Transcript Evolution - Loyola Blakefield

Evolution
Lesson 1:
An Introduction to Charles Darwin
and the Nature of Science
Evolution Project
• New randomized groups
• 4th quarter grade: Daily class work/homework
collected in a final portfolio
• Final Exam grade: Five “In Depth Investigations”
– Graded according to a rubric/ average grade will be final
grade.
• Ends May 28th (We will not observe review days.)
• Consequences of not fulfilling individual work
requirements.
“A scientist, however, gifted, can be
compared with a fly crawling on the inside
wall of a cathedral; if it could draw what it
sees, the fly’s picture of the cathedral would
be as crude as early maps of the world; if it
could voice its speculations about the size,
appearance, and purpose of the cathedral, the
fly’s opinions would be received even more
guardedly.”
-- Frederick Aicken, The Nature of Science , pp.29-30
Evolution As An Idea
“ If I were to give an award for the single best idea anyone has ever
had, I’d give it to Darwin, ahead of Newton and Einstein and
everyone else. In a single stroke, the idea of evolution by natural
selection unifies the realm of life, meaning and purpose with the
realm of space and time, cause and effect, mechanism, and physical
law. But it is not just a wonderful idea. It is a dangerous idea.”
Daniel Dennet
Evolution as an Idea
“Evolution is one of the most powerful
ideas ever to emerge from science. It
is the very foundation of biology and
the key to understanding our own
human origins. The mechanism of
evolution helps determine who lives,
who dies, and who gets the
opportunity to pass on traits to the
next generation. At the same time,
evolution ranks as one of the most
widely misunderstood scientific
principles in America today.”
Richard Hutton, Executive Producer, Evolution WGBH
Jody Patton, Executive in Charge, Clear Blue Sky
productions
Darwin’s Voyage of Discovery
• Take the Pre-Test
• Homework
• Go to the following link:
http://www.pbs.org/wgbh/evolution/educators/lessons/lesson2/act1.html
• Complete the directions in Lesson 2
Activity 1. This will require you to…
• Read the activity
• Print the world map
• Read the excerpts of Darwin’s
Voyage
• Write a paragraph that answers the
question: Who was Charles Darwin?
Darwin and the Galapagos
When your group finishes answering the questions for
In Depth Investigation #1, discuss the following:
1.
2.
3.
4.
How did the Galapagos Islands get there?
How did the first plants get there?
How did the first animals get there?
What is ecological succession?
Galapagos Islands
Galapagos Islands
Ecological Succession
• process in which communities of plants and
animal species in a particular area are
replaced over time by a series of different and
often more complex communities.
• Two stages
– Primary succession
– Secondary succession
Primary Succession
succession in a bare area (no mature soil) that has
never been occupied before
Secondary Succession
succession in an area in which natural vegetation has
been removed or destroyed but the soil remains
Ecological Succession
Darwin’s Theory of Natural Selection
1. Variations exist
2. These variations are heritable
3. Some variations are advantageous and some are
disadvantageous
4. Organisms compete for limited resources
5. Organisms with advantageous variations survive and
reproduce most successfully, leafing more organisms like
them in the next generation
6. Over time, the population changes to become more like the
organisms with advantageous variations
7. Today’s species have descended from past species
8. All organisms are related and are members of a single tree of
life
Darwin’s Theory of Natural Selection
• Individuals in a population show differences,
or variations
• Variations are inherited
• Organisms have more offspring than can
survive – COMPETITION for resources
• Variations that increase reproductive success
(organism survive and reproduce) will have a
greater chance of being passed
Variation in Population
Variations are Inherited
More offspring are produced
than can survive
Competition for available resources
Variations that are successful are
passed to the offspring
English Peppered Moth
Giraffe Evolution?
Long neck or short neck?
The neck allows
feeding from high branches,
serves as a weapon in males,
brings the head to elevated
heights that give the giraffe a
large field of view,
is used as a pendulum while
galloping, and so on
Ultimately, those with long necks
were more successful at
reproducing
Darwin’s Theory of Natural Selection
• Individual organisms differ; variation is
heritable
• Organisms produce more offspring than can
survive; they compete for limited resources
• Some variations are advantageous; individuals
best suited to their environment survive and
reproduce successfully
• Species alive today descent with modification
from ancestral species that lived in the past
Evidence of Evolution
• Fossil Record
• Comparative Anatomy
– Homologous Structures
– Vestigial Structures
– Analogous Structures
• Comparative Embryology
• Comparative Biochemistry
• Geographic Distribution
Fossil Record
Homologous Structures
Vestigial Structures
Analogous Structures
Comparative Embryology
Comparative
Biochemistry
Visualization - http://www.cs.ucr.edu/~eamonn/DNA/
Geographic Distribution
Examples of Natural Selection
English Peppered Moth
Darwin's Finches
Darwin’s Tree of Life
Evolutionary Classification Using Cladograms
• Cladogram – diagram used to show the
evolutionary relationship between organisms
• Cladograms are constructed using derived
characteristics
– Derived characteristics - characteristics that
appear in recent parts of the lineage but not in
older members; new characteristics that evolve
over time
– Each branch or junction shows the appearance of
a new trait
– Cladograms demonstrate when characteristics first
appeared
Cladogram of vertebrates
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
http://biology.unm.edu/ccouncil/Biology_203/Summaries/Phylogeny.htm
Evolution Review
Why is evolution
considered a
theory?
Give a simple
How is variation
definition evolution. important for
natural selection?
Briefly describe
“survival of the fittest”.
Explain why the
environment is
considered the
“selector” in natural
selection?
Compare and
contrast
homologous
structures and
analogous
structures.
How can the study
of embryos show
evidence of
evolution?
How do the following
terms relate to natural
selection: competition,
adaptation, descent
with modification?
How does genetic
mutation influence
natural selection?
Why is it useful for
scientists to be
skeptical?
Explain how plants
and animals could
colonize islands
from the mainland.
Can evolution occur in
individuals? Why or
why not?
Explain Darwin’s
role on the HMS
Beagle.
Give an example of
evolution.
What are vestigial
What does a
structures? Why are cladogram
they considered
illustrate?
evidence of
evolution?
Evolution Review
Why is
evolution
considered a
theory?
Explain how
plants and
animals could
colonize
islands from
the mainland.
Give a simple definition
evolution.
Explain why the
environment is
considered the
“selector” in natural
selection?
How is
variation
important for
natural
selection?
Briefly describe
“survival of the fittest”.
Can evolution occur in individuals? Why/why not?
Give an example of
evolution.
What does a
cladogram
illustrate?
How does genetic
mutation influence
natural selection?
Compare and
contrast
homologous
structures and
analogous
structures.
How do the
following
terms relate
to natural
selection:
competition,
adaptation,
descent with
modification?
How can the study of embryos show evidence of evolution?
Explain
Darwin’s role
on the HMS
Beagle.
Why is it useful for
scientists to be
skeptical?
What are vestigial
structures? Why are
they considered
evidence of evolution?
Primate Evolution
• http://www.pbs.org/wgbh/nova/evolution/fir
st-primates.html