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Biology > Topic 5 on the wild side > Flashcards

Topic 5 on the wild side Flashcards

1
Q

succession

A

Is the progressive change in the composition and diversity of a species in a community in one place over a period of time

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2
Q

primary succession

A

starts in a newly formed habitat where there has never been a community before.

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3
Q

Climax community

A

stable final community
nature of species present depends on environment
have lower biodiversity when preceding stages in succession as dominant species out compete others.

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4
Q

pioneer species

A

the first species to colonise

They are the only species that can cope with the extreme conditions

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5
Q

secondary succession

A

occurs where there is habitat destruction
on bare soil where an existing community has been cleared
soil already contains seeds (seed bank)

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6
Q

deflected succession

A

community that remains stable because of human activity prevents succession
this prevents the loss or change in biodiversity in certain areas.

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7
Q

different methods for studying climate change

A
  1. temperature records
  2. studying peat bogs
  3. pollen grains in peat bogs
  4. dendrochronology
  5. changing rainfall patterns
  6. ice cores
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8
Q

temperature records

A

1650 to present only in certain places may have been collected with less accurate equipment

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9
Q

dendrochronology

A

study of tree rings
every year produce new layers of xylem vessels the diameter of these vary from season to season.
wide vessels in spring. narrow in summer and they produce none in autumn and winter
different width of rings tells us the condition of that year
can’t give precise dates
but can go back 3,000 years

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10
Q

ice cores

A

goes back 400,000 years
as water freezes bubbles of air become trapped with in the ice the ratio of the different O2 isotopes gives an estimated average air temperature when ice was formed

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11
Q

peat bogs

A

peat is the accumulation of partially decayed organic matter
anaerobic and acidic conditions prevent decay.
as absence of oxygen and low pH reduces activity of microorganisms
by studying plant and insect remains especially pollen grains tells us about air temperature.

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12
Q

pollen grains

A

goes back 20,000 years
pollen grains from peat
- plants produce vast amounts of pollen
- pollen grains have a tough outer layer resistant to decay
- each species of plant has distinct pollen
- peat forms in layers the deeper it is the older. use carbon-14 dating to work out age
- each species has a set of optimum ecological conditions. allowing us to infer what temperature conditions where like.

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13
Q

changing rainfall patterns

A

an increase in rainfall amount in winter slight decrease in spring and increase in rainfall on wet days means total rainfall increased on wet days. But less total rainfall as there are less wet days. these changes are consistent with climate model

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14
Q

greenhouse gas

A

a gas in the atmosphere that stops the infra-red radiation from escaping creating a greenhouse effect keeping the earth warm

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15
Q

carbon dioxide

A

greenhouse gas
strong correlation between temperature and CO2 concentration.
CO2 concentration has been rising since 1750 due to the industrial revolution
rise in CO2 concentration leads to a rise in temperature followed by a rise in CO2 released from the oceans leading to further warming

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16
Q

methane CH4

A

greenhouse gas
produced by anaerobic decay of organic mater in landfill. incomplete combustion of fossil fuels absorbs more IR than CO2 but has a shorter retention time could be reduced by better waste recycling and using bio fuels
when burned produces CO2 and H2O

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17
Q

why is global warming a controversial issue

A

science cannot prove theories only disprove them
in complete knowledge of climate system data sets being used to make predictions has limitations
there is not precise way to measure CO2 produced

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18
Q

what are the ethical arguments surrounding climate change and global warming

A
  • well all have the right to choose whether or not we use fossil fuels to achieve good standard of living
  • we have a duty to allow others to improve their standard of living
  • we have a duty to preserve the environment for the next generation
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19
Q

what other factors affect climate change other than CO2

A
  • other greenhouse gases
  • aerosols - extremely small particles or liquid droplets
  • degree of reflection on earth surface covered by ice or snow.
  • the fraction of earth covered with ice and snow
  • extent of cloud cover
  • changes in the sun radiation
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20
Q

why are climate change predictions often incorrect

A
  • limited data
  • limited knowledge of how climate system works
  • limitations in computing resources
  • failure to include all factors affecting the climate
  • changing trends in factors included e.g faster than expected loss of snow or ice or greater CO2 emissions
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21
Q

why do climate models predict a cooler UK

A

as the Artic sheet ice reduces there is an influx in fresh water into north Atlantic which freezes at 0oc expands rising to the surface rather than sinking as salt water does at that temperature
the north Atlantic drift breaks down as a result stopping bringing warm waters to Britain causing surface temperature in north west Europe to fall by 5oc

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22
Q

why are trees particularly vulnerable to climate change

A

they are unable to grow, reproduce and disperse seeds quickly enough to cope with changing conditions.
their distribution changes more slowly than the climate changes

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23
Q

what changes in populations and ecosystems caused by climate change

A
  • changing distribution of species

- altered development and life cycles

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24
Q

increasing temperature means photosynthesis rate becomes

A

faster leading to faster growth
warmer conditions leads to increase in temperature crop yield
in cooler climates photosynthesis is temperature limited a rise in temperature will result in faster photosynthesis as enzyme catalysed reactions occur more quickly. Above a certain temp plants enzymes work more slowly.

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25
Q

temperature coefficient Q10

A

Q10 = rate of reaction at temperature T + 10oc / rate of reaction at temp T
the rate of collision and so the rate of reaction approximately doubles for each 10oc rise in temperature this is shown in the Q10 ratio
describes mathematically what happens to the rate of reactions as temperature increases by 10oc

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26
Q

what is the effect of low temperature on enzyme activity

A

at low temperature reaction is very slow because the enzyme and substrate molecules have low kinetic energy and so move more slowly and collide less often.
meaning there are fewer enzyme substrate complexes formed in a given time

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27
Q

what is the effect of high temperature on enzyme activity

A

as temperature increases rate increases.
as enzyme and substrate molecules have high kinetic energy and so move faster and collides more. therefore the substrate binds with the enzymes active site more frequently.

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28
Q

what is the Q10 for most enzyme controlled reactions

A

Q10 between 2 and 3
this is the factor by which the rate changes
a value of 2 means the rate of reaction doubles with a 10oc rise.
a value of 3 means it triples.

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29
Q

optimum temperature

A

the temperature at which rate of reaction is highest
if the temperature rises above this enzyme molecules vibrates and bonds break preventing substrate from fitting into active site slowing reaction eventually shape of active site is lost and enzyme is denatured.

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30
Q

phenology

A

the study of seasonal events timing of events is a useful biological indicator of global climate change

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31
Q

why may climate change reduce survival rates in hatching birds

A

if temperatures rise there may be a mismatching between hatching time and peak food available
the emergence of adults is synchronised with periods of max food availability

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32
Q

different evidence for evolution (4)

A
  • DNA hybridisation
  • DNA molecular clocks
  • DNA profiling
  • DNA and protein sequencing
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33
Q

DNA hybridisation

A

molecular evidence for evolution by separating strands of DNA of two species and then mixing 1 strand from each species so the strands will form H bonds with each other forming hybrid DNA. nor all bases will have complementary base pair and form H bond. so when heated will denature at lower temperature.
the more similar the sequences the higher the temperature to denature.

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34
Q

DNA molecular clocks

A

use of PCR and automated DNA sequencing machines to rapidly determine DNA base sequence as species evolve they accumulate random mutations at a regular rate becoming more genetically different. For a given gene, mutation rate is fairly constant molecular rate is fairly constant molecular change in DNA overtime used to make a molecular clock , which pinpoints important evolution event.
by comparing no. of differences between species possible to calculate how long ago their shared ancestor existed

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35
Q

DNA profiling

A

PCR and gel electrophoresis.
restriction enzymes cut DNA at specific sequences producing different sized fragment s which can be visualised as series of bands.
If a mutation has occurred the enzyme will not cut the DNA and size of fragment and position of band will change
differences in fragment lengths produced provide info about genetic differences.
the more closely related the more bands on the profile will match

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36
Q

DNA and protein sequencing

A

by comparing the sequence of bases in DNA or the amino acid sequence of different species it is possible to determine how closely related organisms are in evolutionary terms
if 2 species have very few differences they evolved from a common ancestor more recently than organism with more differences.

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37
Q

peer review

A

where reviewers examine paper critically checking work is valid. if it includes the proper controls, use of statistics appropriately and compare it to other research to see if conclusions are justified.
peer remain anonymous as this allows the freedom to be critical without causing offence, it prevents the author from influencing the reviewers.

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38
Q

conferences

A
  • allow scientists to review new findings and question those present
  • allows scientists to communicate with collages discus current ideas and spark new ideas and future projects
  • enable funding bodies to assess outcomes of the research they are paying for
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39
Q

Darwin’s observations and conclusions

A
  • there is a struggle for existence. competition
    organisms produce more offspring than can survive and reproduce. numbers in natural populations stay same overtime.
  • survival of the fittest. Natural selection
    there is a huge variation with species.
    those species best adapted to conditions are more likely to survive and breed.
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40
Q

Darwin’s theory

struggle for existence

A

the idea of competition for survival between members of the same species.
as a population increases in size environmental factors halt the increase.
many individuals die to prediation, competition for food and other resources or due to the rapid spread of disease resulting from overcrowding. population remains constant.

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41
Q

Darwin’s theory

survival of the fittest and natural selection

A

those individuals that are best adapted to conditions in their environment are more likely to survive and breed
they have a selective advantage
individuals with these adaptive features will be more common in the next generation. the organisms that are not well adapted die and do not produce offspring over a period of time the characteristics change to adapted form

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42
Q

evolution

A

the change in allele frequency in a population of organisms overtime

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43
Q

allele frequency

A

relative frequency of a particular allele in a population

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44
Q

speciation

A

the formation of new and distinct species in the course of evolution

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45
Q

how does allopatric speciation occur

A
  • geographical barrier causes 2 populations to become re-productively isolated.
  • the 2 groups are exposed to different selection pressures leading to random advantageous mutations accumulating causing allele frequency in the 2 populations to change
  • overtime the allele frequency changes so much that when reintroduced they are not able to interbreed to produce fertile offspring.
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46
Q

allopatric speciation

A

occurs where populations are geographically isolated from one another.
preventing the group from mating with each other and so the population becomes re-productively isolated.

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47
Q

sympatric speciation

A

this occurs where the 2 populations become reproductively isolated in the same environment without any geographical barriers, due to other isolating mechanisms

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48
Q

what are the isolating mechanisms that cause sympatric speciation (6)

A
  • ecological isolation
  • temporal isolation
  • behavioural isolation
  • physical incompatibility
  • hybrid in-availability
  • hybrid sterility
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49
Q

what is ecological isolation

A

sympatric speciation

the species occupy different parts of the habitat

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50
Q

what is temporal isolation

A

sympatric speciation

the species exist in the same area but reproduce at different times

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51
Q

what is behavioural isolation

A

sympatric speciation

the species exist in same area but do not respond to each other’s courtship behaviour

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52
Q

what is physical incompatibility

A

sympatric speciation

species co-exist but there are physical reasons that prevent them from copulating

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53
Q

what is hybrid in-availability

A

sympatric speciation

in some species, hybrids are produced but don’t survive long enough to reproduce

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54
Q

what is hybrid sterility

A

sympatic speciation

hybrids survive to reproductive age, but cannot reproduce

55
Q

carbon cycle

A

the combined processes by which carbon as a component of various compounds cycles between its major reservoirs: the atmosphere, oceans and living organisms

56
Q

what is the process by dead organic matter is turned into carbonate rocks

A

sedimentation

57
Q

what is the process by which dead organic matter is turn into fossil fuels

A

fossilisation

58
Q

what is photosynthesis

A

the reduction of CO2 to organic substances using energy from sunlight, which is carried out in the chloroplasts of plants and some microbes
some of these sugars are used directly produce energy in respiration others used in growth.
oxygen is a waste product

59
Q

what is Biomass

A

the total amount of living material per unit of area

includes animal, microbial but mainly plant material.

60
Q

decay

A

plants and animals die and animal faeces are broken down. CO2 released during the breakdown by microbes in respiration

61
Q

combustion

A

oxidation of organic molecules outside living cells with the formation of CO2 and water

62
Q

respiration

A

the oxidation of organic substances such as sugars into simpler inorganic compounds CO2 and H2O with the release of biological available energy carried out by all living organisms

63
Q

what is causing the carbon cycle to become unbalanced leading to an increase in CO2 in the atmosphere

A
  • combustion of fossil fuels
  • deforestation
    other factors:
  • volcanic action
  • CO2 being lost to sediment
  • acid rain
  • rising global temperature.
64
Q

deforestation

A

a mature forest is a very stable ecosystem and there is no net absorption of CO2 as absorption = respiration.
when cut down, photosynthesis drops, in the long term respiration also falls but in the short term more CO2 would be released than absorbed.
large amounts of the trees are not used and left to decay releasing more CO2

65
Q

combustion of fossil fuels

A

coal is a product of photosynthesis produced when wood fell into anaerobic conditions not decaying and becomes a carbon sink. which accumulation involves the net removal of CO2 from the air over millions of years
when we extract and burn fossil fuels, the carbon released as CO2 has been cut of from circulation for millions of years
burning more fossil fuels than it is forming
significant addition to the CO2 already in the environment

66
Q

volcanic action

A

volcanoes may release CO2 - an increase in volcanic activity in the future could make a bigger difference to carbon dioxide levels in the air

67
Q

sediment formation

A

carbon dioxide is being lost to sediments in the oceans by various processes, such as the incorporation of carbon into the calcium carbonate skeletons and shells of marine organisms, but this is balanced by various erosion processes.

68
Q

acid rain

A

an increase in acid rain might increase the rate at which carbon dioxide is released by erosion of lime stone, but this is not thought to be a major factor at present

69
Q

rising global temperatures causing increase in CO2 in atmosphere

A

rising temperatures effect co2 balance.
microbial decomposition of peat in soil increases CO2 an increase in temperature prolongs the summer that of arctic tundra may increase decomposition of peat increasing co2 released into the atmosphere.
warmer water holds less co2

70
Q

what are some theories for the disappearing CO2

A

estimated burning fossil fuel produces 5.4x1012 Kg of carbon
estimated deforestation adds 1.6x1012 Kg of carbon
but the actual increase is 3.0x1012 Kg per year
more co2 means more photosyntheis
when co2 levels are raised more carbon is stored in other components of the carbon cycle.
e.g within soil as dissolved organic components
dissolving in the ocean by increased photosynthesis by massive blooms of algae.

71
Q

bio fuels

A

any source of energy produced directly in plants or indirectly in animals, by recent photosynthesis
this provides a renewable energy source and is carbon neutral
the release of CO2 by combustion = the absorption of CO2 by photosynthesis
however you must take into account the CO2 released from other sources e.g CO2 released in the process of transporting the bio fuel.

72
Q

what are some common examples of bio fuels

A

wood, straw, dried chicken litter, vegetable oil and methane, ethanol
ethanol is produced by the fermentation of any kind of cheap and locally available sugar. refining of sugar cane, sugar beet.
methane produced from the anaerobic fermentation of human sewage can be used to generate enough electricity to make sewage plants self sufficient

73
Q

what are some disadvantages of bio fuel production

A
  • destruction of rain forests to plant palm oil trees for bio fuel production is realising vasts amounts of stored carbon cancelling out any gains made by burning bio fuels and also harming wildlife.
  • the use of large quantities of edible corn to make cor oil and ethanol for bio fuel affects food availability
74
Q

reforestation

A

newly panted forests are growing rapidly and turning co2 into wood. very little wold wood and relatively little decay so respiration will be less than photosynthesis.
this means the system is a net absorber of CO2
as the plantation gets older, the system will move towards a balance between photosynthesis and respiration and will no longer be a net absorber. it becomes a carbon store with carbon locked up in biomass
higher temperatures stimulate photosynthesis leading to extra growth.
limit to how much or for how long they can soak up extra

75
Q

autotrophs

A

an organism that can produce complex organic compounds from simple substances in the surroundings (CO2) generally using energy from light (photosynthesis) or inorganic chemical reactions (chemosythesis)

76
Q

heterotrophs

A

obtain energy as organic matter by ingesting material from other organisms

77
Q

primary consumers

A

heterotrophs
also called herbivores
eat plant material

78
Q

secondary consumers

A

heterotrophs
also called carnivores
feed on primary consumers

79
Q

tertiary consumers

A

heterotrophs
also carnivores
eat other consumers. the carnivores at the top of the food chain are some times called top carnivores.

80
Q

food chain

A

shows the feeding relationship in an environment

81
Q

trophic level

A

the position of a species occupies in a food chain

82
Q

food web

A

in reality an ecosystem is more complex where each organisms is eaten or eats several other organisms and this is represented in a food web.

83
Q

law of limiting factor

A

states that when a process is affected by more than one factor, its rate is limited by the factors further from its optimum value.

84
Q

what are the limiting factors of photosynthesis

A

can be limited by temperature and light

but the main factor is CO2 concentration

85
Q

gross primary productivity (GPP)

A

the rate at which energy is incorporated into organic molecules by an ecosystem

86
Q

net primary productivity (NPP)

A

the rate at which energy is transferred into organic molecules that make up the new plant biomass

87
Q

equation for working out Net primary productivity (NPP)

A

NPP = GPP - R
NPP - net primary productivity
GPP - gross primary productivity
R - respiration

88
Q

equation for working out the efficiency of photosynthesis

A

% efficiency = GPP / energy from light x 100

89
Q

detritivores

A

are primary consumers that feed on dead materials called detritus

90
Q

decomposers

A

species of bacteria and fungi that feed on the dead remains of organisms and animal faeces. they are heterotrophs.
they secrete enzymes to digest their food externally before absorption takes place. recycling of organic matter

91
Q

how efficient is the transfer of energy through an ecosystem

A

productivity of an ecosystem will depend on how much energy is captured by the producers and how much is transferred to the higher trophic levels
only 40% of the energy reaching the leaf is absorbed by the chlorophyll. much of this energy is used to make organic molecules, but some is lost during photosynthesis and transferred to the environment
chlorophyll call only absorb certain wavelengths.

92
Q

was is the transfer of energy between trophic levels not very efficient (3 reasons)

A

only 2-10% of the energy in the producers goes into herbivore biomass

  1. not all the available food gets eaten
  2. some undigested food remains in faeces
  3. much of the food absorbed by the consumers is used in respiration
93
Q

energy transfer producers - primary consumers

what does not all the food available gets eaten

A
  • due to limitations in the animals feeding methods

- some parts of the plant will not be eaten by herbivores so the energy will not be transferred

94
Q

energy transfer producers - primary consumers

why does some food remain undigested

A

main component of plant material is cellulose in the cell walls which is tough and mammals have no enzymes to digest it so much of the cellulose passes through the gut intact, so the energy it contains is not transferred

95
Q

energy transfer producers - primary consumers

what is much of the food absorbed used in

A

respiration
the energy released from respiration used in movement and chemical reactions and some is lost to the environment
energy transferred to the surroundings in respiration and to decomposes explains why food chains and webs rarely have more than 5 trophic levels as there comes a point where there is insufficient energy remaining to support another trophic level

96
Q

how efficient is energy transfer primary to secondary consumers

A

the transfer of energy is more efficient as over 10% of the energy in herbivores end up as new biomass
this is because most of it can be eaten and easily digested so less herbivore` biomass lost in faeces.

97
Q

which reaction comes first in photosynthesis

A

light dependent reactions

then light independent reactions

98
Q

where does light dependent reaction occur

A

in the thylakoid membrane of the chloroplast

photolysis occurs in the thylakoid space

99
Q

what happens in the light dependent reaction (6 steps)

A
  1. light absorbed by chlorophyll in the thylakoid membrane
  2. energy from light raises 2 electrons in each chlorophyll molecule to a higher energy level. the chlorophyll are now excited
  3. the electrons leave the excited chlorophyll molecules and pass along a series of electron carrier molecules all of which embedded in thylakoid membrane make up electron transport chain
  4. electron pass from one carrier to the next in a series of oxidation, reduction reactions losing energy in the process. this energy is used in the synthesis of ATP in process called photophosphorlylation
  5. within thylakoid space an enzyme catalyses photolysis to give oxygen, hydrogen ions and electrons. these electrons replace those that were emitted from the chlorophyll molecule so it is no longer + ve charged and electron transport chain can continue
  6. the hydrogen concentration in thylakoid space is raised. the electrons which have passed along the electron chain combine with co-enzyme NADP and H+ from water to form reduced NADPH
100
Q

what is photolysis

A

the process in the light dependent reaction
where enzymes catalysis the reaction to break apart water to give oxygen, hydrogen ions and electrons
this oxygen is the waste product of photosynthesis
it occurs in the thylakoid space

101
Q

what are the features of a chloroplast (8)

A
  • smooth outer membrane
  • smooth inner membrane
  • starch grains
  • DNA loop
  • stroma
  • granum
  • thylakoid membrane
  • thylakoid space
102
Q

chloroplasts

what is the smooth outer membrane

A

this membrane is freely permeable to molecules such as CO2 and H20

103
Q

chloroplasts

what is the smooth inner membrane

A

contains many transporter molecules.
these are membrane proteins which regulate the passage of substances in and out of the chloroplasts.
these substances include sugars and proteins synthesised in the cytoplasm of the cell but used within the chloroplasts.

104
Q

chloroplasts

starch grains

A

stores the product of photosynthesis

105
Q

chloroplast

DNA loop

A

chloroplasts contain genes for some of their own protein

106
Q

chloroplasts

stroma

A

the fluid surrounding the thylakoid membranes.

contains all the enzymes needed to carry out the light independent reactions of photosynthesis

107
Q

chloroplasts

granum

A

a stack of thylakoids joined to one another.

grana (plural) resemble stacks of coins

108
Q

chloroplasts

thylakoid membrane

A

a system of interconnected flattened, fluid filled sacs, where the light dependent reactions take place.

109
Q

chloroplasts

thylakoid space

A

fluid within the thylakoid membrane sacs contain enzymes for photolysis

110
Q

what happens in the light dependent reactions (5 steps)

A

the calvin cycle

  1. carbon dioxide combines with 5 carbon sugar called ribulose bisphosphate RuBP. This is catalysed by enzyme ribulose biphosphate carboxylase RuBISCO
  2. the 6 carbon intermediate formed is unstable and immediately breaks down into 2 3-carbon molecules. GP
  3. GP is reduced to form a 3 carbon sugar phosphate called GALP. The hydrogen for reduction comes from the reduced NADP from the light dependent reactions. ATP from the light dependent reactions provides the energy required
  4. 2 out of every 12 GALPs formed combine to create 6 carbon sugar hexose (glucose) which can be converted to other organic compounds e.g amino acids or lipids.
  5. 10 out of every 12 GALPs are involved in the recreation of RuBP. the 10 GALP molecules rearrange to form 6 5-carbon compounds then phosphorylation using ATP forms RuBP
111
Q

where does the light independent reaction occur

A

in the stroma

112
Q

what is ATP stand for

what is it made up of

A

adenosine triphosphate

  • 3 phosphate groups
  • ribose sugar
  • adenine
113
Q

what is the equation for the hydrolysis of ATP

A

ATP (aq) —-> ADP + hydrated Pi + energy

remove 1 phosphate group

114
Q

what is phosphorylation

A

the addition of an inorganic phosphate Pi in phosphorylation. the phosphate must be separated from water which requires energy
ADP + hydrated Pi + energy –> ATP (aq)

115
Q

what happens overall in the light independent reaction

A

use the reduced NADP and ATP from the light dependent reactions to reduce carbon dioxide to carbohydrates.

116
Q

what is the overall equation for photosynthesis

A

6CO2 + 6H2O ———————> C6H12O6 + 6O2

light energy and chlorophyll

117
Q

biosphere

A

the part of the earth and its atmosphere that is inhabited by living organisms

118
Q

ecosystems

A

a relatively self contained, interacting community of organisms and the environment in which they live and interact

119
Q

habitat

A

the place with a distinct set of conditions where an organism lives

120
Q

population

A

a group of individuals of the same species found in an area

121
Q

community

A

various populations sharing a habitat or an ecosystem

122
Q

niche

A

a role of a species in an ecosystem

123
Q

abiotic factors

A

non living or physical factors that affect species distribution

124
Q

what are some abiotic factors of an habitat (7)

A
  • solar energy input: affected by latitude, season, cloud cover and changes in earth’s orbit. light is vital for photosynthesis but also plays a role in in initiating flowering, seed germination. in animals it might affect behaviour
  • climate: includes rainfall, wind exposure, temperature
  • topography: includes altitude, slop, aspect and drainage
  • oxygen availability: of particular importance in aquatic systems
  • edaphic factors: connected with soil, pH mineral salt availability. geology. soil texture etc.
  • pollution
  • catastrophes
125
Q

what are biotic factors

A

living factors that affect species competition

126
Q

what are some biotic factors (4)

A
  • competition: for resources like food, light, water, space
    inter-specific: between species intra-specific: within species
  • grazing, predation and parasitism: relationships between organisms were one benefits at the others expense
  • mutualism: a relationship in which both partners benefit
  • density development: the effect of biotic factors are related to size of population relative to the area available.
127
Q

what are the key questions to be asked in climate change

A
  1. are CO2 levels rising?
  2. is there global warming
  3. does one cause the other?
  4. how bad will it get?
  5. can humans do anything to combat it?
128
Q

what is the hardy weinberg equation

A

can be used to detect change in allele frequency in a population
it shows the relationship between the allele frequencies in a situation where the gene has only 2 alleles.
p2 + 2pq + q2 = 1
where
p = frequency of dominant allele
q= frequency of recessive allele. p+q=1
frequencies should be expressed first as decimal fractions
the equation predicts that, for any particular values of p and q an unchanging ratio pf phenotype arises; this is the H-W equilibrium.

129
Q

when can the hardy weinberg equilibrium apply

A
  • mating must be random
  • the population must be large
  • there should be no movement of organisms into or out of the population (migration)
  • there must be no mutations
  • there should be no selection pressure, that is, nothing that favours one allele over another.
    if any of these conditions do not apply, the population will not be in eqm and allele frequencies will change
130
Q

science, politics and economics

A
  • the debate become political and then the impassionate methodology of science becomes sidelined
  • data may be interpreted with various hidden agendas and this becomes the news rather than the science
  • scientists can be accused of being influenced by companies that provide funding.
131
Q

what is the fate of sugars made in photosynthesis (6)

A
  1. used in respiration to produce carbon dioxide, water and energy
  2. nucleic acids (DNA and RNA)
    plus phosphates and nitrates from soil
  3. polysaccharides
    starch (storage) cellulose (wall)
  4. lipids (waterproofing and storage)
  5. amino acids ( to make proteins)
    plus nitrates and sulphur from soil
  6. proteins (enzymes, and in membranes.
132
Q

what is the link between the light dependent and light independent reactions

A

ATP and NADPH
the light dependent reaction makes ATP and reduced NADP. these are used in the light dependent reactions (calvin cycle)
- reduced NADP provides reducing power (electrons in hydrogen)
- ATP provides the energy for the process of making carbon dioxide into carbohydrate.

133
Q

what is the light dependent reactions sometimes described as

A

the z-scheme

Biology (13 decks)

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