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Biology > Chapter 13.2 - Energy + Ecosytems > Flashcards

Chapter 13.2 - Energy + Ecosytems Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What are producers?

A

photosynthetic organisms that manufacture organic substances

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2
Q

How do producers manufacture organic substances?

A

Using light energy, water, carbon dioxide and mineral ions

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3
Q

What are consumers?

A

Organisms that obtain their energy by feeding on other organisms

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4
Q

What are primary consumers?

A

Those that directly eat producers (they are first in the chain of consumers)

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5
Q

What are secondary consumers?

A

Those animals eating primary consumers (normally predators)

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6
Q

What are tertiary consumers?

A

Those eating secondary consumers (normally predators)

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7
Q

What are saprobionts?

A

A group of organisms that break down the complex materials in dead organisms into simple ones.

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8
Q

What do saprobionts usually release?

A

They release valuable minerals and elements in a form that can be absorbed by plants - and so contribute to recycling

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9
Q

What is a food chain?

A

Desccribes a feeding relationship in which producers are eaten primary consumers etc

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10
Q

What is each stage in a food chain called?

A

Trophic level

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11
Q

What is biomass?

A

total mass of all living material in a specific area, habitat or region at any given time

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12
Q

What is biomass measured in?

A

grams per square metre(gm-2)

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13
Q

What is the best form to measure biomass in, and why?

A

As dry mass - although fresh mass is easy to assess, varying amounts of water makes it unreliable.
Measuring dry mass overcomes this, although organisms must be killed

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14
Q

How is biomass lost?

A

Urine/faces
Not all of organisms eaten (bones)
Not all of organism digested
Organism dies/decays before eaten
CO2 excreted

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15
Q

What does calorimetry do?

A

Can be used to estimate the chemical energy store in dry mass

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16
Q

Why is bomb calorimetry preferable to simple calorimetry?

A

Reduces heat loss to surroundings

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17
Q

What equation is used in calorimetry to estimate chemical energy in a dry biomass sample?

A

Energy released = specific heat capacity of water x volume of water x temperature increase of water

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18
Q

How could a student ensure all water has been removed from sample before weighing

A

Heat sample and reweigh until mass remains constant

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19
Q

How much will 1kcal raise water temperature by?

A

I degree

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20
Q

How many J of energy does 1 calorie equal to?

A

I calorie = 4.2J

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21
Q

What do pyramids of energy show?

A

The amount of energy available to the next level

22
Q

What is energy measured in, in pyramids of energy?

A

kJm-2 year-1 to ensure seasonal abnormalities are not shown

23
Q

Why is some energy unavailable to the next level in pyramids of energy?

A

-Chemical energy (biomass, usually glucose) is used by each organism in respiration to form ATP
- Respiration releases heat energy to surroundings
- Energy remains stored in dead organisms
- Animals excrete waste
- Whole organism not consumed by next trophic level

24
Q

What % of light energy will be converted to chemical energy in plants?

A

Plants convert 1%-3% of the Sun’s energy available to them into organic matter

25
Q

Why is so little of the Sun’s energy absorbed?

A

Wrong wavelengths
Light may not fall on a chlorophyll molecule
Over 90% is reflected off the atmosphere

26
Q

Define gross primary production(GPP)?

A

Total chemical energy in plant biomass within a given volume or area

27
Q

How much GPP is lost when plants respire?

A

approx 50% - known as respiratory loss (R)

28
Q

Define net primary productivity?

A

The chemical energy store which is left after respiratory losses

29
Q

What is the equation that links NPP and GPP?

A

Net primary production = gross primary production - respiratory losses

30
Q

How do consumers store their energy?

A

In their biomass

31
Q

How much total available energy is lost in consumers and why?

A

Approx 90% due to:
-respiration
-not all food eaten
-egested

32
Q

How can the Net production of consumers be calculated?

A

N= I - (F +R)
I: chemical energy ingested
F: chemical energy lost in faeces +urine
R: respiratory loss

33
Q

Why do most food chains only have 4 or 5 trophic levels?

A

Due to inefficient transfer of energy between levels

34
Q

What is the equation for efficiency of energy transfers?

A

efficiency = energy available after transfer / energy available before x100

35
Q

Define secondary production

A

The rate at which energy is uses to make new organic molecules within heterotrophs (consumers)

36
Q

Outline farming practices used to increase efficiency of energy transfer

A
  • Exclusion of predators
  • Artificial heating - reduces heat loss to environment
  • Restriction of movement
  • Feeding is controlled at optimum (high in kcal)
  • animals treated with growth hormones
37
Q

Outline some disadvantages of factory farms

A

-Unethical
- Overcrowding
-Faster spread of diseases
-Antibiotics appear in food chain

38
Q

What is the flow of nutrients described as?

A

Cyclic

39
Q

What is the role of saprobionts?

A

Feed on remains of dead plants + animals - breaking them down
Secrete enzymes + digest food externally so they can then absorb the needed nutrients ( extracellular digestion)

40
Q

What is mycorrhize?

A

When fungi form a symbiotic relationship with the roots of plants

41
Q

What are hyphae?

A

Fungi made up of long, thin strands which connect with the plant roots

42
Q

What do hyphae help increase?

A

Surface area
Uptake of water

43
Q

What is guano?

A

Bird/seabird poo
This returns a high amount of phosphorus ions to the soil

44
Q

What are natural fertilisers?

A

Consist of dead +decaying remains of plants + animals as well as animal waste (manure)

45
Q

What are artificial fertilisers?

A

Mines from rocks + deposits and converted into different forms and blended together to give appropriate balance of minerals

46
Q

What are disadvantages of using fertilisers?

A

Reduced species diveristy
Leaching of ions
Eutrophication

47
Q

What is leaching?

A

The process by which nutrients are removed from the soil

48
Q

Describe the process of leaching

A

Caused by rainwater dissolving any soluble nutrients and they are carried deep into the soil.
Leached ions can then find their way into waterways

49
Q

What is eutrophication?

A

The process by which nutrient concentrations increase in bodies of water

50
Q

Describe the process of eutrophication

A

1.Aquatic plants grow exponentially since nitrate level is no longer a limiting factor
2. Algal bloom on water surface prevents light from reaching bottom and plants die
3. Oxygen levels decrease as population of saprobionts increase to decay dead matter - fish die
4. Anaerobic organisms reproduce exponentially and produce toxic waste -> water is putrid

51
Q

How can the risk of eutrophication be reduced?

A
  • Don’t used fields near waterways
  • Use crop rotation so different minerals are removed each year
  • Use natural fertilisers
  • Don’t use fertilisers in rainy season

Biology (3 decks)

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