Transcript Evolution PP 2

Warm up –Justify answer
put on page 18 0r 19
 1. A scientist has a hypothesis that a large volcanic
eruption caused a change in global temperature. Which
information gained from ice cores is most useful in
supporting the scientist’s hypothesis.
A levels of dissolved oxygen B identities of trace
metals
C estimates of natural
D amounts of atmospheric
radioactivity
dust
2. Why do scientists study fossils?
A to understand how volcanoes are formed
B to understand life on Earth as it was millions of years
ago
C to understand when mountains were created
D to help predict the future.
Write in Cornell note style









1. What is biodiversity?
2. What does evolution mean?
3. What can cause this and how?
4. What is the theory of evolution
5. Who is the father of this theory and why?
6. How did he come up with his theory?
7. What did his travels reveal?
8. What did he observe?
9. Why was his voyage important?
What is Biological
Diversity?
 Earth has millions of
organisms of every
imaginable shape, size, and
habitat.
The variety and
abundance of species
that make up a
biological community
is called biodiversity..
 http://www.youtube.com/watch?v=8Sgnn
V8nV9g
 Origins and evolution of life
The Big Question is …
How did all these
different
organisms arise?
How are they
related?
The Tree of Life
• All living things share
a common ancestor.
• We can draw a Tree of
Life to show how every
species is related.
•Through Evolution one
species gives rise to
another and the Tree of
Life grows
en.wikipedia.org/wiki/Image:Phylogenetic_tree.svg
What is “evolution”?
 Evolution means change over
time.
What causes this change?
 Mutations - a permanent
change in the DNA sequence
of a gene
What is “evolution”?
 Evolution means change over
time.
What is an adaptation?
 An adaptation is a feature that
is common in a population
because it provides
some improved function.
Warm up –Justify answer
1 Which concept is illustrated by the physical changes in
the size and structure of the horse over time?
 A) genetic engineering
 C) biodiversity
B) succession
D) evolution
2 Traits that enable an organism to survive and
reproduce in its environment are known as
A) Adaptations
B) variations
C) mutations
D) clones
Warm up –Justify answer
put on page 21
1. Survival of the fittest refers to an organisms that can
 A) grow faster
B) develop large muscles
 C) adapt t o the
D) live in cold climates

environment
2) Which process is most responsible for the extinction
of most species of plants and animals that have lived
on Earth?
 a) gene mutation
b) environmental changes
 c) selective breeding
d) decrease in reproduction
What is “evolution”?
 Evolution means change over time
What is the Theory of
Evolution”?
 Change in the gene pool of a population
from generation to generation by such
processes as mutation, artificial/natural
selection, and genetic drift.
 A scientific theory is NOT just a belief,
it is a well-supported tested
explanation.
Timeline of Theory
1785 James
Hutton
postulated that
the earth was
formed by an
ancient
progression of
natural events,
including
erosion,
disruption, and
uplift.
1830 Charles
Lyell published
evidence
pushing the age
of earth back
several million
years.
Early 1800’s
George Cuvier
suggested that
the earth was
6,000 years
old- based on
his calculations.
1858 Alfred
Russell Wallace
publishes
similar theory of
evolution.
1838 Charles
Darwin starts to
theorize on
evolution.
Who is considered the
Father of Evolution?
Charles Darwin
The first person to explain the cause of
biological diversity
How did Darwin come
up with his Theory of
Evolution?
1.Charles Darwin (1809-1882)
Sailed around the world 1831-1836
Darwin went on an
around-the-world
trip on the HMS
Beagle and traveled
to the Galapagos
Islands.
H.M.S Beagle Route
What did
Darwin’s
Travels reveal?
 The diversity of living
species was far greater
than anyone had
previously known!
 Species of different
origins had similar
structures
 These observations led
him to develop the
theory of evolution!!
What did he observe?
 He particularly liked 
and observed the
finches. He also
observed the
tortoises on different 
islands.
He observed each
different group had
its own niche.
He studied 13
different species
and saw how they
adapted to their
environment.
Galapagos Animals Darwin
Studied
Land Tortoises
Blue-Footed Booby
Darwin Finches
Marine Iguanas
Why did tortoises and birds
differ among the islands of
the Galapagos?
 Each island
had its own
type of
tortoises
and birds
that were
clearly
different
from other
islands
Galapagos
Turtles
Why was the Voyage important?
 Darwin collected specimens from
each place they stopped.
 Included shells, animals, fish, plants
and fossils.
 Compared specimens of different
origins and realized some had similar
structures.
Living Organisms and Fossils
 Some of those fossils resembled organisms
that were still alive.
 Others looked completely unlike any
creature he had ever seen.
 As Darwin studied fossils, new questions
arose.
 Why had so many of these species
disappeared?
 How were they related to living species?
Darwin’s Trip
Vocab words we have
covered
On your own Wrap up
 Give two examples of variations in
organism that Darwin observed.
How did he account for their differences?
 What is Natural selection?
Warm Up
1)Which statement best
explains the survival benefit
of high genetic variation in a
species?
A. It prevents a high mutation
rate.
B. It reduces the risk of
extinction due to
environmental change.
C. It can only occur if the
species population size is
already large.
D. It allows the species to
use a variety of strategies
to avoid predation.
2) Islands are the
habitats of many of the
world’s rarest species.
Which of the following
factors contributes
most to this situation?
A. Small land area
B. Genetic isolation
C. Limited food variety
D. Fewer predators
Write in Cornell note style
1. What did Darwin Theorize was the reason why
some animals appeared to have come from
unknown origins ?
2. What is the relationship between adaptation and
mutation?
3. What Is the name of Darwin’s Publication?
4. What is artificial selection?
5. What is natural selection?
6. What are the main components of Darwin’s
Theory?
7. What are evidences of Evolution?
8. What are Homologous Body Structures
Write in Cornell note style
9. What are Analogous structures?
10. What are Vestigial Organs?
Environment, Mutations and Natural
Selection
Environment, Mutations and Natural
Selection
Environmental Variation of
The Galapagos Island
 The smallest, lowest
islands were hot, dry, and
nearly barren-Hood
Island-sparse vegetation
 The higher islands had
greater rainfall and a
different assortment of
plants and animalsIsabela- Island had rich
vegetation.
Darwin was
fascinated by the
tortoises
They varied in
predictable ways from
one island to another.
The shape of a tortoise's shell
could be used to identify which
island it inhabited.
Each species of finches had adapted to its
environment and had its own niche (job / role) and
specialization (the adaptation of an organism or a
part of an organism to a specific function or
condition in response to environmental conditions)
Patterns of Diversity
 Darwin also realized
many places have
similar ecosystems, but
different inhabitants.
 He studied the
correlation between
fossils found and the
organisms alive today.
Glyptodon - lived 2,500,00 to
10,000 years ago
Armadillo - presently lives in the
Americas
Thought Process
 He pondered why some plants and
animals are extinct; while others are
emerging from currently unknown origins.
 Theorized that not all of the species were
dying but actually adapting and evolving.
Who influenced Darwin?
Bishop Ussher:
1581-1656 using the book of Genesis
he calculated universe was created On
October 23,4004B.C. This would make
the Earth was about 5,000 or 6,000
years old at most.
In Darwin's day most Europeans
believed this
Who influenced Darwin?
James Hutton:
1795 Theory of
Geological change
 Forces change
earth’s surface shape
 Changes are slow
 Earth much older than
thousands of years.
 Darwin thought if
earth is much older
then this would
allow time for
species to evolve?
Who Influenced Darwin?
Charles Lyell:
•Book: Principles of
Geography
-Geographical
features can be built
up or torn down
Darwin thought if
earth changed over
time, what about life?
Geologists:
Hutton and Lyell
Fundamentalists said that the
earth was around 6000 years
old
Hutton and Lyell argued that
the earth is many millions of
years old b/c
 layers of rock take time to
form
 processes such as
volcanoes and earthquakes
shaped the earth and still
occur today
Who influenced Darwin?
Thomas Malthus
19th century English economist
If population grew unchecked
(more Babies born than die)
 Insufficient living space
 Food runs out
 Darwin applied this theory
to animals
Lamark
Theory of acquired
characteristics

Lamark said
organisms acquired
traits by using their
bodies in new ways

These new
characteristics were
passed to offspring

Lamark was totally
wrong!
Darwin finally
published his
ideas in 1859
 Other naturalists
were developing the
same theory that
Darwin did.
 Even though he
was afraid of the
Church’s reaction
to his book he
wanted to get credit
for his work.
Survival of the Fittest
• In his Origin of Species,
published in 1859, Darwin
proposed how one species
might give rise to another.
Natural Selection
explains adaption
• Where food was limited,
competition meant that only
the fittest would survive.
• This would lead to the natural
selection of the best adapted
individuals and eventually the
evolution of a new species.
Darwin in 1860
en.wikipedia.org/wiki/Image:Darwin%27s_finches.jpeg
Evolution and Natural Selection
Evolution and Natural Selection
What is Artificial Selection?
 Humans selectively breed organisms
for variations/ traits that are useful.
 Example - a farmer breeds only his best
livestock
Evolution via Natural
Selection
 “Survival of the
Fittest”
 Some individuals
are better suited
for the
environment.
 Members of each
species have to
compete for food,
water and shelter.
What is Natural Selection?
 The traits that
helps an organism
survive in a
particular
environment are
“selected” by
nature .
What are Agents of Evolution?
Agents of Evolution
Geographic Distribution of
Living Species
When the world had one main
landmass (Pangaea) species
migrated to specific areas.
Overtime, as the landmass
shifted apart, organism were
isolated and developed to
best survive in their
environments.
Agents of Evolution
-Natural Selection and Species Fitness
 Overtime, natural selection results in
changes in the inherited
characteristics of a population.
 These changes increase a species
fitness (survival rate)
 “Survival of the Fittest”
Descent with Modification
 Each living
species has
descended
with
changes
from other
species
over time
What is ADAPTATION?
 A changes
in
structure or
behavior that
develops over many
generations to
enable an organisms
to survive
successfully in its
habitat .


Behavioral adaptation
Structural adaptation
What are the key components
of Darwin’s Theory
1. Organisms differ; variation is inherited
2. Organisms produce more offspring than
survive
3. Organisms compete for resources
4. Organisms with advantages survive to pass
those advantages to their children
5. Species alive today are descended with
modifications from common ancestors
What are Evidences of Evolution?
13. Evidence of Evolution
1. Fossil Record
2. Geographic Distribution of Living
Species
3. Homologous Body structures
4. Similarities in Embryology
Evidence of
Evolution
Fossil Record provides
evidence that living
things have evolved
Fossils show the history
of life on earth and
how different groups
of organisms have
changed over time
Transitional fossils show
a clear transition from
one species, or group, to
another.
Evidence of
Evolution
Geographic Distribution
of Living Things
Similar environments have
similar types of
organisms
Similar animals in
different locations
were the product of
different lines of
descent
Descent
 Two types
 Descent with modification- Over
time, natural selection produces
organisms that have different structure,
establish different niches, or occupy
different habitats. As a result, they look
different from their ancestors.
 Common Descent- all living and
extinct organisms were derived
from a common ancestor.
What are Evidences of Evolution?
Evidence of
Evolution
Homologous Body
Structures
 traits that are similar
in different species
because the species
share a common
ancestor.
Ie. Arm, fin and wing
may have evolved
from the forelimb of a
common vertebrate.
Turtle
Alligator
Bird
Homologous Body Structures
Analogous structures
Structures that are
similar in function,
but are not
inherited from a
common ancestor.
Ex. Insect and Bird
Wings
Vestigial Organs
Inherited, but reduced in size and
often unused.
ex. Pythons have hip and leg bones
Evidence of
Evolution
Similarities in
Embryology

In their early
stages of
development,
chickens, turtles
and rats look
similar, providing
evidence that
they shared a
common
ancestry.
Embryological development