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0 - Biology > Ecosystems, Nutrient Cycles & Succession > Flashcards

Ecosystems, Nutrient Cycles & Succession Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

How can carbon be added to the atmosphere?

A
  1. Combustion
  2. Respiration
  3. From the sea
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2
Q

How can carbon be removed from the atmosphere?

A
  1. Photosynthesis
  2. Dissolve into the sea
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3
Q

Where is carbon found?

A
  1. The atmosphere
  2. Plants
  3. Animals
  4. Fossil fuels
  5. Decomposers
  6. The sea
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4
Q

How does atmospheric carbon dioxide vary during the day?

A

Lowest in the day

Highest at night

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5
Q

How does atmospheric carbon dioxide vary during the year?

A

Lowest in the summer

Highest in the winter

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6
Q

What is global warming?

A

Increase in the average global temperature

Caused by the greenhouse effect

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7
Q

How could global warming impact on crop yield?

A

Increase in carbon dioxide/temperature

⇒ Increase in rate of photosynthesis

⇒ Increased crop yield

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8
Q

How might global warming affect pest species?

A

Might affect the life cycle of the pest species (e.g. shorter larval stage)

Could affect abundance/distribution of species

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9
Q

How might global warming affect wild plants/animals?

A

Could affect the distribution/abundance of species

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10
Q

What are the stages of the nitrogen cycle?

A

Nitrification

Denitrification

Nitrogen fixation

Ammonification

Absorption

Consumption

Death/excretion

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11
Q

What is nitrogen fixing?

A

Nitrogen fixing bacteria convert nitrogen in the air into ammonium

Bacteria found in root nodules of leguminous plants and form mutualistic relationships

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12
Q

What is nitrification?

A

Ammonium compounds are oxidised by nitrifying bacteria to nitrate ions

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13
Q

What is ammonification?

A

Saprobiotic microorganisms convert dead organic matter and animal waste into ammonium compounds

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14
Q

What is denitrification?

A

Occurs in anaerobic conditions, denitrifying bacteria use nitrate ions for respiration and release nitrogen

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15
Q

What is the cause of eutrophication?

A

Nitrates in the soil leech into rivers

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16
Q

Why are organic fertilisers less likely to cause eutrophication than artificial fertilisers?

A

Insoluble so less likely to leech

Needs to be broken down

17
Q

What is process of eutrophication?

A
  1. Nitrates cause an algal bloom
  2. This blocks out the light, plants can’t photosynthesise
  3. Plants die and are broken down by saprobiotic bacteria
  4. These bacteria respire aerobically, using oxygen
  5. Aquatic animals die due to lack of oxygen
  6. Anaerobic bacteria decompose the dead organisms making the water putrid
18
Q

What do fertilisers do?

A

Increase productivity

19
Q

How do fertilisers increase productivity?

A

Contain nitrogen in the form of nitrates:

  1. Nitrogen present in DNA & proteins
  2. Nitrogen increase height and leaf height
20
Q

Why is energy lost within a food chain/web?

A

Producers:

  • Some of the Sun’s energy is absorbed/reflected by the atmosphere
  • Not all wavelengths of light can be used in photosynthesis
  • Not all the light falls on the chlorophyll/photosynthesising cells

Consumers:

  • Some parts of the organism aren’t eaten
  • Some parts cannot be digested
  • Energy is lost by excretion (e.g. in urine/faeces)

Both:

  • Energy is lost as heat due to respiration
21
Q
A
22
Q
A
23
Q

What are the three types of ecological pyramid and what are the associated units?

A
  1. Pyramids of number: no units
  2. Pyramids of biomass: kgm-2 or kgm-3
  3. Pyramids of energy: kJm-2year-1 or kJm-3year-1
24
Q

What are the drawbacks of pyramids of number?

A
  1. Size not taken into account
    • 1 large organism = 1 small organism
  2. Impossible to represent accurately when there are large differences in numbers
  3. Only considers one point in time
25
Q

What are the drawbacks of pyramids of biomass?

A
  1. Organisms must be killed so samples are small
    • May not be representative
  2. Different tissues contain different amounts of energy
  3. Only considers one point in time
26
Q

What is the role of an agricultural ecosystem?

A

To produce food for humans, limiting the amount of energy lost between trophic levels

27
Q

What is a pest?

A

An organism which competes with humans for food or space or is a danger to health

28
Q

How are pest species controlled?

A
  • Chemical pesticides
  • Biological controls
29
Q

What are the advantages of using biological controls?

A
  1. Only requires one application because the organisms will reproduce
  2. They are very specific
  3. Maintains a low population of the pest
  4. Pests do not develop resistance
  5. No bioaccumulation (uses less chemicals)
30
Q

What are the advantages of using chemical pesticides?

A
  1. Acts quickly
  2. Can apply to a specific area (where it is required)
  3. Kills most of pests (and a greater variety)
31
Q

What is an integrated system?

A

A combination of biological controls and chemical pesticides aimed at having the minimum impact on the environment

32
Q

In intensive rearing of livestock, how is net productivity maximised?

A
  1. Restrict movement so less energy is lost due to muscle contraction
  2. Keep in warm sheds to reduce heat losses
  3. Fed concentrate so a higher proportion of the food is absorbed
  4. Selectively bred for higher productivity
  5. Slaughtered while still young so more energy transferred to biomass
33
Q

Describe the process of succession

A
  1. Pioneer species colonise barren land
  2. These species die and make the area less hostile
  3. New species colonise and outcompete the pioneer species
  4. This continues until a climax community is reached
34
Q

What are the adaptations of pioneer species?

A
  1. Wind-borne species
  2. Germinate quickly
  3. Can photosynthesise
  4. Withstand extreme conditions
  5. Method of nitrogen fixation
35
Q

What is the purpose of conservation?

A
  1. Maintain diversity
  2. Maintain an ecosystem/habitat
36
Q

Why is conservation important?

A
  1. Many species provide us with resources (e.g. drugs)
  2. Ethical debates: species do not go extinct due to human activity
  3. Help prevent climate change
  4. Help prevent food chain disruption

0 - Biology (13 decks)

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