Ecology

Question 1

Habitat Definition

Answer 1

The place where an organism lives

Question 2

Population

Answer 2

All the organisms of a particular species living in a certain area

Question 3

Community definition

Answer 3

All organisms of all species in a particular area at a particular time.

Found in an ecosystem

Question 4

Ecosystem definition

Answer 4

All the organisms and their environment interacting together in a certain area

A self - supporting system of organisms

Question 5

Biodiversity and affecting factors

Answer 5

The amount of variation shown by species in an ecosystem

Two Measurements:
the number of different species - species richness
the relative abundance of each species - ‘evenness’ of numbers across the species
e.g higher relative abundance = higher biodiversity

Question 6

Biodiversity affects on ecosystem

Answer 6

Ecosystems with high biodiversity are often more stable.
This is due to ecosytem’s dominated by few species are more likely to be affected by ecological disasters

Question 7

Biotic Factors definition

Answer 7

Parts of the environment which are living that affect organisms.
They are biological

Question 8

Biotic Factors

Answer 8

• availability of food and competition for food resources
• predation
• parasitism
• disease
• presence of pollinating insects
• availability of nest sites
• food supply (main affecting factor in river ecosystem)

Question 9

Abiotic Factors definition

Answer 9

Parts of the environment that are non-living affect organisms.
They are physical and chemical factors

Question 10

Abiotic Factors

Answer 10

• climate eg light intensity, temperature, water availability
• hours of daylight
• soil conditions eg clay content, nitrate level, water availability
• pollution
• other factors specific to a particular habitat
  eg salinity (salt content) in an estuary, flow rate in a river, oxygen concentration in a lake

Question 11

Trophic Level Definition

Answer 11

a stage or level in a food chain

Question 12

Herbivore
Carnivore
Omnivore

Answer 12

Herbivore - Animals that only eat plants
Carnivore - Animals that only eat animals
Omnivore - Animals that eat both animals and plants

Question 13

Producer definition

Answer 13

A plant which uses sunlight to make food
The first member of a food chain/food web

Question 14

Primary Consumer Definition

Answer 14

an animal that only eats producers

Question 15

Secondary Consumers definition

Answer 15

an animal that eats primary consumers

Question 16

Tertiary Consumer definition

Answer 16

an animal that eats secondary consumers

Question 17

Top Carnivore definition

Answer 17

an animal which is not eaten by anything else

Question 18

Decomposer definition

Answer 18

organisms such as bacteria and fungi that break down dead, decaying matter

Question 19

Consumer definition

Answer 19

An organism which eats another living organism

Question 20

Predator Definition

Answer 20

any ANIMAL which hunts and eats another animal

Question 21

Prey definition

Answer 21

any ANIMAL which gets eaten by another animal

Question 22

Ecological Pyramids

Answer 22

Two Types: Pyramids of Numbers, Pyramids of Biomass

Question 23

Pyramids of Numbers

Answer 23

Represents the number of organisms in each trophic level in a food chain

Shows population of each organism at each trophic level of a food chain

Producers are at the bottom and bars get smaller the further up you go.

P.S if a producer is one tree/large plant, the size of the bar is very small - its only one tree

Question 24

Pyramids of Biomass

Answer 24

Represents the total mass of the organisms in each trophic level, irrespective of their numbers
- show the relative dry mass of material at each level.
- There is less biomass as you move up the trophic levels

Key: the biomass of an organism in the level above will always be higher, as not all organisms can be consumed and converted into biomass

Question 25

Transfer of energy from source to producer

Answer 25

Producers transfer only 1% of incident energy from light for photosynthesis - not all light lands on green (photosynthesising) parts of the plant.

Question 26

Transfer of energy through trophic levels of food chain/food web

Answer 26

Only 10% of the biomass and energy of each trophic level is transferred to the next as:
- uneaten parts
- glucose used in respiration
- urea is a waste substance
- energy used up in movement

90% energy loss between one trophic level and the next - not efficient

Question 27

Human influences on the environment - Pollution of air by sulfur dioxide

Answer 27

• Released when fossil fuels are burnt
• Dissolves in water droplets in clouds to form sulphuric acid creating acid rain
• Acid rain makes rivers too acidic -> leads to aquatic organisms dying
• It corrodes metals and limestones in buildings
• It leeches minerals out of soil so plants + trees cannot survive

Question 28

Human influences on the environment - Pollution of air by carbon monoxide

Answer 28

• Released in burning of fossil fuels through incomplete combustion
• Toxic to breath

Question 29

Carbon Monoxide effect on Humans

Answer 29

• Bind irreversibly to haemoglobin -> reduces oxygen carrying capacity of red blood cells -> causing tiredness, unconsciousness, death in extreme cases
  -> in pregnant women, insufficient oxygen affects the growth of the foetus

Question 30

Greenhouse Gases

Answer 30

• Gases that absorb infrared radiation from the sun, trapping it above the Earth’s surface (greenhouse effect) -> leads to increase of Earth’s temperature (global warming)

Question 31

Sources of Greenhouse Gases

Answer 31

Water Vapour -> rivers and lakes
Carbon Dioxide -> deforestation, fossil fuels
Nitrous Oxide -> fertilisers, vehicle engines
Methane -> cattle, rice paddy fields
CFC -> refrigerators, aerosol sprays

Question 31

Sources of Greenhouse Gases

Answer 31

Water Vapour -> rivers and lakes
Carbon Dioxide -> deforestation, fossil fuels
Nitrous Oxide -> fertilisers, vehicle engines
Methane -> cattle, rice paddy fields
CFC -> refrigerators, aerosol sprays

Question 32

Effects of Global Warming

Answer 32

• Climate Change
• Water levels increase -> glaciers melt due to higher temperatures -> flooding
• Loss of habitats
• Uninhabitable environments due to climate change -> some species become extinct or migrate to more habitable areas

Question 33

Biological consequences of pollution - Pollution of water by sewage

Answer 33

• If untreated sewage gets to rivers it increases the amount of nutrients and minerals -> more organic matter for organisms to feed on (decomposers)