BSC 196 FINAL EXAM STUDY GUIDE
What is evolution? - ANSWER Change in populations over time (i.e. generations)
Leads to a change in species over time
Responsible for organic diversity on earth (Descent with modification: All
organisms are related through descent from ancestor that lived in remote past)
What are the four principal requirements of evolution by natural selection? -
ANSWER Variation
Fitness Differences
Inheritance
More offspring produced than can survive
How did John Endler test the hypothesis that color patterns in guppies
represent a tradeoff between selection to avoid predation and selection to
attract a mate? - ANSWER Color patterns have evolved through natural
selection. Trade off between mate attraction and predator avoidance.
Manipulated the intensity of predation, bottom of substrate
Why is natural selection not simply a matter of chance? - ANSWER Natural
selection results in adaptive evolution, an improvement in the math between
organisms and their environment. This tends to REDUCE genetic variation
What is adaption? - ANSWER A trait which fosters the survival/reproduction of
an individual within a particular environment. Selection acts on individuals it is a
process of populations
What kinds of testable predictions can be derived from the theory of evolution as
it applies to the fossil record - ANSWER 2.Simple life should be found in the
oldest strata. more complex forms should only occur in recent strata. Before
radioactive dating, relative time scale based on geographical column
3. Transitional forms: There should be intermediate forms between major
taxonomic groups. Best tested in groups likely to fossilize
How do direct observations of natural populations provide evidence of change
over time? - ANSWER
What is homology? - ANSWER Similarity in underlying structural elements. Even
if function and appearance differ.
Morphology
Embryology
Cell Structure
Molecular Structure/biochemical processes
,What kinds of testable predictions can be derived from the theory of evolution as
they apply to homogies at all levels of biological organizations: Structure,
embryonic, cellular and molecular? - ANSWER Embryonic homology: Chordata.
Gill slits, notochord, hollow nerve chord, and tail
Cell Structure: All eukaryotic cells have same structural elements (nucleus, cell
membrane, membrane bound organelles) All prokaryotic cells have same
structural elements (Naked DNA, RNA containing ribosomes)
Molecular: All cells consists of same organic compounds (Proteins lipids
nucleotides carbohydrates). Cellular reactions controlled by enzymes. DNA is
inheritance. DNA.RNA have same chemical structure (Sugar, bases,
phosphates) SAME GENETIC CODE
What does heritability measure? Can natural selection alter the evolution of a
trait that has a heritability of zero? - ANSWER Proportion of phenotypic variation
that is due to genetic differences between individuals.
h2 ranges from 0-1
Selection results in evolutionary change only when h2>0
Measured via resemblance between relatives
How do changes observed in the beak of morphology of medium ground finches
over the last 20 years conform to the criteria for evolution by natural selection? -
ANSWER During the drought, seeds were larger and tougher. Therefor
individuals with deeper beaks had higher survival rates. After drought chicks
hatched had deeper beaks than before.
So selection acts on phenotypes but evolution occurs through changes in gene
frequencies. Natural selection does no adapt organisms to future changes only
past.
How is genetic variation created? What are the major kinds of mutations, and
how do they alter DNA sequences? - ANSWER Mutation is a mistake made
during DNA copying. Origin of variation AND mechanisms of change.
Point: Source of new alleles. Change in one of nucleotide bases. Three kinds,
substitution, insertion, and deletion. Can lead to silent mutations
Chromosomal: Source of new genes, species. 3 characteristics: Chromosomal
breakage, order of base pairs remain unchanged, order of genes is altered.
Common chromosomal mutation is misalignment which leads to a gene
duplication (duplication is typically less harmful)
Do mutations arise by chance or nonrandomly? Are most mutations harmful or
beneficial? - ANSWER Mutations arise randomly and ones that result in a change
of protein are often harmful. Harmful mutations can be hidden from selection in
recessive alleles. Can sometimes be beneficial
,Review the Hardy-Weinberg theorem. If you were given a set of genotype
frequencies, how would you determine the relative allele frequencies? -
ANSWER The hardy weinberg equation describes the genetic makeup we expect
for a population that is NOT evolving at a particular locus
Gene pool: Consists of all the alleles for all loci in a population
Locus is fixed if all individuals are homozygous for same allele
For diploid organisms, the total # of alleles at a locus is the total times
For example, consider a population of 500 wildflowers showing incomplete
dominance for color
320 red flowers (CRCR) = 64% (freq. = .64)
320/500 = .64
160 pink flowers (CRCW) = 32% (freq. = .32)
160/500 = .32
20 white flowers (CWCW) = 4% (freq. = .04)
20/500 = .04
Calculate the number of copies of each allele
CR (320 2) 160 800
CW (20 2) 160 200
To calculate the frequency of each allele
p freq CR 800 / (800 200) 0.8
q freq CW 200 / (800 200) 0.2
The sum of alleles is always 1
0.8 0.2 1
If you were given allele frequencies, how would you determine expected
genotype frequencies at Hardy-Weinberg equilibrium? - ANSWER The frequency
of genotypes can be calculated
CRCR =p2= (0.8)2 0.64
CRCW =2pq= 2(0.8)(0.2) 0.32
CWCW =q2= (0.2)2 0.04
The frequency of genotypes can be confirmed using a Punnett square
p2+2pq+q2=1
p2=homozygous genotype
q2= Homozygous genotype
pq=both
What are the 5 conditions for non evolving populations? (Conditions for the
Hardy-Weinberg equilibrium - ANSWER No mutation
Random mating
No natural selection
Extremely large population size
No gene flow
What is genetic drift? What consequences does genetic drift have for genetic
variation? - ANSWER The three major factors that alter allele frequency and
, bring about the most evolutionary change are natural selection, genetic drift,
and gene flow.
Genetic drift describes how allele frequency change from one generation to the
next do to CHANCE events. The smaller the sample the greater change of
random derivation from predicted result. REDUCE genetic variation from loss of
alleles
Can genetic drift lead to adaptation? What effect does population size have on
genetic drift? - ANSWER Genetic drift is significant in small populations
Can cause allele frequencies to change at random
Lead to loss of genetic variation in populations
Cause harmful alleles to become fixed.
Cannot lead to adaption because this happens by chance
What are the three primary evolutionary forces factors that can take a
population out of Hardy-Weinberg equilibrium? - ANSWER Natural selection,
Genetic drift, and gene flow
Gene flow: Consists of movement of alleles among populations. Alleles can be
transferred through the movement of fertile individuals or gametes. Tends to
reduce variation over time
Natural selection: Involves both chance and sorting. New genetic variations
arise by chance (mutation) Beneficial alleles are sorted and favored by natural
selection (non random). ONLY natural selection consistently increase the
frequencies of alleles that provide reproductive advantage
What is heterozygote superiority? How does heterozygote superiority lead to the
maintenance of the sickle-cell hemoglobin gene in natural populations? -
ANSWER Occurs when heterozygotes have a higher fitness than either
homozygote. Natural selection will tend to maintain two or more alleles at that
locus. Sickle if homozygous leads to anemia but heterozygotes are resistant to
malaria
What are the various modes of selection and how do they alter the frequency
distribution of a trait assuming that variation in the trait is genetically based? -
ANSWER Directional selection: Favors individuals at one end of the phenotypic
range
Disruptive selection: Favors individuals at both extremes of the phenotypic
range
Stabilizing selection: Favors intermediate variants and acts against extreme
phenotypes
What is frequency dependent selection? How does frequency dependent
selection help maintain genetic variation in a population? - ANSWER in
frequency dependent selection, the fitness of a phenotype declines if it becomes
too common in the population (negative). Selection favors which is LESS
What is evolution? - ANSWER Change in populations over time (i.e. generations)
Leads to a change in species over time
Responsible for organic diversity on earth (Descent with modification: All
organisms are related through descent from ancestor that lived in remote past)
What are the four principal requirements of evolution by natural selection? -
ANSWER Variation
Fitness Differences
Inheritance
More offspring produced than can survive
How did John Endler test the hypothesis that color patterns in guppies
represent a tradeoff between selection to avoid predation and selection to
attract a mate? - ANSWER Color patterns have evolved through natural
selection. Trade off between mate attraction and predator avoidance.
Manipulated the intensity of predation, bottom of substrate
Why is natural selection not simply a matter of chance? - ANSWER Natural
selection results in adaptive evolution, an improvement in the math between
organisms and their environment. This tends to REDUCE genetic variation
What is adaption? - ANSWER A trait which fosters the survival/reproduction of
an individual within a particular environment. Selection acts on individuals it is a
process of populations
What kinds of testable predictions can be derived from the theory of evolution as
it applies to the fossil record - ANSWER 2.Simple life should be found in the
oldest strata. more complex forms should only occur in recent strata. Before
radioactive dating, relative time scale based on geographical column
3. Transitional forms: There should be intermediate forms between major
taxonomic groups. Best tested in groups likely to fossilize
How do direct observations of natural populations provide evidence of change
over time? - ANSWER
What is homology? - ANSWER Similarity in underlying structural elements. Even
if function and appearance differ.
Morphology
Embryology
Cell Structure
Molecular Structure/biochemical processes
,What kinds of testable predictions can be derived from the theory of evolution as
they apply to homogies at all levels of biological organizations: Structure,
embryonic, cellular and molecular? - ANSWER Embryonic homology: Chordata.
Gill slits, notochord, hollow nerve chord, and tail
Cell Structure: All eukaryotic cells have same structural elements (nucleus, cell
membrane, membrane bound organelles) All prokaryotic cells have same
structural elements (Naked DNA, RNA containing ribosomes)
Molecular: All cells consists of same organic compounds (Proteins lipids
nucleotides carbohydrates). Cellular reactions controlled by enzymes. DNA is
inheritance. DNA.RNA have same chemical structure (Sugar, bases,
phosphates) SAME GENETIC CODE
What does heritability measure? Can natural selection alter the evolution of a
trait that has a heritability of zero? - ANSWER Proportion of phenotypic variation
that is due to genetic differences between individuals.
h2 ranges from 0-1
Selection results in evolutionary change only when h2>0
Measured via resemblance between relatives
How do changes observed in the beak of morphology of medium ground finches
over the last 20 years conform to the criteria for evolution by natural selection? -
ANSWER During the drought, seeds were larger and tougher. Therefor
individuals with deeper beaks had higher survival rates. After drought chicks
hatched had deeper beaks than before.
So selection acts on phenotypes but evolution occurs through changes in gene
frequencies. Natural selection does no adapt organisms to future changes only
past.
How is genetic variation created? What are the major kinds of mutations, and
how do they alter DNA sequences? - ANSWER Mutation is a mistake made
during DNA copying. Origin of variation AND mechanisms of change.
Point: Source of new alleles. Change in one of nucleotide bases. Three kinds,
substitution, insertion, and deletion. Can lead to silent mutations
Chromosomal: Source of new genes, species. 3 characteristics: Chromosomal
breakage, order of base pairs remain unchanged, order of genes is altered.
Common chromosomal mutation is misalignment which leads to a gene
duplication (duplication is typically less harmful)
Do mutations arise by chance or nonrandomly? Are most mutations harmful or
beneficial? - ANSWER Mutations arise randomly and ones that result in a change
of protein are often harmful. Harmful mutations can be hidden from selection in
recessive alleles. Can sometimes be beneficial
,Review the Hardy-Weinberg theorem. If you were given a set of genotype
frequencies, how would you determine the relative allele frequencies? -
ANSWER The hardy weinberg equation describes the genetic makeup we expect
for a population that is NOT evolving at a particular locus
Gene pool: Consists of all the alleles for all loci in a population
Locus is fixed if all individuals are homozygous for same allele
For diploid organisms, the total # of alleles at a locus is the total times
For example, consider a population of 500 wildflowers showing incomplete
dominance for color
320 red flowers (CRCR) = 64% (freq. = .64)
320/500 = .64
160 pink flowers (CRCW) = 32% (freq. = .32)
160/500 = .32
20 white flowers (CWCW) = 4% (freq. = .04)
20/500 = .04
Calculate the number of copies of each allele
CR (320 2) 160 800
CW (20 2) 160 200
To calculate the frequency of each allele
p freq CR 800 / (800 200) 0.8
q freq CW 200 / (800 200) 0.2
The sum of alleles is always 1
0.8 0.2 1
If you were given allele frequencies, how would you determine expected
genotype frequencies at Hardy-Weinberg equilibrium? - ANSWER The frequency
of genotypes can be calculated
CRCR =p2= (0.8)2 0.64
CRCW =2pq= 2(0.8)(0.2) 0.32
CWCW =q2= (0.2)2 0.04
The frequency of genotypes can be confirmed using a Punnett square
p2+2pq+q2=1
p2=homozygous genotype
q2= Homozygous genotype
pq=both
What are the 5 conditions for non evolving populations? (Conditions for the
Hardy-Weinberg equilibrium - ANSWER No mutation
Random mating
No natural selection
Extremely large population size
No gene flow
What is genetic drift? What consequences does genetic drift have for genetic
variation? - ANSWER The three major factors that alter allele frequency and
, bring about the most evolutionary change are natural selection, genetic drift,
and gene flow.
Genetic drift describes how allele frequency change from one generation to the
next do to CHANCE events. The smaller the sample the greater change of
random derivation from predicted result. REDUCE genetic variation from loss of
alleles
Can genetic drift lead to adaptation? What effect does population size have on
genetic drift? - ANSWER Genetic drift is significant in small populations
Can cause allele frequencies to change at random
Lead to loss of genetic variation in populations
Cause harmful alleles to become fixed.
Cannot lead to adaption because this happens by chance
What are the three primary evolutionary forces factors that can take a
population out of Hardy-Weinberg equilibrium? - ANSWER Natural selection,
Genetic drift, and gene flow
Gene flow: Consists of movement of alleles among populations. Alleles can be
transferred through the movement of fertile individuals or gametes. Tends to
reduce variation over time
Natural selection: Involves both chance and sorting. New genetic variations
arise by chance (mutation) Beneficial alleles are sorted and favored by natural
selection (non random). ONLY natural selection consistently increase the
frequencies of alleles that provide reproductive advantage
What is heterozygote superiority? How does heterozygote superiority lead to the
maintenance of the sickle-cell hemoglobin gene in natural populations? -
ANSWER Occurs when heterozygotes have a higher fitness than either
homozygote. Natural selection will tend to maintain two or more alleles at that
locus. Sickle if homozygous leads to anemia but heterozygotes are resistant to
malaria
What are the various modes of selection and how do they alter the frequency
distribution of a trait assuming that variation in the trait is genetically based? -
ANSWER Directional selection: Favors individuals at one end of the phenotypic
range
Disruptive selection: Favors individuals at both extremes of the phenotypic
range
Stabilizing selection: Favors intermediate variants and acts against extreme
phenotypes
What is frequency dependent selection? How does frequency dependent
selection help maintain genetic variation in a population? - ANSWER in
frequency dependent selection, the fitness of a phenotype declines if it becomes
too common in the population (negative). Selection favors which is LESS
