• 1. If you were asked
to manage this site
for species diversity,
what would you aim
to do? How would
you do it?
• Species richness- the number of species in a
given area.
• Species evenness- the measure of whether a
particular ecosystem is numerically dominated
by one species or are all represented by similar
numbers of individuals.
Biodiversity
• Diversity Increasers
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Diversity Decreasers
Diverse habitats
Disturbance in the habitat (fires, storms, etc.)
Environmental conditions with low variation
Environmental stress
Evolution
Extreme amounts of disturbance
Extreme environments
Extreme limitations in the supply of a fundamental resource
Geographic isolation
Introduction of species from other areas
Middle states of succession (habitat regrowth)
Trophic levels with high diversity
Biodiversity
• Diversity Increasers
Diversity Decreasers
• Diverse habitats
• Disturbance in the
habitat (fires, storms,
etc.)
• Environmental conditions
with low variation
• Evolution
• Middle states of
succession
• Trophic levels with high
diversity
• Environmental stress
• Extreme amounts of
disturbance
• Extreme environments
• Extreme limitations in
the supply of a
fundamental resource
• Geographic isolation
• Introduction of species
from other areas
As far as we can tell, we are the only
species that can value its diversity.
• Should we take care of it?
• How will people later judge our
generation if we do not attempt to
preserve a minimum of diversity,
especially because we know
perfectly well how to accomplish
this?
• Too much interruption might have
unpredicted but severe
consequences for human lives and
society.
What creates all this biodiversity?
the process by which
different kinds of living
organisms have developed
and diversified from earlier
forms during the history of
the earth.
Evolution is the mechanism underlying biodiversity
Modern humans (Homo sapiens) appear
about 2 seconds before midnight
Age of
reptiles
Insects and
amphibians
invade the land
Plants
invade
the land
Fossils
become
abundant
Fossils
present
but rare
Age of
mammals
Recorded human history begins 1/4
second before midnight
Origin of life (3.6–3.8 billion years ago)
• Evolution- a change
in the genetic
composition of a
population over
time.
Evolution and
expansion of life
Cane Toad – Team Think
3. Distinguish between , natural selection, artificial
selection and genetic engineering.
- Which of these took place in this movie? why?
- Now, how would scientists use genetic engineering
to “solve” the cane grub problem?
Evolution
• Evolution by artificial selectionwhen humans determine which
individuals breed.
• Evolution by natural selectionthe environment determines
which individuals are most likely
to survive and reproduce.
• Evolution by genetic engineering
the deliberate modification of the
characteristics of an organism by
manipulating its genetic material.
Some… of the GMOs
• Honey - produced from GM crops.
• Cotton - Resistant to certain
pesticides –
• Rice - Genetically modified to
contain high amounts of Vitamin A.
• Soybean - Genetically modified to
be resistant to herbicides –
• Sugar cane - Made resistant to
certain pesticides.
• Tomatoes - Made for a longer shelf
life
• Corn - Resistant to certain pesticides
• Sweet corn - genetically modified to
produces its own insecticide.
• Canola –
• Potatoes - -
Flax - An herbicide-resistant GM flax was
introduced in 2001, but was soon taken off the
market because European importers refused to
buy it.
Papaya - The first virus resistant papayas were
commercially grown in Hawaii in 1999.
Cotton seed oil –
Meat - Meat and dairy products usually come
from animals that have eaten GM feed.
Peas - Genetically modified (GM) peas created
immune responses in mice, suggesting that
they may also create serious allergic reactions
in people. .
Vegetable Oil - Most generic vegetable oils and
margarines used in restaurants and in
processed foods in North America
Dairy Products - About 22 percent of cows in
the U.S. are injected with recombinant
(genetically modified) bovine growth hormone
(rbGH).
Vitamins -
• Livestock genetically altered to give maximum output at
minimum cost to farmers (high milk production or high
meat output, sheep optimum wool growth, pigs could
be altered to have large amounts of meat with a
minimum of fat)
* Crops
genetically
altered for
resistance to
drought, frost,
pests, disease,
and herbicides
Interpret
the graph
As land
size
increases
the
diversity in
species
increases
Interpret
the graph
Interpret
the graph
The Plot Thickens!
Using the data and knowledge from the last
few graphs, explain the relationship between #
of species and Sunda Islands and New Guinea
Island Biogeography
Unique characteristics of islands
• Isolation
• Disturbances can be catastrophic
• Less genetic diversity (than mainland settings)
Theory of Island Diverstiy
The number of species found on
an undisturbed island is
determined by immigration and
extinction.
This can lead to evolution.
Immigration and emigration are
affected by the distance of an
island from a source of colonists.
Usually this source is the
mainland. As well as size of the
island Islands that are more
isolated are less likely.
* More species
on bigger
islands
* Fewer species
on more isolated
islands
Share data with 2 – 3 other teams and average out
Large
Close
Small
Close
Large
Far
Small
Far
1.5 meter away
1.5 meter away
1 meter away
YOU!
1 meter away
Exit Card
• You are a part of a forestry science team
appointed by the government to determine
what kind of forest islands are the most
desirable in order to save native fauna and
flora, which may migrate between habitat
lands.
• Describe the size of your habitat land, its
distance from the source population and
supporting reasoning as to your decision.
Island Biogeography = immigration –
extinction
As the number of species
on an island increases, the
rate of colonization will
decline because available
ecological niches become
fewer
Source: MacArthur and Wilson.
The Theory of Island Biogeography
Island Biogeography = immigration –
extinction
As the number of species
on an island increases, the
rate of extinction will
increase because species
compete for resources
Species Equilibrium
The number of species on
an island represents a
balance between
colonization and extinction
Source: MacArthur and Wilson.
The Theory of Island Biogeography
How does this relate to landuse/landcover
change?
Species Extinctions
Source: World Conservation Monitoring Centre, "Global
Biodiversity" Chapman & Hall, London, 1992)
Source: Bolger et al., 1997. Response of rodents to habitat fragmentation in coastal southern California.
Ecological Applications, 7(2): 552-563.
(note: trend line added to rodents vs shrub size figure)
Conservation initiatives
Evolution by
Random Processes
• Mutation- occur randomly
and can add to the genetic
variation of a population.
• Genetic drift- change in the
genetic composition of a
population over time as a
result of random mating.
• Bottleneck effect- a
reduction in the genetic
diversity of a population
caused by a reduction in its
size.
• Founder effect- a change in
a population descended
from a small number of
colonizing individuals.
Evolution shapes ecological niches
and determines species
distributions
• Range of tolerance- all species have an optimal
environment in which it performs well. The limit
to the abiotic conditions they can tolerate is
known as the range of tolerance.
• Fundamental niche- the ideal conditions for a
species.
Niches
• Realized niche- the range of abiotic and biotic
conditions under which a species lives. This
determines the species distribution, or areas of the
world where it lives.
• Niche generalist- species that live under a wide
range of conditions.
• Niche specialist- species that live only in specific
habitats.