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Ecology & The Environment Flashcards

1
Q

Definition of Population?

A

All the organism of a particular species found in an ecosystem.

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2
Q

Define Community?

A

All the populations of all the species found in an ecosystem at any one time.

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3
Q

Define Ecosystem?

A

A distinct, self-supporting system of organisms interacting with each other and the environment.

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4
Q

On a Pyramid of energy how much energy is lost on each trophic level? And why?

A

You loose around 90% of energy between each level.

Energy released in respiration is used in making new cells then ‘fixed’ in molecules and pass on to next trophic level. If not, energy is used then lost as heat.

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5
Q

What are the advantage of the pyramid of energy?

A

Energy is directly comparable.
Relative energy flow between different ecosystems can be compared to each other.
Amount of energy lost between levels is easily identifies.
There are not inverted pyramids.
Input of solar energy can be added.

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6
Q

What are the disadvantages of the pyramids of energy?

A

To determine energy value of organism requires complete combustion.
Still difficult to assigning the organisms to a specific trophic level as well as organisms in the food chains and there is a problem of assigning the decomposers and detritivores to a specific trophic level.

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7
Q

Equation for photosynthesis?

A

Carbon Dioxide+Water—->Oxygen+Glucose

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8
Q

Equation for Respiration?

A

Oxygen+Glucose—-> Carbon Dioxide+Water

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9
Q

Draw the Carbon Cycle?

A
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10
Q

Draw the Nitrogen Cycle?

A
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11
Q

What is waste called in the carbon cycle?

A

Detritus

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12
Q

Three type of bacteria/organisms especial to the nitrogen cycle?

A

Decomposers
Nitrogen fixing bacteria
Nitrifying bacteria
Denitrifying bacteria

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13
Q

Why is Nitrogen needed for living organisms?

A

Making protein and bacteria.

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14
Q

Why can’t nitrogen be used directly by living organisms?

A

It is unreactive

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15
Q

What converts nitrogen gas directly into nitrates?

A

Lightning

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16
Q

What nitrogen containing compound is released by decomposers?

A

Ammonia

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17
Q

Which type of bacteria convert ammonia to nitrate?

A

Nitrifying bacteria

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18
Q

Which type of bacteria convert atmospheric nitrogen into nitrates?

A

Nitrogen fixing bacteria

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19
Q

Where are nitrogen fixing bacteria found in?

A

Root nodules of legumes and free in soil (e.g soy beans)

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20
Q

Name the characteristics of all living organisms? (MRS GRENC)

A

Movement
Respiration
Sensitivity
Growth
Reproduction
Excretion
Nutrition
Control/Homeostasis

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21
Q

What is a Producer

A

Plants which photosynthesize to produces food

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22
Q

What is a consumer?

A

Animals that eat plants or other animals

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23
Q

What is a decomposed?

A

Organisms that break down dead material and help to recycle nutrients

24
Q

What are meant by biotic and abiotic factors?

A

Living components of an ecosystem are biotic and the non-living factors are the abiotic factors.

25
What is a habitat?
A habitat is the place where an organism lives.
26
Define biodiversity
The amount of variation shown by species in an ecosystem is called that ecosystems biodiversity.
27
Why is biodiversity beneficial for an ecosystem?
An ecosystem dominated by one species is more likely to be affected by an ecological disaster e.g. a new disease Reduced dependency of one species for another
28
Name three biotic factors that influence the numbers and distribution of organisms
- Availability of food and competition for food and recourses - predation - parasitism - disease - presence of pollinating insects - availability of nests and sites
29
Name three abiotic factors that influence the numbers and distribution of organisms
- climate, such as light intensity, temperature and water availability - hours of daylight - soil conditions - pollution - pH
30
Name three different abiotic factors in water
- depth of water - flow rate - type of material at bottom of stream - concentration of minerals in water - pH - oxygen concentration - cloudiness of water - presence of any pollution
31
32
Name three reasons why energy is lost on each trophic level
This happens between EVERY trophic level - Some parts of organism are not eaten - Some part or organism are not digested and so are not abosorbed - Some materials absorbed from excretory products - Many of the materials are respired to release, loss of CO2 and water
33
Define trophic levels
Different stages of a food chain
34
How and why are quadrats used? Explain method used?
Used to measure the number and of individuals in one species or several, using sampling. It is a 10 by 10, 1m grid. Method - Lay quadrant on survey area - Use random number generator to generate coordinates - count the number of chosen species in quadrat - Estimate the population in survey area
35
Name and explain two consequences of air pollution? (not CO2)
Sulfuric acid - combines with water vapor and forms acid rain, damages aquatic life, soil and plant - Causes respiratory problems in humans Carbon Monoxide -binds to haemoglobin, reducing oxygen carry capacity in blood - Can lead to suffocation & death
36
Reasons for increased pollution?
Two Main reasons: - Population increase - Extent of industries Specific reasons: - Food to sustain increasing population - materials to build homes, schools and industries - fuel to heat homes and power vehicles - space in which building homes, schools and factories - Space needed for farming - Space in which to dump waste
37
How does a greenhouse work. (Not atmospheric)
Short wavelength infrared light enters greenhouse, it is then absorbed and re-radiated as a longer wavelength infrared cannot escape through glass, also stops convection currents. CAUSES GREENHOUSE TEMPERATURE TO INCREASE.
38
How else does a greenhouse increase temperature?
Can use heaters powered by fossil fuels. This can increase the CO2 concentration and water vapor concentration along with temprature, increasing yeild. Heating glasshouse to the optimum temperature can increase yield further.
39
40
What is the difference between organic and inorganic fertilisers.
Organic are made form feaces of farm animals mixed with straw Inorganic are made from inorganic compounds such as potassium nitrate or ammonium nitrate
41
Why are inorganic fertilisers more popular?
Organic fertilisers can only replace a portion of lost nitrogen, inorganic fertilisers can replace all the lost nitrogen ions.
42
Disadvantages of inorganic fertilisers?
Can cause pollution problems like eutrophication and does not improve structure of soil, organic fertilisers can improve soil structure.
43
What are pests?
Organisms that reduce the yield of crop plants or stock animals.
44
What a pesticides?
Chemicals used to kill pests
45
What is biological control?
Use of other organisms to reduce number of pests/ introducing alien organism.
46
Name three disadvantages of pesticides
- Pests may develop resistance, leading to increase in pesticide concentration - More and more expensive - build up in tissue of organism - build up and become more concentrated along food chains - biomagnification - Kill other harmless incests
47
48
Disadvantages and advantages of biological control?
Advantage Does not need to be reapplied Kills majority of pests Disadvantages Cannot kill all pests Can get out of control Unforeseen consequences like dominating habitat - have no natural predator
49
What is bioaccumulation?
When herbivore feed on plant, instead of breaking down or excreting insecticide it become concentrated I n fatty tissue of animal.
50
51
What is biomagnification?
Bioaccumulation continues up the food chain, building up in concentration.
52
How does carbon dioxide and other ‘greenhouse gasses’ contribute to global warming?
Through greenhouse effect, short-wavelength infrared from sun enters atmosphere is then absorbed and re-emitted and long-wavelength infrared, long-wavelength radiation is then absorbed and re-emitted back to earth.
53
Name three consequences of global warming
- Polar caps melting - A change in the major oceans currents - Change in glabal rainfall patterns, move evaporation leading to more rainfall in some areas - Species unable to adapt to rapidly changing ecosystem could become extinct
54
Name two sources of methane
- Decomposition of waste buried in ground - Fermentation of microorganisms in cows and other ruminants - fermentation of bacteria in rice fields
55
Name three problems caused by deforestation
- Destruction of habitats and reduced biodiversity - Reduced soil quality - no tree roots to hold soil together, or plants to return minerals to soil when they die - Soil exposure - lack of tree cover and is blown away - Produce climate change - disruption in the water cycle - Medical application of certain trees less likely to be discovered
56
Name a consequence of pollution of water through sewage
- Reduction of oxygen levels - aerobic bacteria in sewage using oxygen in water supply - Untreated sewage contains pathogenic bacteria - danger to human health
57
Explain eutrophication?
- Surface run-off of fertilisers into waterways like rivers - Excess mineral ions lead to algal bloom - A thick scum formed on surface of water - Algae die and are decomposed by aerobic bacteria - Aerobic bacteria use up oxygen in the water - Algae also block light from reaching plants, stoping production of oxygen in water - Low oxygen levels - Death of fish and other aerobic animals

Bio IGCSE (7 decks)

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