Ecology. Flashcards

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1
Q

What is an ecosystem?

A

An ecosystem is all the organisms living in a habitat and the non-living parts of a habitat.

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2
Q

What are the different levels of organisation in an ecosystem?

A

-Individual organisms
-Populations-groups of individuals of the same species.
-Communities-made up of many populations living together.

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3
Q

What do plants/animals compete with each other for?

A

Light, space, water and mineral ions from the soil. Animals often compete with each other for food, mates and territory.

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4
Q

What is interdependence?

A

Relying on each other. Within a community, each species depends on other species for food, shelter etc. If one species is removed it can affect the whole community. This is called interdependence.

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5
Q

What are the abiotic (non-living) factors which can affect a community?

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 the biotic (living) factors which can affect a community?

A
  • availability of food
  • new predators arriving
  • new pathogens
  • one species outcompeting another so the numbers are no longer sufficient to breed.
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7
Q

What type of adaptations could animals have?

A

Structural, behavioural or functional.

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8
Q

What are extremophiles?

A

Organisms that live in environments that are very extreme, such as at high temperatures, pressures, or salt concentrations. Bacteria living in deep sea vents are
extremophiles.

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9
Q

(RP) Investigating the population size of a common species in a habitat.

A

1)Place a quadrat on the ground at random.
2) Count the number of individual plants of one species in the quadrant.
3) Repeat many times and calculate a mean.
4) Work out the mean in 1m2.
5) Measure the are of the whole habitat and multiply the number of plants in 1m2 by the whole area.

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10
Q

How can you check how plants are spread/distributed in a habitat?

A

1)Strech a long tape, called a transect line, across the area.
2) Place a quadrat down at regular intervals along the line.
3) Count the plants in the quadrat each time.

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11
Q

What is dead material broken down by?

A

Decomposers.

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12
Q

What conditions are required for decomposers to break down dead waste?

A

-Oxygen.
-Moisture.
-A suitable temperature.
- A suitable PH.

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13
Q

If waste is broken down in anaerobic conditions then what is produced?

A

Methane gas.

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14
Q

(RP) Investigate the effect of temperature on the rate of decay of fresh milk by measuring pH change.

A

1) Take a sample of fresh milk.
2) Place in a beaker and cover.
3) Keep warm/at room temp.
4) Measure the pH of the milk at regular intervals over several days.

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15
Q

What does the carbon cycle do?

A

Returns carbon from organisms to the atmosphere as carbon dioxide to be used by plants in photosynthesis.

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16
Q

What does the water cycle do?

A

Provides fresh water for plants and animals on land
before draining into the seas. Water is continuously evaporated and precipitated.

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17
Q

The carbon cycle.

A
  1. Photosynthesis: - Plants absorb CO2 and sunlight to produce glucose and release O2.
  2. Respiration:- Living organisms use glucose for energy, releasing CO2 as a byproduct.
  3. Decomposition:- Dead plants and animals break down, returning carbon to soil and air.
  4. Combustion:- Burning of fossil fuels or wildfires releases CO2 into the atmosphere.
  5. **Absorption and Dissolution: - Oceans absorb CO2 from the air and dissolve it in water.
18
Q

The water cycle.

A

Evaporation-Water turns from a liquid to a gas when it evaporates.
Condensation-water cools and converts from gas to liquid, often forming clouds.
Precipitation-Precipitation occurs when rain, snow, hail and sleet fall from the sky.
Infiltration- Water has fallen as precipitation is absorbed into the ground. This can then be stored within underground rocks called aquifers.
Transpiration-Plants release water vapour through their leaves.

19
Q

What are the apex predators?

A

They are carnivores with no predators.

20
Q

What do decomposers do?

A

Decomposers break down dead plant and animal matter by secreting enzymes into the environment. Small soluble food molecules then diffuse into the microorganism.

21
Q

Which environmental changes affect the distribution of species in an ecosystem?

A
  • temperature
  • availability of water
  • composition of atmospheric gases.
    The changes may be seasonal, geographic or caused by human interaction.
22
Q

What is Biodiversity?

A

Biodiversity is the variety of all the different species of organisms on earth, or within an ecosystem.

23
Q

How does high biodiversity help ecosystems to become stable?

A

By reducing the dependence of one species on another for food, shelter and the maintenance of the physical environment.

24
Q

What does pollution do?

A

It kills plants and animals which can reduce biodiversity.

25
Q

Where can pollution occur?

A
  • in water, from sewage, fertiliser or toxic chemicals.
  • in air, from smoke and acidic gases.
  • on land, from landfill and from toxic chemicals.
26
Q

How are humans reducing the amount of land available for other animals and plants?

A

By building, quarrying, farming and dumping waste.

27
Q

The decay or burning of the peat releases what into the air?

A

Carbon dioxide into the atmosphere.

28
Q

Large-scale deforestation in tropical areas has occurred to do what?

A

-provide land for cattle and rice fields
- grow crops for biofuels.

29
Q

What is global warming?

A

It is a gradual increase in the temperature of the earth.

30
Q

What are the consequences of global warming?

A

-Loss of habitat, as areas are flooded by rising sea levels.
-Changes to the migration of animals.
- Change in distribution of species where temperature/rainfall has changed.

31
Q

What steps have scientists and the government taken to conserve biodiversity?

A

breeding programmes for endangered species
* protection and regeneration of rare habitats
* reintroduction of field margins and hedgerows in agricultural areas where farmers grow only one type of crop.
* reduction of deforestation and carbon dioxide emissions
* recycling resources rather than dumping waste in landfills.

32
Q

Approximately how much biomass is transferred to the next level?

A

Only approximately 10% of the biomass from each trophic level is transferred to the level above it.

33
Q

What are losses of biomass due to?

A

not all the ingested material is absorbed, some is egested as faeces
* some absorbed material is lost as waste, such as carbon dioxide and water in respiration and water and urea in urine.

34
Q

What is food security?

A

It is having enough food to feed a population.

35
Q

Biological factors which are threatening food security include:

A
  • the increasing birth rate.
  • changing diets in developed countries means scarce food resources are transported around the world.
  • new pests and pathogens that affect farming.
  • widespread famine occurring in some countries if rains fail
  • the cost of agricultural inputs
  • conflicts which affect the availability of water or food.
36
Q

How can the efficiency of food production be improved?

A

By restricting energy transfer. This can be done by limiting their movement/controlling the temperature of their surroundings.
Some animals are fed high-protein foods to increase growth

37
Q

What are pyramids of biomass used for?

A

They can be used to compare the amount of biomass in each level of a food chain.

38
Q

What trophic level are producers?

A

Level one.

39
Q

How can we try to stop the number of fish from decreasing?

A

-Control the size of nets used so only older fish are caught and the smaller ones can reproduce.
-Set fishing quotas, so that only a certain number can be caught.

40
Q

What does biotechnology allow?

A

It allows microorganisms to be grown in large quantities for food. They’re grown in fermenters in which conditions are controlled.

41
Q

What is the fungus Fusarium useful for producing?

A

Mycoprotein, a protein-rich food suitable for vegetarians. The fungus is grown on glucose syrup, in aerobic conditions, and the biomass is harvested and purified.

42
Q

What can GM crops provide?

A

More food or food with an improved nutritional
value such as golden rice.