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Biology > Ecosystem > Flashcards

Ecosystem Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Ecosystems are reffered to as ‘dynamic’ what does this term mean?

A

Ecosystem changes over time

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2
Q

Name the three different types of changes that occur to ecosystems

A
  • cyclic changes
  • directional changes
  • unpredictable/eratic changes
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3
Q

define cyclic changes

A

changes that repeat themsleves in a rhytm

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4
Q

define directional changes

A

not cyclic & goes in one direction

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5
Q

define unpredictable/erratic changes

A

no rhytm and no constant direction

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6
Q

Define ecosystem

A

all the interacting living organisms and non living factors in an area

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7
Q

what are abiotic factors that affect an ecosystem?

A
  • water availability
  • temperature
  • 02 availibility
  • light intensity
  • edophic (soil) factors i.e pH/type of soil
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8
Q

what are biotic factors that affect an ecosystem?

A

disease,predation and competition

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9
Q

what is meant by the term ‘niche’?

A

role of each species in an ecosystem

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10
Q

Define trophic level

A

the stage/position in a food chain

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11
Q

Define community

A

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

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12
Q

Define population

A

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

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13
Q

Define biomass

A

the mass of living material in an area

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14
Q

Define producer

A

converts inorganic molecules into organic molecules

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15
Q

Define consumer

A

derives energy from other organisms

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16
Q

How can we measure biomass?

A
  • use a calorimeter
  • measure the dry mass
  • measure the temperature rise of water
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17
Q

what are the biomass unit for normal habitats?

A

gm-2 yr-1

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18
Q

what are the biomass units for marine/water habitats?

A

gm-3 yr-1

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19
Q

Define elogial effieceny

A

efficeny in whihc biomass is transferred from one trophic level to another

20
Q

why is the efficency never 100%?

A
  • sunglight reflected
  • other factors i.e H20 availability affecting photosynthesis rates
  • some energy use for ps to occur
  • energy lost through respiration i.e metabolic heat
  • lost through excretion
  • some parts of the food not edible
21
Q

How can the percentage efficeny of energy transfer between producers and consumers be measured?

A
  • primary energy/consumer energy x 100
  • sample of producers collected
  • sample of consumers collected
  • measure biomass using calorimetre i.e burn sample in 02
22
Q

How can farmers increase ecological efficency?

A
  • keep animals indoors
  • reduce animal movement i.e zero grazing
  • feed animals high protein content
  • vaccinate animals
  • use selective breeding/genetic engineering
  • slaughter animal before mature
23
Q

what is the formula for ecological efficency?

A
  • biomass transferred/ biomass intake
24
Q

decomposers are described as ‘saprophytic’ what does this mean?

A

they do external digestion

25
Q

describe the role of decomposers in decompisition

A
  • bacteria is saprophytic/does external digestion by secreting enzyme
  • absorption of breakdown products
  • releases CO2 and H20
  • break down of proteins makes ammonium ions (NH4+)
26
Q

what is the role of detritivores?

A
  • they do internal digestion increasing the surface area and speeding up the process of decomposition
27
Q

Draw the carbon cycle

A
28
Q

write the formula for the process of nitrification, the type of reaction it is and name the bacteria involved

A

NH4+ –>No2- (nitrites)–> N03- (nitrates)
* nitrosomonas and nitrobacter
* oxidation reaction

29
Q

write the formula for ammonification

A

N02/N03- —> NH4+

30
Q

write the formula for the process of denitrification, the type of reaction it is and name the bacteria involved

A

*N03- —->N2
* anarobic ( only happens when theres no O2)
*dentirifying bacteria - Pseudomonas

31
Q

Write the formula for nitrogen fixation and the bacteria involved

A

*N2 + 2H3 -> 2NH3
*azobacter and rhizobium

32
Q

where can Rhizobium be found?

A

in root nodules

33
Q

where is azobacter found?

A

in the soil

34
Q

Draw the nitrogen cycle

A
35
Q

What are the similarities between the carbon and nitrogen cycle?

A
  • Co2 and NO2 are inorganic gases in the atmosphere
  • elements are fixed to organic compounds
  • both incoperated into plants then animals
  • animals obtains elements by feeding on plant
  • microorganisms return elements to atmosphere ( CO2 released during decomposition and N2 released by dentrifiying bacteria)
  • both break down organic macromolecules into living things
  • both release inorganic molecules CO2 ammonium ions (NH4+)
36
Q

What is the difference between decomposition and dentrification

A
  • decompisition - breaks down dead organic matter and increases nitrate supply
  • wheres denitrification is the conversion of nitrates to N2 reducing nitrate supply
37
Q

Define sucession

A

progressive change in a community of organisms over time

38
Q

what is primary sucession?

A

occurs on land that is newly formed/there is no soil present

39
Q

what is secondary sucession?

A

occurs where soil is present but there is no animal/plant species

40
Q

what are pioneer species?

A
  • species that begin the process of sucession often colonising an area as the first living things there
  • i.e mosses and lichen
  • they arrive before climax
  • are subject to greater change
  • have low biodiversity /less stable
41
Q

what is the role of pioneer species like mosses and lichen?

A
  • fix N2
  • tolerate extreme conditions
  • weather the rocks to create a layer of humus ( soil)
42
Q

Describe the process of sucession

A
  • pioneer species - bgeins with bare rock, mosses and lichen and they have adaptations i.e nitrogen fixation
  • intermediate - out compete pioneer species i.e herb species followed by shrubs
  • climax community - final stable state
  • dominance by a few tree species
  • as the process continues there is increased nitrate /H20/organic content in the soil
43
Q

what is deflected sucession?

A
  • when the natrual flow of sucession is halted i.e mowing the lawn
44
Q

Define th eterm plagioclimax

A

when sucession is artifically stopped

45
Q

what do we use to measure plants?

A

quadrat that are placed randomly

46
Q

what is used to measure distribution

A

belt transect

47
Q

How canwe use a belt transect to measure the distribution?

A
  • use a quadrat every i.e 5m
  • count n of each species
  • use identification key
  • use a method to avoid recounting
  • calculate mean and repeat at different times of the year

Biology (2 decks)

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