Module 5- Ecology and ecosystems Flashcards

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1
Q

What is an ecoystem?

A

An ecosystem includes all the organisms living in a particular area and all the non-living conditions.

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2
Q

What is a producer?

A

The organism that makes its own food

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3
Q

Where is energy and carbon dioxide gained from during photosynthesis?

A

Energy from sunlight
Carbon dioxide from the atmosphere or dissolved in water in aquatic habitats

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4
Q

What is a plant’s biomass?

A

The mass of living material or chemical energy stored in the plant

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5
Q

What are primary/secondary/tertiary consumers?

A

Primary = eat producers
Secondary = eat primary
Tertiary = eat secondary

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6
Q

How can biomass be measured in terms of…

A

The mass of the carbon that an organism contains or the dry mass of its tissue per unit.

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7
Q

How is biomass in an organism found when looking for dry mass?

A

A sample of an organism is dried. This is done by placing it into an oven at a low temperature and checking the weight at regular intervals. When the mass is constant, the mass is completely dry. The mass of carbon is taken by 50% of the dry mass.

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8
Q

How to measure biomass using a calorimeter?

A

A sample of dry biomass is burnt and energy is released which is used to heat a known volume of water. The change in temperature of water is used to calculate the chemical energy of dry biomass.

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9
Q

What is GPP?

A

The total amount of chemical energy converted from light energy by plants

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10
Q

What is respiratory losses?

A

50% of chemical energy is lost to the environment in heat when plants respire. This is known as respiratory losses.

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11
Q

After the respiratory losses, the chemical energy is called what?

A

NPP = Net primary production

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12
Q

What is NPP?

A

The energy available for a plant for growth and reproduction and the energy available to organisms in the next stage of the food chain.

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13
Q

Where is NPP stored?

A

The plants Biomass

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14
Q

What is primary productivity?

A

The total amount of chemical energy in a given area, in a given time

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15
Q

How do consumers collect energy?

A

When a consumer eats a producer or eats an animal that has eaten a producer

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16
Q

How much of the total energy available in the previous trophic level is lost ?

A

90%

17
Q

Explain why some GPP is so low compared with the original light energy available

A

Some solar energy is lost because
* It is the wrong wavelength for photosynthesis
* Reflects off the leaf
* Passes straight through the leaf/misses chloroplasts
* Just heats the leaf
* Misses the leaf/strikes a non-photosynthetic part of the plant

18
Q

What are the 3 reasons why not all energy is passed on to the next trophic level?

A
  • Some parts of organisms are indigestible such as the bones etc.
  • Some is egested through faeces
  • Some is lost to the environment through respiration or urine excretion.
19
Q

What is the total energy that is available to the next trophic level called?

A

Net production of consumers

20
Q

How is net production of consumers calculated?

A

N = I - ( F + R )

21
Q

How to calculate energy efficiency?

A

(Net productivity/total energy available) x 100

22
Q

What are decomposers?

A

Decomposers break down dead or undigested material

23
Q

What are two ways in which a farmer can increase the NPP?

A

simplifying the food web and reducing respiratory losses

24
Q

What are 2 ways in which the food web can be simplified to increase NPP?

A

Insecticides which kill insect pests that eat and damage crops. Killing pests means less biomass is lost from crops
Herbicides kill unwanted weeds which reduces direct competition

25
Q

What are biological agents and how do they increase the efficiency of energy transfer of humans?

A

Parasites which live or lay their eggs inside a pest and kill them.
Pathogenic bacteria and viruses also kill pests

26
Q

How may a farmer reduce respiratory losses in an organism?

A

Reducing their movement so that they lose less through respiration
Kept indoors and warm so less energy is used to keep warm

27
Q

What is the negative of farmers reducing respiratory losses in organisms?

A

Ethical concerns

28
Q

What are the measurements used to measure primary and secondary productivity?

A

Biomass in a given area in a given time
KJ m-2 year-1

29
Q

How can a student suggest how the mass of carbon for a particular organism could be estimated?

A
  • Calculate the mean diameter of the organism
  • Use this to determine the mean biomass
  • Use this % water content to find the dried mass
  • Use the dried density to calculate the mass of the organism
  • Estimate the number of organisms in the given area and multiply by the mean carbon content to find the total carbon.
30
Q

How to determine the chemical energy of a sample.

A

Dry the mass by placing in an oven at a low temp and checking at regular intervals until the mass is constant. Then burn the dry sample and allo the heat energy being released to heat up a known volume of water. The change in temperature of the water is the chemical energy