Biology - ecosystems

Question 1

individual

Answer 1

single organism

Question 2

population

Answer 2

group of organisms of same species that live within the same area

Question 3

community

Answer 3

collection of all the different populations that live together in the same ecosystem

Question 4

habitat

Answer 4

area where organisms live

Question 5

ecosystem

Answer 5

describes the way that the living and non-living components of environment interact

Question 6

biotic factors

Answer 6

• competition for resources
• infectious disease
• predation
• food supply

Question 7

abiotic factors

Answer 7

• light intensity
• pH of water/soil
• temperature
• availability of water
• availability of oxygen
• pollution of air/water

Question 8

what do plants require to survive

Answer 8

• light
• space
• water
• mineral ions from soil

Question 9

what do animals need to survive

Answer 9

• territory
• food
• water
• mates

Question 10

what is interspecific competition

Answer 10

individuals compete with those of another species

Question 11

what is intraspecific competition

Answer 11

individuals compete with those of same species, ‘survival of fittest’

Question 12

predator-prey cycles

Answer 12

• typical cycle, peaks and troughs of population numbers generally follow each other
• more prey means more predators can feed, survive and reproduce leading to an increase in predator numbers
• cycles take a while to sync up because it takes time for populations to respond to species

Question 13

parasitic relationships

Answer 13

• parasite organisms that ‘feed’ off a host without giving anything back to the host
• this means that only the parasite benefits, whereas the host is harmed
• example is animal fleas

Question 14

mutualistic relationships

Answer 14

• organism lives on a host organism, but in return there is an exchange of resources
• both organisms benefit from relationship
• e.g. hermit crabs who place sea anemones on their shells for protection

Question 15

biomass

Answer 15

mass of living organism

Question 16

biomass pyramid

Answer 16

used to represent biomass of food chain as a biomass pyramid

Question 17

what are tropic levels

Answer 17

levels within food chain

Question 18

what are producers

Answer 18

usually, photosynthetic plants
- plants absorb light energy from Sun using chlorophyll
- these are then stored in carbohydrates, fats, proteins - creating plant’s biomass

Question 19

what are primary consumers

Answer 19

herbivores which eat plants

Question 20

what are secondary consumers

Answer 20

carnivores which eat primary consumers

Question 21

what are tertiary consumers

Answer 21

often not present due to the loss of biomass through each stage of the food chain

Question 22

what happens to biomass through the trophic levels

Answer 22

decreases (not always as numbers of organisms increase as you move up too)

Question 23

how is energy lost in different stages of trophic levels

Answer 23

1. energy lost during photosynthesis - photosynthetic plants use only about 1% of Sun’s light energy during photosynthesis, with remainder lost by reflection/transpiration
2. energy lost through respiration - conserving heat and movement
3. energy lost through waste - some of biomass is inedible or indigestible

Question 24

what are the 4 main processes of the carbon cycle

Answer 24

1. photosynthesis
2. respiration
3. decomposition
4. combustion

Question 25

carbon cycle: photosynthesis

Answer 25

sugars formed from process, which are converted to starch or cellulose, or used to make fats and proteins
only process which removes carbon dioxide from the environment

Question 26

carbon cycle: respiration

Answer 26

process releases carbon dioxide as a waste product into environment

Question 27

carbon cycle: decomposition

Answer 27

when organisms die or produce waste, decomposers break down complex organic molecules and return elements to the soil
(decomposers are also known as detritus feeders)

Question 28

carbon cycle: combustion

Answer 28

C + O2 –> CO2
when plant or animal matter are burnt this releases carbon dioxide
mass deforestation and burning increases the amount of CO2 returned to atmosphere, whilst reducing the amount removed through photosynthesis

Question 29

water cycle

Answer 29

1. transpiration: loss of water vapour from plants through stomata to atmosphere
2. evaporation: from surface of sea, rivers and other bodies of water creating water vapour in the atmosphere
3. condensation: water vapour from evaporation condenses to form clouds