Download Name: Date:______ Period:_____ Evolution Unit 5 – Overview

Name:____________________________________
Date:_____________ Period:_____
Evolution Unit 5 – Overview
Schedule – February 11, 2009 through March 27, 2009; Unit Exam Tuesday 3/23/09
Unit 5. Evolution Key Standards (2nd Semester)
5a. The frequency of an allele in a gene pool of a population depends on many factors and may be
stable or unstable over time. Students will apply how natural selection affects the characteristics of
an organism and how mutations are maintained within a gene pool. (7a, 7b, 7c)
Key Elements:
1. Define the following concepts: natural selection, mutation, gene pool
2. Describe the process of natural selection.
3. Give an example of natural selection in nature.
4. Explain how natural selection affects the characteristics of an organism.
5. Explain how a mutation is formed.
6. Discuss how a mutation is maintained within a gene pool.
5b. The frequency of an allele in a gene pool of a population depends on many factors and may be
stable or unstable over time. Evolution is the result of genetic changes that occur in constantly
changing environments. Students will describe how greater variation within a species may lead to
greater survival of that species. (7d, 8b)
Key Elements:
1. Define variation, species.
2. Explain how variation affects a species survival.
3. Give a realistic example of how variation in a species has lead to its greater survival.
5c. Evolution is the result of genetic changes that occur in constantly changing environments.
Students will evaluate the effects of genetic drift and geographic isolation on a species. (8c, 8d)
Key Elements:
1. Define the following: genetic drift, gene pool, geographic isolation, and species
2. Evaluate how genetic drift will affect a species, its gene pool, and its survival.
3. Evaluate how geographic isolation will affect a species, its gene pool, and its survival.
5d. Evolution is the result of genetic changes that occur in constantly changing environments.
Students will identify that analysis of fossil, DNA, and anatomical evidence supports evolution. (8e, 8f)
Key Elements:
1. Define the following: fossil, DNA, anatomical evidence, evolution, homologous structures, and
analogous structures.
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2. Describe how fossil evidence supports evolution.
3. Describe how DNA evidence supports evolution.
4. Describe how anatomical evidence supports evolution.
5. Give a realistic example of how all of the following support evolution: fossil evidence, DNA,
and anatomical evidence.
Note: The abbreviation CCS stands for California Content Standards referenced below.
California Standards Evolution
7. The frequency of an allele in a gene pool of a population depends on many factors and may be
stable or unstable over time. As a basis for understanding this concept:
a) Students know why natural selection acts on the phenotype rather than the genotype of an
organism.
b) Students know why alleles that are lethal in a homozygous individual may be carried in a
heterozygote and thus maintained in a gene pool.
c) Students know new mutations are constantly being generated in a gene pool.
d) Students know variation within a species increases the likelihood that at least some members of
a species will survive under changed environmental conditions.
8. Evolution is the result of genetic changes that occur in constantly changing environments. As a
basis for understanding this concept:
a) Students know how natural selection determines the differential survival of groups of
organisms.
b) Students know a great diversity of species increases the chance that at least some organisms
survive major changes in the environment.
c) Students know the effects of genetic drift on the diversity of organisms in a population.
d) Students know reproductive or geographic isolation affects speciation.
e) Students know how to analyze fossil evidence with regard to biological diversity, episodic
speciation, and mass extinction.
Textbook – Chapters 14 History of Life (pg 390 – 415) 15 Evolution (pg 416-449).
Class Website – www.marric.us/teaching;
Resources - http://www.phschool.com/science/biology_place/glossary/index.html
http://highered.mcgraw-hill.com/sites/0078695104/student_view0/
http://evolution.berkeley.edu/evosite/evo101/index.shtml
http://genetics.hannam.ac.kr/note/evolution.htm FEMS Microbiology Letters Volume 162 Issue 2 Page 325-330, May 1998
Tentative Schedule
Week 1: 2/16 - 2/20 – President’s Day Holiday 2/16 Chapter 14 History of Life (due 2/23),
Week 2: 2/23 - 2/27 –Unit 5 Quiz 1, Chapter 15 Evolutionary Processes (due on 3/5)
Week 3: 3/2 - 3/6 – Unit 5 Quiz 2, Chapter 15 Evolution and Natural Selection
Week 4: 3/9 - 3/13 – Unit 5 Quiz 3, Chapter 17 Classification and Review for Exam
Week 5: 3/16 - 3/20 – Breeding Bunnies and Molecular Clocks and Review for Exam
Week 6: 3/23 – 3/27 – Unit 5 Exam 3/24/00; Portfolio preparation
Evolution Unit Overview
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"In the broadest sense, evolution is merely
change, and so is all-pervasive; galaxies,
languages, and political systems all evolve.
Biological evolution ... is change in the
properties of populations of organisms that
transcend the lifetime of a single individual.
The ontogeny1 of an individual is not
considered evolution; individual organisms do
not evolve. The changes in populations that
are considered evolutionary are those that
are inheritable via the genetic material from
one generation to the next. Biological
evolution may be slight or substantial; it
embraces everything from slight changes in
the proportion of different alleles within a
population (such as those determining blood
types) to the successive alterations that led
from the earliest protoorganism2 to snails,
bees, giraffes, and dandelions." Douglas J.
Futuyma in Evolutionary Biology
What changes in evolution? Actually what
changes is the frequency of an allele. The
frequency of an allele in the gene pool of a
population is how often an allele occurs in
the genotypes of individuals of the same
species that are in the same area - the
same population. How often the allele
occurs depends on lots of factors such as 1) what the allele codes for - is it a critical trait for survival
and 2) is the allele a dominant or a recessive allele. These factors determine whether the allele will be
present for a long time or a short time. Natural selection acts on population by changing the frequency
of different alleles. If an allele is harmful, it will be eliminated from the population or reduced in its
frequency because those individuals in the population exhibiting the trait will not survive. This leads to a
fine difference between genotype and phenotype. Remember genotype is the kinds of genes an individual
has and phenotype is its observable traits. It is the observable traits that are selected for or against
resulting in increased allele frequency or reduced allele frequency, respectively. Since we are also
considering genotypes, recall that the three ways that mutations happen most often are changes in the
DNA (deoxyribonucleic acid) sequence due to insertions, deletions, or substitutions.
It is very easy to get overly concerned about evolution if the focus is on human evolution. If instead the
focus is on the mechanisms of how organisms change over time, a lot of emotional distress can be
avoided. Being a Roman Catholic and believing that God created the Universe does not necessarily
conflict with evolutionary theory. Evolution can be thought of as an accumulation of changes that occur
within a population resulting from genetic and environmental changes. Within a population of organisms
of the same species there are differences between the individuals (variation). A species is a group of
individuals that can interbreed and produce fertile offspring (offspring that can reproduce). The
greater the variation between individuals the greater the likelihood that the species will survive if the
environment changes.
1 Ontogeny: the development of an individual from the moment the egg is fertilized up till adulthood.
2 Protoorganisms: bacteria.
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Since the Earth was created, many environmental changes have occurred and some species have
become extinct and others have apparently changed into different species. If an environment
changes too much and there is not enough variation within the population, few if any individuals will
survive the change, resulting in the species becoming extinct. But if there is sufficient variation so
that some “weirdoes” can survive, then those will be the ones that can reproduce and their
characteristic genes transmitted to the next generation. If there were a few before the change,
then after the change they will be the majority apparently evolving into another species. Looking at
fossils (mineralized remains of organisms) similarities can be observed. Paleontologists and
evolutionary biologists have developed relationships between existing and extinct species by tracing
anatomical and genetic similarities and differences.
Besides mutations and large scale environmental changes, more minor changes can result in
speciation. Speciation is the formation of a new species or group of organisms that can no longer
interbreed with an original species population. These organisms no longer interbreed because their
characteristics (either biological or behavioral) have become too different. This can happen
randomly and by geographic isolation of a species. A random change in the kinds of genes in a
population is called genetic drift. When populations of interbreeding individuals of the same species
are large, the the allele frequency of each successive population is expected to vary little from the
frequency of its parent population unless there are adaptive advantages associated with the alleles.
But with a small breeding population (a group separated by geography), a change in even one
individual can cause a disproportionately greater change in the population’s gene pool. Therefore
small populations are more subject to genetic drift effects than large populations. A situation
exists when large populations are quickly reduced. This population reduction is called a population
bottleneck. Like a bottleneck that is narrower than the bottle genetic variation is reduced. The
reduced variation results in sudden changes in the allele frequency within the gene pool, and of the
population’s characteristics. These types of changes are not gradual and called punctuated because
sudden and drastic changes can occur. So evolutionary changes are not always slow (gradualism) or
always rapid (punctuated equilibrium).
Vocabulary
1. Adaptation: A peculiarity of structure, physiology, or behavior that aids the organism in its
environment
2. Analogous structures: similar because of convergent evolution, and not because of common
ancestry, may have a similar function but a different structure.
3. Anatomical evidence: ________________________________________________________
4. Artificial Selection: a process in which humans consciously select for or against particular
features in organisms.
5. DNA ____________________________________________________________________
6. Evolution change in a species over time; changes in gene frequency in a population from one
generation to the next.
7. Embryology: a branch of biology dealing with embryos and their development. an embryo is an
animal in the early stages of growth and differentiation that are characterized by cleavage, the
Evolution Unit Overview
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laying down of fundamental tissues, and the formation of primitive organs and organ systems;
especially : the developing human individual
8. Era: subdivision of geologic time that divides an Eon into smaller intervals of time
9. Extinct: all individuals of a species are dead
10. Fitness: The genetic contribution of an individual to succeeding generations relative to the
contributions of other individuals in the population.
11. Fossil: remains of an organism or its activities
12. Founder effect A cause of genetic drift attributable to colonization by a limited number of
individuals from a parent population
13. Gene Pool: all of the genes in a population. Any genes that could wind up in the same individual
through sexual reproduction.
14. Genetic Drift Changes in the gene pool of populations due to chance
15. Geographic Isolation: The separation of populations by barriers such as rivers, mountains, or
bodies of water.
16. Geologic Time Scale: Scientists use to measure Earth’s geological and biological events
17. Gradualism: The idea that evolution takes place at a continuous but very slow rate
18. Interbreeding_____________________________________________________________
19. Homologous structures: inherited from a common ancestor, may have a similar structure but
different function.
20. Mass Extinction: affect most major taxonomic groups present at the time — birds, mammals,
reptiles, amphibians, fish, invertebrates and other simpler life forms. They may be caused by the
extinction of an unusually large number of species in a short period of time.
21. Mimicry: adaptations some animals use as protection from predators by using colors and
markings to look like another animal.
22. Mutation: a change in a DNA sequence, usually occurring because of errors in replication or
repair.
23. Natural selection: A process in which some individuals have genetically-based traits that improve
survival or reproduction and thus have more offspring surviving to reproductive age than other
individuals.
24. Paleontology: the study of fossils
25. Period___________________________________________________________________
26. Phenotype: physical appearance of an organism
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27. Population: generally, a group of organisms living close to one another that interbreed with one
another and do not breed with other similar groups.
28. Punctuated equilibrium: A theory of evolution advocating spurts of relatively rapid change
followed by long periods of stasis.
29. Radioactive (radiometric) dating: measures the decay of radioactive isotopes to obtain exact
dates of materials
30. Relative dating: compares the sequence of rock layers and fossils to determine which layer is
older or younger.
31. Reproductive isolation: Two populations are isolated if their members are unable to interbreed
and produce fertile offspring. Structural, behavioral, and biochemical features can prevent
interbreeding and thus isolate populations as distinct species.
32. Survival of the fitness_______________________________________________________
________________________________________________________________________
33. Speciation The origin of new species in evolution.
34. Species__________________________________________________________________
35. Theory___________________________________________________________________
36. Vestigial Structure (organ) A type of homologous structure that is rudimentary and of marginal
or no use to the organism.
37. Variation_________________________________________________________________
38. Darwin___________________________________________________________________
39. Diversity_________________________________________________________________
40. Index fossil: forms of life which existed during limited periods of geologic time and thus are
used as guides to the age of the rocks in which they are preserved
________________________________________________________________________
41. Niche____________________________________________________________________
42. Pesticide_________________________________________________________________
43. Resistant_________________________________________________________________
44. Variation_________________________________________________________________
45. Galapagos Islands___________________________________________________________
Steps of Natural Selection
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Evolution Unit Study Guide
1.
Evolution can be defined as any change in the relative frequency of alleles in the gene pool of a
population.
2.
Differences between the members of a population will most likely be passed onto future
generations if they are due to genetic changes and result in favorable variations.Mutations
that are lethal in homozygous individuals can survive in a population by being carried by
heterozygous individuals (heterozygotes).
3.
Mutations that are lethal in homozyghous individuals can survive in a population by being carred
by being heterozygous individuals (heterozygotes)
A population of land snails colonized a field of yellow grass. At first, the
population contained two types of snails, one with brown bands on their shells
and another with yellow bands on their shells, as shown in the figure below.
After 10 years, most of the snails had shells with yellow bands.
4.
What process most likely led to an increase in the number of snails with yellow bands? Natural
selection.
5.
What is the most likely reason that there are more yellow-banded snails present in the
grassland? The yellow-banded snails were less visible to predators
A field of crops was sprayed with pesticides to control a population of insects that was eating the
crop. Only 1% of the insects survived. The same amount and type of pesticide was sprayed on the
field each year for the next 4 years. The graph below shows the percentage of insects that survived
each year after the pesticide was used.
6.
Why was the pesticide less effective each year in its ability to control the target population of
insects? The insects with greater resistance to the pesticide survived and passed down this
trait to their offspring.
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7.
Population change over evolutionary time.
8.
In a species of plant, the sudden appearance of one plant with a different leaf structure would
most likely be the result of chromosomal mutations.
9.
What would cause a mutation? The insertion, delection or substitution of a nucleotide into DNA
10.
In carrier pigeons there is a rare inherited condition that causes the death of the chicks
before hatching. In order for this disease to be passed from generation to generation there
must be parent birds that are heterozygous for the disease.
11.
Describe natural selection. An organism with favorable genetic variations will tend to survive
and breed successfully.
12.
The idea that evolution takes place at a continuous but very slow rate is knows as gradualism
13.
The idea that evolution takes place at one point in time, followed by a long period without
change is punctuated equilibrium.
14.
A genetic change will be maintained in a population if the change increases fitness.
15.
According to Darwin’s theory of natural selection, individuals who survive are the ones best
adapted for their environment. Their survival is due to the possession of inherited adaptations
that maximize fitness.
16.
When mountain lions prey on a herd of deer, some deer are killed and some escape. Which part
of Darwin’s concept of natural selection might be used to describe this situation? Survival of
the fittest
17.
A change in a sequence of DNA is called a mutation.
18.
Natural selection acts directly on phenotypes.
19.
If a mutation introduces a new skin color in a lizard population, what factor might determine
whether the frequency of the new allele will increase? Whether the mutation makes some
lizards more fit for their environment than other lizards
20.
Greater genetic diversity provides a species with a higher probability of surviving changes to
its environment.
21.
The difference in the fur color of the individual species in a population is described as
variation.
22.
Two animals of different species would not be able to produce fertile offspring.
23.
Spraying DDT to kill mosquitoes became less effective each year the pesticide was used. This
decrease in the effectiveness was probably caused by the fact that DDT resistant mosquitoes
passed on this trait to their offspring.
24.
When penicillin was first introduced it was very effective in destroying most of the bacteria
that cause gonorrhea. Today, certain varieties of this bacterium are resistant to penicillin.
Evolution Unit Overview
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Explain the presence of these penicillin resistant bacteria. Penicillin killed bacteria with no
resistance, while naturally resistant varieties survived and reproduced.
25.
Although similar in many respects, two species of organisms exhibit differences that make
each well adapted to the environment in which it lives. The process of change that may account
for these differences is evolution.
26.
cc (albino), chc (Himalayan), chc h (himalayan)
27.
A random change in gene frequency in a small population is called genetic drift.
28.
Genetic drift is most likely to effect small populations
29.
Geographic and reproductive isolation can result in speciation.
30.
A species of finch (a type of bird) has been studied on one of the geographically isolated
Galapagos Islands for many years. Since the island is small, the lineage of every bird for
several generations is known. This allows a family tree of each bird to be developed. Some
family groups have survived and others have died out. The groups that survive probably have
inherited some advantageous variations.
31.
A single species of squirrel evolved over time into two species, each on opposite sides of the
Grand Canyon. This change was most likely due to the geographic isolation of the two groups.
32.
All the genes of all members of a particular population make up the population’s gene pool
33.
Describe a gene pool. Gene pools contain the possible alleles for each inheritable trait in a
population.
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34.
In genetic drift, allele frequencies change because of chance
35.
Genetic drift tends to occur in populations that
36.
A small population of chimpanzees lives in a habitat that undergoes no change for a long period.
How will genetic drift probably affect this population? It will reduce genetic diversity.
37.
The separation of populations by barriers such as rivers, mountains, or bodies of water is called
geographic isolation.
38.
The geographic isolation of two populations of a species tends to increase differences between
their gene pools because it prevents interbreeding between the populations.
39.
What kind of animal would be best adapted to survive extreme change in temperature?
One with different colors of fur and different lengths of fur.
Comparisons are made between two different organisms by finding the place where the two lines intersect.
The number where the columns and rows intersect shows how many amino acids are different in the
cytochrome c of both organisms. For example, the number of amino acids that are different when comparing a
rabbit's cytochrome c with a tuna's cytochrome c is 17. The larger the number, the greater the difference in
the structure of the cytochrome c molecules of the two organisms.
40.
According to the table, which pair of organisms is least closely related? Tuna and rattlesnake
41.
According to the table, which pair of organisms is most closely related? Human and monkey
42.
In a certain area of undisturbed layers of rock, fossils of horseshoe crabs may be found in the
upper layer, and a lower layer contains fossils of trilobites. Trilobites are extinct aquatic
Evolution Unit Overview
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arthropods resembling modern horseshoe crabs. This information suggests that horseshoe
crabs may have evolved from trilobites.
43.
In the early stages of development, the embryos of dogs, pigs, and humans resemble each
other. This observation suggests that these animals may have a common ancestry
44.
An example of a structure that would be homologous to a bird wing would be a human arm
45.
Fossil trees are petrified when the wood is replaced with minerals
46.
The long, slow process of change in species over time is evolution.
47.
In humans, the pelvis and femur, or thigh bone, are involved in walking. In whales, the pelvis
and femur shown in the figure above are vestigial structures.
48.
Modern sea star larvae resemble some primitive vertebrate larvae. This similarity may suggest
that primitive vertebrates share a common ancestor with sea stars.
49.
The number and location of bones of many fossil vertebrates are similar to those in living
vertebrates. Most biologists would probably explain this fact on the basis of a common
ancestor.
50.
Individuals within a population of rabbits have different colors of fur as shown in the diagram
below. The difference in the fur color of the individual rabbits is described as variation.
51. What are three types of mutation?
Sunny says Hi and Good Luck on your studies. Bunny out.
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