Organisms and their environment

Question 1

food chain definition

Answer 1

chart showing the flow of energy from one organism to the next (beginning with a producer)

Question 2

food web definition

Answer 2

network of interconnected food chains showing energy flow in part of an ecosystem

Question 3

decomposer definition

Answer 3

an organism that gets its energy from dead or waste organic matter

Question 4

ecosystem definition

Answer 4

unit containing all their organisms and their environment, interacting together, in a given area

Question 5

community definition

Answer 5

all populations of different species in an ecosystem

Question 6

trophic level meaning

Answer 6

position of an organism in a food chain

Question 7

interdependance meaning

Answer 7

the way in which living organisms depend on each other to stay alive, reproduce and grow

Question 8

photosynthesis equation

Answer 8

6CO2+ 6H20-> C6H120+6O2

Question 9

predators meaning

Answer 9

organisms that hunt and kill their food

Question 10

prey meaning

Answer 10

organisms that are eaten by predators

Question 11

apex predators meaning

Answer 11

carnivores with no predators

Question 12

what do the arrows in a food chain represent

Answer 12

they represent the direction in which energy (from food) flows from one organism to the next

Question 13

prey and predator_ type of relation

Answer 13

cyclical correlation

Question 14

what do pyramids of numbers show and how

Answer 14

• how many organisms there are at each level

- through size of box

Question 15

general rule for pyramid of numbers

Answer 15

the larger an organism is, the less of them there are (number-wise)

Question 16

what shapes can a pyramid of number acquire?

Answer 16

any! doesn’t have to be pyramid shaped

Question 17

what can you not change in a pyramid of numbers?

Answer 17

trophic level

Question 18

what does a pyramid of biomass show

Answer 18

how much DRY mass the creatures at each level would have

Question 19

shape of pyramid of biomass

Answer 19

nearly always pyramid

Question 20

why nearly always pyramid shaped?

Answer 20

mass of organisms must decrease as go up– 10kg of grass cannot feed 50kg of cows

Question 21

criticisms of pyramids of biomass

Answer 21

• measurements= taken at a moment in time (so does not consider how fast it grows). i.e. grass, grows quickly but is grazed to low biomass
• phytoplankton= live for few days then are eaten, so biomass only represents a few days growth. this would lead to inverted pyramid
• biomass can vary with seasons (i.e. deciduous trees= lose leaves in winter)

Question 22

solutions to problems with pyramids of biomass

Answer 22

calculate biomass over a reasonable period of time (i.e. 1 year)

Question 23

when calculating dry mass, why important to leave out water?

Answer 23

• not nutritionally valuable

- unreliable as some absorb more water, depends on weather, etc)

Question 24

how much energy is passed on to next organism?

Answer 24

10%

Question 25

why not all energy transfered

Answer 25

as used in heat, movement, respiration, life processes, egested, remains in dead organisms, not fully eaten (i.e. bones)

Question 26

which food chains are the most efficient

Answer 26

shorter ones

Question 27

efficient food chain

Answer 27

wheat-> humans

Question 28

how do farmers try to maximise meat production?

Answer 28

• reducing movement

- keeping them warm in winter