Ecology

Question 1

what is an ecosystem

Answer 1

all the organisms living in a certain environment including all the biotic and abiotic factors

Question 2

biotic

Answer 2

living

Question 3

abiotic

Answer 3

non living

Question 4

habitat

Answer 4

place where organism lives

Question 5

producers

Answer 5

organisms that produce organic molecules using sunlight energy e.g plants

Question 6

consumer

Answer 6

organism that eats other organisms

Question 7

primary consumer

Answer 7

organism that eats producer

Question 8

secondary consumer

Answer 8

organism that eats primary con

Question 9

teritary consumer

Answer 9

organisms that eats secondary con

Question 10

what is a food web/chain

Answer 10

shows how energy is transferred through an ecosystem

Question 11

trophic level

Answer 11

a stage in a food chain that’s occupied by a particular group of organisms e.g producers (first trophic level in a food chain)

Question 12

what breaks down/digests things like bones and faeces that can’t get recycled back into the ecosystem because their energy is inaccessible

Answer 12

decomposers

Question 13

ex of decomposer

Answer 13

bacteria fungi

Question 14

60% of available energy from organisms is never taken in by others in 1st place… why?

Answer 14

1. plants can’t use all sunlight that reaches their leaves (some wrong wavelength, some reflected, some passes straight through to other leaves.
2. some sunlight can’t be used due to it hitting parts of tree that can’t p/s e.g. bark
3. indigestable parts of food
4. some food left e.g bones and roots

Question 15

what is the percentage of gross productivity (energy transferred)

Answer 15

40%§

Question 16

why is not all the gross productivity available for thinnest trophic level

Answer 16

respiratory heat loss

organisms use energy from respiration for movement or body heat. so only about 10% is transferred and becomes biomass

Question 17

net productivity

Answer 17

samount of energy transferred to the next trophic level

Question 18

biomass?

Answer 18

stored energy or used for growth. this energy used for growth and reproduction isn’t lost it becomes biomass in an organism

Question 19

Net productivity =

Answer 19

gross productivity - respiratory loss

Question 20

how to work out the efficiency of energy transfer

Answer 20

% effiency of ET = net productivity of trophic level/net productivity of previous trophic level x100

Question 21

as you move up the food chain the energy transfer generally becomes…

Answer 21

more efficient / however always some loss from each trophic level so the more stages in a food chain the greater the overall energy loss.

Question 22

how do you measure the efficiency of energy transfer 2 ways:

Answer 22

calorimeter

measuring an organisms dry biomass

Question 23

how do you use a calorimeter

Answer 23

burning a known mass of the sample with oxygen in a sealed chamber surrounded by water. as it burns it releases energy which heats up the temp of water. temp increase of water is measured. joules energy measured in

Question 24

whats a problem with using a calorimter

Answer 24

unethical! so ecologists normally use existing data to estimate values.

Question 25

how to measure biomass

Answer 25

dry the organism out - (heat it to 80oc until all the water has evaporated. then weigh the organism. biomass is created using energy so it’s an indicator of how much energy an organism contains- the more biomass an organism has the more energy it contains.
then u may multiply the results from the sample to get an estimate of the energy in one trophic level

Question 26

what are the ways of making the transfer of energy between trophic levels more efficient (by farmers)

Answer 26

herbicides
fungicides
insecticides
natural predators
fertilisers 
rearing livestock intensively

Question 27

herbicides

Answer 27

kill weeds that compete with agricultural crops for energy. reducing comp means crops receive more energy so they grow faster and become larger increasing productivity

Question 28

fungicides

Answer 28

kill fungal infections that damage agricultural crops. the crops use more energy for growth and less for fighting infection, so they grow faster and become larger increasing productivity

Question 29

insecticides

Answer 29

kill insect pests that eat and damage crops. killing them means less bionass is lost from crops so they grow to be larger and increase productity

Question 30

natural predators

Answer 30

are introduced to the ecosystem eat the pest species E.G LADYBIRDS eat greenfly this means the crops lose less energy and biomass increasing productivity

Question 31

fetilisers

Answer 31

chemicals that provide crops with ire’s needed for growth e.g nitrates. crops use these up in the soil as they grow so their growth is limited when there aren’t enough minerals. adding fertiliser replaces the lost minerals so more energy from the ecosystem can be used to grow increasing the efficiency of energy conversion.

Question 32

rearing livestock intensively

Answer 32

involves controlling the conditions they live in and when they’re slaughtered, so more of their energy is used for growth and less is used for other activities - the efficiency of energy conversion is increased so more biomass is produced and productivity is increased.