Transcript Big Idea 1: The process of evolution drives the diversity

Big Idea 1: The process of evolution
drives the diversity and unity of life.
Unit 1:Evolution
Chapter 23, Evolution of Populations
23.1, Population genetics provides a
foundation for studying evolution
• Remember populations evolve NOT
individuals.
• Darwin’s Natural Selection was not fully
appreciated with Mendel’s work in genetics,
which Darwin was not aware of at the time of
publication.
23.1, Population genetics provides a
foundation for studying evolution
• Microevolution versus macroevolution
– Micro - is the changes in allele frequencies that
occur over time within a population
– Example: anti-biotic resistant bacteria
– Macro - is evolution on a scale of separated gene
pools.
– Example: the evolutionary history of the horse
(Equidae).
23.1, Population genetics provides a
foundation for studying evolution
• A. The Modern Synthesis
– 1. Population Genetics
• Darwin + Mendel
• The study of how populations change over time.
– 2. Modern Synthesis
• Theory of evolution that integrates math, etc…Modern
Synthesis is still changing today as we gain more
information about evolution.
23.1, Population genetics provides a
foundation for studying evolution
• Before we move on to “B. Gene Pools and
Allele Frequencies” let have a quick review of
some genetic terms we need to be fluent with
for this section.
• Get with a partner and come up with a
definition and picture for each term. Use the
book as a last resort or to check your finished
product. Allow yourself to struggle and access
your prior biological knowledge.
23.1, Population genetics provides a
foundation for studying evolution
• Gene pool, Chromosome, gene, allele,
homozygous, heterozygous, dominant,
recessive, gene flow, genetic drift, mutation,
genotype, phenotype, incomplete dominance,
co-dominance, gene loci (locus), gametes,
zygotes.
• 18 Terms.
23.1, Population genetics provides a
foundation for studying evolution
• B. Gene Pools and Allele Frequencies
• 1. Population – same species, same place,
same time capable of interbreeding to
produce fertile offspring.
• 2. Not all populations are isolate or have sharp
boundaries.
– Gene Pool – all the genes at any one time in a
population.
23.1, Population genetics provides a
foundation for studying evolution
23.1, Population genetics provides a
foundation for studying evolution
– Gene pool consists of all the alleles at all gene loci
in all the individuals of the population.
– Allele frequency – is the proportion of each allele
within the population.
– If only one allele exists at a particular locus it is
said to be fixed.
– When there are two alleles p represents one
alleles and q represent the second allele.
– With this information you can allele frequencies
and genetic variability within a population
23.1, Population genetics provides a
foundation for studying evolution
• C. The Hardy-Weinberg (HW) Theorem
• 1. Preservation of Allele Frequencies
– How do gene pools NOT evolve?
– HW describes how Mendelian inheritance
preserves genetic variation from generation to the
next in population that are NOT evolving.
– To understand how populations evolve first we
will see how they DO NOT evolve.
23.1, Population genetics provides a
foundation for studying evolution
• 2. HW equilibrium
– p2+2pq +q2 = 1
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P2 = for example AA
Pq = for example Aa
Q2 = for example aa
Note that p (all “A”) + q (all “a”) = 1
23.1, Population genetics provides a
foundation for studying evolution
• Example Problem:
23.1, Population genetics provides a
foundation for studying evolution
• 3. Conditions for Hardy Weinberg Equilibrium
– Extremely Large Population Size
– No gene flow
– No Mutations
– Random mating
– No Natural Selection
– Memorize these!!!!!!!!!!
23.1, Population genetics provides a
foundation for studying evolution
• The sources of variation in a real population
– Mutation: only source for new alleles
– Sex Recombination
– Natural Selection: the primary mechanism of
adaptive evolution
– Genetic drift: allele frequency deviation due to
small population
• The bottleneck effect
• The founder effect
– Gene flow: the gain or loss alleles by population
23.1, Population genetics provides a
foundation for studying evolution
• 4. Population Genetics and Human Health
– Used to determine APPROXIMATIONS of PKU
carriers.