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Biology Higher Level > 4.1 & 4.2 > Flashcards

4.1 & 4.2 Flashcards

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1
Q

what is the difference between an autotroph and a heterotroph?

A

autotroph = obtains food by producing organic compounds from inorganic compounds
heterotrophs = obtains food by consuming other organisms

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2
Q

what are the 3 types of heterotroph?

A
  1. consumers
  2. detritivore
  3. saprotroph
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3
Q

what is the difference between a consumer, a saprotroph and a detritivore?

A

consumer; obtains nutrients by digesting other organisms
saprotroph; obtains nutrients from dead organisms via external digestion
detritivore; obtains nutrients from detritus via internal digestion

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4
Q

what is a chi-squared test?

A

a test that calculates the association between species viewed in quadrant sampling

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5
Q

what is the formula for chi-squared?

A

x^2 = Σ (observed value - expected value)^2/ expected value

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6
Q

what is the formula for degree of freedom in a child-squared test?

A

dof = number of groups tested - 1

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7
Q

what is the formula for expected frequency in a chi-squared test?

A

expected frequency = (row total x column total)/ grand total

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8
Q

what is the difference between the abiotic and biotic components of an environment?

A

abiotic factors = non-living things
biotic factors = living things

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9
Q

define species

A

can interbreed to produce fertile offsprings

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10
Q

define population

A

same species living in the same area at the same time

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11
Q

define community

A

multiple populations living in the same area at the same time

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12
Q

define ecosystem

A

the interaction of a community with its abiotic environment

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13
Q

what are the 3 types of species present in a community

A
  1. autotrophic
  2. heterotrophic
  3. mixotrophic
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14
Q

what is a common method used for autotrophs to obtain energy (make food)

A

photosynthesis

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15
Q

what are the 3 types of autotrophs?

A
  1. plants
  2. algae
  3. cyanobacteria
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16
Q

define mixotrophs

A

species that can carry out both heterotrophic and autotrophic nutritions
e.g. venus fly trap

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17
Q

what is speciation?

A

if members of species are isolated, either geographically or behaviourally, they diverge to become 2 different species

18
Q

what is nutrient cycling?

A

recycling of nutrients and minerals
this includes
- carbon
- hydrogen
- oxygen
- nitrogen
- phosphorus
for an ecosystem to be fully sustainable, ^ these nutrients must be continually available

19
Q

what are mesocosms and what does it require?

A

an artificial mini ecosystem to investigate the effects of factors on ecosystem sustainability
- light source
- water
- air
- autotroph, to produce organic compounds and uptake nutrients and minerals
- a saprotroph or a detritivore, to decompose waste material and dead organisms, returning nutrients and minerals to the ground

20
Q

what are the 2 representations of feeding networks?

A
  1. food webs
  2. food chains
21
Q

what is always at the bottom of the food chain?

A

the producer, an autotroph
e.g. grass

22
Q

where does the arrow in a food chain point to the direction of?

A

the direction of energy transfer
e.g.
grass —> beetle —> salmon —> bear

23
Q

what is each stage of the food chain known as?

A

a tropic level

24
Q

why is it so common that most communities only have a maximum of 3 - 4 trophies levels?

A

due to the inefficient nature of energy transfer
loss of energy in the ecosystem
- sunlight (light energy) is brought into the ecosystem whilst the process of heat loss occurs

25
Q

list the 4 main ways of energy loss

A
  1. respiration; therefore losing heat energy to the environment
  2. uneaten parts e.g. roots of plants
  3. undigested parts e.g. hair or cellulose
  4. death of organisms; dead before consumption can occur, their energy pass on
26
Q

only x% of energy within one trophic level moves to the next trophic level due to energy loss

A

10%
- this percentage is very low since
- its organisms convert chemical energy into useful kinetic and heat energy
- the KE and heat energy cannot convert back to chemical energy therefore its lost

27
Q

what is the units measured in for the pyramid of energy?

A

kJ m^-2 yr^-1
width proportional to energy present within the trophic level

28
Q

define biomass

A

the total mass of group of organisms

29
Q

what is the use of a quadrat?

A

used to view the relationship between 2 different organisms within a given area

30
Q

describe the step by step process of using the quadrat

A
  1. select an area and divide it into a numbered grid 0f 1m x 1m squares
  2. use a random number generator to randomly select study areas
  3. select 2 study organisms
  4. create a null hypothesis and an alternative hypothesis
  5. place a quadrat and note which organisms are present in the selected study areas
  6. create a table to show the presents and or absents of the 2 chosen study species (noting the observed frequencies)
  7. calculate the row and column total
  8. calculate the grand total
  9. calculate the expected frequencies; f(e) = (row total x column total)/ grand total
    10 determine the value of chi-squared
  10. find the degrees of freedom
  11. compare chi-squared value to the critical chi-squared table
    - if the chi-squared number is greater than 3.841, then the results are significant and there is a statistical difference between the 2 chosen study organisms, vice versa
31
Q

how does energy flow in a food chain?

A

from organisms to organisms

32
Q

outline the role of an autotroph within an ecosystem (3)

A
  • autotrophs make their own carbon compounds from CO2
  • autotrophs are often producers
  • start the food chain so they are vital to the ecosystem
  • they constitute most plants within an ecosystem
33
Q

using 4 named organisms, outline the meaning of the term food chain (3)

A
  • grass —> beetle —> salmon —> bear
  • a food chain is a diagram that links organisms together that consume on one another
  • starts with a producer, autotroph
34
Q

outline the meaning of the term food chain (2)

A
  • a food chain is a diagram that links organisms together that consumes on one another
  • starts with a producer/ autotroph
35
Q

describe how mesocosms can be used to investigate the sustainability of ecosystems (6)

A
  • mesocosms are small experimental ecosystems
  • they can be terrestrial or aquatic
  • factors can be removed or added to investigate their effects
  • can be sealed to investigate which are sustainable over the long term
  • possible harm to organisms should be considered
  • careful selection of organisms is required for balance
  • oxygen supply must be balanced
36
Q

what are the 3 requirements for a sustainable ecosystem? (3)

A
  • energy; sunlight as this where producers source their energy from and producers are the foundation of every food web in every ecosystem
  • nutrients; decomposers guarantee the availability of inorganic nutrients through recycling
  • waster removal; bacteria serve to breakdown and sometimes detoxify harmful waste material
37
Q

how do saprotrophs feed? (4)

A
  • saprotrophs are heterotrophs that
  • obtain organic nutrients from dead organisms and waste material via
  • external digestion that occurs when they secrete
  • enzymes
38
Q

outline the use, transfer and efficiency of energy within an ecosystem (8)

A

energy is used for
- growth and repair
- respiration
- feeding and reproduction
- energy is transferred form one trophic level to the next
- lots of energy is lost from producers to primary consumers
- only 10% of energy is transferred from one organism to the next
energy is lost in
- incomplete digestion
- uneaten food
- energy transfer through an ecosystem is inefficient

39
Q

why is heat generated by living organisms lost from the ecosystem? (2)

A
  • heat is transferred from warmer to cooler bodies
  • at each transfer heat is lost to the abiotic environment
40
Q

what is the function of ATP? (4)

A
  • ATP is used to fuel various cellular functions
  • it is a universal energy currency of the cell
  • it is used for endocytosis and exocytosis
  • nerve transmission
  • growth and repair
  • movement
  • light emission

Biology Higher Level (50 decks)

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