Download Adaptation and Change

Ultra Deep Field

Here is what happened when professional astronomers pointed
the Hubble Space Telescope at absolutely nothing and left it
there, first for 10 days, and then for 11 days. Then they made the
images into a 3-D presentation. Hang on to your seat! By the
way, 13 billion light years are about equal to
880,000,000,000,000,000,000,000 (880 sextillion) miles. Be sure
you have your sound on. ... and this was aimed at a blank spot in
the sky?

Hubble Ultra Deep Field 3D
Evolution, Change and
Diversity
Adaptation and Change
What does it mean to be “alive”?
Characteristics of a living organism:
Made of
i) carbon, hydrogen, nitrogen, and oxygen
ii) cells (organization of life processes)
Able to
iii) reproduce
iv) grow and develop
v) move
vi) consume “food”, remove waste
vii) maintain homeostasis
Importance of Adaptation
“Variety is the spice of life” True or False?
 What is the value of diversity?


“All plants and animals, regardless of size, shape,
or level of complexity, share certain
characteristics.”
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Requirements for energy
Basic cell structure and function
Adaptation to a particular habitat
Adaptations
Inheritable changes in an organisms’
appearance
behaviour
structure
mode of life
that make the organism better able to survive
in a particular environment
The Theory of Evolution
Attempts to explain why living organisms are so
different in form and function
while being
similar in biochemistry & molecular makeup
A process by which populations of living
things change over a series of
generations
*Does not include individual change or development
Evolution Project
Theorists/Scientists
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Lamarck
Malthus
Wallace
Darwin
Linneaeus
Huxley
Johanssen/Leaky
Becquerel
Wegener/Lyell
Popes Mendel
Scopes
Hominids
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Sahelanthropus tchadensis
Ardipithicus ramidus
A. anamensis
A. afarensis
A. africanus
P. robustus
P. boisei
H. rudolfensis
H. habilis
H. ergaster
H. erectus
H. heidlebergensis
H. archaic
H. neandertalensis
H. sapiens
Evolution according to Lamarck
Evolution Reversed?
The Great Human Odyssey – CBC Documentary Series
Evidence for Evolution

Direct Evidence

Fossil Record
Fossil formation
 Carbon Dating


Rapid Reproduction


Bacteria produce many generations in a short period
Indirect Evidence

Geological Time Scale
Biogeography
Living Organisms
Embryology
 Anatomy
 Physiology
 Biochemistry

The Fossil Record

A fossil is any trace of an
organism that lived long ago

Examples:
 Enclosed in resin (amber)
 Covered by sediment that
eventually becomes rock
 Minerals filter into the body
and turn to rock – cast/copy
(petrification)
 Trace fossils – tracks or
impressions left in soft
sediment that later hardens
Observe How Fossils Are Made
Law of Superposition
“Most sedimentary rocks are laid
down in horizontal
layers…increasing in age from
top to bottom as long as the
layers are not disturbed.”
Fossils found in the undisturbed
lower layers of sedimentary rocks
are usually older and less complex
than those found in upper layers.
Scientist can use this rule to
determine the relative age of
many fossilized organisms.
The Fossil Record cont’d…
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Geologists estimate age of sedimentary rock based on
its thickness and location above or below other layers
Relative age and radioactive dating used collectively
helps determine both:
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

the age of the Earth (4.5 billion years old)
when the 1st life forms appeared (3.5 billion years ago)
By piecing together fossil evidence according to age
and similarity of structure, scientists have been able to
study patterns of relationships among organisms =
phylogeny  evolutionary history
Radiometric Dating (Geologic Time Scale)
What is radiometric dating?
Radioactive Dating

Scientists calculate the ages of rocks
and fossils accurately by measuring
the decay of radioactive isotopes

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Carbon-14 Method used to date
rocks and fossils younger than 50 000
yrs

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Ex) potassium-40; uranium-238;
carbon-14
Carbon has 2 isotopes
C14 turns into N14
C14 has a half-life of 5730 yrs
Scientists know the approximate
percentages the organisms start with;
compare this to the present state
How Do We Know Evolution Happens?
Discussion Questions:
1.
2.
3.
Gingerich discusses specifically only the whale fossils found in
Egypt's "valley of the whales," but he points out that this now desert
area was once a sea. Discuss the other kinds of fossils, and the types of
rocks that must have been present for him to make this conclusion.
Examine the cladogram of whales and their ancestors presented in this
video. Note that this diagram does NOT show modern whales
evolving from any specific fossil form, but form the common ancestors
of known fossil species and modern animals. Discuss the important
difference between this view of evolutionary history, and the old view
-- which often attempted to identify specific fossils as THE ancestors
of a living form.
Discuss the similarities and differences between whale flippers and
flukes and fish fins, using the scientific terms "homologous structures"
and "analogous structures" in the discussion.
What about mummies?

Leonardo the
mummified
dinosaur
Secrets of the Dinosaur Mummy

http://watch.discoverychannel.ca/#clip93
695
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http://watch.discoverychannel.ca/#clip93
694
Biogeography
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Discrepent Event:
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Animals that evolved from similar ancestors on different
continents
These ancestors had no way to get between continents
at the time

Too much of a coincidence?

Plate tectonics and Pangaea…
Biogeography
Biogeography
Common Ancestors…
Conclusions…
Life forms have become more complex over time
while many simple life forms continue to exist
Many fossils show strong similarities to existing
organisms
Disadvantage: fossil records are rare and incomplete
Evidence from Living
Organisms
Embryology
Anatomy
Physiology
Biochemistry
Embryology
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The early stages of
development show a
number of relationships not
obvious in the fully grown
organisms.
The more alike the
development of 2
organisms, the more closely
related they are.
They probably inherited the
same basic body plan from a
common ancestor
As development progresses
their patterns become more
different
Comparative Anatomy
(CBC Info Morning Science Corner, May 30, 2012)
Homologous Structures

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Same basic structure and
same pattern of early
growth but may serve
different functions
Overall pattern of structure
still resembles common
ancestor
Inherited structures become
modified due to gradual
adaptation to different
environments
The greater number of
homologous structures two
organisms share, the more
closely related they are
Homologous bones from human (I), dog
(II), pig (III), cow (IV), tapir (V) and horse
(VI):
r — Radius, u — Ulna, a — Scaphoid, b — Lunare,
c — Triquetrum, d — Trapezium, e — Trapezoid,
f — Capitatum, g — Hamatum, p — Pisiforme
Becoming Human Activity
Divergent Evolution
 The presence of similar structures (e.g. bone
structure) in very different animals leads
scientists to believe that these animals had a
common ancestor
 Divergent evolution is when two or more
species evolve from one common ancestral
species
Analogous Structures
Similar functions
and, perhaps,
appearances, but
are quite different
anatomically
 Indicates these
organisms did not
evolve from a
common ancestor

Convergent Evolution
 Animals that occupy a similar niche,
regardless of ancestry, often evolve parts
that function similarly
 The underlying structures may not be the
same, but they serve the same purpose
 These are called analogous structures
Vestigial Organs
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Structures that have no function in the living organism,
but may have been used in the ancestors
May be homologous with still-used structures in other
related organisms
As the organism adapts to a new lifestyle, it changes in
form and behaviour, the once useful structure reduces
size and function
Biochemistry

Chemical analysis show that similar organisms
have similar chemical structures
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DNA molecules
Amino acid sequences
Certain proteins

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Ex) Cytochrome C
Some scientists consider this the most
compelling evidence for evolution
Physiology
Similarities among the functions of any of the
parts of the organisms
 Example: digestion, waste excretion, hormone
function, muscle movement

Selective Breeding

Within a population (breeding group) of
organisms there is constant change over time

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Mutation and duplication of existing alleles can
produce new alleles or genes
Meiosis and fertilization can reshuffle alleles
New alleles and genetic recombination are the
source of evolution
 Humans direct and speed evolution by selecting
only individuals with the most desirable traits to
breed

How does geography affect evolution?

Biogeography =
geographical
distribution of
organisms

6 regions
separated by
impassable
barriers

Each contains
organisms unique
to that region
How is the distribution of organisms
determined?

Climate and other
environmental factors
affect distribution
patterns over short
periods (1000’s of
years)

Changes in the positions
of the continents occur
over longer periods
(millions of years)
Continental drift 
plate tectonics
 Pangea 
supercontinent
225 million years ago

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Convergent evolution = development of similar
forms in geographically different areas in
response to similar environments
Curriculum Outcomes
Evaluate current evidence that supports the theory
of evolution. (316-2)
 Analyse and describe examples where scientific
understanding was enhanced or revised as the result
of the invention of a technology (116-2)
 Outline evidence and arguments pertaining to the
origin development, and diversity of living
organisms on Earth (316-4).
