Transcript What determines where particular species live and

Module 3:
Biodiversity and Evolution
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.
Biodiversity
• Biodiversity is an important indicator in the
study of habitats.
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.
Evolution
• “Nothing in biology makes sense except in the
light of evolution”
– Theodosius Dobzhansky, 1973.
Maintaining Biodiversity
• Maintaining biodiversity is important for many
reasons.
• Actions to maintain biodiversity must be taken
at local, national and global levels.
2.3.1. Biodiversity
Module 3: Biodiversity and Evolution
Learning Outcomes
• define the terms ‘species’, ‘habitat’ and
‘biodiversity’
• explain how biodiversity may be considered
at different levels;
– habitat,
– species
– genetic
Biodiversity
• The biodiversity of an area is a measure of:
– Different ecosystems
– Number of species
– Number of individuals of each species
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
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
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
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Morphological
Physiological
biochemical
Ecological
behavioural
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
Examples of habitats
• Name of the place
• A description of dominant vegetation
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Coniferous forest
Oak woodland
Tropical rainforest
Grassland
• A type of environment
– Freshwater pond
– Rock pool on a rocky shore
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?
The state of the planet
Programme 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?
Measuring Biodiversity
Measuring Biodiversity
learning Outcomes
• explain the importance
of sampling in
measuring the
biodiversity of a habitat
describe how random
samples can be taken
when measuring
biodiversity
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
Measuring biodiversity
• Distribution
– Where the species is found
• Abundance
– How many of each species are present
– Estimating abundance
• Take a representative sample
• Multiply up
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
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
Recording results
• Prepare a table
– Space for all species
– Space to record the data for each sample site
Sampling techniques
• Quadrats
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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
Sampling techniques
• Belt transect
– Interrupted belt transect
– Continuous belt transect
– Used to survey rocky
shores or sand dunes
Interrupted belt transect
continuous belt transect
Measuring abundance
• Percentage Cover
– Proportion of quadrat’s
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
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Abundant
Common
Frequent
Occasional
Rare
• Species frequency
– Proportion of quadrats
with the species present
Rocky Shores
Some text, photos and diagrams taken from:
Marine Field Course Guide to Rocky Shores (1992) by S.J. Hawkins & H. D. Jones
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.
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.
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.
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
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
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.
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.
Sampling in School Grounds
• Suggested activities
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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
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
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Sweep netting
Kick sampling
Tree sampling
Pitfall trap
Tulgren funnel
Light trap
Surveying school grounds
• Suitable methods that could be used in
school include
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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.
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
Why do we need to study habitats?
• Assess human impact
• EIA – Planning process
• To highlight the importance of maintaining
habitats and reducing the damage
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 Simpson’s Index of Diversity (D)
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
Simpson’s 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
Progress Question
• Use Simpson’s index to calculate the diversity
of a habitat that contains the following
organisms
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20 woodlice
5 mice
1 shrew
32 earthworms
15 grasshoppers
1 owl
• Comment on the diversity of this habitat
Calculating simpson’s
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
Answers to progress questions
• D = 1 – 0.306
• D = 0.694
2.3.2 Classification
Module 3: Biodiversity and evolution
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.
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.
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
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
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
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?
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.
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
Hierarchy of classification
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Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
– This is the basic unit of classification
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.
Hierarchy of classification
Taxon
Domain
No. of similarities
Size of group
Degree of relatedness
small
Large
Distant to common
ancestor
large
small
Recent common
ancestor
Kingdom
Phylum
Class
Order
Family
Genus
Species
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
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.
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.
Binomial Classification
• Universal system based on Latin names
– Generic name
– Specific name
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.
Binomial system of nomenclature
• Examples
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Homo sapiens
Panthera leo
Panthera tigris
Lutra lutra
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
Five Kingdom Classification
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Prokaryotae
Protoctista
Fungi
Plantae
Animalia
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 9+2 microtubules
Protoctista
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Eukaryotic
mostly unicellular
Plant-like or animal-like organisms
Includes
– Chlorophyta (green algae)
– Phaeophyta (brown algae)
Fungi
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Eukaryotic
Heterotrophic nutrition
Cell walls made of chitin
Usually form mycelium
Carbohydrate stored as glycogen
Sexual or asexual reproduction
Plantae
• Features
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Eukaryotic
Multicellular
Possesses chlorophyll and other pigments
Autotrophic nutrition
Cells walls of cellulose
Carbohydrate stored as starch.
Animalia
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Eukaryotic
Multi-cellular
Heterotrophic nutrition
No cell walls
Carbohydrate stored as glycogen
Display nervous co-ordination
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.
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
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.
New developments
• Scanning Electron Microscopy
– Looks at morphology in greater detail
• DNA sequencing
– Helps classification to reflect phylogeny using
nucleotide sequence data
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
Why three domains?
• Eubacteria are prokaryotic and
fundamentally different from Archaeae and
eukaryotae
• Archaeae share characteristics with
eukaryotae
– RNA polymerase
– Similar DNA replication mechanisms
Five kingdom
classification
Three domain classification
2.3.3 Evolution
Module 3: Biodiversity and Evolution
Evolution
• “Nothing in biology makes sense except in the
light of evolution”
– Theodosius Dobzhansky, 1973.
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.
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.
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
Continuous variation
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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
Continuous variation
• Use a tally chart and plot results in a histogram
Discontinuous variation
• 2 or more distinct categories with no intermediate
values
• Examples
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Earlobes
Blood groups
Bacteria
Flowers
attached or unattached
A, B, AB or o
flagella or no flagella
colour of petals
• Genetically determined
• The environment has little or no effect on
discontinuous variation
Discontinuous variation
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
Learning Outcomes
• Outline the behavioural, physiological and
anatomical (structural) adaptations of
organisms to their environments.
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
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Structural
Behavioural
Physiological
biochemical
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
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
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
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
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,
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.
The Saguaro Cactus
The fennec fox
Polar bear
Midge larvae
Marram Grass
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.
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.
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.
Evolution by natural selection
• Darwin’s 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
• Darwin’s 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
The theory of natural selection
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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.
Environmental factors
• Factors that can limit population size include
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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
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.
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
Progress Questions
• State the key observations made by Charles
Darwin
[4 marks]
• Explain the terms
– Selection pressure
– Selective advantage
[3 marks]
Learning outcomes
• Discuss the evidence supporting the theory of
evolution, with reference to fossil, DNA and
molecular evidence.
Fossils
• Fossil
– Remains of organisms that are preserved in
sedimentary rocks
• Examples of fossils
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?
Brachiopods
• Change gradually over time
• Can be used to age rocks
Armadillo vs. Glyptodons
Fossil Evidence
• One of the earliest birds
• many features that are
typical of the reptiles
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
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
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
DNA evidence
• Sequencing the bases in DNA allows for comparison
• Comparing other primates with human DNA, shows
evolutionary relationships
Differences in coding
sequence
1.2%
primate
Chimpanzee
1.6%
Gorilla
6.6%
baboons
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]
Learning Outcome
• Discuss why the evolution of pesticide
resistance in insects and drug resistance in
microorganisms has implications for humans
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
Arms Race
• MRSA
– Methicillin resistant Staphylococcus aureus
– Developing resistance to an ever increasing range
of stronger and stronger anti-biotics
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
Pesticide resistance
• Resistance
– Breakdown of insecticide using enzymes
– Modification of target receptor proteins on cell
membrane
• Example
– Anopheles mosquito
• Resistant to DDT and pyrethroids
Practice Questions
• Answer questions
Learning Outcomes
Evolution
• 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
2.3.4 Conserving Biodiversity
Module 3: Biodiversity and Evolution
Maintaining Biodiversity
• Maintaining biodiversity is important for many
reasons.
• Actions to maintain biodiversity must be taken
at local, national and global levels.
Global Problem
Endangered species
Learning Outcomes
• Outline the reasons for the conservation of
animal and plant species, with reference to
economic, ecological, ethical and aesthetic
reasons.
Definition of conservation
• Management of human use of the biosphere
so that it may yield the greatest sustainable
benefit to present generations while
maintaining it’s potential to meet the needs
and aspirations of future generations.
– World conservation strategy
conservation
• Conservation is the protection of ecosystems,
habitats and species
• These means taking action to halt destruction
and extinction
Conservation
• Conservation involves
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Managing areas of land
Taking steps to encourage new habitats
Removing animals to captivity
Growing plants in cultivation
Reasons for conserving species
• The main reasons given for conserving species
are
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Economic
Ecological
Ethical
aesthetic
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.
Ecological reasons
• Keystone Species
– Keep ecosystems in balance
• Photosynthesis
– Removes CO2 from the air and replaces oxygen
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.
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
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.
Genetic Diversity
• Genetic diversity within species allows that
species to adapt and evolve
• Threats to species with a low genetic diversity
include:
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Climate change
Increase in levels of pollution
Emergence of new diseases
Arrival of pest species
Stages of human impact on genetic
diversity
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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
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.
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
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Major human developments
Agricultural land
Large bodies of water
humans
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.
Agriculture
• Read through the list below, decide which of
the changes due to global warming would
benefit agriculture  give reasons!!
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Higher CO2 levels
Higher temperature
Longer growing seasons
Greater evaporation of water
Greater precipitation
Sea level rise
Increase in salinity of soil
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
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
Biodiversity for medicine
• Potential new medicines from plants
• Possible vaccines from wild micro-organisms
• Study of traditional medicines
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.
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
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”
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
Four key aims of in situ conservation
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A natural healthy environment
Sustainable use of the natural environment
A secure environmental future
Enjoyment of the natural environment
National Parks
• In South and East Africa National parks
protect the largest of the land mammals
• A national park should be:
– Comprehensive
– Adequate
– representative
Advantages reserve designation
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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
Conflicts with designations
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Protected animals raid farmland
Hunting for food
Illegal harvesting of timber
tourism
Examples of reserves
• Phinda reserve – South Africa
– Release of natural fauna
• NNR in UK – protect specific
species
– Snake’s head fritillary
Fritillaria meleagris
• Marine Nature reserve
– Skomer marine nature reserve,
pembrokeshire
In situ conservation - UK
• Designated areas in the UK
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SSSI – sites of special scientific interest
National parks
AONB – areas of outstanding natural beauty
NNR – National nature reserve
ESA – Environmentally sensitive areas
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
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
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After release
Too tame or too used to captivity to survive
Difficulties in finding food
The original threat is still there
Inbreeding depression
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
– 1940
20,000 geese
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).
Case Study:
Nene Goose (Branta sandivicensis)
• Captive breeding programme
– 1951
2 females and 1 male
» sent to the wildfowl’s 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.
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
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
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
– Botanist’s noah’s ark
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.
International Co-operation
• The loss of habitat and the number of
endangered species is a worldwide problem
– Needs a worldwide solution
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
CITES appendix 1
• Appendix I includes species threatened with
extinction.
• Trade in specimens of these species is
permitted only in exceptional circumstances.
The convention of international
trade in endangered species of
wild flora and fauna
• Appendix one includes species that are
threatened with extinction
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Gorillas
Tigers
Leopards
Asiatic lion
Monkey puzzle tree
Cycad
Araucaria araucana
Cycas beddomei
CITES Appendix 1
CITES Appendix 1
CITES Appendix 1
CITES Appendix 1
CITES Appendix 1
• And finally the pitcher
plant
– Nepenthes rajah
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.
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.
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
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)
invertebrates
Convention on Biological Diversity
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
Learning Outcomes
• Discuss the significance of environmental
impact assessments (including biodiversity
estimates) for local authority planning
decisions.
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