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A Level Biology > Topic 5 > Flashcards

Topic 5 Flashcards

1
Q

What is a biosphere

A

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

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2
Q

What are biotic factors and give example

A

Living factors

Competition,predation ,mutualism

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3
Q

What are abiotic factors and give examples

A

Non living factors

Climate
Pollution
Topography
Solar energy input

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4
Q

What is a habitat

A

A distinct set of conditions where an organisms lives and several populations of organisms live there

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5
Q

What is meant by ecosystem

A

An area with a distinct set of features that affects where an organism lives

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6
Q

What is a population

A

A group of interbreeding individuals from the same species

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7
Q

What is a community

A

Various populations sharing a habitat or ecosystems

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8
Q

What is a niche

A

The role of an organism in its environment

Ie if It’s a predator or prey

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9
Q

What does topography mean

A

It includes things like altitude,drainage

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10
Q

What are edaphic factors

A

They are connected with soil,mineral concentration

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11
Q

What is abundance

A

In a certain area it’s the number of individuals of a single species

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12
Q

What is Distribution

A

This is the location of a particular species in your area of investigation

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13
Q

Why is it important that sampling is random

A

In order to avoid biases

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14
Q

When is non random sampling used

A

When there is a high variation in abiotic features or distribution in a habitat

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15
Q

What is systematic sampling

A

When samples are taken along a line at fixed intervals

I.e. Quadrats are placed along a transect

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16
Q

How are frame quadrats used in an investigation

A

An area could be selected and using a randon number generator co ordinates can be selected and this is where the quadrat is placed

Plant species is percentage cover is measured by how much the quadrat covers it

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17
Q

How are point quadrats used

A

They are placed on the group with the pins going through holes

And every plant that touches the pin is recorded

Percentage cover is measure by calculating the amount of pins that touch a given species

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18
Q

How are interrupted transects used

A

Measurements are taken at intervals i.e. Placing the quadrat down at every 5 m

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19
Q

How are lone transects used

A

along a transect a tape measure is placed and the species that touch the tape measure are recorded

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20
Q

What is succession

A

When a community started by organisms changes over time

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21
Q

What are the two types of successions

A

Primary and secondary succession

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22
Q

Distinguish between primary and secondary succession

A

Primary succession occurs in newly formed habitats where there hasn’t been a community

Secondary succession occurs on bare soil where a existing community had been previously

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23
Q

In primary succession what are the pioneer species and why are they crucial

A

They are species like algae and lichens and are the first organisms to colonise bare rock

They are the only species that are capable of coping with the extreme temperature lack of soil,water,nutrients

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24
Q

What 2 things occur in the pioneer phase of succession

A

The pioneer species begin to break up the rock surface which enables some organic material to build up in the spaces marking the beginnings of soil

They change the conditions in the habitat which enables it to be suitable for other species

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25
Q

As succession continues what does the development or Moss spores cause (Stage 2)

A

It allows the build up of more organic matter called hummus in the soil meaning water can be held up meaning seeds begin to germinate and survive

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26
Q

As succession continues in primary succession what do improving conditions in the habitat enable
(Stage 2)

A

It allows for large taller plant species to colonise and they compete with plant species

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27
Q

What happens when larger plant species compete with existing in plant species in primary succession (stage2)

A

They end up winning and replace the existing community

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28
Q

In primary succession what eventually occurs in the community as succession continues (last stage)

A

The community is dominated by trees and it results in a stable climax community

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29
Q

What is the dominant species of the community in primary succession

A

The species that exerts an overriding influence over the rest of the plant,mircrobe and animal species

And it has the highest abundance

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30
Q

What is meant by co- dominance

A

When several species share the role as the dominant one

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31
Q

What is a climax community

A

It means the ecosystem is supporting the largest and most complex community of plants and animals and is stable

It’s the final stage of succession

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32
Q

What is secondary succession and where does it occur

A

It’s when a community begins to develop on bare soil that has been occupied by a previous community

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33
Q

For pioneer species give some adaptations of seed dispersal (start of secondary succession)

A

Wind dispersal

Rapid growth

Animals

Abundant seed population

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34
Q

What is deflected succession

A

When a community is only remaining stable due to human activity preventing succession from running its course

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35
Q

Give some comparisons between primary and secondary succession

A

Primary- takes a longer time to complete

Secondary- takes less time to complete

Primary- it occurs in an area that’s lifeless or barren

Secondary-takes place on an area that was previously inhabited

Primary-soil is absent at the beginning of primary succession and environment isn’t suitable for life

Secondary -soil is present at the beginning of secondary succession and some of previous occupants remain

Primary -No hummus in the beginning as soil is absent

Secondary-hummus is present from the beginning by decomposition of previous occupants

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36
Q

What is primary productivity

A

The rate energy is incorporated into organic molecules in ecosystem

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37
Q

What are autotrophs

A

Organisms that can make their own organic compounds from inorganic compounds they are producers

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38
Q

What is meant by some primary producers being photosynthetic

A

Means they gain energy from sunlight

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39
Q

What is meant by chemosythetic autrophs

A

They make organic molecules from energy that’s is released from chemical reactions

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40
Q

What are hetrophs

A

These are organisms that can’t synthesis food for themselfves so rely on other organisms to gain food

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41
Q

What is meant by photolysis

A

This is the splitting of water into hydrogen and oxygen from energy from sunlight

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42
Q

What are the uses of glucose in a plant

A

Can be converts into starch

Used to make cellulose

Fats

Amino acids

43
Q

What are the two main stages in photosynthesis

A

Light dependant reactions

Light independent reactions

44
Q

What is reduction and what is oxidation

A

Reduction is gaining of electrons

Oxidation loss of electrons

45
Q

What is the site of photosynthesis in a plant and where is it located

A

Cholorplast and it’s located in the palisade mesophyll

46
Q

Name the parts of the chloroplast and their functions

A

Thylakoids membrane-system of fluid filled sacs which has proteins and electron carriers in the memebranes that are involved in LDR

Starch gran-stores the products of photosynthesis

Granum-stacks of thylakoids joined together

Stroma-a fluid that surrounds the thylakoids and contains enzymes needed to carry out light independent reactions

Inner membrane-contains transports molecules that regulate passage of substances in and out of chloroplast

DNA loop- contains genes for proteins of chloroplast

Outer membrane is permeable for molecules I

47
Q

What are the two types of chlorophyll called

A

PS1 PSII

48
Q

Describe stages in LDR when light is first absorbed by PS1 and PS 11 chlorophyll

A

1 cholorphyll molecules are in an exited state as light energy raises two electrons in each cholophyll molecule to a higher level

  1. After leaving the excited state electrons go along a series of electron carrier molecules this forms an electron transport chain which is embedded in thylakoid membrane
  2. .psII chlorophyll, its electrons as they pass from carrier to carrier, lose energy in a series of oxidation and reductions,
  3. PS1 cholophyll loses its electrons and they are replaced by electrons from PSII chlorophyll
49
Q

What is the energy that the electrons lose in PSII chlorophyll used for

A

It’s used in photophosphotylation which is the synthesis of ATP

50
Q

Describe the remaining stages in LDR from photolysis

A

5.The electrons from the PSII have to be replaced for electron flow to continue

6 in the thylakoids space photolysis occurs which produces electrons,oxygen gas and hydrogen ions and they replace the electrons lost from PSII chlorophyll meaning its not got a charge

7 reduced Nadp forms from electrons from the PS1 chlorophyll combing with Co enzyme NAdp and hydrogen ions from water

51
Q

What are the Reduced Nadp and ATP used for

A

They are used in the light independent reactions

52
Q

What is ATP

A

It’s an energy transferring molecule and it has a adenine base,5-base ribose and 3 phosphate groups

53
Q

Describe how ATP releases energy

A

ADP first forms in which the third phosphate is removed and becomes hydrated with water molecules forming bonds

The formation of theses bonds between water and phosphate causes a lot of energy to be released which drives reactions

54
Q

What enzyme catalysed the breakdown of ATP into ADP

A

Atpase

55
Q

What is phosphorylation

A

The synthesis of ATP by adding an inorganic phosphate to ADP

56
Q

Where does the L I R take place and what does it use

A

It takes place in the storma and it used reduced Nadp and ATP

57
Q

What is the Calvin cycle and what molecule is made

A

It fixes carbon in organic molecules and GAlp is made

58
Q

Where does the light independent reaction take place and what is used in the reaction

A

It takes placed in the stroma of chloroplasts ATP and reduced Nadp are used

59
Q

What is the GAlp used for

A

To make glucose

60
Q

Describe each stage of the Calvin cycle

A

The 6CO2 combines with RUBp and the reaction is catalysed with the enzyme Rubisco

  1. the 6- carbon compound that is formed breaks down to form 2-3 Carbon molecules called Glycerate3-phosphate
  2. this 3-carbon compound is reduced to form Galp

The reduced Nadp from the light dependant reaction provides the hydrogen for the reduction of GP into GAlp

While ATP provides the energy for this reaction

  1. 2 out of every 12 Galps formed are involved in the making of hexose this is converted to other organic compounds
  2. 10/12 Galps are used in the recreation of RUBp and ATP is used in the phosphorylation forming RUBP
61
Q

What can the glucose be used for

A

Used in making starch and cellulose

Can be used In Respiration

Can be used to make amino acids

Used to make sucrose

62
Q

What are autotrophs

A

They are produced and can make their own food via photosynthesis

64
Q

What are heterotrophs

A

They are organisms that obtain energy(organic matter) by ingesting material from organisms

65
Q

What are primary consumers

A

These are herbivores that consume plant material

66
Q

What are secondary consumers

A

These are carnivores they feed on primary carnivores

67
Q

What are tertiary consumers

A

They are top of the food chain and feed on other consumers

68
Q

What are decomposes

A

They feed on dead remains of organisms and animals faces

69
Q

What are detritvores

A

They feed on dead organic matter called detritus and they primary civsynwrs

70
Q

Give reasons as to why not all energy is passed into trophic level

A

Some food pass as waste so energy is lost

Some energy is lost by respiration which energy is used for movement or body heat

Not all light energy is used by plant lost photosynthesis or reflected

71
Q

What is GPP

A

The rate at which energy is by an ecosystem absorbed into organic molecules

72
Q

What is net primary productivity

A

The amount of energy available to the next trophic level

73
Q

How is NPP calculated

A

Gross productivity-respiratory loss

74
Q

What pieces of evidence is their for climate change

A

Dendrochronology

Temperature records

Pollen in peat bogs

Rain fall patterns

75
Q

What is dendrochronology

A

The study of tree rings

76
Q

What is peat

A

It’s formed when organic matter decays,it’s remains of dead plants in which pollen grand are well preserved

77
Q

What is trophic level

A

The position of a species in a food chain

78
Q

Give reasons as to why pollen from peat is useful when studying climate change

A

Peat is resistant to decay due to our layer

We get a large sample as it’s produced in vast amounts by plants

Peat forms in layers so the deeper it is the older the peat we can find it’s she

Plant species have a certain type of pollen so we can identify the plant species from the peat

79
Q

What is the green house effect

A

When gases in the earths atomsphere absorb energy that reflected from the surface of the earth hence warming it up

80
Q

Give examples of greenhouse gases

A 
Oxygen
Water 
Co2
Methane 
Nitrous oxide
81
Q

Why is climate change such a controversial issue

A

Scientific methods can’t prove theories only disprove them

Not many people believe in climate change

Scientific evidence is sometimes biased

Data sets used in making predictions are limited

82
Q

What is extrapolation

A

Is the extending of a line in order to make assumptions

83
Q

What does extrapolation allow us to assume

A

That present trends shown will continue

We have enough data to establish a trend accurately

84
Q

What factors affect climate change

A

Green house gases
Changes in suns radiation
The fraction of earth covered with ice and snow

85
Q

What problems are their with climate models

A

Limited data
Limited knowledge
Failure to take into account all climate change factors

Limiting in computing resources

Changing trends in factors

86
Q

What are the two categories for changes that can be attributed to climate change

A

Changing distribution of species

Altered development and life cycle

87
Q

How can change in distribution of species be caused by climate change

A

Some species may become more dominant as they can cope better with the new conditions and some may lose out

Crop yield may reduce Due to spread of pests and disease

88
Q

What other factors change as a result of global warming

A

Changing rainfall patterns seasonal cycles

Life cycle

89
Q

Describe how ATP works to produce energy

A

A phosphate is removed from the ATP forming ADP and the phosphate is hydrated in water it forms bond and this releases a lot of energy to drive reactions in cells

90
Q

What is evolution

A

Change in allele frequency in a population over time and it occurs as a result of natural selection

91
Q

Describe the stages in natural selection

A

Gene mutation causes different allele which means individuals in a population vary as they have different alleles

This means individuals are adapted to their environments than others selection pressures act on the population

Individuals with this allele are more likely to survive as it increases their chances of survival It means they can reproduce and pass on their gene

It means the greater proportion of the next generation are going to inherit the beneficial allele

They in turn are more likely to survive reproduce and their genes are passed in meaning the frequency of the beneficial allele increases from generation to generation

92
Q

Give some examples of evidence for evolution

A

DNA molecular clocks
DNA hybridisation
DNA profiling
Dans and protein sequencing

93
Q

Describe what happens in DNA hybridisation

A

DNA hybrid is made by mixing different strands of DNA

It’s then heated to see how long it takes to denature,DNA relatedness is measured by seeing the temperature needed to denature the hybrid

The more similar base sequences of the two species the higher the temperature needed for them to denature

94
Q

What is speciation

A

The formation of new species as a result of isolation

95
Q

State the two types of speciation and the difference between them

A

Allopatric and sympatric

Allopatric is when the populations are geographically isolated

Sympatric this is when the two populations are reproductively isolated e without a geographical barrier

96
Q

What is meant by niche

A

The role an organism that plays in its environment

97
Q

What is carbon fixation

A

That inorganic carbon from carbon dioxide is incorporated into organic molecules initially GO

98
Q

What is the carbon cycle

A

The movement of carbon between organisms and the atmosphere

99
Q

How is carbon absorbed from the atmosphere

A

It’s absorbed by plants when they carry out photosynthesis

100
Q

How is the carbon passed on from plants

A

When they are eaten and digested by animals

101
Q

State ways the carbon returns to the atmosphere

A

By respiration of organisms

By decomposes respiration on dead organisms

By combustion when we burn fossil fuels

102
Q

State ways we can prevent an net overall increase in carbon emissions

A

Reforestation

Using biofuels as they are carbon neutral

103
Q

What is carbon fixation

A

The first stage of the carbon cycle in which Co2 is combined with RuBP

104
Q

What is meant by genetic diversity in a gene pool

A

The variety of alleles in a gene pool

A Level Biology (9 decks)

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