NATIONAL QUALIFICATIONS CURRICULUM SUPPORT
Biology
Unit 3, Part 1: Biodiversity
Teacher’s Notes
[HIGHER]
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Acknowledgement
Learning and Teaching Scotland gratefully acknowledges this contribution to the National
Qualifications support programme for Biology.
The publishers gratefully acknowledge permission to use the following sources: Text from
Scotland’s Biodiversity – It’s in Your Hands, The Scottish Executive, 2004, p19–23, ISBN
0755841209, Crown Copyright © Scottish Executive, Scotland’s Biodiversity – It’s in Your
Hands, The Scottish Executive, 2004, p19–23; Screenshot of
http://www.treesforlife.org.uk/forest/humanimpacts/fragmentation.html; Text from ‘Lesser
Kestrels but Why?’ by Tony Aitken, DART Publishing, 1994 © Tony Aitken, DART
Publishing.
Every effort has been made to trace all the copyright holders but if any have been
inadvertently overlooked, the publishers will be pleased to make the necessary arrangements
at the first opportunity.
© Learning and Teaching Scotland 2011
This resource may be reproduced in whole or in part for educational purposes by educational
establishments in Scotland provided that no profit accrues at any stage.
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Contents
(a)
Mass extinction
4
(b) Measuring biodiversity
10
(c)
20
Threats to biodiversity
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1.
Biodiversity
(a)
Mass extinction
Fossil evidence indicates that there have been several mass extinction events in the past. Following each mass extinction event,
biodiversity has been regained slowly and some surviving taxonomic groups radiate
There are difficulties in estimating past and current species extinction rates. The extinction of megafauna is correlated with the
spread of humans.
The escalating rate of ecosystem degradation caused by humans is causing the rate of species extinction to be much higher tha n
the natural background rate.
Links to prior/prerequisite knowledge
Unit 2: Environmental Biology and Genetics (Intermediate 2) should have been achieved, in relation to:
 evolutionary response to environmental change (Darwin’s finches)
 how biodiversity can be affected by habitat destruction ca used by human activities.
New content areas
Fossil evidence of several mass extinctions in the past (Cretaceous and Permian periods). These are commonly referred to as the
big 5.
Regaining biodiversity after a mass extinction and the surviving taxonomi c groups which radiate.
The rate of ecosystem degradation that is human led is accelerating the rate of species extinction. This rate is much higher than
would occur naturally.
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Background information
Mass extinction information sourced from http://palaeo.gly.bris.ac.uk/palaeofiles/triassic/extinction.htm .
Mass extinctions are periodic rises in the extinction rate above the background level. They are events that are not caused by
changes in habitat or competition but catastrophes.
Perhaps over 95% of all extinctions have occurred as background events, with the rest consisting of catastrophic events which :




were geologically rapid (occurred within a few million years)
occurred across the globe (not localised events)
had a large number of species becoming extinct in the same time period (both land and marine organisms)
spread across all the world’s ecosystems.
Mass extinctions are dramatic events that significantly decrease the Earth’s biodiversity. These events are used to mark
momentous occasions in geological time. Scientists have begun to class events according to their ecological impact on Earth,
rather than by the number of species that have been lost.
Five main extinction events have been recognised, these are known as the big 5:
1.
2.
3.
4.
5.
the late Ordovician event 438 million years ago – 100 families* became extinct
late Devonian 360 million years ago – 30% of families became extinct
end Permian 245 million years ago – the biggest extinction of all time when over 50% of all families were lost
late Triassic – 35% of families died out
the Cretaceous Tertiary (K-T) 65 million years ago – ended the reign of the dinosaurs.
*A family consists of a few thousand species.
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Student activity a1 to be completed here.
Regaining biodiversity information sourced from http://www.macroevolution.net/the-concept-of-radiation.html.
Large groups of related organisms are often described as arising via a process of divergent specialisation called radiation, in
which a single ancestral form gives rise to numerous descendant or ‘specialised’ types. (A good example to jog students’
memories would be to mention Darwin’s finches.)
It is suggested that after a major event, such as a mass extinction, radiation starts again as the extinction has eliminated the
majority of established organisms that came into being in the previous radiation.
Radiation starts with simpler, smaller and more generalised forms of an organism, such as a non-specialised finch that develops
over a period of time into more specialised forms.
Always, a primitive, small, generalised type initiates the new radiation. The various forms produced by any given radiation are
always more progressive than those produced by the preceding one.
At the end of a radiation, all the various specialised types it produces are wiped out again. All that remains is a small, pr imitive,
generalised type (which founds a new radiation) and a few other types (whose descendants eventually become extinct).
Background rate of extinction
The background extinction rate, also known as the normal extinction rate, refers to the standard rate of extinction in Earth’s
geological and biological history. It is noteworthy that this ‘normal’ rate refers to natural processes, before humans became a
primary contributor to extinctions. Given normal extinction rates , species typically exist for 5–10 million years before
becoming extinct.
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Extinction rates during the past century have ranged from 100 to 10,000 species per year (assuming that the normal extinction
rate applies). That rate is between 100 and 1000 times faster than the background rate of species extinction (which is normally
1–10 extinctions per year). This is a direct result of human activities.
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Identification of key concepts
 Understanding what is meant by mass extinction and how these events occur.
 There have been five main episodes of mass extinction because of catastrophic even ts. Students should be able to name two
of these mass extinction periods.
 Scientists predict that we are heading for a sixth mass extinction because of the damaging ecological impact that humans
have had on the world.
 After a period of mass extinction, biodiversity is slowly regained and results in organisms evolving that are specialised for
their niche. This process of radiation stems from a simple, primitive organism yet results in a wide range of specialised and
progressive organisms.
 The more specialised organisms tend to survive while the more primitive ancestor dies out.
 The background extinction rate is the normal rate at which organisms become extinct. This is normally between 1 and 10
extinctions per year, per one million different species.
 The extinction rate has been greatly accelerated to somewhere in the region of 100 –1000 species per year as a result of
human activities.
Identification of particular areas of difficulty
The data-handling exercise is challenging, but with guidance from the teac her it should be accessible to students.
Links to sources of further information
www.scotland.gov.uk/biodiversity
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Links to websites, animations, PowerPoints, audio and video files etc
http://www.well.com/~davidu/extinction.html
http://palaeo.gly.bris.ac.uk/palaeofiles/triassic/extinction.htm
http://www.bbc.co.uk/scotland/learning/learningzone/clips/10497/
Video – mass extinction threat to Amur leopard to illustrate species under threat of extinction.
http://www.bbc.co.uk/scotland/learning/learningzone/clips/7129/
Human impact on endangered turtles.
Other useful information to stimulate interest
http://rainforests.mongabay.com/0908.htm
http://www.guardian.co.uk/environment/2010/mar/07/extinction -species-evolve
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(b)
Measuring biodiversity
(i)
Genetic diversity
Measurable components of biodiversity include genetic diversity , species diversity and ecosystem diversity.
Genetic diversity comprises the genetic variation represented by the number and frequency of all the alleles in a populatio n. If
one population dies out then the species may have lost some of its genetic diversity and this may limit its ability to adapt to
changing conditions.
Links to prior/prerequisite knowledge
Students must have a basic understanding of Mendelian geneti cs and be able to define terms such as species, habitat,
population, ecosystem, allele, gene, heterozygous, homozygous, dominant, recessive, chromosome and biodiversity
(Intermediate 2/Standard Grade). Students should recognise that genes are found on stru ctures called chromosomes and that
these differ amongst and within populations.
New content areas
Biodiversity has three main measurable components:
 genetic diversity
 species diversity
 ecosystem diversity.
Genetic diversity can be measured by counting the total number of different alleles that exist in a popula tion and how frequently
they occur.
If a population loses some of its genetic diversity (eg due to human activities) then it may not be able to adapt to future
environmental conditions.
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Background information
2010 was the International Year of Biodiversity. Measuring biodiversity and the development of techniques to maintain
biodiversity is a topical issue at local, national and global level s. Students should be encouraged to discuss these issues before
the core learning outcomes are introduced.
The Scottish government has produced a document that details the importance of biodiversity ( Scotland’s biodiversity: its in
your hands, 2004). This may be used for the development of a discussion. T he importance of personal commitment to
maintaining biodiversity should be explored.
Genetic diversity information sourced from http://cnx.org/content/m12158/latest/.
Genetic diversity refers to the variation that exists in the nucleotides, genes, chromosomes or entire genomes of organisms. A
genome is the entire complement of DNA located within the cells of an organism. Research into genetic variation is important
for studies on biodiversity, the functioning of ecosystems and the effects of humans on natural populations. It is also
fundamental for understanding the spread of disease and for the development of medicines. Variation at its most basic level
exists in the order of the four nucleotides (aden ine, guanine, thymine and cytosine) in molecules of DNA (deoxyribonucleic
acid). This in turn leads to variation in short sections of DNA, known as genes. The order of these genes determines the order of
amino acids in proteins manufactured by an organism and therefore has an effect on the physical appearance, or phenotype, of
an individual.
Many organisms are diploid, meaning they have two sets of chromosomes in the nucleus of each cell. Each chromosome carries
a version of each gene, known as an allele. The alleles inherited by an individual may be genetically identical (the organism is
homozygous for the gene) or different (the organism is heterozygous). The number of times an allele appears in a population is
the allele frequency, which is used as a mea sure of the genetic variation in a population.
Mutations during meiosis may lead to plants becoming triploid or tetraploid, ie having three or four sets of chromosomes,
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respectively. Harmless mutations and the random meeting of gametes during fertilisati on can lead to the introduction of new
characteristics to the population. If these changes are beneficial to the organism they will be favoured by natural selection and
the characteristic will become more common in the population. The number of chromosomes in the genotype of an organism
does not necessarily reflect the complexity of the organism. For example , the chromosome complement of humans is 46 and in
sheep it is 54. Genetic diversity within humans is now known to be dependent on the geographical loca tion of the population.
Anthropologists and biologists have identified people from Africa as having the greatest genetic variation. This research was
published in the scientific journal Science (Science, 22 May 2009, vol. 324, no. 5930, pp 1035–1044). See
http://news.bbc.co.uk/1/hi/health/8027269.stm for a summary of the findings.
The importance of maintaining genetic diversity into the future has been widely researched. Studies show that large populations
generally have more genetic variation than smaller ones. Human activities such as burning fossil fuels, pollution, deforestat ion
and the overexploitation of wild populations threaten animal s and plants, and thus limit their ability to adapt in a changing
environment. Preserving genetic diversity in plants for future food production is discussed in a report produce d by the United
Nations entitled The State of the World’s Genetic Resources for Food and Agriculture (Rome, 2010; this can be sourced online
at http://www.fao.org/docrep/013/i1500e/i1500e.pdf ).
Identification of key concepts
 Explain why biodiversity is important and why there is a need to maintain biodiversity locally, na tionally and globally.
 Research and discuss current estimates of global biodiversity .
 State how biodiversity is measured and identify the problems associated with measuring biodiversity .
 Carry out practical fieldwork by sampling species and be able to dis cuss problems associated with this.
 Suggest improvements to overcome problems with sampling and classifying species .
 Be able to define the term ‘genetic diversity’.
 State that genetic diversity can be measured by the number and frequency of alleles in a p opulation.
 Explain why it is necessary to prevent extinction and the loss of genetic diversity within populations .
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Identification of particular areas of difficulty
Being able to complete fieldwork on sampling species – may be difficult in some schools to access, or there may be time
constraints.
Links sources of further information
Measuring biodiversity – Practical fieldwork
http://www.field-studies-council.org/outdoorscience/diy.htm (London Outdoor Science)
http://www.nhm.ac.uk/education/online-resources/urban-tree-survey/ (Natural History Museum – guide to urban tree survey)
http://www.practicalbiology.org/ (Practical Biology)
Research task – Why is maintaining biodiversity important?
http://www.unep.org/geo/geo4/report/05_Biodiversity.pdf (United Nations Environment Programme)
http://www.nerc.ac.uk/research/issues/biodiversity/ (Natural Environment Research Council)
Links to websites, animations, PowerPoints, audio or video files etc
www.wri.org (World Resources Institute)
http://www.cbd.int/2010/welcome/ (Convention on Biological Diversity) has a good Red List of ‘species of the day’
http://www.eol.org/ (Encyclopaedia of Life)
Other useful information to stimulate interest
Life in the Undergrowth series to highlight diversity among the insects; why were the insects so successful?
Blue Planet DVD – Deep Sea as a discussion of the many species we are yet to discover .
Public Broadcasting Service (PBS) Documentary ‘The Crater Lions’ http://www.pbs.org/wnet/nature/craterlions/index.html can
be used as an introduction to the effects of inbreeding and the need to maintain genetic diversity in wild populations.
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(b)
Measuring biodiversity
(ii)
Measuring species diversity
Species diversity comprises the number of differen t species in an ecosystem (the species richness) and the proportion of each
species in the ecosystem (the relative abundance). A community where a dominant species is abundant has less species diversit y
than one with the same species richness but where the abundance of species is more evenly distributed.
The effects of isolation and habitat fragmentation on species diversity.
Links to prior knowledge/prerequisite knowledge
Curriculum for Excellence outcomes
I understand how animal and plant species depe nd on each other and how living things are adapted for survival. I can predict
the impact of population growth and natural hazards on biodiversity.
SCN 4-01a
Standard Grade outcomes
The Biosphere – Control and Management
Obtain and present information on the pollution of water by organic waste, to include the effect on oxygen levels and numbers
of organisms present. Explain what is meant by ‘indicator species’.
Intermediate 2 outcomes
Unit 2: Environmental Biology and Genetics
2(i) Factors affecting the variety of species in an ecosystem
The importance of biodiversity at species level. Biodiversity defined as the range of species in an ecosystem. A species defi ned
as a group of organisms that can interbreed to produce fertile offspring. A stable ecosystem has a wide range of species and
food webs. The removal of one or more species and the consequences this has on other organisms/populations in the food web.
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New Higher Biology outcomes
1.
Biodiversity. (b) Measuring biodiversity
Biodiversity has three main measurable components: genetic diversity, species diversity and ecosystem diversity. Attempts are
underway to produce a central catalogue of all known species.
New content areas
 Measuring the species diversity of a local area .
 Using a species richness index of indicator species to assess environmental quality .
 The difference between two communities where one has an abundance of one dominant species compared to one with the
same species richness but a more evenly distributed abundance of species.
 The effects of isolation and habitat fragmentation on species diversity .
Background information
Species diversity is only one component of the concept of biodiversity. Species diversity is a measure of the diversity within an
ecological community that incorporates both the evenness of species ’ abundances and the species richness (the number of
species in a community).
Species diversity is influenced by species richness. All else being equal, communities with more species are considered to be
more diverse. For example, a community containing 20 species would be more diverse than a community with 10 species.
Species diversity is also influenced by the relative abundance of individuals in the species found in a community. Evenness
measures the variation in the abundance of in dividuals per species within a community. Communities with less variation in the
relative abundance of species are considered to be more ‘even’ than communities with more variation in relative abundance.
Consider the following two communities.
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Community X
Species
1
2
3
4
5
6
7
8
9
10
Community Y
Abundance
10
10
10
10
10
10
10
10
10
10
Species
1
2
3
4
5
6
7
8
9
10
Abundance
91
1
1
1
1
1
1
1
1
1
All ten species in Community X have the same abundance, whereas there is great variation in abundance across the ten species
in Community Y. For this reason, we would consider Community X to be more even.
All else being equal, communities with greater evenness are considered to have greater species diversity. Even though the
species richness of the two communities is equal (species richness = 10 in each community), Community Y is less diverse than
Community X because most of the individuals in Community Y are members of the same species.
Determining which community has greater species diversity is easy when either species richness or evenness is held constant
while the other parameter varies, but often communities will vary in both richness and evenness. Scientists have developed a
variety of indices that incorporate both species richness and evenness in a single measure of species diversity (eg the Shann on–
Wiener index and Simpson’s index – further information on page 19. Different diversity indices assign different weightings to
species richness and evenness, so the most useful index to choose depends on the circumstances.
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Measurements of simple species richness are related to area size, but are also affected by sampling intensity. When relatively
small numbers of samples are taken from a given area, the numbers of species identified will be lower than if greater numbers
of samples are collected. The more samples that are collected, the greater the number of species that will be found.
Information sourced from ‘The Encyclopedia of Earth’ at www.eoearth.org.
The term ‘habitat fragmentation’ refers to the fragmentation in an organisms’ habitat. This can be caused by slow geological
processes that, in time, alter the organisms’ environment, or by humans. Habitat fragmentation by humans happens rapidly and
can cause the number of species in a habitat to decrease and can cause extinctions.
Identification of key concepts
 Definitions of ‘species richness’ and ‘relative abundance’.
 Measuring the species diversity of a local area .
 Using a species richness index of indicator species to assess environmental quality .
 The difference between two communities where one has an abundance of one dominant species compared to one with the
same species richness but a more evenly distributed abundance of species.
 The effects of isolation and habitat fragmentation on species diversity .
Identification of particular areas of difficulty
Understanding the equations of the Simpson and Sharon indexes for measuring species diversity.
Definitions of ‘species richness’ and ‘relative abundance’:
 species richness – the number of different species in an ecosystem
 relative abundance – the proportion of each species in the ecosystem.
Links sources of further information
http://cnx.org/content/m12174/latest/ – contains information on species diversity and a glossary of terms.
www.nhm.ac.uk – includes images of world maps and biodiversity and information about Natural History Museum research
projects. Their education link has several suggested activities that could be us ed or adapted to suit each class or teacher.
http://teachers.sduhsd.net – teacher media centre.
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http://zoology.muohio.edu/ – various papers on species diversity.
All links to sources to further information could be used by the teacher to further their own understanding of the content in this
section or used as extension work or research task for pupils . Images from the sites could be used in PowerPoints or the
suggested learning activities from the sites could be adapted and used in class.
See Student activity b(ii) for resources that could be used as consolidation or revision techniques with this section of work.
See Measuring Species Diversity PowerPoint b(ii).
Links to websites, animations, PowerPoints, audio or video files etc
www.countrysideinfo.co.uk – contains lots of interactive activities, visual and audible resources and a generally useful site for
students to build interest in this section of the course.
www.eoearth.org – useful for habitat fragmentation.
Other useful information to stimulate interest
Many useful reference documents can be accessed direct ly from the websites of the Scottish Executive, Scottish Biodiversity
Forum and UK Biodiversity Action Plan.
www.scotland.gov.uk/publications
www.ukbap.org.uk
Kindrogan FSC centre offer a course to allow students a chance to take part in activities directly related to this sub -section, and
the biodiversity topic as a whole. More information and prices can be found at http://www.field-studiescouncil.org/outdoorclassroom/biology/aqa/ .
Further reading:
Magurran, A.E. (1988) Ecological Diversity and its Measurement. Princeton University Press, Princeton, NJ.
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Simpson's diversity indices
The term ‘Simpson’s diversity index’ can actually refer to any one of three closely related indices.
Simpson's index (D) measures the probability that two individuals randomly selected from a sample will belong to the same
species (or some category other than species). There are two versions of the formula for calculating D. Either is acceptable, but
be consistent.
D = Σ(n/N) 2
n = the total number of organisms of a particular species
N = the total number of organisms of all species
The value of D ranges between 0 and 1
With this index, 0 represents infinite diversity and 1 represents no diversity. That is, the bigger the value of D, the lower the
diversity. This is neither intuitive nor logical, so to get over this problem, D is often subtracted from 1 to give:
Simpson's index of diversity: 1 – D
The value of this index also ranges between 0 and 1, but now the gr eater the value, the greater the sample diversity. This makes
more sense. In this case, the index represents the probability that two individuals randomly selected from a sample will belo ng
to different species.
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(c)
Threats to biodiversity
(i)
Overexploitation
Exploitation and recovery of populations of a particular species. Reduction of a population to a level that still can recover.
Small populations may lose the genetic variation necessary to enable evolutionary responses to environmental change (the
bottleneck effect). This loss of genetic diversity can be critical for many species, as inbreeding results in poor reproductive
rates. Some species have a naturally low genetic diversity in their population and yet remain viable.
(i)
Habitat loss
Habitat fragments typically support lower species richness than a large area of the same habitat. Habitat fragments suffer from
degradation at their edges and this may further reduce their size; species adapted to the habitat edges may invade the habita t at
the expense of interior species. To remedy widespread habitat fragmentation, isolated fragments can be linked with habitat
corridors, allowing species to feed, mate and recolonise habitats after local extinctions.
Links to prior knowledge/prerequisite knowledge
Unit 2: Environmental Biology and Genetics (Intermediate 2) should have been achieved, in relation to:
 the need for genetic diversity for the survival of a species
 evolutionary response to environmental change
 Ecosystems.
New content areas
New content areas are detailed below; support notes follow in Background information.
Exploitation and recovery of populations of particular species.
Reduction of a population to a level that can still recover.
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The effect of small populations on the evolutionary response to environmental changes (the bottleneck effect) and rates of
reproduction due to inbreeding.
Prevalence of species having naturally low genetic diversity within their population but still remaining viable.
Habitat fragments typically support lower spe cies richness than a large area of habitat. Habitat fragments suffer from
degradation at their edges and this may further reduce their size; species adapted to the habitat edges may invade the habita t at
the expense of interior species.
To remedy widespread habitat fragmentation isolated fragments can be linked with habitat corridors , allowing species to feed,
mate and recolonise habitats after local extinctions.
Background information
Overexploitation and recovery of populations of particular species: The main changes in biodiversity experienced in
Scotland relate to the felling of ancient forest, the grazing of sheep and deer, the intensification of agriculture and commercial
fishing, the planting of non-native conifers, the spread of urban development, the introduction of fish farming and the increase in
pollution.
Reduction of a population to a level that still can recover : Endangered animals and plants are at risk of extinction – there are
so few of them that they might soon be wiped out altogether. Although some plants and animals have always evolved more
successfully than others, human activity is changing the world in such a way that many more animals and plants are endangered
than would otherwise be. Species can come back from the brink , eg the American bald eagle was removed from the endangered
species list in 2007 following human intervention and conservation.
Small populations may lose the genetic variation necessary to enable evolutionary responses to environmental change –
the bottleneck effect: A population bottleneck (or genetic bottleneck) is an evolutionary event in which a significant percentage
of a population or species is killed or otherwise prevented from reproducing .
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Some species have a naturally low genetic diversity in their pop ulation and remain viable: the cheetah is the classic example.
The cheetah occurs naturally in the African savannah in low densities, one per every 40 or 50 square miles. Cheetahs have been
found to have extremely low genetic variability, indicating that a ll cheetahs today are most likely descended from a very small
population that experienced a genetic bottleneck. They are nevertheless a successful predator, although there is concern that
their low genetic diversity may make them exceptionally vulnerable t o epidemic diseases or make it difficult for them to adapt
to major climatic changes.
Habitat fragments typically support lower species richness than a large area of habitat : the impact of competition for
resources: Habitat fragmentation is a secondary effect of habitat destruction. The primary effect is the elimination of
individuals or populations from the portion of the landscape that has been destroyed . The secondary effect, habitat
fragmentation, occurs when remaining populations are isolated because the links between habitat patches have been destroyed.
Habitat fragments suffer from degradation at their edges and this may further reduce their size – species adapted to the
habitat edges may invade the habitat at the expense of interior species: Habitat fragmentation is a major problem across the
Earth. A decrease in the overall area of habitat is serious enough, but when combined with fragmentation, it can undermine th e
integrity of whole ecosystems. Roads, urbanisation and agriculture are among the ma in human activities which break up natural
areas, often with disastrous implications for wildlife. A healthy forest will be large enough to support those organisms with the
largest range, which are usually the top predators. The reduction in area can have a direct effect on these species and since they
often play a vital role in regulating populations of other creatures, the integrity of the ecosystem can be seriously upset.
Thinking on this large scale, it has also been suggested that climate change may fo rce certain species to migrate. If their natural
habitat is too fragmented, many might not be able to do this and they will therefore be at risk of extinction.
To remedy widespread habitat fragmentation, isolated fragments can be linked with habitat corrid ors, allowing species
to feed, mate and recolonise habitats after local extinctions: Reconnecting habitats isn’t always straightforward and care
needs to be taken not to create further problems. For example, by linking up two woodlands with the intention o f spreading red
squirrel populations, one might actually allow the introduced grey squirrel into an area it did not formerly inhabit. Issues such
as surrounding land use and land ownership need to be addressed. Nonetheless, re -establishing a more connected landscape
should be seen as a conservation priority.
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Identification of key concepts
Relationship between genetic diversity and the impact of overexploitation on levels of biodiversity in Scotland and the wider
world.
Investigation of habitat structure and impact on species richness: Physical habitat structure is nearly as important as
competition. Animal species diversity is positively correlated with habitat structural complexity in many terrestrial and aqu atic
communities. Competition for food is often determined by relative foraging success, and habitat structure is known to affect
foraging dynamics in a wide variety of animal communities (examples include fish, lizards, birds, mammals and insects) .
Habitat structure can also affect the social beha viour of many animals.
Identification of particular areas of difficulty
Species that have low genetic diversity but remain viable , eg the cheetah
Links sources of further information
www.scotland.gov.uk/biodiversity
Pages 19–23 from the following document are of particular interest:
Scotland’s Biodiversity – It’s In Your Hands © Crown copyright 2004, ISBN 0-7559-4120-9
This document is also available on the Scottish Executive website , www.scotland.gov.uk
Links to websites, animations, PowerPoints, audio or video files etc
1.
Teacher support materials for lesson delivery: an overview of suggested learning outcomes to be met during the teaching
and learning of this topic and key terms can be foun d in the PowerPoint Teacher Support C(i) + (ii) 1. Included in the
PowerPoint is a web link to ‘Trees For Life – Restoring the Caledonian Forest’, where students can research the human
impact on habitat fragmentation in Scotland’s Caledonian forest.
2.
Suggested student activity: Student activity c(i) 1. Overexploitation – think, pair, share task. Discussion/debate task
detailed in the PowerPoint file
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3.
Suggested student activity: Student activities c(i) and c(ii) Threats to biodiversity treasure hunt. Instructions and
resources for this active learning task are detailed in the Word document .
Website link:
Trees For Life – Restoring the Caledonian Forest: http://www.treesforlife.org.uk/forest/humanimpacts/fragmentation.html
Other useful information to stimulate interest
Many useful reference documents can be accessed direct ly from the websites of the Scottish Executive, Scottish Biodiversity
Forum and UK Biodiversity Action Plan.
www.scotland.gov.uk/publications
www.ukbap.org.uk
www.scotland.gov.uk/publications
www.ukbap.org.uk
There has not been a copyright form completed for the links below as they have not been directly used, only referenced for
points of interest:
Thought/discussion-provoking news article
http://www.bbc.co.uk/news/science-environment-11655925
Interesting/useful/stimulating video clips
http://www.bbc.co.uk/nature/programmes/tv/state_planet/habitat.shtml
http://www.bbc.co.uk/iplayer/episode/p00bgtqj/One_Planet_UN_enviro_chie f_urban_biodiversity_and_rapid_evolution/
http://www.bbc.co.uk/iplayer/episode/b00vhfx0/Saving_Species_Episode_26/
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http://www.bbc.co.uk/learningzone/clips/biodiversity -and-the-human-implications/5505.html
http://www.bbc.co.uk/nature/blueplanet/webs/further_forest.shtml
Suggested background reading
Life Ascending: The Ten Great Inventions of Evolution , Nick Lane, 2010 (paperback)
ISBN 13: 9781861978189; ISBN 10: 1861978189
Genetics, Evolution and Biodiversity, John Adds, Erica Larkcom, Ruth Miller, 2004, Nelson Advanced Science (paperback)
ISBN 13: 9780748774920; ISBN 10: 0748774920
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(iii) Introduced non-native species
Introduced (non-native) species are those that humans have moved either intentionally or accidentally t o new
geographical locations. Those that become established within wild communities are termed ‘naturalised’ species. Invasive
species are naturalised species that spread rapidly and eliminate native species. Invasive species may well be free of the
predators, parasites, pathogens and competitors that limit their population in their native habitat. They may prey on
native species or out-compete them for resources.
(iv) Anthropogenic climate change
Biological and other sources of data for analysing the effects of climate change on biodiversity. The challenges
associated with modelling the impact of climate change on species and ecosystem diversity.
Links to prior knowledge/prerequisite knowledge
Competition and climate change should have been defined and the effects explored in both:
– Intermediate 2 Biology: Unit 2 Environmental Biology and Genetics
– Standard Grade Biology: The Biosphere; How It Works
In both courses students should be able to discuss interspecific and intraspecific competition using named examples (red and
grey squirrel, cormorants) and give examples of the resources that plant and animals compete for.
Climate change due to human activity (anthropogenic) will have been studied in both courses and more importantly students
will have been exposed to such issues at a variety of levels, therefore prior knowledge is expected.
New content areas
The introduction of non-native species is a whole new concept for students to consider. In addition, students will not have
considered the challenges associated with measuring the impact of climate change .
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Background information
‘The most important direct drivers of biodiversity loss and ecosystem service changes are habitat change, climate change,
invasive alien species, overexploitation, and pollution.’ Millennium Ecosystem Assessment Report.
It is suggested that students should examine the effects of invasive non -native species in Great Britain and worldwide.
The vast majority of non-native species introduced to Great Britain over the millennia hav e caused no significant harm. In
fact, many contribute to economic and social wellbeing through their use in certain sectors , such as agriculture, forestry,
horticulture and pets.
However, given suitable conditions, some non -native species find themselves unchecked and able to dominate native species,
transform ecosystems or cause general environmental harm. These are invasive non -native species.
Invasive non-native species damage our environment, the economy, our health and the way we live. They threaten our native
plants, animals and habitats, cost the British economy over £2 billion pounds per year and can threaten our health. For
example, it is expected to cost many millions of pounds to deal with invasive weeds such as Japanese knotweed located at the
sites of infrastructure for the 2012 London Olympics.
It may also be worth highlighting the effect of climate change on non -native species. Climate change will have a substantial
impact on species diversity in the coming years , both by affecting the distribution of our native species and by enabling some
non-native species to become more common. Increasingly we could see more non -native species that are currently benign
become invasive as the climate changes. Recent research already shows that the range and abundance of some mobile species,
including butterflies, marine molluscs, migratory birds and plants , are consistent with the patterns of climate change seen in
the UK over the past 30 years. Climate change response will be one factor driving natural r ange extensions of species.
Recognition should also be given to the sectors involved in tackling issues involving invasive non -native species and those
that provide the legal framework and guidance on such issues.
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Identification of key concepts
 Define ‘invasive non-native species’.
 Identify the reasons why people have intentionally introduced non -native species to new geographic locations.
 Outline reasons why non-native species may have accidentally moved to new geographic locations .
 Recognise that some non-native species are harmless and actually contribute to the economy and social wellbeing .
 Identify why invasive non-native species are able to out-compete native species.
 Describe the damage and consequences that can be caused to the environment and economy by non-native species.
 Create a world map or student portfolio to exemplify invasive non-native species in Great Britain and worldwide – student
learning task (see below for examples of such species and refer to Student activities c(iii) and (iv) 3 for details).
 Highlight the effect of climate change on non -native species in terms of species diversity.
 Outline the challenges that are associated with monitoring the impact of climate change on species and ecosystem diversity .
 Planned case study.
 Climate change modelling software (www.science direct.com can be very useful for relevant journals, but there is a fee).
Identification of particular areas of difficulty
The main challenge will be analysing the effect of climate change in biodiversity. However, this difficulty is expected as
students must recognise that there are specific elements of this research that are challenging to the specialists and they need to
be able to identify these elements.
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Links sources of further information
www.nonnativespecies.org ‘The Invasive Non-Native Species Framework Strategy for Great Britain’ Document
Examples of invasive non-native species in Great Britain
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Water primrose (Ludwigia grandiflora) Ludwigia, which is currently unmanageable in France, is an aquatic plan t native to
South America.
Japanese knotweed is native to Japan, Taiwan and China, and was introduced to Europe as an ornamental plant in the early
19th century.
North American ruddy duck, https://secure.fera.defra.gov.uk/nonnativespecies/index.cfm?pageid=244 .
The grey squirrel was introduced to this country from North America in the 19th century and has spread widely, especially
in lowland areas, with a population now estimated at over 2 millio n.
Signal crayfish can have direct effects on native species, for example by predation, or can upset the natural ecological
balance. Non-native fish can also introduce novel diseases and parasites to which our native populations may have no
resistance.
Parakeets.
American mink.
Rhododendron ponticum.
Himalayan balsam.
Giant hogweed.
Hedgehogs – Western Isles.
Rats introduced to Ailsa Craig.
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Examples of invasive non-native species worldwide
1.
2.
3.
4.
Lion fish – Caribbean.
Domesticated animals introduced to New Zealand.
Garlic mustard.
Rabbits in New Zealand.
Links to websites, animations, PowerPoints, audio or video files etc
Links to practicals
 Use contacts such as zoos, botanical gardens, DEFRA, Scottish National Heritage, Association of Science Education (ASE)
and the Forestry Commission to:
- source data to analyse the effects of non-native species,
- research developments that are being made or action that is being taken to address the local examples of invasive nonnative species.
 The following websites will be of particular use when researching Learning activities c(iii) and (iv):
http://www.scotland.gov.uk/Topics/Environment/Wi ldlife-Habitats/InvasiveSpecies
http://www.rspb.org.uk/ourwork/policy/species/nonnative/index.aspx
http://www.environmentlaw.org.uk/rte.asp?id=214
http://www.defra.gov.uk/wildlife-pets/wildlife/management/non-native/
https://secure.fera.defra.gov.uk/nonnativespecies/index.cfm?pageid=244
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http://www.nowpublic.com/environment/non-native-species-affecting-u-s-coasts-rivers-and-streams
Other useful information to stimulate interest
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