Welcome to BIO 464 Biodiversity,
www.calacademy.org
Winter/Spring Term, 2012
Prof. Linda M. Kohn <linda.kohn@utoronto.ca>
Office: South Bldg. 3047; Telephone 828-3997
usaconnection.tripod.com
Lecture 1: What is Biodiversity?
Objectives: Know what the three scales of biodiversity are and why each
is important. Consider the pros and cons of biological, phylogenetic and
morphological species concepts and compare each of these ways of
defining species with the concept of the ESU. How is biodiversity
measured and how has it been measured in your Case Study site (or in the
habitat of your Case Study species, if a species is your focus)?
Reading: Chapters 2 and 3, TEXT. PDFs by Hey et al. and Green,
plus 2 short pieces about polar-bear grizzly hybrids in the Arctic,
and coywolves, and don’t miss a fascinating story about red wolf
conservation linked on today’s Study Guide.
There are three scales of Biological Diversity
Figure is from Chapter 2 of your text: Primack RB 2010 Essentials of Conservation Biology
Sinauer Associates, Inc. Sunderland, MA.
Genetic diversity
• This level of diversity can differ by alleles (different variants of
the same gene, determining phenotypes such as blue or brown
eyes),
• by entire genes (which determine traits, such as the ability to
metabolize a particular substance),
• or by units larger than genes such as chromosomal structure.
Genetic diversity can be measured at many different levels,
including population, species, community, and biome. Which
level is used depends upon what is being examined and why.
Genetic diversity is important at each of these levels. WHY?
Define “gene pool.”
What changes allele frequencies
and combinations in populations?
How does genetic diversity arise?
Mutation ->new alleles -> shifts in allele frequencies in populations due to
selection or genetic drift -> genetic exchange and recombination ->
heterozygosity
Species Concepts:
1) Morphological:
All members look similar –
Similarity in form, physiology
or biochemical features to a
“type” - widely used.
2) Biological:
Groups of interbreeding
populations: a reproductive
community, an ecological
unit, a genetic unit (gene
pool).
3) Phylogenetic: smallest
diagnosable cluster of
individuals that shares a
common ancestor (a
monophyletic grouping).
Assumes the species is a
basal, irreducible, distinct
unit (i.e., there are no
varieties or subspecies).
How does one species become many (= speciation)?
Where does species diversity come from?
Potential factors: genetic diversity, population size, space
(habitat), ecological/environmental variety, breeding behaviors.
Within a species:
• Populations of conspecific individuals become spatially
separated (allopatry),
• Different populations of conspecific individuals live under
different ecological conditions (allopatry or sympatry),
• Some individuals become polyploid (can also occur via
hybridization between two species) -> reproductive
isolation,
• Gene duplication or other processes occur that
reproductively isolate populations.
Between species:
• Hybridization,
• Competition.
Adaptive radiation starts with one genotype in a new place free of
predators or parasites - that then colonizes and adapts to a variety of
new niches and environments to produce many new species.
Figure is from Chapter 2 of
your text: Primack RB 2010
Essentials of Conservation
Biology Sinauer Associates,
Inc. Sunderland, MA.
Today’s rate of speciation is 100-1000 times slower than the
present rate of species extinction:
• Evolving biological communities require enough space (habitat)
and the earth is losing habitat to human development pressures.
• Even protected areas like National Parks may not be not large
enough for speciation to occur.
Figure is from Chapter 2 of your text: Primack RB 2010 Essentials of Conservation
Biology Sinauer Associates, Inc. Sunderland, MA.
The coarsest scale of biodiversity is community level diversity:
Groups of species together occupying a locality (an ecosystem).
Communities are shaped by:
• The physical environment of an ecosystem,
• Succession,
• Niche, carrying capacity,
• Food webs & guilds,
• Keystone species - crucial to the community,
• Keystone resources (e.g. mangroves, elevational gradients)
www.aims.gov.au
www.coralstar.com
A Community includes organisms occupying different trophic levels.
Figure is from Chapter 2
of your text: Primack RB
2010 Essentials of
Conservation Biology
Sinauer Associates, Inc.
Sunderland, MA.
In thinking about your Case Studies consider
How do humans influence food webs?
In a community, why are some species more important than
others?
Figure is from Chapter 2 of your text: Primack RB 2010 Essentials of Conservation
Biology Sinauer Associates, Inc. Sunderland, MA.
Kelp is a keystone species protected by otters.
What is the take-home message of this figure?
http://www.sciencecases.org/sea_otters/figure5.gif
www.sciencecases.org/ sea_otters/sea_otters4.asp
Homework: Is the species level useful in conservation?
Summarize figure 9 and apply to this question. We will have
a discussion in next week’s class on What is the most
useful unit for conservation -species, ESUs or DUs?
To prepare, see study guide
AND read PDFs.
Coral reefs are the second most
diverse community, tropical
rainforests number one.
www.cdislands.com/photos_ usvi/vir7/xvi40605.jpg
zero --# of species--->most
Fig 9: Bird guilds and ecological specialization
(light bars for the tropics, dark bars for the
temperate zone)
http://www.globalchange.umich.edu/globalchange1/current/lectures/klin
g/rainforest/rainforest.html#BIODIV
Welcome to BIO 464 Biodiversity,
www.calacademy.org
usaconnection.tripod.com
Winter/Spring Term, 2012
Prof. Linda M. Kohn <linda.kohn@utoronto.ca>
Office: South Bldg. 3047; Telephone 828-3997
Lecture 1: What is Biodiversity?
Objectives: Know what the three scales of biodiversity are and why each
is important. Consider the pros and cons of biological, phylogenetic and
morphological species concepts and compare each of these ways of
defining species with the concept of the ESU. How is biodiversity
measured and how has it been measured in your Case Study site (or in the
habitat of your Case Study species, if a species is your focus)?
Reading: Chapters 2 and 3, TEXT. PDFs by Hey et al. and Green,
plus 2 short pieces about polar-bear grizzly hybrids in the Arctic,
and coywolves, and don’t miss a fascinating story about red wolf
conservation linked on today’s Study Guide.
How do we measure biodiversity?
1. Genetic diversity
2. Species diversity
a.
Species richness = the number of species in an area (number of species, S,
cannot exceed the number of individuals sampled, N)
b.
-
Evenness is an average frequency of occurrence of species in an area = S/N
Can range from 1/N if only one species is in sampled area
to 1.0 if each species is represented only once (S = N).
Say five different snake species occur in a community of 50 snakes.
Even abundance would be ___ snakes of each species.
c.
Diversity combines richness, evenness and abundance in one value.
D. Spatial patterns of Diversity (text pages 32-33):
Alpha diversity = number of species found in a small area.
Gamma diversity = number of species in a large region or continent.
Beta diversity = the rate of change of species composition along an
environmental or geographical gradient. It links alpha and gamma diversity.
2.6
Region 3 would be a conservation priority only if all three mountains could be protected, even though beta
diversity is highest for region 3 because each mountain has a distinct group of species.
D. Spatial patterns of Diversity (text pages 32-33):
Alpha diversity = number of species found in a small area.
Gamma diversity = number of species in a large region or continent.
Beta diversity = the rate of change of species composition along an
environmental or geographical gradient. It links alpha and gamma diversity.
2.6
Region 3 would be a conservation priority only if all three mountains could be protected, even though beta
diversity is highest for region 3 because each mountain has a distinct group of species.
How do we measure biodiversity?
1. Genetic diversity
2. Species diversity