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A Level Biology : Content > Topic 5B : Climate Change & Evolution > Flashcards

Topic 5B : Climate Change & Evolution Flashcards

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1
Q

climate change

A

a large scale shift in the planet’s weather patterns or average temperatures over a period of time

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2
Q

global warming

A

the increase in average/mean temperature of the earth’s surface

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3
Q

greenhouse effect

A

natural situation in which heat is retained in the earth’s atmosphere by greenhouse gasses through absorbing and re-radiating infrared radiation

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4
Q

greenhouse gases

A

gasses such as carbon dioxide and methane in the troposphere that cause the greenhouse effect

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5
Q

dendrochronology

A

the study of growth rings in trees for the purpose of analysing pst climate conditions or determining the dates of past events

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6
Q

explain how temperature records can be used as evidence for climate change

A

since 1850s the temperature around the world has been measured using thermometers and temperature records have been created showing fluctuations in temperature leading to climate change

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7
Q

explain how dendrochronology can be used as evidence for climate change

A

trees produce one ring within their trunks each year and the thickness of the ring depends on the climate when it was formed.

warmer climate means rings are ticker as conditions for growth are better.

scientists can take cores through tree trunks then date each ring by counting them back from when the core was taken.

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8
Q

what are the four evidences for climate change

A

pollen in peat bogs

dendrochronology

temperature records

records showing increase of carbon dioxide levels

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9
Q

explain how pollen in peat bogs can be used as evidence for climate change

A

peat bogs accumulate in layers so the age of the preserved pollen increases with depth.

scientists take cores from peat bogs and extract pollen grains from different aged layer and then identify plant species the pollen came from.

sample only shows species successful at that time as only fully grown plants produce pollen.

scientists know the climates that different plants species live in now and when they find preserved pollen from similar plants it indicates the climate was similar.

a gradual increase in pollen from a plant species thats more successful in warmer climates shows rise in temperature.

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10
Q

anthropogenic climate change

A

changes in climate caused by human activity

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11
Q

how has human activity caused global warminf

A

by enhancing the greenhouse effect so that less is lost to space

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12
Q

state two human activities that increase the atmospheric carbon dioxide concentration

A

destruction of natural sinks (things that keep carbon dioxide out of the atmosphere by storing carbon), trees store carbon as organic compounds.

when trees are burnt, carbon is released or when decomposers break down organic compounds and respire them.

burning fossil fuels like coal, oil, natural gas and petrol release carbon dioxide

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13
Q

state two human activities that increase the atmospheric methane concentration

A

more fossil fuels are being extracted so there is more decaying waste and there are more cattle which give off methane as a waste gas

farming

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14
Q

give 5 limitations of models for climate change

A

we don’t know how greenhouse gases will change

we don’t know exactly how much each emissions scenario will cause global temperature to rise by

the change in atmospheric greenhouse gas concentrations due to natural causes isn’t known

we don’t know what attempts there will be to manage atmospheric concentration of greenhouse gases or how successful they will be

we don’t know what effect increasing greenhouse gas concentrations will actually have on climate due to complex feedback systems involved

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15
Q

extrapolation

A

use available data on which to base estimations of value which fall outside the known range

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16
Q

causal link

A

one factor directly affects a change in another

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17
Q

correlation

A

mutual relationship between two or more things

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18
Q

how does an increase of temperature affects the rate of enzyme activity

A

enzyme controlled reactions increase because more heat means more kinetic energy causing molecules to move faster.

enzymes are more likely to collide with substrate molecules

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19
Q

how can models of future climate change be generated

A

extrapolate data

models assume the pattern continues and do not consider factors that might change eg reduction in greenhouse gas emissions

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20
Q

state two effects of climate change

A

Changing rainfall patterns

seasonal cycles

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21
Q

what impacts do increased atmospheric warming have on climate change

A

weather events becoming more extreme

changes to ocean currents

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22
Q

how does global warming affect distribution of species

A

warming climates cause animals to move towards the poled or to higher altitudes where they would have to compete with species that were already there leading to one of them outcompeting the other and becoming extinct causing decreased biofiversity

23
Q

what does the temperature coefficient (Q10) tell you about a reaction

A

how much the rate of a reaction changes when te temperature is raised by 10 degrees

24
Q

carbon cycle

A

the movement of carbon between organisms and the atmosphere

25
Q

explain the carbon cycle

A

carbon absorbed by plants during photosynthesis

carbon passed on to animals when they eat plants and to decomposers when they eat dead organic matter

carbon returned to atmosphere as all living organisms carry out respiration which produces carbon dioxide

if deaf organic matter ends up in places where there aren’t any decomposers the carbon compounds can be turned into fossil fuels

carbon in fossil fuels released as carbon dioxide when burnt (combustion)

26
Q

how does biofuels stop the increase in atmospheric carbon dioxide concentration caused by burning fossil fuels

A

biofuels are produced from biomass and are often made from crops which can be replanted after harvesting

biofuels are burnt to release energy producing carbon dioxide

amount of carbon dioxide produced is the same as the amount of carbon dioxide taken in when material is growing

27
Q

how does reforestation reduce carbon dioxide in the atmosphere

A

more trees means more carbon dioxide absorbed by photosynthesis

carbon dioxide is converted into carbon compounds and stored as plant tissues in the trees

28
Q

reforestation

A

planning of new trees in existing forests that have been depleted

29
Q

who and why would support the increase of biofuels usage

A

farmers as some governments fund the farming of crops for biofuels

drivers as the price of fuels is usually lower than oil based fuels

30
Q

who and why would oppose the increase of biofuels usage

A

consumers as using farmland to grow crops for biofuels could cause food shortages

conservationists as forests have been cleared to grow crops for biofuels

31
Q

who and why would support the increase of wind turbines usage

A

companies that make wind turbines as their sales would increase

environmentalists as wind turbines produce electricity without increasing carbon dioxide concentration in the atmosphere

32
Q

who and why would oppose the increase of wind turbines usage

A

local communities as people think that wind turbines ruin landscape

bird conservationists as many birds are killed by flying into wind turbines

33
Q

evolution

A

when the frequency of an allele in population changes over time

34
Q

explain the stages of natural selection

A

individuals within population vary because they have different alleles which are caused by gene mutation

selection pressure occurs meaning that some individuals are better adapted to the environment than others

individuals that have advantageous alleles are more likely to survive and reproduce and out compete the others

this means greater proportion of the next generation inherit the advantageous allele so the frequency of the allele increase from generation to generation

35
Q

how does isolation lead to speciation

A

populations of the same species become reproductively isolated reducing the gene flow between two populations which means that natural selection acts on each population separately and new species are developed

36
Q

what causes reproductive isolation

A

allopatric speciation

sympatric speciation

37
Q

allopatric speciation

A

formation of two species from an original one due to geographical isolation

38
Q

sympatric speciation

A

formation of two species from one original species due to reproductive isolation whilst occupying the same geographical isolation

39
Q

explain how geographical isolation leads to species becoming reproductively isolated

A

populations will experience different conditions and different selection pressures leading to mutations happening independently in each population and so different allele frequencies.

changes in allele frequency leads to differences accumulating in the gene pools of the separated populations causing changes phenotype frequencies.

eventually, different populations become genetically distinct so they wouldn’t be able to breed with one another to produce fertile offspring

40
Q

what are the different changes that prevent successful breeding between species

A

seasonal changes

mechanical changes

behavioural changes

41
Q

mechanical changes

A

changes in genitalia

42
Q

seasonal changes

A

individuals from same population develop different flowering or mating seasons or become sexually active at different times of the year

43
Q

behavioural changes

A

group of individuals develop courtship rituals that aren’t attractive to main population

44
Q

genomics

A

branch of science that used DNA technology to determine the base sequence of an organism’s genome and the function of its genes

45
Q

speciation

A

the evolution of two different species from an existing one

when a population is split and reproductively isolated, there are different selective pressures in the two groups

46
Q

genomics as evidence for evolution

A

organisms have evolved from shared common ancestors

closely related species diverged more recently

organisms that diverged away from each other more recently should have more similar DNA as less times has passed for changes in the DNA sequence to occur

47
Q

proteomics

A

study of proteins eg shape,size and amino acid sequence of proteins

48
Q

proteomics as evidence for evolution

A

related organisms have similar DNA sequences and so similar amino acid sequences in their proteins so organisms that diverged away from each other more recently should have more similar proteins as less time has passed for changes to occurs

49
Q

scientific community

A

all the scientists around the world

50
Q

what are the three main ways scientists share and discuss their work

A

scientific journals

peer review

conferences

51
Q

scientific journals

A

academic magazines where scientists can publish articles describing their work

used to share nee ideas, theories, experiments, evidence and conclusions

52
Q

peer review

A

happens before scientists can publish their work and other scientists who work in the area check if the work is valid and supports the conclusions ensuring that each piece of work has the highest possible standards

53
Q

conferences

A

meetings that scientists attend so they can discuss each other’s work.

scientists with important or interesting results might be invited to present their work in the form of a lecture or poster presentation.

other scientists can then ask questions and discuss their work with them face to face.

conferences are valuable because they’re an easy way for the latest theories and evidence to be shared and discussed.

54
Q

describe and explain how global warming could affect plant species

A

changes in rainfall patterns or growing seasons could lead to plants becoming extinct or changes in their distribution

temperature may become too hot for some species so enzyme activity would be reduced causing them them to become extinct

increased carbon dioxide means more photosynthesis

A Level Biology : Content (18 decks)

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