topic 5

Question 1

what are most of the sugars used by plants synthesised into

Answer 1

respiratory substartes

Question 2

what is the biomass of a plant

Answer 2

the biologicl molecules

Question 3

what is biomass

Answer 3

the chemical energy store in a plant

Question 4

how is biomass measured

Answer 4

mass of carbon in an organism

Question 5

what is dry mass

Answer 5

mass of the organism when the water contents is removed

Question 6

how do you measure dry mass

Answer 6

the sample of the organism is dryed in an oven
mass of the organism is weighed at regular intervals
once the mass is content then the water contents is removed

Question 7

how do you estimate the chemical energy stored in biomass

Answer 7

by burning the biomass in a colorimeter

Question 8

describe the process of calorimetry

Answer 8

sample of dry biomass is burnt
the enrgy released is used to heat the volume of water
change in temperature is used to calculate the chemical energy

Question 9

what is the gross pimary production

Answer 9

the chemical energy store in plant biomass in a given area or volume

Question 10

what is the net primarry production

Answer 10

the chemical energy store in plant biomass after respiratory losses to the environment have been taken account

Question 11

what is thee equation for NPP

Answer 11

NPP= GPP - R

Question 12

how do consumers get their energy

Answer 12

by injesting plants and animals

Question 13

how is energy lost

Answer 13

faeces
the food isnt eaten
urine
some is lost to the environment

Question 14

what is the equation for the net productioon of consumers (N)

Answer 14

N= I - (F+R)
I= chemical energy store in ingetedd food
F-= chemical energy lost to the environment
R= respiratory lossees to the environment.

Question 15

what do food chains and webs show

Answer 15

the transfer of energy hrough an ecosystm

Question 16

what is thee role of decomposers in a food web

Answer 16

they break down undigested material

Question 17

what are the two differnt ways that the transfer of energy can be increased

Answer 17

• energy lost to other organisms e.g pests is reduced
• the energy lost through respiration is reduced

Question 18

what happens when we use insectides on pests

Answer 18

kills insects and pests that eat crops. so less biomass is lost from crops so NPP is greater

Question 19

what is the role of using herbicides in order to increase the transfer of enrgy

Answer 19

killing weeds removes direct competition with the crop for energy from the sun

Question 20

how do farmers incrrease the net production of their livestock

Answer 20

by controlling their conditions
so more energy is used for growth and less is used for respiration
e.g. placing them in pens so movement is restricted
- keeping them indoors to less energy is wastedd by heat loss

Question 21

what are saprobiants

Answer 21

type of decomposer which breaks down dead plants and animals

Question 22

what is the role of saprobionts

Answer 22

they secrete enzymes and digest their food externally