Unit 1 Section 7: Evolution of Living
Things - Part b
Misconceptions about evolution:
find out if you have any misconceptions about evolution.
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To understand evolution, you must be
familiar with many different terms and theories. Any discussion of the topic is
useless without an agreement on these terms. Even the definition of
evolution can be debated.
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*Evolution
Video* : Gene frequency, natural selection and speciation
Fossils
Most living things change very slowly. While
some changes can be observed directly, much what we know about the history of
life on earth comes from the fossil record. A fossil is any trace
of a long-dead organism. Most fossils are formed when sediment is deposited by
wind or water. These sedimentary fossils usually develop only from hard body
parts. The soft body parts decompose before they can be replaced by hard
minerals. The special conditions needed for the formation of fossils cause the
fossil record to be less than complete. Because of this, the fossil record is
open to interpretation. Different scientists can look at the same fossil and
reach different conclusions about its place in the history of life.
Burgess Shale Fossils: See
some of the very interesting organisms found in Canada.
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Fossil imprint of an organism.
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Fossil track of an
organism.
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Organism preserved
in amber (fossilized tree sap).
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In 1669, Nicolaus Steno proposed the Law
of Superposition stating that successive layers of rock or soil were
deposited on top of one another by wind or water. This means that the lowest
layers are the oldest, while the top layers are the most recent. This law is
still accepted today and allows scientists to give fossils a relative age.
Carbon dating
can be used
to determine the actual age of an object. The only requirement is that the
object must have carbon in its structure.
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Paleontologist
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Species:
A group of organisms that mate
and produce fertile offspring.
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Morphology:
a comparison of internal and external structures of organisms.
The morphological concept of species uses the
internal and external structure and appearance of organisms to determine a
species. These characteristics are easy to observe, making species
identification relatively convenient. The morphological concept of species
has limitations. All individuals within a morphological species do not look
alike. Humans, for example, do not all look alike. We are, however, all Homo
sapiens.
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The biological
concept of species states that a species is a population of organisms
that can successfully interbreed but cannot breed with other groups.
Scientists who study evolution today do not like this definition because
the reproductive compatibility of extinct organisms cannot be tested and
the definition is unsatisfactory for organisms that reproduce asexually.
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 Important terms
related to evolution theory:
 (bio lab 115)
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Natural
selection: organisms with favorable variations survive and reproduce
at a higher rate. These favorable characteristics are then passed on to
their offspring.
- Stabilizing
selection: individuals with the average form of a trait have the
highest fitness.
- Directional
selection: individuals with an extreme form of a trait have a greater
fitness.
- Disruptive
selection: individuals with extremes on either side of the average
trait have a greater fitness than individuals with the average trait.
- Speciation:
the formation of a new species from an existing one.
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Adaptive
radiation: many species appear to be related to a single ancestral
species.
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 (A) Divergent
evolution: two closely related species becoming more and more
dissimilar because of environmental adaptations.
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(B) Convergent
evolution: unrelated species becoming more and more similar in
appearance because of a shared environment.
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(C) Parallel evolution - Pattern
of evolution in which two
species maintain the same degree of similarity while each undergoes
change along an independent path.
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Coevolution:
two or more species changing because of changes in a species with which
they are interacting.
- Gene pool:
the collection of genes for all the traits in a population.
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Allele
frequency: the percentage of a specific allele of a gene in the gene
pool.
- Genetic
equilibrium: (see Hardy-Weinberg principle below) allele frequencies do not change from generation to
generation.
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Genetic
drift: allele frequencies in a population change as a result of
events or chance.
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Gene flow:
the process of genes moving from one population to another.
- Immigration:
the movement of individuals into a population.
- Emigration:
the movement of individuals out of a population.
Distribution of the B
type blood allele in native populations of the world. (Click map)
- Phylogeny:
(a.k.a. evolutionary trees)
inferred evolutionary relationships among organisms.
The Hardy-Weinberg Principle:
A population
will remain in genetic equilibrium if, and only if, all of the following
conditions are met.
- No mutations
occur.
- Individuals
neither enter nor leave the population through migration.
- The population
is large.
- Individuals mate
randomly.
- Natural
selection does not occur.
Hardy-Weinberg equilibrium
equation
(p² + 2pq + q² = 1)
- a simple equation that
can be used to discover the probable
genotype
frequencies in a population and to track their changes from one generation
to another.
Punnett square for Hardy-Weinberg equilibrium
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p² + 2pq + q² = 1 |
Females |
| A (p) |
a (q) |
| Males |
A (p) |
AA (p2) |
Aa (pq) |
| a (q) |
Aa (pq) |
aa (q2) |
The final 3 possible genotypic frequencies in the offspring:
f (AA) = p2 or f (Aa)
= 2pq or f (aa) = q2
Evolution Theory Basic Timeline:
1809 - Lamarck
1844 - Darwin
1858 - Wallace
1859 - "The
Origin of Species" by Charles Darwin
July 10-25, 1925 -
"Scopes Monkey Trial"
1.7 b Assignment - Evolution of Living Things
Scoring criteria
Part A
- Find out if you
have any of the misconceptions about evolution as others have. Use the
link
at the top of the page along with is handout .
word
version
web version
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View the online Evolution video at the top of this page (Gene frequency, natural selection and speciation) to find out about some very interesting fossils.
- complete this handout
while
watching the video
- Summarize how the
Hardy-Weinberg principle is used to describe evolution?
- What is the Hardy-Weinberg principle?
- How can it be used?
- Visit this lab:
Lab bench see how the Hardy-Weinberg principle works
(Honors
question)
Visit this biology
lab site
and complete the virtual lab on the Hardy-Weinberg principle. Cut and paste
or use
print screen to copy your answers into your assignment for the following
parts.
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Sample problems 1,2,3 from
concepts 8,9,10
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Lab quiz
(Regular biology does 4 also)
- Visit this blog site
started by another high school and pick a blog dealing with the topic of
evolution. Sign up and post your comments on the topic. Give the name of the blog creator, topic of blog,
URL for blog, and what you added.
- Click on a name
- Hit comments button
- Click "set up new account" Follow direction on page
- Once finished with new account make a comment in box and post
Honors biology: Along with part A above complete this
"to Do" activity.
- Complete the
"To Do" activity below. If this is done as homework have your
parent or guardian sign your log for verification of completion. You will
not need a stamp or signature by the teacher.
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How important is your opposable thumb?
Individually, ask your teacher for tape for the following:
- Tape the thumb on
your dominant hand to the finger next to it.
- Obtain a stamp or
signature on your tape from the teacher or parent.
- Leave the thumb
taped down for as long as you can.
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Use this data sheet
Record the
date & start
time and the end time.
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Keep a record of
all the ways this changes things you do during the day.
- Record is due
tomorrow.
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Part B
- Define species.
Compare and contrast the two concepts of species (morphological & biological).
- Describe
the graphs depicting disruptive, stabilizing, & directional selection. What
do they show?
- Explain the
difference between Divergent and Convergent evolution?
- A species of
butterfly feeds on only one species of flower. Through many flower
generations, the location of the nectar moves deeper and deeper into
the flower. As this happens, some butterflies evolve longer tongues to
reach the nectar. What type of evolution is this?
- View the allele
frequency for human blood types above.
- Which allele for blood type is least frequent in north America?
- Which allele for blood type is most frequent in north America?
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Discover how groups of organisms are related
to each other (phylogeny) by constructing a Cladogram
. Use your text (15.8
pg. 306) and your research skill to complete this handout
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Who is Lamarck
and how is he link to the theory of evolution?
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What is the
"Scopes Monkey Trial" ?
- Describe in your
words specific important evidences that have been use in the
development of evolution theory from the following: (scroll down)
- comparative anatomy
- paleontology
- embryology
- molecular biology
- biogeography
Honors biology: Along with part B complete this
simulation.
- Perform this
simulation for genetic drift
. (5 questions to answer)
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Evolution of Living Things:
1.7 c
What is the Evidence
supporting Evolution?
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What are homologous
structures?
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Before
you begin this assignment watch this
"Elements of Evolution" and
complete the quiz at the end.
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Turn in the
answers to your teacher.
Evidence Supporting Biological Evolution
A long path leads from the origins of primitive
"life," which existed at least 3.5 billion years ago, to the
profusion and diversity of life that exists today. This path is best understood
as a product of evolution.
Contrary to popular opinion, neither the term nor
the idea of biological evolution began with Charles Darwin and his foremost
work, On the Origin of Species by Means of Natural Selection (1859). Many
scholars from the ancient Greek philosophers on had inferred that similar
species were descended from a common ancestor. The word "evolution"
first appeared in the English language in 1647 in a non-biological connection,
and it became widely used in English for all sorts of progressions from simpler
beginnings. The term Darwin most
often used to refer to biological evolution was "descent with modification,"
which remains a good brief definition of the process today.
Darwin
proposed that evolution could be explained by the differential survival of
organisms following their naturally occurring variation--a process he termed
"natural selection." According to this view, the offspring of
organisms differ from one another and from their parents in ways that are
heritable--that is, they can pass on the differences genetically to their own
offspring. Furthermore, organisms in nature typically produce more offspring
than can survive and reproduce given the constraints of food, space, and other
environmental resources. If a particular off spring has traits that give it an
advantage in a particular environment, that organism will be more likely to
survive and pass on those traits. As differences accumulate over generations,
populations of organisms diverge from their ancestors.
Fields of science contributing evidence:
The Fossil Record - paleontology
Common Structures - comparative anatomy
The Distribution of Species - biogeography
Similarities
During Development - embryology
Evidence from Molecular Biology - molecular biologist
1.7 c Assignment - Evolution of Living things
Scoring RubricHtmlWord Document
You are now part of a scientific team. The team consist of
people specializing in each of the following areas: Paleontology, Molecular
biology/Genetics, Anatomy/Physiology. Go to the following site Evidence for
Evolution WebQuest
and
complete the task.
- Read Activity 2, Complete
the task by following the process listed on the web site (Observations
Lead to a Theory).
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Discuss in your group who will represent each
area of specialization and how your group will present its findings
(Important that each member discuss and share their finding with the others in
group - everyone in group must have a good understanding of all areas).
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Provide a list of group members and their area
of specialty to the instructor
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Your group may change its visual presentation
(webpage, power point, poster, video, etc.)
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Your text (ch.13 & 14) also contains information for this assignment along with
the online text
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Print out and read Evidence for Evolution
rubric, bring to presentation.
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Remember read and follow the directions
carefully.
Research Links:
Earth's
Age:
Evolution Theory:
