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A level Biology > 6.6 ecosystems > Flashcards

6.6 ecosystems Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

define ecosystem

A

a community of animals, plants and bacteria interrelated with the physical and chemical environment

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2
Q

define habitat

A

a place where an organism lives

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3
Q

define population

A

all of the organisms of one species who live in the same lace at the same time and can breed together

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4
Q

community

A

al the populations of different species who live in the same place at the same time and can interact with each other

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5
Q

define biotic factors

A

environmental factors associated with living organisms in an ecosystem that affect each other

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6
Q

give 6 examples of biotic factors

A

producers
consumers
decomposers
predation
disease
competition

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7
Q

define abiotic factors

A

non-living components of an ecosystem that affect other living organisms

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8
Q

give 6 examples of abiotic factors

A

light intensity
soil pH
water availability
humidity
temperature
concentration of pollutants

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9
Q

why are ecosystems referred to as dynamic

A

because ecosystems are changing

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10
Q

what are the three types of changes in an ecosystem that affect population size

A

cyclic changes
directional changes
unpredictable changes

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11
Q

define cyclic changes

A

changes that repeat themselves in a rhythm

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12
Q

give an example of a cyclic change

A

tides
predator and prey relationship

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13
Q

define directional changes

A

changes that aren’t cyclic and go in one direction. They tend to last longer than the lifetime of organisms with the ecosystem

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14
Q

give an example of a directional change

A

erosional processes
depositional processes
glaciation

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15
Q

define erratic changes

A

theses changes have no rhythm or constant direction

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16
Q

give examples of erratic changes

A

hurricane
earthquake
tsunami

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17
Q

define biomass transfer

A

transfer of biomass from one trophic level to another

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18
Q

define trophic level

A

the level at which an organism feeds in a food chain

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19
Q

how is biomass lost in a food chain

A

dead organisms
not all of the animal being eaten
respiration
senses
reproduction
heat energy

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20
Q

what is the trend in biomass as you go up a food chain

A

biomass is less at higher levels

21
Q

what is biomass

A

dry mass of the organism

22
Q

How is biomass obtained by scientists

A

drying the organism by putting it in an oven to evaporate all of the water

23
Q

how do you calculate the ecological efficiency of the transfer of biomass

A

(biomass at higher trophic level/biomass at lower trophic level)*100

24
Q

define productivity

A

the rate of production of new biomass by producers

25
Q

define gross primary productivity

A

the rate at which plants convert light energy into chemical energy through photosynthesis

26
Q

define net primary productivity

A

the rate at which energy is stored as biomass by the producer that is available for the next consumer

27
Q

what is the difference between primary and secondary productivity

A

primary - plant
secondary - animal

28
Q

how can we make energy conversion more efficient when farming plants

A

greenhouses
fertiliser
light banks
pesticides
crop-rotation

29
Q

How cans humans manipulate energy transfer when farming animals

A

battery farming
antibiotics
killing them young
selective breeding

30
Q

how do saprotrophs eat?

A

they secrete enzymes on dead or waste material which digest the material into smaller pieces which are then absorbed into the saprotroph’s body

31
Q

why are bacteria and fungi vital for recycling within ecosystems

A

if bacteria and fungi did not break down dead organisms, energy and valuable nutrients would remain trapped within the dead organism

32
Q

why do living things need nitrogen?

A

to make proteins and nucleic acids

33
Q

what kind of nitrogen do plants require

A

fixed nitrogen (NH4+,NO-)

34
Q

how is fixed nitrogen produced

A

lightning and the Haber process only makes up about 10% of fixed nitrogen the rest is by bacteria

35
Q

how much of the atmosphere is made of nitrogen

A

79%

36
Q

what bacteria fix nitrogen

A

Azotobacter
Rhizobium

37
Q

Describe the role of Azotobacter

A

bacteria that lives freely within the soil and fix nitrogen gas, which is in the air within the soil, using it to manufacture amino acids

38
Q

what is the role of Rhizobium

A

lives inside the root nodules of leguminous plants and is nitrogen fixing
It has a mutualistic relationship with the plant by supplying it with fixed nitrogen and receiving carbon compounds such as glucose

39
Q

what is the role of leghaemoglobin

A

absorbs oxygen to keep conditions anaerobic for nitrogen reductase

40
Q

What is ammonification

A

organic nitrogen in soil and urea —> NH4+ by bacteria involved in putrification

41
Q

what is nitrification

A

chemoautotrophic bacteria in soil oxidise ammonium ions to nitrite ions and the into nitrate ions

42
Q

What is the role of nitrosomanas

A

oxidising ammonium ions to nitrite ions(nitrification)

43
Q

What is the role of Nitrobacter

A

Oxidise nitrite ions to nitrate ions (nitrification)

44
Q

Whet is denitrification and its conditions

A

occurs in anaerobic conditions such as waterlogged soils and use nitrates as a source of oxygen to produce nitrogen gas and nitrous oxide

45
Q

define climax community

A

the final stable community that exists after the process of succession has occurred

46
Q

define deflected community

A

happens when succession is stopped or interfered with such as by grazing or lawn mowing

47
Q

define pioneer species

A

the species that begins the process of succession

48
Q

define succession

A

progressive changes in a community of organisms over town

A level Biology (25 decks)

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