Biotechnology applications If I was taking the AP test, I would be sure to know about… –Stem...
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Biotechnology applications If I was taking the AP test, I would be sure to know about… –Stem Cells: and the controversy –Application of biotech such as
Biotechnology applications If I was taking the AP test, I would
be sure to know about Stem Cells: and the controversy Application
of biotech such as 416-423 Diagnosis of disease Gene therapy
Development of drugs Forensics and paternity Short tandem repeats
(STRs) Environmental clean-up Genetically modified organisms.
Slide 2
Charles Darwin
Slide 3
Pre-Darwin Lyell: Geology, Uniformitarianism very old earth.
Malthus: Exponential Population Growth LaMarck: Evolution.
Inheritance of acquired characteristics (wrong, but still
evolutionary)
Slide 4
The Voyage of the HMS Beagle
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Natural Selection Observation 1: Variation
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No two organisms are completely alike.
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Observation 2: Reproduction
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And overproduction
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Inference 1: Differential fitness in the environment due to
variations.
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The struggle for existence
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Inference 2: Over the span of geological time (billions of
years), inheritance of adaptations will lead to evolution of the
population.
Slide 12
Fundamental Conclusions 1.To develop the diversity of life seen
on the Earth today, the Earth has to be incredibly old. 2.If
organisms evolve from pre-existing organisms, then all organisms
should share a universal common ancestor
Slide 13
tree thinking
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Unsettled by Darwin 1.Origin of Life 1.Origin of species
1.Nature of variation/inheritance
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2. THE MODERN SYNTHESIS 1.1: Natural selection is a major
mechanism of evolution
Slide 16
The Modern Synthesis Connects Darwinian evolution to genetics
and modern understanding of inheritance.
Slide 17
Where Traits come from: Trait
Slide 18
Variation comes from Mutation Mutation: A change in a DNA
sequence. Happens spontaneously and unavoidably.
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Mutations create alleles Alleles: Different versions of the
genes for a trait.
Slide 20
Evolution Defined: Evolution: Changes in allele frequencies
over time.
Slide 21
Ex. Galapagos Finches Grant and Grant: Studied the finch
population on an isolated island in the Galapagos. Measured the
beak dimensions of all birds on the island every year for
decades.
Slide 22
Connected changes in beak dimensions to fluctuations in the
environment (precipitation, seed sizes)
Slide 23
Evolution Misconception Alert! Misconception: Individuals
evolve. Evolution is a population level phenomenon. Individuals DO
NOT evolve! The evolution of a population emerges from the
individual fitness of members of that population. As they survive
and reproduce or not, the frequencies of alleles in the next
generation will change accordingly.
Slide 24
Slide 25
Pg. 468-475 Watch Bozeman science on Hardy Weinberg
calculations
Slide 26
Evolution Changes in the genetic makeup of populations overtime
Changes in the genetic makeup lead to changes in phenotypes-
variation Favorable variations for a particular environment are
known as adaptations
Slide 27
Microevolution and Macroevolution Microevolution refers to the
changes in the genetic makeup over time Macroevolution refers to
the origin and extinction of species and that fuel the
diversification of life
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Populations evolve, individuals do not Population- a group of
individuals of a single species that live and interbreed in a
particular geographic area at the same time
Slide 29
Gene Pools and Gene Frequencies Gene Pool- the sum of all the
alleles in a population; the sum of the genetic variation within a
population Allele Frequency- the proportion of each allele in the
gene pool Genotype Frequency- the proportion of each genotype
(homozygous dominant, heterozygous, homozygous recessive) in a
population
Slide 30
Hardy-Weinberg Theorem Describes the gene pool of an idealized,
non- evolving population to which others may be compared States
that the frequency of alleles and genotypes in a populations gene
pool remains constant from generation to generation provided that
only Mendelian segregation and recombination of alleles are at
work
Slide 31
Evolution vs. Genetic Equilibrium To understand how populations
evolve over time, scientists find it helpful to determine what
happens when no change takes place Hardy-Weinberg principle: Allele
frequencies in a population will remain constant unless one or more
factors cause those frequencies to change. Genetic Equilibrium
Slide 32
5 conditions are required to maintain genetic equilibrium If
conditions are not met, the population will evolve. 1.Random
Mating: All members of the population must have an equal
opportunity to produce offspring. An example of this condition not
being met: Female birds usually select their mates based on plumage
Colorful plumage is selected for
Slide 33
2. Large Population: Large populations are less likely to be
changed through Genetic Drift REVIEW!!! What is genetic drift?
Slide 34
3.No movement into or out of the population because individuals
may bring new alleles into a population A populations gene pool has
to be kept together and separate from the gene pools of other
populations
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4. No mutations Mutations introduce new alleles, which changes
the frequencies
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5. No natural selection All genotypes in the population must
have equal probabilities of survival and reproduction. No selective
pressures!!
Slide 37
Conditions of Hardy-Weinberg Equilibrium 1.The population size
is extremely large 2.There is no gene flow occurring (no movement
of individuals into or out of the population) 3.There is no
mutation 4.Random mating occurs 5.There is no natural selection
acting on the population
Slide 38
Any departure from the five conditions usually results in
evolution
Slide 39
Two major uses for scientists Useful for predicting the
approximate genotype frequencies of a population from its allele
frequencies Allows biologists to evaluate which mechanisms are
acting on the evolution of a particular population
Slide 40
Hardy-Weinberg Equilibrium p 2 + 2pq + q 2 = 1 p represents the
frequency of one allele (usually dominant) q represents the
frequency of the other allele (usually recessive) p 2 represents
the frequency one homozygous genotype (usually homozygous dominant)
q 2 represents the frequency other homozygous genotype (usually
homozygous recessive) 2pq represents the frequency of the
heterozygous genotype
Slide 41
Frequencies are usually given as percentages, but should be
converted to decimals to work the problems; move the decimal 2
places to the left The frequency of p and q must also equal 1: p +
q = 1
Slide 42
Solving Hardy-Weinberg Problems Examine the question to
determine what piece of information you have been given about the
population. In most cases, you will be given the percentage or
frequency of the homozygous recessive phenotype or homozygous
dominant phenotype Remember that genotype and phenotype are not the
same The recessive phenotype represents the genotype q 2 always The
dominant phenotype represents the combination of the p 2 genotype
and the 2pq genotype
Slide 43
The first objective is to find out the value of p or q. If this
is achieved, then every other value in the equation can be
determined by simple calculation. Take the square root of q 2 to
find q Determine p by subtracting q from 1 Determine p 2 by
multiplying p by itself Determine 2pq by multiplying p times q
times 2 Check that your calculations are correct by adding up the
values for p 2 + 2pq + q 2 (the sum should equal 1 or 100%)
Slide 44
Example Problem: In the Caucasian American population
approximately 70% of people can taste the chemical
phenylthiocarbamide (PTC), the dominant phenotype, while 30% are
non-tasters, the recessive phenotype. Determine the frequency of :
The homozygous recessive phenotype (q 2 ): The dominant allele (p):
Homozygous tasters (p 2 ): Heterozygous tasters(2pq):
Slide 45
Darwins Observations Resources are limited Organisms will fight
or struggle for resources Variation in organisms leads to
differential success Those organisms that are able to survive and
reproduce will pass their characteristics on to the next
generation
Slide 46
Defining Survival of the Fittest Fitness refers to the best
adapted individuals for a particular environment Survival refers to
the ability to not only live, but reproduce, thus passing on
adaptive traits to the next generation LINK IT TO GENES!!!
Favorable phenotypes dont just appear Favorable mutations to genes
result in adaptive phenotypes
Slide 47
Darwins Ideas On The Origin of Species By Means of Natural
Selection Major points of Darwins Theory: Species are not constant,
they change over time (evolve) All species share a common ancestor
The mechanism that produces changes in a species is natural
selection Natural Selection: The differential survival and
reproduction of individuals in a population based on variations in
their phenotypes