Transcript Evolution, Change and Diversity

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?
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Hubble Ultra Deep Field 3D
Creation Stories
Christian/Jewish/Islam
 Aboriginal – African/Australian/North and
South American/Asian
 Egyptian/Greek/Roman
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Scientific Explanation
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The History of the Universe
How/Why did such different and distant cultures
produce such similarly sequenced explanations (stories)
of how life and the Earth originated?
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Makes sense to them
Logical sequence
 Clues in their surroundings
 Recognized the necessities for life
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We’re all human
Similar reasoning abilities
 Similar niche and needs
 Altered by individual cultures and experiences
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Comforting concept of a “Creator”
Changed by time and place
 Satisfies need to have “started somewhere”
 Satisfies curiosity about meaning of and for life,
past/present/future
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Vatican Astronomer
Evolution, Change and
Diversity
Adaptation and Change
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).
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What does it mean to be “alive”?
Characteristics of a living organism:
Made of:
i) carbon, hydrogen, nitrogen, and oxygen
ii) arranged as carbohydrates, lipids, proteins
and nucleic acids (biological molecules)
iii) arranged as cells (organization of life processes)
Able to:
iv) reproduce
v) grow and develop (limited life span)
vi) exchange material with the environment
vii) respond to stimulus
viii) maintain homeostasis
ix) Generate heat
Importance of Adaptation
“Variety is the spice of life” True or False?
 What is the value of diversity?
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“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
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Lamarck
Malthus
Wallace
Darwin
Linneaeus
Huxley
Johanssen/Leaky
Becquerel
Wegener/Lyell
Popes Mendel
Scopes
Hominids
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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
Evolutionary
Tree
All Primates
History of Man
SPECIES
TIME PERIOD
Ardipithicus ramidus
5 to 4 million years ago
Australopithecus anamensis
4.2 to 3.9 million years ago
Australopithecus afarensis
4 to 2.7 million years ago
Australopithecus africanus
3 to 2 million years ago
Australopithecus robustus
2.2 to 1.6 million years ago
Homo habilis
2.2 to 1.6 million years ago
Homo erectus
2.0 to 0.4 million years ago
Homo sapiens archaic
400 to 200 thousand years ago
Homo sapiens neandertalensis
200 to 30 thousand years ago
Homo sapiens sapiens
200 thousand years ago to present
Evolution of Man
Evolution Reversed?
The Great Human Odyssey – CBC Documentary Series
Evidence for Evolution
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Direct Evidence
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Fossil Record
Fossil formation
 Carbon Dating
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Rapid Reproduction
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Bacteria produce many generations in a short period
Indirect Evidence
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Geological Time Scale
Biogeography
Living Organisms
Embryology
 Anatomy
 Physiology
 Biochemistry
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The Fossil Record
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A fossil is any trace of an
organism that lived long ago
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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
What about mummies?
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Leonardo the
mummified dinosaur
Secrets of the Dinosaur Mummy
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http://watch.discoverychannel.ca/#clip93
695
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http://watch.discoverychannel.ca/#clip93
694
Law of Superposition – Relative Age
“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.
Radiometric Dating (Geologic Time Scale)
What is radiometric dating?
Radiometric
Dating video
Radioactive Dating
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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
Radiometric Dating
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
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
*Problems –
fossil records are rare and incomplete
Read pgs. 508 to 515 in the Biology 12 Text.
 Do the Practice Questions, #1 and 2 on pg. 515
 Do the Section 11.2 questions on pg. 516
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How Do We Know Evolution Happens?
Discussion Questions:
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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.
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
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Too much of a coincidence?
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Plate tectonics and Pangaea…
How does geography affect evolution?
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Biogeography =
geographical
distribution of
organisms
6 regions
separated by
impassable
barriers
Each contains
organisms unique
to that region
Biogeography
Biogeography
Common Ancestors… ?
Divergent Evolution
How is the distribution of organisms
determined?
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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
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
Embryology
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)
Evidence of Divergent Evolution
The presence of similar structures (ex. bones) 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
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Similar functions and,
perhaps, appearances
but are quite different
anatomically
Indicates these organisms
did not evolve from a
common ancestor
Convergent Evolution
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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
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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
Becoming Human Activity
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
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
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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
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Conclusions…
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Divergent Evolution =
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Evidence  Homologous/ Vestigial Structures
Convergent evolution = development of similar
forms in geographically different areas in
response to similar environments
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Evidence  Analogous Structures
Resources
 Bill Nye: Greatest Discoveries –
Evolution
 Dinosaur asteroid 'sent life to Mars'
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).
