Mr p bio 3 energy transfers

Question 1

what are trophic levels?

Answer 1

the levels organisms occupy in a food web

Question 2

what are producers also known as and what do they do in terms of the food chain?

Answer 2

they are organisms start the food chain and are autotrophs so they build up organic compounds from simple molecules via photosynthesis

Question 3

what are consumers known as?

Answer 3

heterotrophs

Question 4

what do heterotrophs rely on?

Answer 4

an external source of organic compounds (have to take in organic compounds)

Question 5

what do decomposers do?

Answer 5

break down complex organic compounds in dead organisms

Question 6

what are decomposers also known as?

Answer 6

sacrobionts

Question 7

what are 2 examples of sacrobiotic decomposers?

Answer 7

bacteria and fungi

Question 8

what is a food web?

Answer 8

many food chains within a habitat linked together

Question 9

what does a higher diversity mean?

Answer 9

the more complex the food web so that any one change in the food web will have less of an effect

Question 10

what do food chains not give and what can be constructed to resolve this?

Answer 10

doesnt give quantitive information (like no. or organisms, amount of biomass or energy stored at each level. egological pyramids can be constructed

Question 11

what are the three types of ecological pyramid

Answer 11

-number
-biomass
-energy

Question 12

how are pyramids of number formatted?

Answer 12

bars are drawn which are proportional to the numbers of organisms present at eadch trophic level

Question 13

disadvantages of using pyramids of number

Answer 13

size of an organism not taken into account and this results in inverted pyramids for some food chains

Question 14

how are pyramids of biomass formatted?

Answer 14

more reliable than pyramids of no. and show the biomass at each trophic trophic level rather than the no. of organisms which overcomes the problem of size

Question 15

why shouldnt fresh mass be used in pyramids of biomass?

Answer 15

-fresh mass can be measured but is measured but is unreliable as water content varies so important to use dry mass, half of which is approximately the mass of carbon in the organism

Question 16

what is are the conditions required for measuring dry mass?

Answer 16

involves killing organsims so the samples tend to be small aand will also effect reliability

Question 17

what is biomass/ dry mass measured in?

Answer 17

mass of its tissue per unit area per time e.g. kg m^2 yr

Question 18

what does the pyramid of biomass not take into account?

Answer 18

only represents the situation at a given point in time doesnt take into account any changes at diff times of the year

Question 19

why can biomass pyramid be inverted?

Answer 19

because biomass may fluctuate

Question 20

what reasons is energy lost at each trophic level?

Answer 20

movement or digestion, heat, waste products, uneaten parts

Question 21

what do energy pyramids show?

Answer 21

energy at each stage stage and energy lost at each stage

Question 22

what is the advantage of energy pyramid?

Answer 22

most accurate

Question 23

what is a disadvantage of energy pyramid?

Answer 23

hard to know how much energy is in everything

Question 24

what does the producer bar on the energy pyramid represent?

Answer 24

light energy converted to chemical energy in photosynthesis

Question 25

why is only 1-3% of the available sunlight comverted to chemical energy?

Answer 25

-some light reflected
-some light absorbed by atmosphere
-some light is wrong wavelength
-some light doesnt fall on chloroplasts and misses chlorophyll

Question 26

what is the GPP?

Answer 26

gross primary production (energy which is converted to organic molecules

Question 27

what is NPP?

Answer 27

Net primary production (the energy which is availabke to next trophic level)

Question 28

how is NPP calculated?

Answer 28

NPP= GPP - R (R is respiratory loss)

Question 29

how is lots of energy lost between producer and primary consumer?

Answer 29

large amount of plant may be indigestable so some NPP passes out as faeces
not all plant may be eaten
some energy lost as excretion
energy lost as heat during respiration

Question 30

what is NP?

Answer 30

energy accumulated by producers and available to consumers

Question 31

how is NP calculated?

Answer 31

NP= I- (F + R)

Question 32

how do you calculate the efficiency of energy transfer?

Answer 32

(energy available after transfer/energy available before transfer) x100

Question 33

what equipment can be used to find the chemical energy in an organism?

Answer 33

calorimeter

Question 34

what is the process of using a calorimeter to find chemical energy in an organism?

Answer 34

-a sample of the organism is placed into the cup and ignited
-when burnt, energy released as heat energy
-temp change is measured
-larger the temp change, larger the amount of chem energy present
-use equation transferred equation

Question 35

how do we make the results of using a calorimeter comparable?

Answer 35

calculate the energy transferred per gram

Question 36

how can farmer increase efficiency of food chain?

Answer 36

-decrease size of food chain so less energy lost at each trophic level
-intensive rearing to ensure as much energy as possible converted to biomass (e.g. chickens kept indoors and kept warm) increases NP
-fertilisers (More minerals for growth)
-herbicides reduces comp for water, light and minerals so increases NPP
-insecticides increases GPP as higher SA of leaf to absorb light

Question 37

negatives of pesticiides?

Answer 37

-pests may develo resistance
-may have harmful effects on animals or enviorenment
-costly as needs to be repeatedly re-applied
-not specific