Transcript Species - bYTEBoss

The Evolutionary History of
Life
“Of course, long before you mature,
most of you will be eaten.”
“The picture’s
pretty bleak,
gentlemen. The
earth’s climate is
changing, the
mammals are
taking over, and
we all have
brains the size of
a walnut.”
“Now this
end is called
the
thagomizer,
after the late
Thag
Simmons.”
“Evolution’s been good to you, Sid.”
Top Ten Myths About
Evolution
1.
Humans and great apes had a common
ancestor about 5 million years ago
 Humans and monkeys had a common
ancestor about 50 million years ago

2.
“Theory” does not mean “hypothesis” or
“guess”
 Music Theory
 Stress Theory
 Quantum Theory
 Number Theory
“Theory” means an organized set of
related ideas.
3.

If you find your room trashed and your
TV and stereo missing, will you hesitate
to call the police because nobody saw it
happen?
4.

Maybe not. But once the origin
happens, everything after that is history.
And historical evidence is preserved in
the physical record.
5.
“Survival of the Fittest”
 “The winner of the Super Bowl is the team
with the most points.”
 What does “fittest” mean?
6.
7.
Darwin suggested birds had evolved
from reptiles in 1859; Archaeopteryx
was discovered in 1862.
 Piltdown Man
Famous Early Fossil Man Hoax
Controversial from the start because
it didn’t match evolutionary
expectations.

8.
Are you a vegetable or mineral?
 Humans have hair and nurse young just
like all other mammals
 Traits like nurturing, cooperation and
monogamy are often favored by evolution
because they enhance survival of species

9.
Is the following number sequence
random:
592653589793238462643383279?
 It not only looks random: it is random.
 But lacking in meaning? No. These are
the digits of pi beginning with the fourth
decimal place.
 Random does not mean “meaningless”

The Scientific Meaning of Random
Something cannot be predicted with
better accuracy than that predicted by
statistics.
 The phenomenon is its own simplest
description

Randomness and Evolution
Biological systems are far too complex to
describe or predict mathematically
 We have incomplete information
 Significant events like climate change or
asteroid impact are unpredictable.

10.
The Second Law of Thermodynamics is
often paraphrased as:
 ”Things always go from bad to worse”
 ”Disorder in the Universe is always
increasing"
The Second Law of
Thermodynamics
The Second Law is about entropy
 ________ = (Heat
Absorbed)/Temperature
 Entropy can decrease locally if it
increases elsewhere
 Intuitive notions of “_______” are of no
relevance whatsoever

Chemical Reactions are not
Random
Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na
Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl
Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na
Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl
Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na
Cl Na Cl Na Cl Na Cl Na Cl Na Cl Na Cl
Na Cl Na Cl Na Cl Na Cl Na Cl
Channeled Scablands, Washington
Scabland Terrain, Oregon
The Geologic Record
Physical evidence records mostly smallscale,  Fossils show a gradual increase in
complexity with time
 Fossil forms ________ between major
groups are well documented
 Over most of its history, life on Earth
was _______

Were the Dinosaurs Failures?
Human History =
 Dinosaurs =
 Dinosaurs had:




years for every year of human history
years for every day
hours for every second
Prebiotic Evolution
The basic molecules of organic chemistry
are easily made
 The first self-replicating molecule was
almost certainly  DNA assembles from simpler materials all
the time

DNA

Total length of human DNA in a single
cell is about 2 meters
 A human body contains about
 The total length of DNA in a human
body is thus __________, or twenty
billion kilometers, the circumference of
the orbit of Pluto.

Plants and Animals
CO2 + H2O + Energy = Sugars,
Starches, etc. + O2 (toxic waste).
 O2 is actually toxic (even to us!)
 Idea: Take the sugars and starches
(from somebody else) combine it with
the waste O2, and get energy

Amazing Events in Life History
“Invention of Sex”  We are a team  The Great Freeze
 Mass Extinctions

 Dinosaurs
=
 Permian extinction
Selection
Deliberate selection for desirable traits
by humans (only since ca. 1700)
 Unsystematic selection for desirable
traits by humans (domesticated animals
and plants)
 Unconscious and unintentional selection
by humans (self-domestication of
animals)
 Natural selection with no human
intervention at all

Lessons from Selection



Artificial selection has produced organisms
radically different from their natural state
Natural selection has resulted in dramatic
changes in natural populations with and
without human intervention
Microorganisms and viruses change with
dazzling speed (mutation of flu viruses,
resistance to antibiotics, move to new
hosts)
This Descended from Wolves?
Evolution By Natural Selection
Charles Darwin and Alfred Russell
Wallace, 1859
 Organisms are adapted to their
environments
 Individuals vary
 More organisms are born than can
possibly survive
 Variations best suited to the environment
tend to survive and be passed on.

Mutations
Change in
 “If you fix it often enough, you’ll break it”
 Most organisms already adapted
 Chance of random
 Many mutations are
 Radical changes
 Mutations may be useful

Convergent Evolution
Unrelated organisms may develop
similar features
 Often dictated by physical constraints
 Shark, tuna, dolphin, seal, squid,
penguin, ichthyosaur
 Deer, pronghorn, impala
 Albatross, pterosaur

Exaptation
Modification of existing structure to serve
new function
 Fin – paw – wing – hand
 Scale – feather
 There are no half-formed organisms

What Good is Half an Eye?
What Does a Bug See?
What Does a Bug See?
What Good Is Half An Eye?
A “partially-developed” eye can be very
useful
 Selection will favor:
More Receptors (Sharper Image)
Wider Angular Spread (Better direction
discrimination)
Better Image Processing

What Good is Half a Wing?
Gliders
Powered Flight


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



Pterosaurs?
Fish

Snakes
 Lizards

Physics of Gliding
Terminal Velocity
 Air Resistance = Gravitational
Acceleration

 200
km/hr for a human
 20 km/hr for a mouse



Selection favors duration and control
Two Bumblebee Myths
Theoretically, bumblebees should not be
able to fly.
 Bumblebees can’t glide well. Neither
can many aircraft
A bumblebee can carry more than its own
weight, something no airplane can do.
 C-5A empty 238,000 lb., maximum
takeoff weight 840,000 lb.
Classification of Dogs and Humans
Kingdom
 Phylum
 Class
 Order

Family
 Genus
 Species

Animalia
Chordata
Mammalia
Carnivora
(Dogs)
Canidae
Canis
familiaris
Primates
(Humans)
Hominidae
Homo
sapiens
“Actually, I considered
this an extreme honor.
Besides, I knew no
one was going to write
and ask to name a
new species of swan
after me. You have to
grab these
opportunities when
they come along.”
Below Species

Ideally, species is a genetic group
capable of breeding


 As
used for humans, has little scientific
meaning

The Five Kingdom System



Protista (one-celled organisms)

Bacteria*
 Ediacaran Fossils? (ca. 700 m.y.
ago)

Above a Kingdom
Bacteria differ from all other kingdoms
in lacking a cell nucleus
 We need a bigger box
 Superkingdoms or





Need electron microscopes and
molecular biology to see differences
Moral of the Story
Isolation creates
variation which leads to
speciation
Objectives
1. Be able to define species in terms of
population___________________.
2. Explain under what circumstances
species will, and will not, change.
Objectives
3. Describe the process of speciation, with
reference to allopatric, parapatric, and
sympatric modes.
4. Distinguish the various types of isolating
mechanisms that can lead to speciation.
The Case of the Road-Killed Snails
A. Sometimes it is easy to see how an animal that
flies long distances would be able to take its
genes from one place to another, but what about
the slow-moving snail?
B. Yet even snails confined to relatively small
areas show genetic variation that could possibly
lead to eventual speciation many years hence.
On the Road to Speciation
A. What is a Species?
1. The morphological species concept express
the following:
a. Species, ____________________.
b. Attempting to determine whether similar,
yet different, animals are the same species by
appearance (__________) is not reliable due to
the subtle variations that are displayed.
2. The Biological Species concept relies on
reproduction to define relatedness of species.
a. Ernst Mayer says, “Species are groups of
interbreeding natural populations that are
reproductively isolated from other such
groups”.
b. As good as it is, this definition is
troublesome for organisms that are nonsexually reproducing and
those___________________ _______.
3. __________ is the attainment of reproductive
isolation, but genetic changes between
populations of the same species can be
countered by gene flow.
4. __________is the process whereby local
units of a population become reproductively
isolated from other units and thus experience
changes in gene frequencies between them.
B. Reproductive Isolating Mechanisms
1. Reproductive isolating mechanisms are
any heritable features
___________________ _________
________ that _________ interbreeding
between genetically divergent populations.
2. Prezygotic mechanisms take effect before
or ____________ fertilization.
a. ___________: patterns of courtship may be
altered to the extent that sexual union is not
achieved (for example: albatross courtship rituals).
b. ____________: different groups may not be
reproductively mature at the same season,
month or year (example: periodical cicadas).
c. ___________: two populations are mechanically
isolated when differences in reproductive organs
prevent successful interbreeding (example: floral
arrangements in sage plants discriminate
between different bee pollinators).
d. ____________: potential mates may be in the
same general area by not in the same habitat
where they are likely to meet ( example: different
species of manzanita shrubs live at different
altitudes and habitats).
e. _____________: incompatibilities between egg
and sperm prevent fertilization (example: signals
to pollen grains to begin growing toward the
egg).
Isolation creates
variation which leads to
speciation
3. Postzygotic mechanisms take effect
________ fertilization.
a. Sometimes fertilization does occur
between ______________, but the hybrid
embryo is weak and dies.
b. In some instances the _________ are
vigorous but __________ (example: mule
produced by a male donkey and a female
horse).
Speciation in Geographically isolated Populations
A. _________________Defined
1. In this model some physical barrier arises
and prevents gene flow between populations.
2. Allopratic refers to the “ _________” the
two species occupy.
3. Reproductive isolating mechanisms evolve in
the genetically diverging populations and will
result in complete speciation when the two
species can no longer interbreed.
B. The Pace of Geographic Isolation
1. Isolation may be _________ as in an
____________ that results in separation of
species.
2. ___________, on the other hand, may
produce conditions that yield separate
over _____________.
3. Studies of enzymes from fishes on the
Atlantic and Pacific sides of the Isthums of
Panama reveal molecular differences.
C. Allopatric Speciation on Archipelagos
1. An archipelago is an island chain
some distance away from a continent.
2. The finches of the Galapagos
Islands are evidently ancestors of
mainland finches that invaded first a few
islands and then spread to others,
diverging as time progressed.
Models for Other Speciation Routes
A. Sympatric Speciation
1. In this model, species may
___________________ _____________, in the
absence of a physical barrier.
2. Literally means “____________________
_________________”.
3. In two crater lakes of East Africa exist
small fish called Cichlids.
a. The species in each lake are alike in
their mitochondrial DNA and unlike the
species in neighboring lakes and streams.
b. The lakes are small so the fish must
live in sympatry.
4. Polyploidy is the inheritance of three or
more of each type of chromosomes due to
improper separation of chromosomes
during meiosis or mitosis.
a. Speciation is instantaneous for
__________ that are polyploid.
b. Polyploid animals are _________
because of dosage compensation which
regulates the level of gene expression in
chromosomes.
B. _______________
1. Daughter species form from a small
proportion of individuals along a common border
between two populations.
2. Literally means “__________________”.
3. Interbreeding individuals produce hybrid
offspring in this region called a ___________.
Isolation creates
variation which leads to
speciation
Patterns of Speciation
A. Branching and Unbranched Evolution
1. Cladogenesis applies to populations that
become isolated from one another and
subsequently _____________________.
2. Anagenesis is a pattern of descent in
which species form within a single,
____________________.
B. Evolutionary Trees and Rates of Change
1. ________________summarize
information about the continuity of
relationships among species.
2. The ______________of speciation is
represented by tree diagrams with
branches at slight angles to each other to
show slow change over time.
3. The _______________of speciation is
drawn with short, horizontal branches that
represent abrupt periods of speciation
followed by stable periods.
C. Adaptive Radiations
1. An ____________is a burst of
microevolutionary activity that results in
the formation of ______________
_____________.
2. The presence of adaptive zones
presents
Isolation creates
variation which leads to
speciation
D. Extinctions- End of the Line
1. Extinction is the rather inevitable loss of
species as local conditions change over
periods (usually long) of time.
2. Mass extinctions are abrupt
disappearances due to catastrophic,
global events.
Why Some Biologists
Prefer Intelligent Design
Over Evolution
“It is absolutely safe to say that
if you meet somebody who
claims not to believe in
evolution, that
person is
ignorant,
stupid or
insane.”
- Professor Richard Dawkins
Evolutionary Biologist
A Scientific Dissent From Darwinism
761 scientists listed by doctoral degree or current position.
Evan Pugh
Prof. of Chemistry, Pennsylvania State University Member of the National Academy of Sciences
Lyle H. Jensen
Eugene Buff
Ph.D. Genetics Institute of Developmental Biology, Russian Academy of Sciences
Henry Schaefer
Paul Ashby
Alan Linton
Professor Emeritus, Dept. of Biochemistry University of Washington
Director, Center for Computational Quantum Chemistry University of Georgia
Ph.D. Chemistry Harvard University
Emeritus Professor of Bacteriology University of Bristol (UK)
Dean Kenyon
Emeritus Professor of Biology San Francisco State University
David W. Forslund
Robert W. Bass
Ph.D. Astrophysics, Princeton University Fellow of American Physical Society
Ph.D. Mathematics, Rhodes Scholar, Johns Hopkins University
Daniel W. Heinze
Ph.D. Geophysics Texas A&M University
“We are skeptical of claims for the ability of random mutation and
natural selection to account for the complexity of life. Careful
examination of the evidence for Darwinian theory should be
encouraged.”
1) Difficulty Forming
the First Cell
2) Logical Evidence of
Design
Difficulty Forming
First Cell
Can very simple elements of a world come together and create a
complex organism?
AIR
WATER
EARTH
Modern Cells-complex
How Did the First Cell Evolve?

“A particularly remarkable
molecule was formed by
accident, a molecule that had
the ability to reproduce itself.
“

Similar molecules clustered
together.

They wrapped a protective
membrane around
themselves as a barrier.
- Professor Richard Dawkins
Hypothetical First Cell
Requirements for First Cell:
1.
2.
3.
4.
Problem 1
 The
first cell required two
types of complex molecules.


Non-living Molecules
Organic Molecules
Water
Carbon
dioxide
Methane
Phosphate
Ammonia
DNA
A single
DNA molecule
stretched to its full
length extends more
than SIX feet.
Problem 2
Where to
find a
membrane?
Cell Membranes

Composed of complex ___________ molecules.
Phospholipid Chemical Structure
Problem 3
How did the self-replicating molecule
wrap the membrane around itself?
Problem 4
How do food and waste get
in and out?
Modern Cell Membranes
Protein Channel in Membrane
Side View
Front View
What is the chance of even one simple protein
molecule forming at random?
Evolutionists estimate
it to be only 1 in 10113.
That’s a 1 with 113
0’s after it!!!
Any event that has
1 chance in 1050
is dismissed by
mathematicians as never happening.
10113 is larger than the total number of all the
atoms in the universe!
Without a membrane embedded with
protein channels, the first cell could not
have functioned.
“It was my science
that drove me to the
conclusion that the
world is much more
complicated than can
It is only through the
supernatural that I
can understand the
mystery of existence.”
be explained by science.
- Professor Allan Sandage
worked with Edwin Hubble
at Mount Wilson Observatory
Cell Membrane Animation
Cause and Effect
Random
Forces
Forces vs.
Directed by
Intelligence
Product of
Random
Force
Product of Directed Force
Product of Undirected Force
Product of Directed Force
Product of Random Force
Product of Design
Bacterial Flagellum
Macroevolution
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The Fossil Record
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The Fossil Record

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Gaps in the Fossil Record

Gaps exist because:
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History of Life on Earth

Three main events:

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Origin of Cellular Organisms
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Beginning of Multicellular Life
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Colonization of Land
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Colonization of Land
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Continental Drift
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Continental Drift
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Isolation creates
variation which leads to
speciation
Movement of the Continents Over
Time
The Five Mass Extinctions
Radiation

Example:
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loss of flight or sight
Adaptive Radiation
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Origin of Mammals
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Origin of Mammals
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Differences from reptiles:
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From Reptile to Mammal

From Reptile to Mammal

Mammalian jaw is more advanced
Overview
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