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A level Biology > Unit 2.1 - All organisms are related through their evolutionary history > Flashcards

Unit 2.1 - All organisms are related through their evolutionary history Flashcards

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1
Q

What do ALL organisms one from and when?

A

A common ancestor, billions of years ago

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2
Q

What does the way organisms are named reflect?

A

That they all came from a common ancestor billions of years ago

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3
Q

Taxonomy

A

The branch of science concerned with classification

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4
Q

The branch of science concerned with classification

A

Taxonomy

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5
Q

Phylogenetic

A

Methods of classification that reflect an organism’s evolutionary history

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6
Q

Phylogenetic

A

Evolutionary relatedness

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7
Q

Evolutionary relatedness

A

Phylogenetic

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8
Q

What are grouped together under phylogenetic classification?

A

Closely related organisms

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9
Q

What does it mean if organisms are in the same group?

A

More recent common ancestor, and may show physical similarities

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10
Q

Who and when does the system of classification we now use originate from?

A

Carl Linnaeus in the 18th century

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11
Q

What type of methods of classification reflect on an organism’s evolutionary history?

A

Phylogenetic methods of classification

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12
Q

Taxa

A

Levels of classification

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13
Q

Levels of classification

A

Taxa

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14
Q

What so large Taxa contain?

A

Smaller taxonomic groups

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15
Q

What contains smaller taxonomic groups?

A

Large Taxa

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16
Q

Whats the pattern in relatedness of organisms in terms of the taxonomic groups?

A

Animals become more related as you move down the taxonomic groups

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17
Q

What happens to organisms as you move down the taxonomic groups?

A

They become more closely related

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18
Q

Largest taxonomic group

A

Domain

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19
Q

Smallest taxonomic group

A

Species

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20
Q

List the taxonomic groups

A

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

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21
Q

List the taxonomic groups of humans from top to bottom

A

Domain - eukaryotes
Kingdom - animalia
Phylum - Chordata
Class - mammalian
Order - primates
Family - hominidae
Genus - homo
Species - sapiens

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22
Q

Back bone phylum

A

Cordata

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23
Q

Cordata

A

Back bone phylum

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24
Q

Can an animal belong to more than 1 taxon at any level? What’s the word for this?

A

No - Taxa are discrete

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25
Q

What do you call the diagrams frequently used to show the genetic relatedness of species?

A

Phylogenetic trees

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26
Q

What does the point at which 2 species cross over on a phylogenetic tree represent?

A

A common ancestor for 2 organisms

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27
Q

What represent a common ancestor for 2 organisms?

A

The point where the points cross on a phylogenetic tree

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28
Q

What does it mean if 2 species evolved more recently from another organism?

A

More closely related and therefore share a lot more of the same DNA

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29
Q

What do organisms that are closely related share a lot of?

A

The same DNA

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30
Q

What did we depend on in the past for classification?

A

Comparative anatomy

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31
Q

What do we depend on now for classification and why?

A

Biochemical, DNA comparisons
More reliable

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32
Q

Why is the fact that DNA is shred between closely related species a useful fact for classification of previously Iiving organisms?

A

We’re able to extract DNA from old archeological samples

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33
Q

Why are we able to extract DNA from old archeological samples?

A

It remains stable due to its structure, so it remains in good condition for thousands of years

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34
Q

What does more time passing usually mean in terms of DNA?

A

More time for DNA to change = more changes

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35
Q

What do genes change via during evolution?

A

Via mutation and natural selection

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36
Q

Why do genes change during evolution?

A

Evolutionary pressures were different in new environments

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37
Q

What do ALL living species belong to 1 out of 3 possible groups?

A

1 out of 3 of the groups in the domain system

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38
Q

What was the domain system originally defined on the basis of?

A

rRNA base sequences

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39
Q

What is the domain system now defined on the basis of?

A

DNA base sequences

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40
Q

3 domains

A

Eubacteria
Archaea
Eukaryota

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41
Q

Description of eubacteria domain

A

Familiar bacteria (e.g - E. Coli, salmonella, strep A)
Prokaryotes

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42
Q

2 prokaryote domains

A

Eubacteria and archaea

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43
Q

Archaea domain description

A

Also bacteria, but often have unusual metabolism (e.g - generate methane)
Live in marginal (extreme) environments
Prokaryotes

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44
Q

Which domain lives in extreme environments and give examples of these?

A

Archaea
Frozen soil in the Antarctic
In geothermal springs

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45
Q

Eukaryota domain description

A

Included plantae, animalia, fungi and protoctista
Eukaryotes

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46
Q

Features of Eukaryota domain

A

Membrane bound organelles, DNA in a nucleus with a nuclear envelope..

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47
Q

What’s the kingdom system based on?

A

Morphological similarities between organisms, not DNA analysis

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48
Q

Which group is based n morphological similarities between organisms, not on DNA analysis?

A

Th kingdom system

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49
Q

Main features of the prokaryotae kingdom

A

Includes all bacteria (eubacteria and archaea) and Cyanobacteria
Microscopic, single called organisms with no membrane bound organelles
Cell wall made from pectidoglycan or Murein (not cellulose)

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50
Q

What are the 5 kingdoms?

A

Prokaryotae
Protoctista
Fungi
Plantae
Animalia

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51
Q

Protoctista kingdom main features

A

Eukaryotic organisms
Single celled
No tissue differentiation
(E.g - amoeba, paramecium, paracytes)

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52
Q

Fungi kingdom main features

A

Heterophobic eukaryotes
Cell wall made up of chitin
Reproduce by spores
Grow in long threads called hyphae (together = mycelium)

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53
Q

Plantae kingdom features

A

Multicellular eukaryotes
Photosynthetic
Cellulose cell walls

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54
Q

Animalia kingdom main features

A

Multicellular eukaryotes
Heterophobic
No cell wall
Nervous coordination

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55
Q

Which kingdom is known as the “dustbin group” and why?

A

Protoctista as it’s such a diverse group that anything that doesn’t fit into the others goes into

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56
Q

Heterophobic

A

Have to consume complex organic molecules made by other organisms (don’t photosynthesise)

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57
Q

Name 2 heterophobic kingdoms

A

Animalia and fungi

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58
Q

Differences between Plantae and fungi kingdoms

A

(Plantae first, then fungi)
Cellulose cell wall, chitin cell wall
Reproduce by seeds, reproduce by spores
Photosynthetic, heterophobic

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59
Q

Photosynthetic

A

Use energy from sunlight to make complex organic compounds (e.g - carbohydrates) from simple, inorganic molecules (CO2, H20)

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60
Q

Name a good piece of evidence for evolutionary relationships and give an example

A

The presence of homologous structures
e.g - the pentadactyl limb in vertebrates

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61
Q

What’s comparative anatomy evidence of?

A

Common ancestry

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62
Q

Homologous structures + example

A

Same evolutionary origin (common ancestor) but have very different functions
(e.g - the wing of a bat and the flipper of a whale)

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63
Q

Analogous structures + example

A

Different evolutionary origins but have similar biological functions
(e.g - the wing of a bird and the wing of an insect)

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64
Q

What type of evolution do homologous structures result from?

A

Divergent evolution

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65
Q

What type of structures does divergent evolution lead to?

A

Homologous structures

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66
Q

What do analogous structures result from?

A

Convergent evolution

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67
Q

What type of structures does convergent evolution result in?

A

Analogous

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68
Q

Divergent evolution

A

When a population is split in 2 by geographical barriers and develop different traits under their respective selective pressures
(Have a common ancestor)

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69
Q

Convergent evolution

A

Species from different evolutionary origins occupying similar adaptations to similar selective pressures
(Adapted separately from different starting points, but reach the same end point - converge)

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70
Q

Example of convergent evolution + explanation

A

Dolphins and sharks
Dolphins - evolved from land mammals
Sharks - evolved from fish
Similar body shapes, but would need to track back million of years to find a common ancestor

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71
Q

What are the 4 methods of indicating how closely relate species are?

A
  1. DNA base sequence
  2. DNA hybridisation
  3. Amino acid sequence
  4. Immunology
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72
Q

What happens to DNA base sequences during evolution?

A

Species undergo changes in their DNA base sequences, which accumulate until the organisms are so different that they’re considered to be different species

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73
Q

Relationship between relatedness and DNA base sequence

A

More closely related = more similar DNA base sequence

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74
Q

Which method has confirmed evolutionary relationships in the past and corrected mistakes made in classification based on physical appearances?

A

DNA base sequencing

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75
Q

DNA sequencing

A

Reading the sequence of bases in a DNA molecule

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76
Q

What occurs during DNA base sequencing and why?

A

Specific sequences of DNA are targeted (e.g - a specific gene)
We can then compare that gene between species
(Remember that DNA is extraordinarily long)

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77
Q

What’s the issue with DNA base sequencing of only one gene?

A

The data is not representative of the whole DNA and so 2 species could appear more closely related then they really are

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78
Q

What does DNA hybridisation involve?

A

Comparing the DNA base sequence of 2 species

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79
Q

Describe the stages of DNA hybridisation

A
  1. DNA is extracted from both species
  2. DNA is heated to separate the 2 strands
  3. DNA is cut into fragments
  4. Fragments from 2 species are mixed
  5. Where they have complementary base sequences, they hybridise together
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80
Q

What has to be done to get a result from DNA hybridisation and what is this result?

A

Has to be heated -
The higher the temperature required to separate the new hybrid DNA molecules, the more similar the DNA due to the hydrogen bonds formed

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81
Q

What does 1 degree Celsius difference in desaturation temperature for DNA hybdridisation result in?

A

1% difference in DNA sequence

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82
Q

Even though humans and chimpanzees have 95% of their DNA in common, they have huge differences in appearance and behaviour. Why?

A

Due to gene regulation between the 2 species

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83
Q

Gene regulation

A

A process used to control the timing, location and amount in which genes are released

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84
Q

How is amino aid sequencing done?

A

The sequence of amino acid sin protein is determined by the DNA base equence
The degree of similarity in amino acid sequence reflects how closely related 2 organisms are

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85
Q

Example of amino acid sequencing that’s led to evolutionary trees

A

Part of the fibrinogen molecule of various mammal species have been compared
Their differences have led to evolutionary trees

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86
Q

What’s the problem with observing the amino acid sequence to indicate how closely related species are?

A

Can have differences in the DNA sequence that don’t cause differences in the amino acid (different codons of amino acids)
(Not as sensitive as using the DNA base sequence)

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87
Q

What’s not as sensitive as using the DNA base sequence for indicating how closely related species are?

A

Using the amino acid sequence

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88
Q

What does immunology do?

A

Compare proteins of different species

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89
Q

Describe the process of immunology

A

Antigen of one species
+
Specific antibodies of another
Mixed
Form a precipitate

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90
Q

What would show a closer evolutionary relationship during immunology?

A

The antigen and antibody reacting more to make more precipitate

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91
Q

Example of an antigen used during immunology

A

Blood protein albumin

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92
Q

Why is biological classification said to have a “tentative nature”?

A

Classification can change over time as more techniques and information become available

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93
Q

What is a species defined as?

A

A group of organisms able to interbreed to produce fertile offspring

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94
Q

Which domain includes extremophiles?

A

Archaea

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95
Q

Extremophiles

A

Bacteria living in extreme environments

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96
Q

Examples of extreme environments that extremophiles can endure

A

Very high and very low temperatures (e.g - geothermal springs, frozen ice)
High salinity
Acidic + alkaline
High pressure

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97
Q

Extremophiles living in very high temperatures

A

Thermophiles

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98
Q

Extremophiles living in an area of high salinity

A

Halophiles

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99
Q

Extremophiles living in very low temperatures

A

Psychrophiles

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100
Q

What do you call the groups in which fungi grow?

A

Hyphae (together - mycelium)

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101
Q

Name the kingdoms with photosynthetic organisms

A

Prokaryotae
Plantae
Protoctista

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102
Q

What are the photosynthetic pigments of plantae attached to?

A

Thylakoids

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103
Q

Hierarchical

A

Each group is subdivided into smaller groups

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104
Q

Ribosomes of eukaryotes vs prokaryotes

A

80s vs 70s

105
Q

What changes genes?

A

Mutations

106
Q

What’s the name of the system used when naming organisms?

A

Binomial system

107
Q

What’s the names of the first and second names used in the binomial system?

A

Genus + species

108
Q

How do we correctly write out a binomial name?

A

Genus name starting with an uppercase letter
Species name in lowercase

109
Q

Which names for organisms can be misleading?

A

Common names

110
Q

What’s the purpose of the binomial system?

A

Avoids confusion
Can accurately identify species internationally
Each scientific name is distinct

111
Q

When a scientist discovers a new species, which part of the binomial name can they choose and which part must they not choose randomly and why?

A

Choose - species name
Keep - Genus name (if there are other species in the genus)

112
Q

What can a scientist that discovers a new species do?

A

Choose the species name of an organism

113
Q

Species definition

A

A group of organisms that can interbreed to produce fertile offspring

114
Q

Give an example of two closely related species that interbreed to produce a hybrid - what’s the same between them both?

A

Zebra and donkey
Have the same GENUS

115
Q

What is a zebronkey?

A

A hybrid of a male zebra and a female donkey

116
Q

What’s the problem with hybrids from closely related species?

A

They’re infertile and cannot produce offspring

117
Q

What type of offspring are infertile?

A

Hybrids

118
Q

Why are hybrids infertile?

A

The number of chromosomes in the parents are different
Egg and sperm DO combine, but the zygote has an uneven amount of chromosomes
Cannot form homologous pairs during meiosis
Cannot form viable gametes
=infertile

119
Q

What’s the difference between a domestic dog and a wolf?

A

Different SUB species

120
Q

Give an example of two species that the only difference is a sub-species and discuss whether they can therefore interbreed to produce fertile offspring

A

Domestic dog + wolf
They CAN still interbreed to produce fertile offspring - it’s only the SUB-species that’s different

121
Q

What does evolutionary change occur due to?

A

Natural selection

122
Q

Describe and explain how an evolutionary change occurs/ natural selection

A
  1. Genetic variation exists due to spontaneous mutations
  2. Competition between organisms (limited resources)
  3. A mutation may give an organism a selective advantage
  4. Organism is better adapted to the environment and survives
  5. Organism reproduces, passing on its beneficial alleles
  6. Frequency of advantageous alleles increase
123
Q

Why does genetic variation exist?

A

Due to spontaneous mutations

124
Q

What could a mutation give to an organism that’s good?

A

A selective advantage

125
Q

What adapts to new environments?

A

The entire population, not just individuals

126
Q

What does it mean if an organism has a “selective advantage” during natural selection?

A

It’s better adapted, so it can out-compete other species

127
Q

What are the 3 types of biodiversity?

A

Genetic
Species
Ecosystem

128
Q

Genetic diversity

A

Count the gene forms in a population

129
Q

Species diversity

A

Count the species in a community

130
Q

Ecosystem diversity

A

Count the ecosystem types in a landscape

131
Q

What are the 2 aspects to biodiversity?

A

The species richness - the number of species in a given environment
The species evenness - the number of individual organisms within each species

132
Q

Species richness

A

The number of species in a given environment (local or wide-ranging)

133
Q

What’s the word for the fact that biodiversity varies depending on where you are?

A

Varies spatially

134
Q

What’s the general pattern with biodiversity in terms of the equator?

A

More biodiversity close to the equator

135
Q

List some factors that affect biodiversity across the globe (4)

A

UV light
Humidity + rainfall (water availability)
Temperature
Amount of species and individuals

136
Q

How does UV light affect biodiversity?

A

Causes a higher rate of mutation - leads to rapid evolution

137
Q

How does a stable temperature affect biodiversity?

A

Favourable conditions for plants to grow - biodiversity of animals generally depends on plant life

138
Q

How does humidity/rainfall (water availability) affect biodiversity?

A

Provide favourable conditions for plants to grow - the biodiversity of animals generally depends on plant life

139
Q

Niches

A

Food types

140
Q

Word for food types

A

Niches

141
Q

How does having more species types affect biodiversity?

A

More habitats and niches (food types)

142
Q

How does having more species and individuals affect biodiversity?

A

Competition is high, so individuals are more specialised and narrow the exploitation of niches, making it difficult to move out of the area

143
Q

When is it difficult for a species to move out of an area?

A

When there’s more species and individuals, and so competition is high, so individuals are more specialised and narrow the exploitation of niches

144
Q

Give 4 examples of different habitats

A

Rainforests
Deserts
Coral reefs
The Antarctic

145
Q

What are the pros and cons of the desert environment?

A

High light intensity
Low rain fall /humidity, so no plants, so no basis for ecosystems to grow, so very few animals

146
Q

Why are plants important for biodiversity?

A

Provide the basis for ecosystems to grow, so without them there’s also few animals

147
Q

What makes coral reefs have large amounts of biodiversity?

A

Nutrient loops

148
Q

Are there many plants in the Antarctic? Why?

A

There’s obviously a lot of water, but its frozen, so its not available for plants to row, so no, there’s virtually no plants in the Antarctic

149
Q

Where abouts to species that live in the Antarctic live and why?

A

Near the coast as they depend on plant and marine life in the sea

150
Q

What are the cases of biodiversity changing over time?

A

Succession
Natural selection
Human influence

151
Q

Succession

A

Over time, a community of organisms changes its habitat

152
Q

Community

A

A number of organisms of different species living together in the same environment and interacting with one another. They can influence and change a habitat together.

153
Q

What forms at the bottom of a pond during succession when bits of dead plants and leaves sink there?

A

Detritus

154
Q

Detritus

A

Dead bits of plants and leaves that have sank to the bottom of a pond

155
Q

What happens as detritus forms at the bottom of a pond?

A

More plants grow from it and it gets deeper, causing the pond to become shallower until eventually, the habitat has changed

156
Q

How does the habitat of a pond change?

A

Through succession
Detritus form from bits of plants and leaves dying
Sink to the bottom
More plants grow from it
Detritus gets deeper
Pond becomes shallower
Habitat has eventually changed

157
Q

What can happen to plants once the habitat of a pond has changed via succession?

A

Different types of plants can grow there

158
Q

What does succession do to animal biodiversity (in general)?

A

Increases it

159
Q

What doe succession do to plant biodiversity (in general)?

A

Decreases it

160
Q

Climax community

A

The last stable stage of succession

161
Q

The last stable stage of succession

A

The climax community

162
Q

What is usually the climax community?

A

Forest

163
Q

What is a climax community usually dominated by?

A

1 plant type

164
Q

Why does plant biodiversity decrease with succession?

A

A climax community (the last stable stage of succession) is usually dominated by 1 plant type

165
Q

What did Darwin come up with?

A

The theory of evolution through natural selection

166
Q

What’s a good example of natural selection causing biodiversity?

A

Darwin’s finches

167
Q

What did Darwin’s finches help him do?

A

Come up with the theory of evolution through natural selection

168
Q

What had the Galapagos finches adapted for?

A

Adapted to be suitable for their diets

169
Q

How did Darwin use the finches to come up with the theory of evolution through natural selection?

A

He travelled the world collecting bird samples and carefully documented the environments that they lived in to see the relationship between the beak shape and their diets

170
Q

How did biodiversity come about with the Galapagos finches?

A

Ancestral finch landed on one of the islands, breaded and grew the population which spread out to different habitats which they adapted to
Therefore, over time, natural selection led to an increase in Biodiversity

171
Q

Adaptive radiation

A

1 type of organism adapts to different types

172
Q

Why is it initially strange to think of the fact that there’s so much Biodiversity in the Galápagos Islands?

A

-formed fairly recently - they’re volcanic islands that emerged from volcanic eruptions in fairly recent geological time
-hundreds of miles from the nearest mainland - any animal/plant there must have come from the mainland, which would happen rarely due to the distance

173
Q

What type of islands are the Galápagos Islands?

A

Volcanic islands that emerged from volcanic eruptions in fairly recent geological time

174
Q

Why is there so much biodiversity in the Galápagos Islands?

A

Include dozens of islands with different habitats and Environments
Mountainous, dry, lush vegetation, rocky
So, they provide habitats for many different organisms

175
Q

Give 4 types of habitats present in the Galápagos Islands

A

Mountainous
Dry
Lush vegetation
Rocky

176
Q

Genetic diversity

A

The total number of genetic characterises in the genetic makeup of a species

177
Q

Genetic variability

A

The tendency of genetic characteristics to vary

178
Q

What does genetic diversity serve as?

A

A way for populations to adapt to changing environments

179
Q

Polymorphism

A

Describes the presences of several different forms or types of individuals among the members of a single species. Polymorphism results from the presence of polymorphic genes (i.e - multiple alleles of the same gene)

180
Q

Polymorphic genes

A

Multiple alleles of the same gene

181
Q

2 examples of species demonstrating clear polymorphism

A

Domestic dogs
Snails with different shells

182
Q

Describe the differences in a particular snail species and explain why this is advantageous

A

Genetically determined factors give them unique colours and patterns that help them blend into new environments

183
Q

How can biodiversity be assessed within a species at a genetic level?

A

By looking at the variety of alleles in the gene pool of a population (i.e - the proportion of polymeric loci across the genome)

184
Q

Gene pool

A

The number of different alleles within the genome

185
Q

Genome

A

Total genes of a population

186
Q

What’s the same for all domestic dogs?

A

Genome

187
Q

What’s an example of polymorphic alleles in humans?

A

Blood groups

188
Q

Which is the recessive blood group in humans?

A

O

189
Q

How can biodiversity be assessed at a molecular level?

A

Using DNA fingerprinting and sequencing

190
Q

What do researchers do instead of counting every single allele (which would be very difficult) in a population to look for variation between individuasls?

A

Collect samples of DNA and analyse the base sequences

191
Q

Why do researchers collect samples of DNA and analyse base sequences to look for variations between individuals?

A

Because there’s difficulty involved in counting every single allele in a population

192
Q

A greater variation in WHAT implies a greater genetic diversity of a species?

A

Greater variation in the base sequences in the DNA samples of different individuals

193
Q

What are many plants and animals used to support?

A

Human civilisation

194
Q

What could each species represent?

A

An important human asset

195
Q

List 4 reasons why biodiversity is important

A

A potential source of food
Essential raw materials (cotton, rubber, wood…)
Useful chemicals and pharmaceuticals
Disease resistant genes which can be spliced into new genomes to produce useful GM crops

196
Q

Do many plant species provide stable foods for humans worldwide? Why is this an issue?

A

No, few do, such as wheat and rice
A low biodiversity like this is risky - climate change or other factors could lead to the disappearance of these supplies, and then what?

197
Q

Essential raw materials we get from nature

A

Cotton
Rubber
Wood

198
Q

Examples of useful chemicals and pharmaceuticals produced by plants

A

Antibiotics, aspirin and many drugs used to treat heart disease

199
Q

What do pretty much all drugs come from?

A

Plants and fungi

200
Q

What can disease resistance genes be used for?

A

Can be spliced Ito new genomes to produce useful GM crops

201
Q

What could lead to an incalculable loss in terms of biodiversity?

A

Extinction of a plant species before its chemical properties have been investigated

202
Q

What is essential that we do to protect biodiversity?

A

Conservation

203
Q

What does more space usually lead to in terms of biodiversity?

A

More biodiversity

204
Q

Why is conservation essential?

A

Extinction of a plant species before its chemical properties have been investigated would amount to an incalculable loss

205
Q

What has climate change caused throughout evolutionary history?

A

Mass extinctions

206
Q

What’s been the cause of mass extinctions in the past?

A

Climate change

207
Q

What have previous mass extinctions caused by climate change been followed by?

A

Rapid expansion and diversification of species

208
Q

What are there fears currently that human activities are leading towards?

A

A sixth mass extinction event, with a massive loss of biodiversity

209
Q

What would be the cause of a sixth mass extinction event with a massive loss of biodiversity?

A

Human activities

210
Q

What would happen to biodiversity under a mass extinction event?

A

Huge losses

211
Q

Give 2 examples of habitats with high numbers of species

A

Rainforest
Coral reef

212
Q

What must we count when measuring biodiversity?

A

the number of different species (species richness)
the number of individuals of each species (species evenness)

213
Q

Species richness

A

the number of different species

214
Q

What are the 2 ways in which an area can be sampled?

A

gridding
sampling along a line (transect)

215
Q

When is gridding used? include an example

A

Where 2 areas can be compared (e.g - mown or unmown grass)

216
Q

When are transects used? Include an example

A

where there is a gradual change in the enviornment (e.g - under a tree to into the open)

217
Q

What do we place on our grid or transetcs?

A

Quadrats

218
Q

What are quadrats used especially for?

A

measuring plant biodiversity

219
Q

How are quadrats used?

A

The area to be samples is divided up into a grid pattern with indexed coordinates
Quadrats are placed on the coordinates on a random basis - this can be achieved by using a random number table

220
Q

How can quadrats be placed on a random basis?

A

by using a random number table

221
Q

Why are quadrats useful?

A

They give you a specific and consistent area that’s repeatable

222
Q

What can we do with the data we have after counting the number of plant species within a quadrat?

A

We can expand the data to represent the whole field

223
Q

What must samples be in order to collect reliable data?

A

Random
Representable

224
Q

Why must samples be random?

A

to reduce bias

225
Q

Why must samples be representative?

A

They must be large enough to be an accurate estimate

226
Q

Why must samples be both random and representative?

A

in order to collect reliable data

227
Q

Where should you place quadrats and why?

A

In multiple various positions in order to get more reliable data that’s representative of the entire field

228
Q

What’s an alternative method of sampling used in aquatic ecosystems?

A

Kick sampling

229
Q

Describe the method of kick sampling

A
  1. Place the bottom edge of the net on the stream bed on the downstream side of the sample point
  2. Kick into the stones upstream of the net
  3. empty contents into a tray of stream water
  4. identify and count invertebrates
  5. return invertebrates gently into the stream
230
Q

Give 6 variable that we need to control between 2 streams when doing kick sampling

A

depth of water
temperature
speed of current
oxygen and ion concentration
light intensity
time of year

231
Q

Give 4 factors to control to ensure standardisation of sampling when doing kick sampling

A

same sampling area
same mesh size
same distance from bank
same time spent kicking

232
Q

Why would the values obtained be underestimates when using kick sampling?

A

Animals not caught in net
animals not dislodged from bank
uneven kicking
animals too small to identify

233
Q

How would we improve our confidence in a sample taken?

A

Take more samples

234
Q

What does the Simpson Diversity index give us?

A

An overall measure of the species richness in an ecosystem

235
Q

What are the steps in calculating the Simpson Diversity index of an ecosystem?

A
  1. collect random sample for organisms
  2. Identify each of the organisms found
  3. Count the total number of organisms
  4. calculate D (the index)
236
Q

What’s ‘n’ in the Simpson Diversity index calculation?

A

the number of individuals per species

237
Q

What’s N in the Simpson diversity index calcilation?

A

The total number of organisms

238
Q

What do we need to obtain from our sample in order to calculate the Simpson Diversity index?

A

the number of species and the number of individuals of each species

239
Q

Do we need to actually be able to identify each individual species in order to calculate a Simpson Diversity index?

A

no, just distinguish between the,

240
Q

What is the Simpson Diversity index generally rounded up to?

A

Usually to 1d.p

241
Q

What’s the relationship between the value of the Simpson diversity index and the biodiversity of an ecosystem?

A

The closer to 1 the value is, the higher the biodiversity of the area

242
Q

What is the value of the Simpson diversity index always less than?

A

1

243
Q

What does the Simpson Diversity index take into account?

A

Both the variety of species and how many there are of each one

244
Q

What does having more evenly distributed species lead to?

A

higher biodiversity

245
Q

What is the Simpson Diversity index particularly useful for?

A

Comparing different habitats which may have similar conditions except for 1 factor, for example pollution or being near a road

246
Q

What are some sources of error when investigating the biodiversity of animals?

A

Possibility of recounting as they move
Some are camouflaged
Some are easier to catch than others
Can misidentify

247
Q

What are possible sou

A
248
Q

Polymorphism actual definition

A

More alleles for a specific gene than can be explained by mutation alone

249
Q

What are the 3 main ways of classifying adaptations?

A

Structural
Behavioural
Physiological

250
Q

Structural adaptations + example

A

Physical differences (e.g - giraffe neck)

251
Q

Behavioural adaptations + example

A

Differences in patterns of activity (e.g - tortoises hibernating)

252
Q

Physiological adaptations + example

A

Variations in detection and response by vital organs (e.g - elephants with ears sensitive to lower frequencies)

253
Q

What is it that’s we’re comparing the similarity of during DNA hybridisation?

A

DNA base sequence
(Not just DNA in general)

254
Q

What does the lowest different in separation temperature between 2 organisms compares to others mean?

A

They have the most recent common ancestor

255
Q

What’s it important to ensure when assessing the biodiversity of an area?

A

That we have a low range in our results
That we survey a large enough area

256
Q

How many decimal places is Simpson’s Diversity Index usually rounded to?

A

2

257
Q

What do you need to remember to include in hazard and risk questions?

A

When this risk is there

258
Q

How do we assess diversity within 1 species?

A

look at the number of alleles for a specific gene

A level Biology (26 decks)

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