Ecology Intro

Question 1

Population

Answer 1

A group of organisms of the same species that occupy a particular space at a particular time that can potentially interbreed

Question 2

Community

Answer 2

Populations of all the different species in an area

Question 3

Ecosystem

Answer 3

The community of a given area as well as the non living components of this area in the environment

Question 4

What do foodwebs show?

Answer 4

The transfer of energy from one species to the next using arrows
Aka if one species eats another, the energy flow points to consumer

Question 5

Trophic level

Answer 5

Each stage of the foodweb which represents one species

Question 6

What do arrows show in foodwebs?

Answer 6

The direction of energy flow aka points to the consumer

Question 7

Producer

Answer 7

Makes its own organic compounds using light energy from sun in photosynthesis

Question 8

Primary consumer

Answer 8

Eats the producer

Question 9

Secondary consumer

Answer 9

Eats the primary consumer

Question 10

Tertiary consumer

Answer 10

Eats the secondary consumern

Question 11

What are photoautotrophs?

Answer 11

Producers that can produce their own organic compounds from light energy in photosynthesis

Question 12

What do the consumers eat of the previous trophic level?

Answer 12

The REMAINING biomass of the previous tropic level, that is organic substance of the consumer used to store energy in tissue

Question 13

What is biomass?

Answer 13

The mass of carbon per given area
Or the dry mass of tissue per given area
That can be passed on to next trophic level as the energy used in these carbon containing molecules are used up

Question 14

How does biomass occur in a plant?

Answer 14

Synthesise own organic substances from light energy, contains carbon and stores ENERGY
Some used in respiration
Rest is used for growth of stored

Question 15

GPP stands for..?

Answer 15

Gross Primary Production

Question 16

What is GPP?

Answer 16

The CHEMICAL ENERGY store in plant biomass in a given area or volume
A measure of photosynthesis as it’s a measure of energy that enters the ecosystem system from a plant by synthesising organic compounds that stores energy

Question 17

NPP stands for…?

Answer 17

Net Primary Production

Question 18

What is NPP?

Answer 18

The chemical energy store in plant biomass in a given area or volume AFTER RESPIRATORY LOSSES have been taken into account
So a measure of the energy stored in biomass of the plant as this can be passed on to next trophic level or used for growth/reproduction

Question 19

How does biomass occur in an animal?

Answer 19

Consumes previous trophic level’s biomass
Some uses energy stored in this dry tissue in respiration to release energy in form of ATP and some lost in excretion + egestion
Left forms the biomass

Question 20

Equation for NPP

Answer 20

GPP - R = NPP
R = respiratory losses

Question 21

What is NPP a measure of?

Answer 21

The chemical energy stored in plant biomass (measure of glucose) taking the energy lost in respiration into account that can be passed on to consumers

Question 22

Net production of consumers

Answer 22

The energy stored in a consumers biomass in a given area taking into account respiratory and faeces/urine losses after consuming biomass from previous trophic level

Question 23

The rates of production

Answer 23

Used to compare productivity (amount of energy that enters ecosystem) in a given area and time

Question 24

Units of rates of production

Answer 24

J/KJ
In a given area
In a given time

Question 25

Why do we need to compare productivity per given area?

Answer 25

To allow for fair comparison by standardising the size of area we are looking at: some habitats vary in size

Question 26

Why do we compare productivity in a given time eg year?

Answer 26

Some ecosystems vary in effect of seasons so will account for impact of season’s temperature, weather humidity etc by standardising it

Question 27

Symbol for net production of consumers

Answer 27

N

Question 28

Equation for net production of consumers

Answer 28

N = I - (F+R) I = chemical energy store from ingested food from previous trophic level (biomass passed on) F = Energy lost to the environment by faeces and urine R = energy lost to the environment by respiration

Question 29

Why do we measure biomass as a measure of DRY tissue?

Answer 29

Interested in the organic substances in solid material that is used for growth/ passed on to next trophic level Water content varies greatly over time

Question 30

How to estimate chemical energy store in dry biomass

Answer 30

Using calorimetry

Question 31

How to dry a sample of tissue to obtain the dry biomass

Answer 31

Take fresh sample of tissue and heat at 100oC to evaporate off all the water Weigh and heat until no further change in mass to make sure all water evaporated off

Question 32

Using the calorimeter to combust a sample of dry biomass

Answer 32

The bomb that the dry biomass is combustion in, is surrounded by a water bath, and the heat of combustion causes a rise in the temperature of this water That can be measured using a thermometer

Question 33

Features of a calorimeter

Answer 33

Steel bomb to ensure high heat conduction to the water Stirring rod to regularly stir to evenly distribute heat energy in water Water inside an insulating layer to reduce heat loss to outside

Question 34

Calculating energy release from biomass (production) from data

Answer 34

Specific heat capacity of water x mass of water used in calorimeter x temperature raise = energy released Divide by mass of tissue to find energy released per gram etc

Question 35

Should drying the sample be heated above 100 degrees or below 100 degrees?

Answer 35

No not above 100 - causes sample to burn Below 100 will not evaporate away all of the water so we do not obtain dry biomass

Question 36

How to obtain a large amount of energy for growth of a plant

Answer 36

Requires a higher value of GPP (more photosynthesis for more organic molecules to be stored as biological molecules) And less respiratory losses by respiration

Question 37

Why would one habitat have a higher GPP value?

Answer 37

Because more photosynthesis is happening due to: Higher light intensity Higher temperature Greater rainfall Leaves of trees have a higher surface area

Question 38

Why would NPP not be used for visible growth?

Answer 38

Energy released by biomass used for reproduction/active transport of ions into roots etc