13.1-5 Energy and ecosystems.

Question 1

What do Producers do in the food chain or web?

Answer 1

They manufacture organic substances using light energy, carbon dioxide, water and mineral ions. (Plants need mineral ions to create chlorophyll).

Question 2

What do consumers do in the food chain or web?

Answer 2

They feed on other organisms.

Question 3

What do saprobionts (decomposers) do in the food chain or web?

Answer 3

Break down complex materials in dead organisms into simple ones.

By externally digesting complex molecules into soluble molecules they can absorb into their cells.

Question 4

Whats another term for Decomposers?

Answer 4

Saprobionts

Question 5

True or false: Most animals rely on a single food source in a habitat.

Answer 5

False.

They rely on multiple food sources.

Question 6

What do you get when many food chains link together through having the same organisms?

Answer 6

A food web.

Question 7

What is each stage in a food chain known as?

Answer 7

A Trophic level.

(hence trophy)

Question 8

What do arrows on food chains and webs repesent?

Answer 8

They represent the direction of energy flow.

Question 9

What do pyramids of numbers show?

Answer 9

The quantity of organisms.

Question 10

What do pyramids of biomass show?

Answer 10

Shows organisms at different trophic levels related to their dry mass per square metre.

Question 11

What is biomass?

Answer 11

The dry mass of living material determined for a given trophic level.

Question 12

What are the units for dry mass?

Answer 12

Grams per square metre of the area or cubed.

Question 13

What does the pyramid of biomass show/represent?

Answer 13

Dry mass of all organisms on each trophic level at a particular time.

Question 14

What is a weakness of measuring biomass?

Answer 14

Time, as you can’t rely on measuring at only one point in time as organisms will change mass over time.

Question 15

What do pyramids of energy do?

Answer 15

They use energy values in a given area over a specific period of time for each trophic level.

By doing this it can measure the energy content of a material.

Question 16

What’s the unit for energy on pyramids of energy?

Answer 16

KJ_m^-2_yr^-1

Question 17

What do we use to find out how much energy is in a substance?

Answer 17

We use a Bomb colorimeter.

Question 18

What is the process of using a bomb colorimeter?

Answer 18

• Weigh dry sample
• Burn in pure oxygen in a sealed chamber.
• Heat released causes a rise in temperature.
• 4.184J of energy is needed to raise 1g of water 1°C

Question 19

What do you need to calculate the energy release?

Answer 19

The volume of water and the temperature rise.

Question 20

What do energy pyramids need to take into acount?

Answer 20

Seasonal fluctuations of activity as it measures energy values which will change during these fluctuations.

Question 21

Give a weakness of energy pyramids.

Answer 21

Dont show fate of energy at each trophic level.

They rarely include other parts of the ecosystem that cannot be used to determine the efficiency of food chains.

Question 22

Define Photoautotrophs.

Answer 22

Plant or algea that make complex molecules (food) from simple ones.

Question 23

Wahat happens the sunlight energy when it hits a leaf? Include percentages.

Answer 23

5% Reflected

5% Passes through

50% Innapropriate wavelengths

33% Lost as heat from photosynthesis

5% Lost as heat from respiration.

40% Is absorbed

2% is stored.

Question 24

What is the Net primary production equation? And define the components.

Answer 24

NPP=GPP-R Net Primary production of energy = Gross primary production - Respiration.

Gross primary production: Total energy converted to chemical energy by photosynthesis.

Respiration: Release of chemical energy used in metabollic processes.

Net Primary Production: Chemical energy that accumulates in plants after immediate losses.

Question 25

What is NPP is regards to the enerhy chain or web?

Answer 25

NPP is energy thats avaliable to the primary consumer.

Question 26

True or False: NPP (Net primary productuion) is only in plants?

Answer 26

True. Other organisms like animals have other production terms.

Question 27

How is energy transferred to the next trophic level?

Answer 27

* Organism is consumed by primary, secondary, tertiary ect. consumer. * Death, production of urine and faeces and loss of organic tissue allows the energy from the organism to be passed on to decomposers.

Question 28

Plants have the Net primary production. What do animals have?

Answer 28

Net secondary production. (NSP) (Get it, As they come second always in food chain after producers)

Question 29

Define secondary production.

Answer 29

The rate at which energy is used to make new organic molecules within hetrotrophs (Animals and fungi) which is known as secondary production.

Question 30

Define Hetrotrophs.

Answer 30

Organisms that are animals and fungi. They do not make their own food.

Question 31

How do you measure efficiency of chemical potential energy transferred between trophic levels? And what are the units?

Answer 31

Efficiency = (Energy avaliable after the transfer/Energy avaliable before the transfer) x 100 Measured in Kilojoules per square metre per year (kJm^-2year^-1)

Question 32

Why is energy lost between trophic levels ?

Answer 32

* Some organisms can't be eaten e.g. bones, fur ect. * Once ingested, some organisms can't be digested. * Energy is lost in excretory materials such as urine. * Energy is lost in form of heat from respiration and body heat.

Question 33

Whats the equation for Gross primary production (GPP), Net primary production (NPP) and respiration losses?

Answer 33

GPP = NPP + Respiration losses NPP = GPP - Respiration losses Respiration losses = GPP - NPP

Question 34

What's the equation for Net production?

Answer 34

Net production = Food energy intake - (energy in faeces and urine + respiration losses)

Question 35

What's the equation for percentage efficiency?

Answer 35

Percentage efficiency = Net production/ food intake x 100%

Question 36

Why does the farming practise of restricting movement reduce energy loss?

Answer 36

Less metabollic reactions for movement needed so less respiration will occur. Correlating with less energy being lost as there's less respiration loss.

Question 37

Why does the farming practise of keeping the environment warm reduce energy loss?

Answer 37

Less energy lost as heat energy as its being used up by organism regulating body temperature in cold environments. So more energy can be passed on.

Question 38

Why does the farming practise of control feeding reduce energy loss?

Answer 38

Giving the animals food with digestable nutrients, so no overproduction of waste. This maximises energy storage.

Question 39

Why does the farming practise of excluding predators reduce energy loss?

Answer 39

Less energy and biomass lost from decomposing dead animals. So more is passed onto next trophic level in food web.

Question 40

Why does the farming practise of use of insecticides reduce energy loss?

Answer 40

Less producers are killed preventing large losses of population and biomass. Means more energy is absorbed by producers overall and passed onto next trophic level of primary consumer. Also, insects eating leaves reduce photosynthesis of that plant so reduces it's energy production. Lastly, Insects can tranfer diseases to plants which can effect energy transfer, also farmers could have reduced yields or damage tothe part of the plant being sold.

Question 41

Why does the farming practise of using herbicides reduce energy loss?

Answer 41

Stops competition from unwanted weeds and plants so plant's leaves can absorb more energy overall to pass onto the primary consumer. As they dont risk competing and losing over space for themsleves and yield energy.

Question 42

What are the two types of fertiliser?And where are they used?

Answer 42

Natural - Used in Organic farming systems. Artificial - Used in Inorganic farming systems.

Question 43

What are the four types of fertiliser application?

Answer 43

* Ammonium salts (ammonium nitrate, ammonium sulphate) * Animal manure * Bone meal * Urea

Question 44

What advantages are there to the plants with extra nitrogen to their fertiliser?

Answer 44

1. Plants make more DNA and proteins quicker for growth. 2. Plants develop earlier. 3. Grow taller 4. Larger Surface Area of leaves 5. Greater rate of photosynthesis 6. Overall greater productivity and higher yields 7. Leads to cheaper foods

Question 45

Why should farmers not use excess fertiliser?

Answer 45

It causes eutrophication and reduced species diversity.