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Title: Module 3: Biodiversity and Evolution


1
Module 3Biodiversity and Evolution
2
Biodiversity and evolution
  • Evolution has generated a very wide variety of
    organisms.
  • The fact that all organisms share a common
    ancestry allows them to be classified.
  • There is increasing recognition of the need to
    maintain biodiversity.

3
Biodiversity
  • Biodiversity is an important indicator in the
    study of habitats.

4
Classification
  • Classification is an attempt to impose a
    hierarchy on the complex and dynamic variety of
    life on Earth.
  • Classification systems have changed and will
    continue to change as our knowledge of the
    biology of organisms develops.

5
Evolution
  • Nothing in biology makes sense except in the
    light of evolution
  • Theodosius Dobzhansky, 1973.

6
Maintaining Biodiversity
  • Maintaining biodiversity is important for many
    reasons.
  • Actions to maintain biodiversity must be taken at
    local, national and global levels.

7
2.3.1. Biodiversity
  • Module 3 Biodiversity and Evolution

8
Learning Outcomes
  • define the terms species, habitat and
    biodiversity
  • explain how biodiversity may be considered at
    different levels
  • habitat,
  • species
  • genetic

9
Biodiversity
  • The biodiversity of an area is a measure of
  • Different ecosystems
  • Number of species
  • Number of individuals of each species

10
Biodiversity
  • structural and functional variety in the living
    world
  • Levels of biodiversity
  • Range of habitats in which different species live
  • The differences between species
  • Genetic variation between individuals of the same
    species

11
Species - definition
  • Species
  • a group of organisms, with similar
    morphological, physiological, biochemical and
    behavioural features, which can interbreed to
    produce fertile offspring, and are reproductively
    isolated from other species
  • This often leads to disagreements and
    uncertainties when classifying or identifying
    species

12
Species the two groups of criteria
  • Group of organisms
  • Capable of interbreeding
  • Capable of producing fertile offspring
  • Reproductively isolated from other groups
  • biospecies
  • Group of organisms showing similarities in
    characteristics
  • Morphological
  • Physiological
  • biochemical
  • Ecological
  • behavioural

13
Habitat definition
  • A habitat is the place where individuals in a
    species live.
  • Organisms show adaptations to their habitat
  • A full description of the habitat includes the
    physical and biological factors that characterise
    that environment

14
Examples of habitats
  • Name of the place
  • A description of dominant vegetation
  • Coniferous forest
  • Oak woodland
  • Tropical rainforest
  • Grassland
  • A type of environment
  • Freshwater pond
  • Rock pool on a rocky shore

15
The State of the planet
  • David Attenborough presents a series of three
    programmes looking at the state of the planet
    to address the concern below.
  • One species (humans) can so alter its environment
    that it can destroy whole species, and indeed
    whole environments.
  • How great is the damaged that is being caused?
  • Why is it that what we do is so destructive?
  • What can we do to change?

16
The state of the planetProgramme No. 1
  • The Biodiversity on Earth
  • In order to understand the impact that humans are
    having on the environment we first need to
    understand the variety of life on the planet, the
    biodiversity.
  • Watch the DVD and answer the questions on the
    worksheet.
  • After watching the DVD write out your thoughts on
    the statement
  • Why conserve ecosystems?

17
Measuring Biodiversity
18
Measuring Biodiversitylearning Outcomes
  • explain the importance of sampling in measuring
    the biodiversity of a habitat describe how random
    samples can be taken when measuring biodiversity

19
Measuring biodiversity
  • To measure biodiversity you need to find out
  • What species are present
  • The abundance of each species
  • The distribution of each species across the area
  • Compile a species list
  • Identification keys
  • Observation
  • Trapping of mobile animals

20
Measuring biodiversity
  • Distribution
  • Where the species is found
  • Abundance
  • How many of each species are present
  • Estimating abundance
  • Take a representative sample
  • Multiply up

21
Random sampling
  • Study a small part of the habitat
  • Sample sites must be selected at random
  • Take samples at regular intervals
  • Use random number tables
  • Select co-ordinates from a map

22
Number of samples
  • The number of samples taken will depend on
  • The size of the habitat
  • The time of year
  • The diversity of the habitat being studied

23
Recording results
  • Prepare a table
  • Space for all species
  • Space to record the data for each sample site

24
Sampling techniques
  • Quadrats
  • Choose a suitable quadrat size
  • Place quadrat at random
  • Identify plants
  • Measure their abundance
  • Transects
  • Put a tape measure across the habitat
  • Record all species touching the line
  • Can record at intervals

25
Sampling techniques
  • Belt transect
  • Interrupted belt transect
  • Continuous belt transect
  • Used to survey rocky shores or sand dunes

26
Measuring abundance
  • Percentage Cover
  • Proportion of quadrats area occupied by the
    species
  • Grids can help with estimates
  • Use a point frame within a quadrat
  • Include bare ground
  • Abundance scale subjective
  • ACFOR scales
  • Abundant
  • Common
  • Frequent
  • Occasional
  • Rare
  • Species frequency
  • Proportion of quadrats with the species present

27
Rocky Shores
Some text, photos and diagrams taken from Marine
Field Course Guide to Rocky Shores (1992) by S.J.
Hawkins H. D. Jones
28
Learning Outcomes
  • To understand that zonation occurs on a rocky
    shore, and the factors that control this
    distribution
  • To identify a range of organisms living on a
    rocky shore
  • To understand the importance of carrying out
    biological surveys
  • To carry out a paper-based transect looking at
    the distribution of organisms on a rocky shore
  • To present results as a kite diagram, and write a
    report of their findings.

29
Rocky Shore Ecology
  • The seashore is the boundary between land and
    sea.
  • A sharp change in environmental conditions occurs
    between the low tide mark and the splash zone.
  • Most shore plants and animals have evolved from
    marine ancestors.

30
Zonation
  • Biomass, biodiversity and community complexity
    increases towards the lower shore as conditions
    are better for marine organisms competition for
    space and food is intense.
  • Species occur in distinct communities or
    horizontal bands on the shore known as zonation.

31
Splash zone
As you can see from these diagrams organisms show
zonation. You can also see that the organisms
present varies according to the exposure of the
shore.
Low tide
32
Activity
  • For each zone write in the degree of stress for
    each abiotic and biotic factor
  • Add on two arrows to show the direction of
    increasing stress caused by abiotic (red) and
    biotic (green) factors on the rocky shore

33
Factors affecting the distribution of organisms
  • Survival is most difficult near the top of the
    shore.
  • Biomass and biodiversity of animals and plants is
    low.
  • Those plants and animals that can survive have
    little competition e.g. for space, and may be
    abundant.

34
Rocky Shore Transect
  • On the A4 rocky shore draw a belt transect
    using 3cm2 quadrats.
  • Calculate the abundance of each species of
    plant and animal in each quadrat, record your
    results in the table provided.
  • Write a report on the distribution of organisms
    on the rocky shore
  • Extension Activity
  • Present your results as a kite diagram for five
    seaweeds and five animals.

35
Sampling in School Grounds
  • Suggested activities
  • Transect in grass outside chapel
  • Random quadrat sampling of two sites
  • Optimum quadrat size for pinkie fields
  • Optimum quadrat number
  • Species frequency on pinkie fields
  • Comparison of percentage cover and ACFOR
  • All students quantify the same 10 quadrats and
    allow for comparison

36
Sampling Animals
  • If the animals are mobile
  • Observation
  • Observation of signs left behind
  • Owl pellets, droppings, burrows etc
  • Catch or trap animals and estimate numbers from
    the trapped sample
  • Catching animals
  • Sweep netting
  • Kick sampling
  • Tree sampling
  • Pitfall trap
  • Tulgren funnel
  • Light trap

37
Surveying school grounds
  • Suitable methods that could be used in school
    include
  • Sweep netting in the long grass
  • Tree sampling
  • Pitfall trap
  • Tulgren funnel
  • To allow for a comparison, each sample should be
    done at two sites, and some abiotic readings
    should be taken.

38
Summary of the impact of sampling
  • Sampling may cause damage to a habitat
  • Temporary disturbance
  • Long term disturbance
  • Example
  • Trampling
  • Digging for pitfall traps etc

39
Why do we need to study habitats?
  • Assess human impact
  • EIA Planning process
  • To highlight the importance of maintaining
    habitats and reducing the damage

40
Learning Outcomes
  • describe how to measure species richness and
    species evenness in a habitat
  • Use Simpson's Index of diversity (D) to calculate
    the biodiversity of a habitat using the formula D
    1 (?(n/N)2)
  • Outline the significance of both high and low
    values of Simpsons Index of Diversity (D)

41
Measuring Biodiversity
  • Species richness
  • Number of species present in the study area
  • Species evenness
  • Measure the abundance of individuals in each
    species
  • Increasing species richness and species evenness
    will increase biodiversity

42
Simpsons diversity Index
  • Measure of biodiversity taking into account
    species richness and species evenness
  • Formula
  • D 1 ?(n/N)2
  • n number of individuals of a particular species
  • N total number of all individuals of all species

43
Progress Question
  • Use Simpsons index to calculate the diversity of
    a habitat that contains the following organisms
  • 20 woodlice
  • 5 mice
  • 1 shrew
  • 32 earthworms
  • 15 grasshoppers
  • 1 owl
  • Comment on the diversity of this habitat

44
Calculating simpsons
species n n/N (n/N)2
woodlice 20 0.27027 0.073046
mice 5 0.067568 0.004565
shrew 1 0.013514 0.000183
earthworm 32 0.432432 0.186998
grasshopper 15 0.202703 0.041088
owl 1 0.013514 0.000183
Sum 74 0.306063
45
Answers to progress questions
  • D 1 0.306
  • D 0.694

46
2.3.2 Classification
  • Module 3 Biodiversity and evolution

47
Classification
  • Classification is an attempt to impose a
    hierarchy on the complex and dynamic variety of
    life on Earth.
  • Classification systems have changed and will
    continue to change as our knowledge of the
    biology of organisms develops.

48
Learning Outcomes
  • Define the terms classification, phylogeny and
    taxonomy.
  • Explain the relationship between classification
    and phylogeny.
  • Describe the classification of species into the
    taxonomic hierarchy of domain, kingdom, phylum,
    class, order, family, genus and species.

49
Definitions
  • Classification
  • The grouping of organisms into categories based
    on various features
  • Phylogeny
  • Study of evolutionary relationships between
    organisms
  • Taxonomy
  • The study of the principles of classification
  • Taxon
  • Classificatory group

50
Natural Classification
  • Concept of the species
  • Capable of breeding to produce fertile offspring
  • Have common ancestry
  • Have very similar genes
  • Hierarchy of classification
  • Closely related species are placed together in
    groups
  • Closely related groups are placed together in a
    larger group
  • Modern classification reflects the evolutionary
    distance between species

51
Evolutionary tree
  • Any two species alive today will share a common
    ancestor from the past
  • The time when the two species started to evolve
    separately is a branch point on the tree

52
Progress Questions
  • What is meant by the term classification?
  • What is meant by the term phylogeny?
  • What is the relationship between natural
    classification and phylogeny?

53
Answers to progress questions
  • What is meant by the term classification?
  • Classification is the sorting of living things
    into groups
  • Natural classification does this by grouping
    things by how closely related they are
  • What is meant by the term phylogeny?
  • The study of evolutionary relationships between
    organisms
  • What is the relationship between natural
    classification and phylogeny?
  • Natural classification groups things according to
    how closely related they are
  • This should match the evolutionary tree produced
    by considering how recently organisms shared a
    common ancestor.

54
Classifying living things
  • Carl Linnaeus 18th Century
  • Devised a scheme of classification
  • Organisms were put into a series of ranked
    categories
  • Categories are taxonomic groups (TAXON)
  • 5 kingdom classification

55
Hierarchy of classification
  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
  • This is the basic unit of classification

56
Taxon Description
Kingdom Largest group of organisms sharing a few common features.
Phylum Major subdivision of a kingdom.
Class A group of related orders- subdivision of a phylum.
Order A group of related families- subdivision of a class.
Family A group of closely related genera- subdivision of an order.
Genus A group of related species- subdivision of a family.
Species A group of organisms capable of breeding and producing fertile offspring.
57
Hierarchy of classification
Taxon No. of similarities Size of group Degree of relatedness
Domain small Large Distant to common ancestor
Kingdom
Phylum
Class
Order
Family
Genus
Species large small Recent common ancestor
58
Examples of Classification
Taxon Tiger Human Fruit fly
Domain Eukaryota Eukaryota Eukaryota
Kingdom Animalia Animalia Animalia
Phylum Chordata Chordata Arthropoda
Class Mammalia Mammalia Insecta
Order Carnivora Primate Diptera
Family Felidae Hominidae Drospophilidae
Genus Panthera Homo Drosophila
Species tigris sapiens melanogaster
59
Learning Outcomes
  • Outline the binomial system of nomenclature and
    the use of scientific (Latin) names for species.
  • Use a dichotomous key to identify a group of at
    least six plants, animals or micro organisms.
  • Outline the characteristic features of the
    following five kingdoms Prokaryotae (Monera),
    Protoctista, Fungi, Plantae, Animalia.

60
Confusion over common names
In North America, this animal is a moose.
In Europe, this animal is an elk.
In North America, this animal is an elk.
In Europe, this animal is a red deer.
61
Binomial Classification
  • Universal system based on Latin names
  • Generic name
  • Specific name

62
Rules for using system
  • Name printed in Italics, or underlined if hand
    written
  • First letter of generic name in capitals
  • Once generic name has been used, it can be
    abbreviated in later text to the first letter.
  • If specific name not known, write sp.
  • If referring to all members of a genus, specific
    name written in plural spp.

63
Binomial system of nomenclature
  • Examples
  • Homo sapiens
  • Panthera leo
  • Panthera tigris
  • Lutra lutra

64
Identifying Living things
  • Dichotomous key
  • Asks a series of questions in pairs
  • You are then directed to another question or to
    an identification
  • Look at the Classification and Taxonomy fact
    sheet
  • Look at the example of a classification key as
    shown
  • Other examples
  • Textbook pg 207
  • Revision guide pg 77

65
Five Kingdom Classification
  • Prokaryotae
  • Protoctista
  • Fungi
  • Plantae
  • Animalia

66
Prokaryotae
  • Oldest group of organisms on earth
  • Two groups originally recognised but have now
    been separated into two domains
  • Archaea
  • Eubacteria (includes cyanobacteria)
  • Distinguishing features of eubacteria
    (Prokaryotae)
  • Organisms lack nuclei organised within membranes.
  • No envelope-bound organelles.
  • No 92 microtubules

67
Protoctista
  • Eukaryotic
  • mostly unicellular
  • Plant-like or animal-like organisms
  • Includes
  • Chlorophyta (green algae)
  • Phaeophyta (brown algae)

68
Fungi
  • Eukaryotic
  • Heterotrophic nutrition
  • Cell walls made of chitin
  • Usually form mycelium
  • Carbohydrate stored as glycogen
  • Sexual or asexual reproduction

69
Plantae
  • Features
  • Eukaryotic
  • Multicellular
  • Possesses chlorophyll and other pigments
  • Autotrophic nutrition
  • Cells walls of cellulose
  • Carbohydrate stored as starch.

70
Animalia
  • Eukaryotic
  • Multi-cellular
  • Heterotrophic nutrition
  • No cell walls
  • Carbohydrate stored as glycogen
  • Display nervous co-ordination

71
Learning Outcomes
  • Discuss the fact that classification systems were
    based originally on observable features but that
    more recent approaches draw on a wider range of
    evidence to clarify relationships between
    organisms, including molecular evidence.
  • Compare and contrast the five kingdom and three
    domain classification systems.

72
Modern Classification
  • In the 19th and early 20th century
    classification was based on observable features
  • Morphology
  • Embryology
  • Anatomy
  • Homologous features
  • Evolutionary origin in the same ancestral
    structure
  • E.g. pentadactyl limb of tetrapods

73
New developments
  • The following scientific developments can now be
    used as a method of classifying organisms
  • Primary structure of proteins
  • Cyctochrome C is a protein used in respiration
  • By comparing the sequence of amino acids in the
    primary protein structure can determine how
    closely related the species are.

74
New developments
  • Scanning Electron Microscopy
  • Looks at morphology in greater detail
  • DNA sequencing
  • Helps classification to reflect phylogeny using
    nucleotide sequence data

75
The Three Domains
  • 1990 Carl Woese
  • New classification system after studying
    ribosomal RNA
  • Argued that the differences in bacteria were so
    great they needed separating
  • Bacteria Eubacteria
  • Archaeae Archaebacteria
  • This gives three domains
  • Bacteria
  • Archaea
  • Eukaryotae

76
Why three domains?
  • Eubacteria are prokaryotic and fundamentally
    different from Archaeae and eukaryotae
  • Archaeae share characteristics with eukaryotae
  • RNA polymerase
  • Similar DNA replication mechanisms

77
Five kingdom classification
78
Three domain classification
79
2.3.3 Evolution
  • Module 3 Biodiversity and Evolution

80
Evolution
  • Nothing in biology makes sense except in the
    light of evolution
  • Theodosius Dobzhansky, 1973.

81
Learning Outcomes
  • Define the term variation.
  • Discuss the fact that variation occurs within as
    well as between species.
  • Describe the differences between continuous and
    discontinuous variation, using examples of a
    range of characteristics found in plants, animals
    and microorganisms.
  • Explain both genetic and environmental causes of
    variation.

82
Variation
  • Variation is the differences that exist between
    individual organisms.
  • Interspecific variation (between species)
  • Differences that are used to assign individuals
    to different species
  • Intraspecific variation (within a species)
  • Individuals of the same species show variation
  • Variation can be inherited or influenced by the
    environment.

83
Types of variation
  • There are two main types of variation
  • Continuous variation
  • Discontinuous variation
  • There are two main causes of variation
  • Genetic variation
  • Environmental variation

84
Continuous variation
  • Existence of a range of types between two
    extremes
  • Most individuals are close to a mean value
  • Low numbers of individuals at the extremes
  • Both genes and the environment interact in
    controlling the features
  • Examples
  • Height in humans
  • Length of leaves on a bay tree
  • Length of stalk of a toad stool

85
Continuous variation
  • Use a tally chart and plot results in a histogram

86
Discontinuous variation
  • 2 or more distinct categories with no
    intermediate values
  • Examples
  • Earlobes attached or unattached
  • Blood groups A, B, AB or o
  • Bacteria flagella or no flagella
  • Flowers colour of petals
  • Genetically determined
  • The environment has little or no effect on
    discontinuous variation

87
Discontinuous variation
88
Causes of variation
  • Genetic Variation
  • Genes inherited from parents provide information
    used to define our characteristics
  • Environmental Variation
  • Gives differences in phenotype (appearance) but
    not passed on by parents to offspring
  • Examples
  • Skin colour tans with exposure to sunlight
  • Plant height determined by where the seed lands

89
Learning Outcomes
  • Outline the behavioural, physiological and
    anatomical (structural) adaptations of organisms
    to their environments.

90
Adaptations
  • Adaptations help organisms to cope with
    environmental stresses and obtain the things they
    need for survival.
  • They are features which have evolved over time
    and are continually subjected to selection
    pressures
  • Adaptations can be
  • Structural
  • Behavioural
  • Physiological
  • biochemical

91
A well adapted organism
  • List what a well adapted organism must be able to
    do in order to survive
  • E.g. find enough food / photosynthesis
  • Try to list 6 things

92
Behavioural adaptation
  • Any aspect of the behaviour of an organism that
    helps it to survive the conditions it lives in.
  • Example
  • Desert rat remains underground during the day

93
Physiological / biochemical adaptations
  • These ensure the correct functioning of all cell
    processes
  • Example
  • Some yeast can respire both aerobically and
    anaerobically depending on the availability of
    oxygen

94
Anatomical adaptations
  • A structure which enhances the survival of the
    organism
  • Example
  • Desert rats have very long loops of henle to aid
    the reabsorbtion of water.
  • Fennec fox has large ears

95
Pupil Activity
  • Watch the selection of video clips from planet
    earth
  • Make notes on the adaptations organisms show to
    their environments
  • Almost a fun game
  • Identify the three adaptations for the organisms
    shown - FUN,

96
Pupil Activity
  • Adaptations of xerophytic plants
  • For the list of adaptations given decide whether
    they are physiological, behavioural or structural
    adaptations.
  • Identifying adaptations
  • Look at the selection of photos
  • For each organism try to give an adaptations that
    suits the organism to its habitat.

97
The Saguaro Cactus
98
The fennec fox
99
Polar bear
100
Midge larvae
101
Marram Grass
102
Pupil Activity
  • Collect a copy of the worksheet on adaptations of
    xerophytic plants
  • For each adaptation given, explain how this
    adaptation helps the plant to survive.

103
Learning Outcomes
  • Explain the consequences of the four observations
    made by Darwin in proposing his theory of natural
    selection.
  • Outline how variation, adaptation and selection
    are major components of evolution
  • Define the term speciation.

104
Evolution and Natural Selection
  • Evolution
  • Gradual development of organisms over time
  • Natural Selection
  • Theory proposed by Darwin as a mechanism to
    explain how evolution occurred.

105
Evolution by natural selection
  • Darwins four observations
  • Variation exists among offspring
  • Offspring appear similar to parents and inherit
    features from them
  • Organisms have the ability to produce large
    numbers of offspring
  • Populations of organisms stay relatively stable
    over time
  • Darwins conclusions
  • There is a struggle to survive
  • Better adapted organisms survive and pass on
    their characteristics
  • Over time changes may give rise to a new species

106
The theory of natural selection
  • Variation
  • Overproduction
  • Struggle for existence
  • Survival of the fittest
  • Advantageous features inherited
  • Gradual change in the population
  • Write out a short explanation for each of these
    points.

107
Environmental factors
  • Factors that can limit population size include
  • Availability of food
  • Predators
  • Disease
  • Competition for space
  • Find a mate
  • Physical and chemical factors
  • Selection pressure
  • An environmental factor which determines which
    species survive

108
Speciation
  • Speciation is the formation of a new species from
    a pre-existing one.
  • If two populations of the same species become
    isolated from each other
  • different selection pressures mean that the
    populations develop different adaptations
  • Speciation has occurred when the two populations
    can no longer breed together to produce fertile
    offspring.

109
Types of Speciation
  • Allopatric speciation
  • Geographical
  • Two populations become separated
  • Sympatric speciation
  • two species remain in the same geographical area
    but a reproductive barrier arises, which prevents
    one member of the population breeding with another

110
Progress Questions
  • State the key observations made by Charles Darwin
    4 marks
  • Explain the terms
  • Selection pressure
  • Selective advantage 3 marks

111
Learning outcomes
  • Discuss the evidence supporting the theory of
    evolution, with reference to fossil, DNA and
    molecular evidence.

112
Fossils
  • Fossil
  • Remains of organisms that are preserved in
    sedimentary rocks
  • Examples of fossils

113
Fossil Evidence
  • Fossils show certain facts
  • In the past species were very different than
    species today
  • Old species have died out
  • New species have arisen
  • New species often similar to old species
  • Questions
  • Why does one species die out?
  • Why would a similar one replace it?
  • Did one give rise to the other?

114
Brachiopods
  • Change gradually over time
  • Can be used to age rocks

115
Armadillo vs. Glyptodons
116
Fossil Evidence
  • One of the earliest birds
  • many features that are typical of the reptiles

117
Gaps in the fossil record
  • The fossil record is incomplete for many reasons
  • Only the hard parts of the animals become
    fossilised
  • Fossils can only form under certain conditions
  • After they have formed fossils could become
    damaged or destroyed by rock movements

118
More recent evidence
  • Biological molecules provide strong evidence for
    evolution
  • Many biological molecules are found in all
    organisms
  • All life on earth has a common ancestor
  • Closely related species more similarities
  • Cytochrome C shows patterns of changes

119
Protein Evidence
  • The primary structure of protein molecules is
    determined by the sequences of bases in DNA
  • Vital proteins e.g. DNA and RNA polymerase are
    found in all living organisms

120
DNA evidence
  • Sequencing the bases in DNA allows for comparison
  • Comparing other primates with human DNA, shows
    evolutionary relationships

Differences in coding sequence primate
1.2 Chimpanzee
1.6 Gorilla
6.6 baboons
121
Progress Questions
  • Explain how DNA analysis and biochemistry can be
    used to clarify the evolutionary relationships
    between closely related species 5 marks
  • Explain how fossils can be used as evidence for
    evolution 3 marks
  • Explain the significance of fossils such as
    Archaeopteryx 2 marks

122
Learning Outcome
  • Discuss why the evolution of pesticide resistance
    in insects and drug resistance in microorganisms
    has implications for humans

123
Drug resistance in micro-organisms
  • Using antibiotics changes the environment for the
    bacteria
  • Mutation giving resistance gives individual
    bacterium a selective advantage
  • It survives
  • Over time number of resistant types of bacteria
    increase
  • Some antibiotics are now ineffective

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Arms Race
  • MRSA
  • Methicillin resistant Staphylococcus aureus
  • Developing resistance to an ever increasing range
    of stronger and stronger anti-biotics

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Pesticide Resistance
  • A pesticide is a chemical designed to kill pests
  • Insecticide kills insects
  • Insecticide applies selection pressure on insect
    populations to develop resistance
  • Due to short life cycles resistance spreads
    quickly through the whole population

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Pesticide resistance
  • Resistance
  • Breakdown of insecticide using enzymes
  • Modification of target receptor proteins on cell
    membrane
  • Example
  • Anopheles mosquito
  • Resistant to DDT and pyrethroids

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Practice Questions
  • Answer questions

128
Learning OutcomesEvolution
  • Define the term variation.
  • Discuss the fact that variation occurs within as
    well as between species.
  • Describe the differences between continuous and
    discontinuous variation, using examples of a
    range of characteristics found in plants, animals
    and microorganisms.
  • Explain both genetic and environmental causes of
    variation.
  • Outline the behavioural, physiological and
    anatomical (structural) adaptations of organisms
    to their environments..
  • Explain the consequences of the four observations
    made by Darwin in proposing his theory of natural
    selection.
  • Define the term speciation.
  • Discuss the evidence supporting the theory of
    evolution, with reference to fossil, DNA and
    molecular evidence.
  • Outline how variation, adaptation and selection
    are major components of evolution.
  • Discuss why the evolution of pesticide resistance
    in insects and drug resistance in microorganisms
    has implications for humans

129
2.3.4 Conserving Biodiversity
  • Module 3 Biodiversity and Evolution

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Maintaining Biodiversity
  • Maintaining biodiversity is important for many
    reasons.
  • Actions to maintain biodiversity must be taken at
    local, national and global levels.

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Global Problem
132
Endangered species
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Learning Outcomes
  • Outline the reasons for the conservation of
    animal and plant species, with reference to
    economic, ecological, ethical and aesthetic
    reasons.

134
Definition of conservation
  • Management of human use of the biosphere so that
    it may yield the greatest sustainable benefit to
    present generations while maintaining its
    potential to meet the needs and aspirations of
    future generations.
  • World conservation strategy

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conservation
  • Conservation is the protection of ecosystems,
    habitats and species
  • These means taking action to halt destruction and
    extinction

136
Conservation
  • Conservation involves
  • Managing areas of land
  • Taking steps to encourage new habitats
  • Removing animals to captivity
  • Growing plants in cultivation

137
Reasons for conserving species
  • The main reasons given for conserving species are
  • Economic
  • Ecological
  • Ethical
  • aesthetic

138
Economic reasons
  • Natural ecosystems provide services
  • Examples
  • Regulation of atmosphere and climate
  • Formation and fertilisation of soil
  • Recycling of nutrients
  • Growth of timber, food and fuel
  • Ecosystems also provide goods such as wood and
    fish for free.

139
Ecological reasons
  • Keystone Species
  • Keep ecosystems in balance
  • Photosynthesis
  • Removes CO2 from the air and replaces oxygen

140
Ethical reasons
  • Species become extinct as a result of human
    action
  • Humans have a responsibility to maintain species,
    ecosystems and habitats for future generations
  • All organisms have a right to survive and live in
    the way to which they have become adapted.

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Aesthetic Reasons
  • People enjoy
  • visiting wild places
  • Observing wildlife
  • The large animals are sustained by an
    interdependent web which includes a huge number
    of species
  • Recovery of patients
  • Wellbeing physical, intellectual and emotional
    health

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Learning Outcomes
  • Discuss the consequences of global climate change
    on the biodiversity of plants and animals, with
    reference to changing patterns of agriculture and
    spread of disease.
  • Explain the benefits for agriculture of
    maintaining the biodiversity of animal and plant
    species.

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Genetic Diversity
  • Genetic diversity within species allows that
    species to adapt and evolve
  • Threats to species with a low genetic diversity
    include
  • Climate change
  • Increase in levels of pollution
  • Emergence of new diseases
  • Arrival of pest species

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Stages of human impact on genetic diversity
  • Clearing vegetation
  • Reduce the size of natural habitats
  • Reduce population size
  • Reduce gene pool for species
  • Decrease genetic variation
  • Decrease ability of species to evolve

145
Modern Agriculture
  • Reduces the variation and genetic diversity of
    domesticated plants and animals, this has led to
    the extinction of varieties within a species.
  • Examples
  • Monoculture
  • Selective breeding
  • Estimate one locally adapted breed of animal is
    lost world wide each week.

146
Climate change
  • As climate changes the species are unable to
    adapt due to the loss of genetic variation.
  • Slow migration of populations, communities and
    ecosystems towards the poles
  • Obstruction to migration include
  • Major human developments
  • Agricultural land
  • Large bodies of water
  • humans

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The Golden Toad
  • The golden toad of Costa Rica may have been
    driven to extinction by climate change,
  • The toad's demise has been revealed by research
    into the changing populations of species in Costa
    Rica.
  • The scientists concluded that rising temperatures
    may have been to blame.
  • The disappearance of the toad is part of a
    pattern of change that is affecting not only
    amphibians but also reptiles and birds as well.
  • The Monte Verde golden toad is a very small toad
    found in the tropical forests of Monteverde,
    Costa Rica.
  • It is believed to be extinct since no live
    specimens have been seen since 1989
  • researchers still hope that it continues to live
    in underground burrows.

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Agriculture
  • Read through the list below, decide which of the
    changes due to global warming would benefit
    agriculture ? give reasons!!
  • Higher CO2 levels
  • Higher temperature
  • Longer growing seasons
  • Greater evaporation of water
  • Greater precipitation
  • Sea level rise
  • Increase in salinity of soil

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Climate change and agriculture
  • Human diet is limited
  • Three staple foods wheat, maize, rice
  • Fish stocks cod
  • Crops are genetically uniform and susceptible to
    disease
  • Wild varieties hold genes which could vary the
    genome of our crops

150
Climate change and the spread of disease
  • Migration of insect vectors and disease
  • Tropical disease spread by Anopheles mosquito and
    the tsetse fly may become a problem in Europe
  • Climate change is already responsible for
  • Epidemic of bird malaria in Hawaii
  • Viral distemper among lions in Serengeti
  • Black Stem Rust in wheat

151
Biodiversity for medicine
  • Potential new medicines from plants
  • Possible vaccines from wild micro-organisms
  • Study of traditional medicines

152
Learning Outcomes
  • Describe the conservation of endangered plant and
    animal species, both in situ and ex situ, with
    reference to the advantages and disadvantages of
    these two approaches.
  • Discuss the role of botanic gardens in the ex
    situ conservation of rare plant species or plant
    species extinct in the wild, with reference to
    seed banks.

153
Introduction - recap
  • The threats to biodiversity are caused by human
    activities, which are endangering species
    directly.
  • Species are now being put at risk from habitat
    loss, hunting, and damage by introduced species,
    and loss of disease resistance by pollution.
  • Other species are put at risk if a product from
    the organism becomes a status symbol or is used
    in folk medicine

154
Endangered Species
  • Endangered species are those that have such small
    numbers that they are at risk of extinction
  • Little genetic variability leaves them
    susceptible to genetic and infectious diseases
  • living dead

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Conservation of endangered species
  • The conservation of endangered species can be
  • In situ
  • Animals and plants are protected in their natural
    environment
  • Ex situ
  • Animals are cared for in zoological collections
  • Plants are cared for in botanical gardens

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Four key aims of in situ conservation
  • A natural healthy environment
  • Sustainable use of the natural environment
  • A secure environmental future
  • Enjoyment of the natural environment

157
National Parks
  • In South and East Africa National parks protect
    the largest of the land mammals
  • A national park should be
  • Comprehensive
  • Adequate
  • representative

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Advantages reserve designation
  • Conservation
  • Protection of biodiversity
  • Protection of cultural and natural heritage
  • Areas maintain ecological integrity
  • Opportunities for sustainable land uses
  • Scientific research
  • Meets need of indigenous people

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Conflicts with designations
  • Protected animals raid farmland
  • Hunting for food
  • Illegal harvesting of timber
  • tourism

160
Examples of reserves
  • Phinda reserve South Africa
  • Release of natural fauna
  • NNR in UK protect specific species
  • Snakes head fritillary
  • Fritillaria meleagris
  • Marine Nature reserve
  • Skomer marine nature reserve, pembrokeshire

161
In situ conservation - UK
  • Designated areas in the UK
  • SSSI sites of special scientific interest
  • National parks
  • AONB areas of outstanding natural beauty
  • NNR National nature reserve
  • ESA Environmentally sensitive areas

162
Ex situ conservation - animals
  • The 3 main aims of zoos are conservation,
    education and research.
  • Captive Breeding Programmes
  • Rare and endangered species are bred in captivity

163
Captive breeding programmes
  • Advantages of captive breeding programmes
  • Fewer animals need to be caught in the wild
  • Reduces the chances of extinction
  • Reintroduction into the wild
  • Problems with captive breeding programmes
  • After release
  • Too tame or too used to captivity to survive
  • Difficulties in finding food
  • The original threat is still there
  • Inbreeding depression

164
Case Study Nene Goose (Branta sandivicensis)
  • Largest native bird on Hawaii, it is a
    non-migratory species, which only lives on the
    isolated island.
  • C19 20,000 geese
  • 1940 40 geese
  • Reason for decline - the introduction of
    non-native terrestrial predators, e.g. rats,
    dogs.
  • The mongoose was originally introduced to control
    the rat numbers, but found the geese and their
    eggs easier prey (biological control gone wrong
    again).

165
Case Study Nene Goose (Branta sandivicensis)
  • Captive breeding programme
  • 1951 2 females and 1 male
  • sent to the wildfowls and wetlands trust in
    England.
  • 1971 1200 geese
  • in wildfowl sanctuaries around the world.
  • 1600 geese
  • release back onto Hawaii
  • Measures were put in place to protect the geese,
    such as netting around nesting areas, and control
    of the predatory species.

166
Ex situ - plants
  • Botanical Gardens
  • Collect seeds from the wild
  • Seeds stored and germinated in protected
    conditions
  • Can increase the number of individuals of a
    species very quickly
  • KEW Gardens
  • 40 000 species of vascular plants
  • Important in maintaining biodiversity and genetic
    diversity in plants

167
Disadvantages botanical gardens
  • Collection of wild seeds will cause some
    disturbance
  • Collected samples not representative
  • Seeds stored may not be viable
  • Plants bred asexually are genetically identical

168
Seed Banks
  • E.g. millennium seed bank, West Sussex
  • Seeds kept in a cold store
  • The moisture content of seeds are reduced under
    low temperature and then frozen.
  • Some specialise in preserving varieties of crop
    plants
  • Botanists noahs ark

169
Learning Outcomes
  • Discuss the importance of international
    cooperation in species conservation with
    reference to the Convention in International
    Trade in Endangered Species (CITES) and the Rio
    Convention on Biodiversity.

170
International Co-operation
  • The loss of habitat and the number of endangered
    species is a worldwide problem
  • Needs a worldwide solution

171
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172
The convention of international trade in
endangered species of wild flora and fauna
  • Consists of three Appendices protecting around
    25,000-30,000 species
  • Aim
  • Ensure that international trade in specimens of
    wildlife does not threaten their survival
  • CITES main aims involve the regulation and
    monitoring of international trade

173
CITES appendix 1
  • Appendix I includes species threatened with
    extinction.
  • Trade in specimens of these species is permitted
    only in exceptional circumstances.

174
The convention of international trade in
endangered species of wild flora and fauna
  • Appendix one includes species that are threatened
    with extinction
  • Gorillas
  • Tigers
  • Leopards
  • Asiatic lion
  • Monkey puzzle tree Araucaria araucana
  • Cycad Cycas beddomei

175
CITES Appendix 1
176
CITES Appendix 1
177
CITES Appendix 1
178
CITES Appendix 1
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CITES Appendix 1
  • And finally the pitcher plant
  • Nepenthes rajah

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CITES Appendix 2
  • Appendix II includes species not necessarily
    threatened with extinction,
  • trade must be controlled in order to avoid
    utilization incompatible with their survival.

181
CITES Appendix 3
  • This Appendix contains species that are protected
    in at least one country, which has asked other
    CITES Parties for assistance in controlling the
    trade.

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Mammals
  • The following entire groups (orders or families)
    of mammals are included in CITES Appendices I or
    II
  • all primates
  • all cetaceans
  • (whales dolphins)
  • all cats
  • (leopard, tiger, etc)
  • all bears
  • all elephants
  • all rhinoceroses

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Reptiles
  • The following entire groups (orders or families)
    of reptiles are included in CITES Appendices I or
    II
  • all crocodylians
  • (alligators, crocodiles, caimans,etc)
  • all sea turtles
  • (Cheloniidae)
  • all Boidae
  • (boas, pythons)

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invertebrates
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Convention on Biological Diversity
186
Convention on Biological Diversity (CBD)
  • Signed in 1992 at the Earth Summit in Rio de
    Janeiro
  • Covers
  • Use and conservation of biodiversity
  • Sustainable development
  • co-operation between countries and states
  • UK government launched the Biodiveristy Action
    Plan in response to the convention

187
Learning Outcomes
  • Discuss the significance of environmental impact
    assessments (including biodiversity estimates)
    for local authority planning decisions.

188
Environmental Impact Assessment
  • CBD Agenda 21 sustainable development
  • Ecologists sample an area
  • report on the likely impact of the development
    on the species and their habitats
  • Developers and planners
  • Take into account the effects highlighted and
    seek to minimise them
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