5.3 Energy and Ecosystems Flashcards

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1
Q

What are producers?

A

Photosynthetic organisms that manufacture organic substances using light energy, water, carbon dioxide and mineral ions

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2
Q

What are consumers?

A

organisms that obtain their energy by feeding on other organisms rather than using the energy of sunlight directly

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3
Q

What are primary consumers?

A

Those that directly eat producers (green plants) because they are the first in the chain of consumers

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4
Q

What are secondary consumers?

A

those animals eating primary consumers, usually predators but may also be scavengers or parasites

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5
Q

What are tertiary consumers?

A

those eating secondary consumers, usually predators but may also be scavengers or parasites

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6
Q

What are saprobiants?

A
  • decomposers
  • group of organisms that break down the complex materials in dead organisms into simple ones
  • in doing so they release valuable minerals and elements in a form that can be absorbed by plants and so contribute to recycling
  • majority of this is carried out by fungi and bacteria
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7
Q

What is a food chain?

A
  • a feeding relationship in which the producers are eaten by primary consumers etc.
  • each stage is referred to as a tropical level
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8
Q

What is a food web?

A

Most animals do not rely on a single food source and within a single habitat many food chains will be linked together to form a food web

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9
Q

What is biomass?

A
  • a biological material derived from living or recently living organisms.
  • In the context of biomass for energy this is often used to mean plant based material,
  • but biomass can equally apply to animal derived material
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10
Q

What happens within an ecosystem?

A

within any ecosystem, plants synthesise organic compounds (those obtaining carbon) from carbon dioxide obtained from the atmosphere or in the case of aquatic plants the water. These organic compounds include glucose, lipids, cellulose and proteins

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11
Q

How do you measure biomass?

A
  • Biomass can be measured in terms of mass of carbon or dry mass of tissue per given area per given time
  • Grams per metre squared per year
  • Kilograms per hectare per decade
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12
Q

What is biomass composed of?

A
  • biomass is carbon based and is composed of a mixture of organic molecules containing hydrogen, usually including atoms of oxygen, often nitrogen and also small quantities of other atoms
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13
Q

What is the equation for biomass?

A

Net Primary productivity = Gross Primary productivity - respiratory loss
NPP=GPP-R

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14
Q

What is the GPP?

A

a measure of the total energy or mass in a plant

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15
Q

What is the NPP?

A

what becomes available to organisms in the next trophic (feeding) level

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16
Q

Why is most of the suns energy not converted to organic matter by photosynthesis?

A
  • over 90% of the suns energy is reflected back into space by clouds and dust or absorbed by the atmosphere
  • not all wavelengths of light can be absorbed and used for photosynthesis
  • light may not fall on a chlorophyll molecule
  • a factor, such as low carbon dioxide levels, may limit the rate of photosythesis
17
Q

Why is there a low percentage of energy transferred at each stage of the food chain?

A
  • some of the organism is not consumed
  • some parts are consumed but cannot be digested and are therefore lost in the faeces
  • some of the energy is lost in excretory materials
  • some energy losses occur as heat from respiration and lost to the environment
18
Q

What is the net production of consumers?

A

N = I - (F+R)
N = net production
I = ingestion
F = Faeces
R = respiration

19
Q

How do you reduce energy transfer in modern farming?

A
  • animals kept inside in warm conditions -> reduces energy loss by ‘heating’ their bodies
    >restricting movement -> kept in cramped conditions
20
Q

What do fertilisers do in modern farming?

A

encourage plant growth - more yield
> eutrophication - rivers, lakes encourage plant growth

21
Q

What do pesticides do in modern farming?

A

Kill organisms that damage crops
> Chemical pesticides might kill other species
> biological control - use the predator of the pest - invasive species

22
Q

What do greenhouses do in modern farming?

A

Control temperature, confined space no in or out for pests, water levels, carbon dioxide

23
Q

What does diet do in modern farming?

A

high protein and low fibre diets this could reduce the amount of faeces

24
Q

What does selective breeding do in modern farming?

A

breeding for fast growth and high yields

25
Q

What does growth hormones and antibiotics do in modern farming?

A

accelerating growth and prevention of bacterial disease
ethical issues