19 - Organisms and their environment

Question 1

Food chain

Answer 1

Shows the transfer of energy from one organism to the next, beginning with a producer.

Question 2

Food web

Answer 2

A network of interconnected food chains

Question 3

Producers

Answer 3

An organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis (aka autotroph)

Question 4

Consumers

Answer 4

An organism that gets its energy by feeding on other organisms. Classed as primary, secondary, tertiary, and quaternary according to their position in a food chain (usually no higher bc inefficient - aka heterotroph)

Question 5

Primary consumer

Answer 5

First consumer in a food chain, they eat producers

Question 6

Secondary consumer

Answer 6

Second consumer in a food chain, eat primary consumer

Question 7

Tertiary consumer

Answer 7

Third consumer in a food chain, eats secondary consumer

Question 8

Quaternary consumer

Answer 8

Fourth consumer in a food chain, eats tertiary consumer

Question 9

Herbivore

Answer 9

Animal that gets energy from eating plants

Question 10

Carnivore

Answer 10

Animal that gets its energy by eating other animals

Question 11

Decomposer

Answer 11

Organism that gets its energy from dead waste or organic material (aka saprotroph)

Question 12

Trophic Level

Answer 12

The position of an organism in a food chain, food web, or ecological pyramid.

Question 13

What do arrows in a food chain/web represent?

Answer 13

They represent the energy being transferred

Question 14

Ecosystem

Answer 14

A unit containing the community of organisms and their environment, interacting together

Question 15

Energy loss in food chains - list how it’s lost

Answer 15

Through movement, respiration, excretion and not eating the whole organism (mostly lost as heat)

Question 16

Pyramid of numbers

Answer 16

Compares the number of organisms at each trophic level

Question 17

Pyramid of biomass

Answer 17

Compares the mass of biological material at each trophic level

Question 18

Pyramid of energy

Answer 18

Compares the amount of energy passing through each trophic level over a period of time

Question 19

Respiration

Answer 19

A chemical process that involves the breakdown of nutrient molecules (specifically glucose) in order to release the energy
6O2 + C6H12O6 –> 6CO2 + H2O
Oxygen + Glucose –> Carbon Dioxide + Water

Question 20

Photosynthesis

Answer 20

A chemical reaction that requires energy, water, and carbon dioxide to synthesize glucose. Oxygen is a byproduct.

Question 21

Decomposition

Answer 21

When living organisms die, cells are broken down. The decomposers use the material they gain to respire.

Question 22

Combustion

Answer 22

The burning of fuels (like fossil fuels) (in oxygen) to release energy. Carbon dioxide is also released (byproducts in the form of oxides)

Question 23

Fossilisation

Answer 23

Forming of fossils xD

Question 24

Carbon Cycle

Answer 24

1. Carbon dioxide in the atmosphere is used in photosynthesis
2. Animals eat plants
3. Death and waste - plants and animals die
4. Animal respiration puts carbon dioxide back in the atmosphere
5. Decomposition puts carbon dioxide back in the atmosphere
6. Without decomposition fossils and fossil fuels are formed
7. When fossil fuels are combusted it puts carbon dioxide back in the air

Question 25

Nitrogen Cycle

Answer 25

1. Lightning and nitrogen fixing bacteria do nitrogen fixation - nitrates in soil
2. Plants absorb nitrate ions
3. Plants are eaten by animals
4. Death, excretion, and deamination turn plants and animals into proteins and urea
5. Decomposers break down the proteins into ammonium ions through decomposition
6. Nitrification to make nitrates in the soil with nitrifying bacteria
7. Denitrification turns the nitrates into nitrogen with denitrifying bacteria and puts it back in the air

Question 26

Nitrogen fixation

Answer 26

Convert nitrogen gas into nitrates. Done by nitrogen fixing bacteria, lightning, fertiliser (haber process)

Question 27

Denitrification

Answer 27

Converting nitrates into nitrogen gas. Done by denitrifying bacteria

Question 28

Nitrification

Answer 28

Converting ammonium ions into nitrite and then nitrate - done by nitrifying bacteria

Question 29

Decomposition (in terms of the nitrogen cycle)

Answer 29

Breakdown of plants and animals by microorganisms, forming ammonium ions

Question 30

Deamination

Answer 30

Happens in animals. Converting amino acids into urea. Basically dying or making pee, but not peeing.

Question 31

Four factors that affect population growth rate

Answer 31

Food supply, predation, disease, competition

Question 32

Four factors that determine how the size of a population changes over time

Answer 32

Number of births and immigration increase population size, number of deaths and emigration decrease population size

Question 33

Sigmoid curve of population growth

Answer 33

1. Lag phase
2. Exponential growth/log phase
3. Stationary phase
4. Death phase

Question 34

Lag phase

Answer 34

Organisms are adapting to the environment before they are able to reproduce; in addition, at this stage there are very few organisms so reproduction doesn’t make larger numbers of offspring

Question 35

Log phase / exponential growth phase

Answer 35

Food supply is abundant, birth rate is rapid and death rate is low, growth is exponential and only limited by the number of new individuals that can be produced (how many babies fit in a nest or smth like that)

Question 36

Stationary phase

Answer 36

Population levels out due to a factor in the environment, such as a nutrient becoming limited as it isn’t being replenished or not having enough space. Birth rate and death rate are equal and will remain so until either the nutrient is replenished or becomes severely limited

Question 37

Death phase

Answer 37

Population decreases as death rate is now greater than birth rate; this is usually because food supply is short or metabolic wastes produced by the population have built up to toxic levels