Download Biodiversity PPT Notes

History of Biological Diversity
Evolution: Darwin’s travel
Developing the Theory of
Evolution
The Galápagos Islands
• Darwin noticed that the
different islands all seemed
to have their own, slightly
different varieties of animals.
• Somewhat similar species
that suited their particular
environment.
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Darwin’s Theory of Evolution by Natural Selection
Origin of Species: Darwin’s Book
In 1859 On the Origin of Species presented evidence and proposed a
mechanism for evolution that he called natural selection.
• Today, scientists use evolution
to mean cumulative change in
a group of organisms through
time.
• Natural selection is not
synonymous with evolution –
it is a mechanism by which
evolution occurs.
• Artificial selection: (instead
of natural) humans select
which organism get to
reproduce and pass on genes
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Darwin’s Theory of Evolution by Natural Selection
Peppered Moth: Natural Selection
• The light colored form was the predominant form in England prior to
the Industrial Revolution.
• Around the middle of the 19th century the darker form began to appear.
It was first reported in 1848. By 1895 98% of the moths in Manchester
were the dark variety.
• In recent years, the burning of cleaner fuels and Clean Air regulations
has reduced the pollution there and the lighter colored moths have
increased in numbers.
First 6 Minutes
Types of Selection:

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a. Artificial Selection – humans select for variations
in plants and animals that they find useful.
b. Natural Selection
– also means “Survival of the Fittest”.
- Fitness in this sense does not mean strongest.
- Fitness in Darwin terms means reproduction. The one who
survives long enough to reproduce the most is the one with the
highest fitness.
Types of Natural Selection
-Evolution acts on the phenotype of the individual, not the
genotype.
 - There are 4 types of selection that can occur on a
population.

1. Directional Selection
 – when individuals at one end of the curve have a higher fitness than
individuals in the middle or at the other end of the curve.

 2.
Stabilizing Selection
 – when individuals near the center of the curve have higher
fitness than individuals at either end of the curve, narrowing of
the graph.
 3.
Disruptive Selection
 – when individuals at either end have a higher fitness and
individual near the middle of the curve are selected against.
- Over time with enough selection a population can go
through genetic drift.
a. genetic drift – random change in allele frequency.
4. Sexual Selection: the ability to attract a mate
HOMEWORK
PAP and Academic
Support for Evolution
• Evidence for evolution comes from:
1. The fossil record: remains in layers of rock
2. Comparative anatomy
a. Analogous structures
b. Homologous Structures
c. Vestigial Structures
3. Comparative embryology
4. Comparative biochemistry
5. Geographic distribution
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Evidence of Evolution
1. Support of Evolution: Fossil Record
• Fossil Record – Fossils
are the remains of
ancient organisms
found in layers of rock
in the Earth.
Support of Evolution
• The layers of rock
tell the history of
the Earth, while the
fossils found within
the rock tell a history
of life.
• The fossils are
thought to be the
same age as the rock
they are found in.
Support for Evolution: The fossil Record
• Researchers consider two major classes of traits when
studying transitional fossils:
• Derived traits are newly evolved features, such as
feathers, that do not appear in the fossils of common
ancestors.
• Ancestral traits are more primitive features, such as
teeth and tails, that do appear in ancestral forms.
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Evidence of Evolution
2. Support for Evolution: Comparative Anatomy
•
A. Homologous structures are anatomically similar structures inherited
from a common ancestor.
• Similar structures with different function (similar bones) (common
ancestor)
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Evidence of Evolution
Support for Evolution
Comparative anatomy
• B. Analogous structures
can be used for the same
purpose and be superficially
similar in construction, but
are not inherited from a
common ancestor.
• Structures are different but
have similar function.
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Evidence of Evolution
Support for Evolution
Comparative anatomy
• C. Vestigial structures are structures that are the reduced forms of
functional structures in other organisms.
• Evolutionary theory predicts that features of ancestors that no longer
have a function for that species will become smaller over time until
they are lost.
snake pelvis
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human appendix
Evidence of Evolution
3. Support for Evolution: Comparative embryology
• Embryos of many
animals with back-bones
are very similar.
4. Support for Evolution: Comparative Biochemistry
• Common ancestry can be seen in the complex metabolic molecules that many
different organisms share.
• The more closely related species are to each other, the greater the
biochemical similarity.
Similarities in DNA
and protein sequences
suggest relatedness.
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Evidence of Evolution
5. Support for Evolution: Geographic distribution
• The distribution of plants and animals that Darwin
studied were what first suggested evolution to him.
• The distribution of plants and animals around the world is
studied in the field of biogeography.
• Evolution is linked to migration patterns, climate, and
geological forces (such as plate tectonics).
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Evidence of Evolution
Adaptation- an
inherited trait that increases a
population’s chance of survival and reproduction
in a particular environment
• Fitness is a measure of the relative contribution
an individual trait makes to the next generation.
• The better an organism is adapted to its
environment, the greater its chances of survival
and reproductive success.
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Evidence of Evolution
• Through adaptations, populations often
become suited to a specific job called a niche.
• 1. niche – the role a population plays in a habitat
- job, profession, role
• 2. Competition arises when 2 populations
occupy the same niche.
Camouflage
Adaptation
Types of adaptations
• Camouflage is a suite of
morphological adaptations that allow
an organism to blend into its
environment.
• Mimicry is a type of morphological
adaptation where a species evolves
to resemble another species.
Mimicry
• Antimicrobial resistance develops in
some bacteria in response to sublethal exposure to antibiotics.
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Evidence of Evolution
Can you find the hidden animals?
Giraffe
Wolf
Willow Ptarmigan
Caiman
Great
Horned
Owl
American
Pike
Bluecrowned
Parrot
Horned
Adder
Leopard
Gyrfalcon
California Ground Squirrel
Spotted Deer
Impala
Cheetah
Common Snipe
Wandering Tattler
Nighthawk
Coyote
Blue Dacnis
Hide and Seek: ALL
Population Genetics - study of the traits in a population
A. Population – a group of interbreeding organisms (a species) living in a
given area
B. Gene Pool – combined genetic material of all the members of a population
C. Gene Flow-the transfer of alleles or genes from one population to another.
D. Genetic Drift- any change in the allelic frequency in a population that results
from chance.
E. Allele – forms that a gene can take
F. Allele Frequency – the number of each allele for a trait


This “changing of the gene pool” (allele frequency) has a name
—› Evolution.
Evolution – the changes in the gene pool of a population over
time.
Speciation – formation of a new species
1. Reproductive Isolation
- 2 or more species cannot interbreed


2. Geographic /Allopatric Isolation
- 2 populations are separated by geographic barriers
●examples: rivers, mountains, bodies of water
Types of Evolution
Convergent Evolution: less alike to more alike
 Divergent Evolution=Adaptive Radiation: more alike to
less alike
 Coevolution: evolve together
 Punctuated equilibrium: happens in short period of time

Convergent Evolution:



Occurs when different organisms that live in similar environments become
more alike in appearance and behavior.
Less alike to more alike
Examples: - Bird wings/insect wings
- Shark fins/dolphin fins
Draw the diagram
in Notes
Divergent Evolution=Adaptive Radiation

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One species gives rise to many species
More alike to less alike
Also known as adaptive radiation.
Examples: - Darwin’s Finches.
- Brown bears and polar bears
Draw this diagram in
notes
Coevolution

Co-evolution occurs when, two or more organisms evolve
together.
Gradual equilibrium

Predicts that little of evolutionary
change takes place in small
gradual steps.
Punctuated equilibrium
 predicts that a lot of evolutionary
change takes place in short
periods of time tied to speciation
events.
Charts to compare evolutionary relationships:

Cladogram: a chart that is composed of many different
clades or branches. It is similar to a family tree as it has
many different branches, but it is set up in a slightly
different format than a typical tree. Organisms listed are
all related, but the cladogram depicts the successive
points of species divergence from common ancestral
lines.
Cladogram Example:
Which species developed first: Ferns or
Mosses?
How long ago was the development of vascular
tissue?
Assuming this cladogram is correct, would we
find a fossil for a fern that is in rock 425 million
years old?
Charts to compare evolutionary relationships:

Dendrogram – a branching diagram representing a
hierarchy of categories based on degree of similarity or
number of shared characteristics, especially in biological
taxonomy.
Dendrogram Example:
Who is most closely related to the Brown bear?
Who is furthest related to the Brown bear?
Who is most closely related to the Lesser panda?
PAP Homework
New Species
Change over
Time
Natural
Selection
Survival of the
Fittest
Darwin
Dog Breeds
Naturalist
Anatomical
Evidence
Galapagos
Turtles
Finches
Shaped
Shells
DNA
Whale Bones
Vestigial
Structures
Homologous