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Biology paper 2 > Ecology > Flashcards

Ecology Flashcards

1
Q

What are the 4 levels of ecological organisation

A

Individual organism
Population
Communities
Whole ecosystem

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2
Q

What is interdependence

A

All organisms in an ecosystem depend upon each other. If the population of one organism rises or falls, then this can affect the rest of the ecosystem

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3
Q

What is competition

A

Plants compete for light, water, space and minerals
Animals compete for food, mates and territory
Competition can be interspecific or intraspecific

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4
Q

What is an ecosystem

A

The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment

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5
Q

What are 7 abiotic factors

A
  • Light intensity
  • Temperature
  • Moisture levels
  • Soil pH and mineral content
  • Wind intensity and direction
  • Carbon dioxide levels for plants
  • Oxygen levels for aquatic animals
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6
Q

What are 3 biotic factors

A
  • Availability of food
  • New pathogens
  • One species out competing another so the numbers are no longer sufficient to breed
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7
Q

What are the producers of biomass for life on Earth

A

Photosynthetic organisms

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8
Q

What are the 4 Trophic levels

A

Producer - Photosynthesises to produce glucose
Primary consumer - Eats producer
Secondary consumer - Eats primary consumer
Tertiary consumer - Eats secondary consumer

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9
Q

In a stable community the numbers of predators and prey rise and fall ……

A

In cycles

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10
Q

Belt transect practical method (6 Marks)

A

1 - Extend a measuring tape from one side of the habitat to another.
2 - Place a quadrat at 0m on the tape.
3 - Count the numbers/estimate percentage cover of each species.
4 - Use a key to identify each species.
5 - Record results in a table.
6 - Move the quadrat along the measuring tape.

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11
Q

Quadrat random sampling method (6 Marks)

A

1 - Divide the area to be sampled into a grid using measuring tapes placed at right angles to each other.
2 - Use random numbers to generate coordinates within the grid on which to place the quadrats.
3 - Place a quadrat at each coordinate.
4 - Count the numbers/estimate percentage cover of each species in each quadrat.
5 - Use a key to identify each species.
6 - Record results in a table.
7 - Calculate the average of each species

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12
Q

Explain the importance of the carbon and water cycles to living organisms

A

Maintaining this carbon balance allows the planet to remain hospitable for life

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13
Q

What does the carbon cycle do?

A

The carbon cycle returns carbon from organisms to the atmosphere to be used by plants in photosynthesis

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14
Q

Explain the role of microorganisms in cycling
materials through an ecosystem by returning carbon to the atmosphere as carbon dioxide and mineral ions to the soil.

A

Microorganisms help return minerals and nutrients back to the environment so that the materials can then be used by other organisms.

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15
Q

The effect of water availability on the rate of decay

A

With little or no water there is less decomposition because decomposers cannot survive
Without water, enzymes that decompose biological material cannot be excreted

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16
Q

The effect of temperature on the rate of decay

A

At colder temperatures decomposing organisms will be less active, therefore the rate of decomposition remains low
But eventually decomposers will be killed and enzymes will denature so decay will stop

17
Q

The effect of oxygen on the rate of decay

A

Most decomposers need oxygen to survive and without it there is little or no decomposition.
However, some can respire anaerobically and still decay, used in biogas generators

18
Q

What gas is produced by anaerobic decay

A

Methane

19
Q

How to investigate the effect of temperature on the rate of decay of fresh milk by measuring pH change - (6 marks)

A

1 - Place 20 cm3 of fresh milk into three beakers
2 - Decide the three temperatures you will investigate. Write these onto the sides of the beakers.
3 - Use universal indicator paper or solution to determine the pH of the milk in the three beakers
4 - Cover each beaker in cling film and incubate at the appropriate temperature
5 - Use universal indicator paper or solution to determine the pH of the milk in the three beakers after 24, 48 and 72 hours

20
Q

How does temperature affect the distribution of species in an ecosystem

A

For example, many species of bird fly south for the winter, in search of warmer climates

21
Q

How does availability of water affect the distribution of species in an ecosystem

A

The distribution of many plants and animals change dependent on rainfall

22
Q

How does composition of atmospheric gases affect the distribution of species in an ecosystem

A

Many species are unable to survive in areas that are very polluted and so have migrated to get away from these areas with high levels of toxic atmospheric gases

23
Q

What is biodiversity

A

The variety of all species of organisms on Earth, or within an ecosystem

24
Q

How does biodiversity increase stability of ecosystems

A

Reduces the dependence of one species on another for food and shelter

25
Q

Where can pollution occur

A

Water - From sewage, fertiliser or toxic chemicals
Air - From smoke and acidic gases
Land - from landfill and from toxic chemicals

26
Q

Why does deforestation occur

A
  • Provide land for cattle and rice fields
  • Grow crops for biofuels
27
Q

5 ways to maintain biodiversity

A
  • Breeding programmes for endangered species
  • Protection and regeneration of rare habitats
  • Reintroduction of field margins and hedgerows where farmers only grow one type of crop
  • Reduction of deforestation and co2 emissions by governments
  • Recycling resources
28
Q

Why is only 10% of biomass transferred in each trophic level

A
  • Not all the ingested material is absorbed as some is egested as faeces
  • Some absorbed material is lost as waste, such as co2 and eater in respiration and water and urea in urine
29
Q

What is food security

A

Food security is having enough food to feed a population.

30
Q

Biological factors which are threatening food security include:

A
  • Increasing birth rate
  • Changing diets in developed countries means scarce food resources are being transported around the world
  • New pests and pathogens
31
Q

How can the efficiency of food production can be improved

A

Restricting energy transfer from food animals to the environment
- Limit movement
- Control temp of their surroundings

32
Q

What is Genetic modification

A

Involves adding a specific stretch of DNA into the plant’s genome, giving it desired characteristics
GM crops could provide more food or food with an improved nutritional value such as golden rice

33
Q

The carbon cycle

A
  • Co2 is REMOVED from the air in photosynthesis by green plants and algae - they use the carbon to make carbs, proteins and fats
  • Co2 is RETURNED to the air when plants, algae and animals respire.
  • Decomposers respire when they turn mineral ions to the soil
  • Co2 is RETURNED to the air when wood and fossil fuels are burnt, as they contain carbon from photosynthesis
34
Q

The water cycle

A
  • Suns energy causes evaporation
  • Water vapour also from transpiration in plants
  • Vapour rises and condenses to form clouds
  • Water is returned to the land by precipitation
  • Surface run off into the seas
  • Cycle repeats
35
Q

Factors that affect rate of decomposition

A

Temp - faster in warmer conditions
Water - grow faster in moist conditions, makes food easy to digest, needed for respiration
Oxygen - Most decomposers respire anaerobically

36
Q

Method to investigate the effects of temp on decay

A
  • Make a solution of milk and phenolphthalein indicator
  • Add sodium carbonate which will cause the solution to become alkaline and therefore appear pink
  • Place the tube in a water bath at a specific temperature
  • Add lipase enzyme and begin stopwatch
  • Time how long it takes before pink colour disappears
  • Repeat at diff temps
37
Q

What environmental changes affect the distribution of species in an ecosystem

A
  • Water availability causes populations to migrate
  • Temperature, insects move to hotter regions
  • Atmospheric gas composition, some organisms cant grow in presence of to much sulphur dioxide

Biology paper 2 (3 decks)

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