Module 3: Biodiversity and Evolution

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Module 3Biodiversity and Evolution
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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.

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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.

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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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2.3.1. Biodiversity

• Module 3 Biodiversity and Evolution

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Learning Outcomes

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

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Biodiversity

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

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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

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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

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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

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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

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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

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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?

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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?

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Measuring Biodiversity
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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

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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

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Measuring biodiversity

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

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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

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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

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Recording results

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

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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

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Sampling techniques

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

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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

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Rocky Shores
Some text, photos and diagrams taken from Marine
Field Course Guide to Rocky Shores (1992) by S.J.
Hawkins H. D. Jones
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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.

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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.

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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.

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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
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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

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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.

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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.

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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

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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

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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.

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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

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Why do we need to study habitats?

• Assess human impact
• EIA Planning process
• To highlight the importance of maintaining
  habitats and reducing the damage

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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)

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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

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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

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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

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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
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Answers to progress questions

• D 1 0.306
• D 0.694

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2.3.2 Classification

• Module 3 Biodiversity and evolution

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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.

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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.

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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

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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

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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

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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?

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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.

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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

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Hierarchy of classification

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

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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.
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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
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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
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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.

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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.
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Binomial Classification

• Universal system based on Latin names
• Generic name
• Specific name

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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.

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Binomial system of nomenclature

• Examples
• Homo sapiens
• Panthera leo
• Panthera tigris
• Lutra lutra

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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

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Five Kingdom Classification

• Prokaryotae
• Protoctista
• Fungi
• Plantae
• Animalia

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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

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Protoctista

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

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Fungi

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

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Plantae

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

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Animalia

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

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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.

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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

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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.

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New developments

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

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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

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Five kingdom classification
78
Three domain classification
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2.3.3 Evolution

• Module 3 Biodiversity and Evolution

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Evolution

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

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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.

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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

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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
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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

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Learning Outcomes

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

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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

124
Arms Race

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

125
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

126
Pesticide resistance

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

127
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

130
Maintaining Biodiversity

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

131
Global Problem
132
Endangered species
133
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

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Conservation

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

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Reasons for conserving species

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

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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.

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Ecological reasons

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

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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.

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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

149
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

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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

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Biodiversity for medicine

• Potential new medicines from plants
• Possible vaccines from wild micro-organisms
• Study of traditional medicines

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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.

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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

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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

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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

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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

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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

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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

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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

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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).

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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.

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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

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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

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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

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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

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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

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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

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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.

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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
185
Convention on Biological Diversity
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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

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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