gas back into atmosphere

Question 17

Explain the process of nitrogen fixation by soil bacteria and lightning in the nitrogen cycle

Answer 17

The atmospheric Nitrogen can get fixed into ammonia and ammonium ions by bacteria in soil.
High energy in lightning breaks bond between nitrogen atoms which react with oxygen makin nitrate ions which falls to the ground in rainwater

Question 18

Explain the process of Nitrogen fixing by root nodule bacteria in the nitrogen cycle

Answer 18

Some bacteria that live in root nodules of legumes that fix atmospheric nitrogen into ammonia. This is an example of nitrogen fixation. This is also a mutualistic relationship

Question 19

Explain the process of absorption by roots in the nitrogen cycle

Answer 19

Nitrate ions are soluble in water so they are easily absorbed by root hair cells