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(A) Biology > B4 > Flashcards

B4 Flashcards

1
Q

What is an ecosystem

A

All the organisms and living conditions present in an area

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2
Q

What are all the organisms living within an ecosystem called

A

A community

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3
Q

What is a habitat

A

The place an organism lives (emg a pond)

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4
Q

What is a population

A

The total number of organisms in a species that live in a specific area

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5
Q

What is a producer

A

Organisms that make their own food through photosynthesis

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6
Q

What is a consumer

A

Organisms that cannot make their own food and must eat other organisms to gain energy

ALL ANIMALS ARE CONSUMERS

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7
Q

What are decomposers

A

A special group of consumers

They gain their energy by feeling on dead or decaying material

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8
Q

What is an autotroph

A

An organism which generates its own energy

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9
Q

What is a photoautotroph

A

An organism that uses simple inorganic molecules to synthesise complex organic molecules

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10
Q

How do photoautotrophs increase their biomass

A

Photoautotrophs absorb energy from the sun in photosynthesis and create glucose.

This is then turned into carbohydrates, fats and proteins, which are then used as energy stores for growth and repair

As an organism grows its biomass increases - the mass of living material

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11
Q

What is biomass

A

The total living mass of organisms in an area

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12
Q

How is energy transferred between organisms

A

Consumers eat producers, which pass on lipids, proteins, carbohydrates and glucose

This energy is stored and transferred in the production of atp.

This organism then grows and its biomass increases

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13
Q

What is a food chain

A

A chain that displays what an organism eats

The arrows show the biomass transfer from one organism to the next

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14
Q

What is a trophic level

A

Each step in a food chain

E.g a producer would be trophic level one

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15
Q

What is a food web

A

A complex ‘web’ of food chains that are interlinked.
These are needed as not only one animal is eaten by another. Usually it would have multiple predators

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16
Q

What are the main factors in an ecosystem

A

Biotic - living factors (E.g the plants and animals)

Abiotic - non-living (physical) factors (E.g the rainfall, temperature or wind speeds in an ecosystem)

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17
Q

How do biotic factors effect communities

A

Organisms may compete with each other for food and space

Competition is the main biotic factor

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18
Q

How does light intensity (abiotic factor) affect communities

A

Light intensity is needed for photosynthesis

The greater the accessibility of light the greater the success of a plant

Plants evolve to grow successfully - in areas of low light intensity plants have larger leaves

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19
Q

How does temperature (abiotic factor) affect communities

A

Temperatures greatest effect is on the enzymes which control metabolic reactions

In warmer climates plants develop more rapidly as their metabolisms are faster.

This also affects cold blooded animals like lizards who need the sun to warm them up

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20
Q

How do moisture levels (abiotic factor) affect communities

A

For most plant and animal species, a lack of water leads to death
(Emg water is the main component in blood plasma)

Water is needed to maintain turgor pressure in plants and for photosynthesis

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21
Q

How does soil pH (abiotic factor) affect communities

A

The pH of a soil affects the minerals it contains.
Some plants grow better in acidic soil such as ferns
Some plants grow better in alkaline soils such as cucumbers

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22
Q

What do plants need to survive

A

Light
Water
Carbon dioxide
Minerals
Space

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23
Q

What do animals need to survive

A

Food
Water
Breeding partners
Space (territory)
Shelter

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24
Q

What is competition

A

When two or more organisms are contesting for a resource

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25
Q

What are the main relationships between species in a community

A

There are three main ecological relationships between organisms

Predations mutualism and parasitism

26
Q

What is interdependence

A

How different organisms depend on each other within a community

27
Q

What is predation

A

A predator - prey relationship

The size of the predator population directly affects the size of the prey population

28
Q

Mutualism

A

A relationship where both organisms benefit

E.g oxpeckers (small birds) eat the ticks and fleas living on buffalos skin
They gain food and free the buffalo from irritation and disease

29
Q

Parasitism

A

A parasitic relationship
Only one organism (the parasite) gains, while the organisms it lives of (host) suffers

E.g tapeworms in a digestive system

30
Q

What is a pyramid of biomass

A

A pyramid showing the transfer of biomass between organisms.
As the trophic level increases the size of animals increases but the number of them decreases.
This means the biomass decreases going up the pyramid

31
Q

What is a pyramid of numbers

A

A pyramid that shows the number of organisms at each trophic level.
This doesnt always look like a traditional pyramid

E.g 1 oak tree is eaten by 2000 caterpillars.
(This is known as an inverted pyramid)

32
Q

Why are pyramids of biomass rarely inverted

A

As the biomass is plotted.
Both number and size of organisms is taken into account

33
Q

How do you calculate biomass

A

The average biomass of an organism is calculated then multiplied by the number of organisms.

34
Q

How do you measure biomass

A

You need to calculate the ‘dry mass’ as water can vary between individuals

This is done by killing the organism and drying it in a kiln

35
Q

How do you draw a pyramid of biomass

A

Take the biomass of each organism and divide it by a sensible scale factor (e.g 1cm = 10kg) then draw each trophic level and label them

Try to place each new level in the center of the previous one

36
Q

What percentage of sunlight energy does each plant transfer into food

A

Producers only transfer around 1% of energy from the sunlight into food stores

This happens due to limiting factors in photosynthesis

37
Q

Why does biomass decrease at each trophic level

A

Plants use half of their energy in increasing biomass and respiration

Consumers will then eat the plant and absorb its biomass, however not all of its biomass will be absorbed as often the whole organism is not eaten (emg the roots)

Consumers will convert 10% of the energy into mass

Consumers lose energy in transportation

They lose biomass in excretion and egestion

Biomass is also lost when energy is used for movement and growth

Not all organisms are eaten so energy is lost there as well

38
Q

What is egestion

A

Removal of indigestible waste from an organism

39
Q

What is excretion

A

Removal of waste metabolic products from an organism

40
Q

How do you calculate the efficiency of biomass transfer

A

(Biomass available after the transfer ÷ biomass available before the transfer) ×100

41
Q

Why do food chains have a limited number of trophic levels

A

As eventually the transfer of energy becomes so low not enough energy can be transferred to sustain a life process

42
Q

What is nutrient cycling

A

The process of nutrients being moved around an ecosystem through biotic and abiotic components

43
Q

What are the main processes in the water cycle

A

Evaporation - the sun heats water turning it into water vapour

Condensation - As the water vapour begins to cool it condenses back into water forming clouds

Precipitation - water falls as rain, snow or hail when the water droplets get larger

Percolation - water falls through gaps in soils and rocks

Transpiration - loss of eater vapour from the plants to the atmosphere

Surface run-off - water that isn’t absorbed into the soil (soil is saturated) runs off into the nearest body of water

44
Q

What does interspecific mean

A

Competition between different species

45
Q

What does intraspecific mean

A

Competition between organisms in the same species

46
Q

What is commensalism

A

Where one organism benefits and the other is neutral

47
Q

What is a symbiotic relationship

A

A long term interaction between two different species

48
Q

Describe the process of the nitrogen cycle

A

Nitrogen - fixing bacteria in the roots convert nitrogen in the atmosphere into ammonia

Nitrifying bacteria convert the ammonia into nitrites the nitrates (nitrogen fixation)

Plants now absorb nitrates through the roots where its transported by the xylem to the rest of the plant (assimilation)

Nitates in the soil may be converted back to a gas by denitrifying bacteria (denitrification)

Animals gain nitrogen when they eat plants and when the die decomposers break them down into the soil(or there waste) (then nitrification happens)

49
Q

What is the carbon cycle

A

A process by witch carbon is recycled through the atmosphere

50
Q

How is carbon removed from the atmosphere

A

It is removed by the plants (e.g algae) during photosynthesis to create glucose

51
Q

How is carbon transferred between organisms / into the soil

A

When animals eat plants some carbon is transferred, through proteins and carbohydrates

Carbon is also taken into the soil after decomposition

Over millions of years plants and animals break down to make fossils

52
Q

How is carbon released back into the atmosphere

A

Respiration - by plants an animals carbon dioxide is released
Decomposition - Decomposers also respire while breaking down plants and animals

Burning fossil fuels - when fossil fuels are burnt the naturally trapped carbon is released into the atmosphere

53
Q

What factors affect the rate of decomposition

A

Temperature - higher temps prevent decomposition as enzymes used denature + results in the death if the microorganism

Moist environments - if not enough water is available reactions in the microorganism will slow down or be prevented. This stops the rate of decomposition

Aerobic conditions - Oxygen is needed for the microorganisms to respire.
If there is no oxygen there will be no decomposition as the microorganisms cant survive

54
Q

How to calculate rate of decay

A

Rate of decay = change in mass (g) / time (day)

55
Q

What are the most common decomposers

A

Bacteria fungi

56
Q

What are detritivores

A

Small animals which shred organic material into smaller pieces
This speeds up the rate of decomposition as the surface area to volume ratio is greater.

E.g worms

57
Q

How do fungi release nutrients into the soil

A

They release enzymes that break down organic matter.
They can then absorb SOLUBLE nutrients into their bodies and use them for growth and as an energy store

Bacteria and fungi can be eaten by other organisms resulting in the nutrients being passed on

Some of the nutrients they break down are directly released into the soil / environment (if not absorbed)

58
Q

What is an organic compound

A

A compound containing both carbon and hydrogen

59
Q

Where can nitrifying bacteria be found

A

In the root nodules of legumes

(Plants such as peas pr lentils)

60
Q

What is the difference between a habitat and an ecosystem

A

Habitat is the natural environment in which a specific organism lives

Ecosystems are the relationships between the biotic and abiotic components of the environment

(A) Biology (8 decks)

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