Transcript Conservation and Biodiversity

Conservation
and Biodiversity
IBESS Topic 4
4.1 Biodiversity in Ecosystems
Biodiversity is the variety of species we have on earth, all the genetic
information they carry and where they live that makes them unique.
 Species diversity – The amount of and types of species that live within a
community.
 Genetic diversity – the variety of genetic information that can make up one type
of species.
 Habitat diversity – All the different types of ecosystems, communities and areas
that a biome can have within it.
Natural Selection
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Charles Darwin: a Theologian by study. An avid bird watcher and
Biologist by trade.
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Considered and investigated that all species must have had similar
ancestors (fossils) and over time adapted to their environment to
survive. (HMS Beagle)
Natural Selection and Evolution:
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To Evolve is to change. Evolution is the process of organisms changing
over time.
Natural Selection is the mechanism that provides the “oomph” needed
for organisms to go through the process of evolution.
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I have categorized Nat. Sel. into three groupings:
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Environmental condition
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Genetic trait needed for survival and passed to offspring
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Over-production of offspring (more are born than will survive)
Competition for resources (i.e. – living space, sunlight, food, mates)
Each species has a varied gene pool, which leads to diverse phenotype s with in the
population
The Variety of genes within a population insures improved changes and adaptation to an
every changing environment.
Passing of these traits ensures the survival of the offspring
Change is inevitable
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Our Earth is ever changing. The movement of the plates, changes in Atmosphere and
climate, (ice-ages, global warming)
Speciation
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Speciation: The formation of a new species occurs when:
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Isolation: A species has been separated over a long
period of time and adapted to their environments,
genetically changing their species so they can no longer
breed together.
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Through a geographical barrier. (little to no gene flow)
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Through Behavioral diversity. (choosing differences)
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i.e.: Chipmunks at the Grand Canyon, Mexican Spotted Owl and
the Northern Spotted Owl, Galapagos tortoises and birds.
Plant and Animal organisms tend to mate with others that act the
same way they do. (think human cultural differences)
Reproductive Isolation.
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Organisms that live in the same habitat mate at different times of
the year. (very true for different species or sub-species of plants).
Different species have different reproductive parts.
Again (behavior ties in), mating rituals and niche building.
Measuring Diversity
Diversity Indices:
1st: 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.
An estimated quantitative measurement of how diverse a species is or the abundance of
species within an ecosystem.
Simpson’s diversity index:
Measures both species richness (number of…) and species evenness (abundance)
D=
N(N-1)
∑ n(n-1)
N = total number of organisms of all species.
n = total number of organisms of one species.
D = 0 <>1 ; Where 0 is very diverse and 1 is little to no diversity.
Site Sampling:
 An internet site to read: On your own time. (It may help with your group lab).
What it means
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Low species diversity suggests:
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relatively few successful species in the habitat
the environment is quite stressful with relatively few ecological niches
and only a few organisms are really well adapted to that
environment
food webs which are relatively simple
change in the environment would probably have quite serious
effects
High species diversity suggests:
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a greater number of successful species and a more stable
ecosystem
more ecological niches are available and the environment is less
likely to be hostile
complex food webs
environmental change is less likely to be damaging to the ecosystem
as a whole
D = 1-
∑ n(n-1)
N(N-1)
A second way to analyze the diversity index.
0< D > 1
Less diverse More.
The inverse of the other equation.
Simpson’s Diversity Index can be expressed either way. I have seen this
version used more frequently than the other one.
2nd Shannon-Wiener Index (H)
This index is determined by both the number of species and the even distribution of
individuals among those species (relative dominance). It indicates the degree of uncertainty of predicting the
species of a given individual picked at random from the community. In other words, if the diversity is high, you
have a poor chance of correctly predicting the species of the next individual picked at random. The formula is:
H = - sum(Pi ln[Pi])
Where:
Pi (relative abundance) = ni/N
Where:
ni = number of individuals in species i
N = total number of individuals in all species
H (the uncertainty of predicting the species) will range from 0 for a community with a single species, to over 7 for
a very diverse community.
3rd Species Evenness (E)
Using species richness (R) and the Shannon-Wiener index (H), you can also compute a measure of evenness. The
formula is:
E = H/ln(R)
Evenness (E) is a measure of how similar the abundance of different species are. When there are similar
proportions of all species then evenness is one, but when the abundance are very dissimilar (some rare and some
common species) then the value increases.
Species
Number
n(n-1)
(n)
Woodrush
2
Holly
(seedlings)
8
Bramble
1
Yorkshire
Fog
1
Sedge
3
Total (N)
15
Practice 1
Use Simpson’s
Index to fill in the
rest of the table
and calculate
the diversity of
the habitat.
Practice 2
Numbers of individuals
Use Shannon-Weiner Method:
Two different fields are sampled for
wildflowers. The sample from the first field
consists of 300 daisies, 335 dandelions and
365 buttercups. The sample from the
second field comprises 20 daisies, 49
dandelions and 931 buttercups (see the
table on right). Both samples have the
same richness (3 species) and the same
total number of individuals (1000).
Diversity Measurement
Community1
Community 2
Species richness (R)
3
3
Evenness (E)
.9985
.3215
Dominance (high/low)
Low
High
Relative Diversity
(high/low)
High
Low
Shannon-Weiner Index (H)
1.094
.293
Flower
Species
Field 1
Field 2
Daisy
300
20
Dandelion
335
49
Buttercup
365
931
Total
1000
1000
Practice 3
1. Use both Simpson's index and Shannon Wiener
indices to determine which of the following three
communities of 100 individuals is most diverse.
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Community 1 contains 10 species with 91 individuals in
the first species, and one individual in each of the
remaining species.
Community 2 also contains 10 species, but there are 10
individuals in each species.
Community 3 only contains 5 species, with 20 individuals
in each species.
Geological Evolution
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As climates shift, plates move and the terrestrial parts
of the Earth change, organisms have had to adapt.
When they can not adapt to the many changes, they
do not survive, pass their traits to offspring (as a
species).
When a whole species can not adapt and survive –
Extinction
 When there are a few species left, or less species
friendly habitat – Endangered
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Areas of Endangerment –
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Critically endangered
Endangered
Vulnerable
Threatened
Geologic Evolution
Earth was formed approximately 4.6 bya.
 First life forms:
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single cell/bacterial like organisms.
lived in aquatic environments.
65 mya – dinosaurs became extinct. (most recent,
but not most devastating)
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~200,000ya Humans were first seen on earth.
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Humans are relatively young on the time scale
compared to some of the other organisms still
living today.
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ex: turtles/alligators
Geological Time Scale
Geological Evolution
 There
were approx. 5 mass extinctions that have
taken place over the life of the earth.
Mass Extinction
MYA
Geological Period
Estimate of loss
1st
440
Ordovician-Silurian
25% of all families
2nd
364
Devonian
19% of all families
3rd
251
Permian Triassic
95% of all species, 54% of all families
4th
199 – 214
End of Triassic
23% of all families, unknown % of
vertebrates
5th
65
Cretaceous-Tertiary (K-T boundary)
17% of all families and all large
animals including dinosaurs
6th
Current
Holocene
Unknown
The most famous mass extinction is the K-T extinction. (Or
Dinosaur extinction.)
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~65 mya the dinosaurs slowly disappeared from earth.
Most believe it did not happen overnight (widely debated a
couple decades ago), but over a long period of time. Many
thousands to hundreds of thousands years.
K-T stands for Cretaceous-Tertiary. Occurring during the end
of Cretaceous and beginning Tertiary Geological periods of
time.
Most Scientists today believe that the change in climate
caused a mass extinction of the land and ocean large
animals and the small plankton. Most small animals including
the growing diversity of small mammals, and plants survived.
The change in climate was from:
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several meteors hitting the earth. The most famous being in
the Yucatan Peninsula of what is today known as Mexico
and the volcanic unrest of Deccan Plateau of what is known
as India today.
The change in climate was caused by the natural disasters of
that time.
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Volcanoes, Earthquakes, release of carbon and methane
into the atmosphere from the melting glaciers and
increased sulfur and carbon into the atmosphere.
The disasters caused the sun to disappear behind the haze
of smoke and particulates in the atmosphere to cause
heavy amounts of acid rain.
This climatic change caused the amount of photosynthesis
production to decrease and thus many plants died off or
adapted by shrinking in size to survive.
Which in turn caused less food for the plant eaters and less
plant eaters for the meat eaters. And so on. (positive feedback)
 This also caused a change in temperature (overall global
decrease) which most larger animals could not handle
(thought to be exothermic).
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Succession
 Succession
is a scaffolded process of the
formation or re-formation of an ecosystem
to a stable state.
Conservation
a
careful preservation and protection of
something; especially : planned
management of a natural resource to
prevent exploitation, destruction, or
neglect – Merriam-Webster dictionary
CITES
 Convention
on International Trade in
Endangered Species of Wild Fauna and
Flora.
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CoP16 – The 16th Conference of the Parties
 March
3-14th Bangkok.