processes of evolution & genetics
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Processes of Evolution & Genetics. Part 1. Learning Objectives: Part 1. Demonstrate an understanding of the historical context in which the theory of evolution was originally formed. - PowerPoint PPT PresentationTRANSCRIPT
Processes of Evolution & GeneticsPart 1
Learning Objectives: Part 1
1. Demonstrate an understanding of the historical context in which the theory of evolution was originally formed.
2. Demonstrate an understanding of the theory of evolution and the mechanisms of evolution (especially natural selection)
1. Illustrate this understanding through accurate examples 3. Demonstrate an understanding of the mechanisms that
underpin inheritance1. Describe the link between meiosis and Mendelian genetics2. Explain how Mendelian inheritance patterns can be modified
by linkage & sex chromosomes
What is Evolution?
• Evolution • __________________• More specifically:
• _________________________________• What does this definition imply?
• Populations ___________, not _____________
• It is __________• What does this mean?
What is Evolution?• Evidence that supports the theory of evolution
• ___________• ________________
_______________________
History of Evolutionary ThoughtPre-Darwinian Views• ___________
• _____________________
• Earth is ___________
• _________________(4th century)• _________________of organisms from _________• _____________________ – closer to ________,
greater excellence
History of Evolutionary Thought• Precursors to the Theory of Evolution
• 5 scholars & their contributions
Scholars Brief Summary of ContributionCharles Lyell ‘Principles of Geology’
UniformitarianismGeorges Curvier Saw potential of fossils
CatastrophismCarolus Linnaeus ‘Father of Taxonomy’Thomas Malthus ‘An Essay on the Principles of
Population’Jean-Baptiste Lamarck Inheritance of Acquired Characteristics
Transformational evolution
History of Evolutionary Thought
Charles Lyell (1797-1875)• __________________
• ___________________• Natural processes _________________________
________________________________________• Processes are _________________• Used to reconstruct ____________________
History of Evolutionary Thought
Georges Cuvier• _______________
• How does this idea compare to the concept of stasis?
• __________________• ___________event(s) explain
• ____________________• ____________________• 1796 paper: Mammoth
Remains
History of Evolutionary Thought
Carolus Linnaeus (1707-1778)• Developed __________________
• Species, genus, class, order, kingdom• Binomial Nomenclature
• Genus, species• Example: ___________
History of Evolutionary ThoughtThomas Malthus (1776-1834)• “An Essay on the Principles of
Population”• _____________________________
• Inspired Darwin• ____________________________
______________________________
History of Evolutionary Thought
Jean-Baptiste Lamarck (1744-1829)• Inheritance of __________________
• ______________________________• Central idea: When life forms reproduce, _____
______________________________________• Changed in form over time for _________________
• Now know: Mechanism is _____________• Offspring _________________________
Development of Natural SelectionCharles Darwin• Using Mathus’ essay and Lyell’s uniformitarian view,
combined with his own observations on biological variation and sexual reproduction, _______________
• _________________• _________________• _________________• _________________
Development of Natural SelectionCharles Darwin• _______________________
• Natural selection explains _________________• Shifts in traits in response to ___________________
• Descent ___________________• Similar traits indicate _________________• ______________________
• ________________________• Affects individual’s _____________________________• Transmitted ___________________________________
Development of Natural SelectionKey Points to Natural Selection• _________________________
• Traits are ___________________to the next generation• Over ______________, successful ______________
• Later generations ____________________________
• All species can ____________________________
Development of Natural Selection
Key Points to Natural Selection• Competition for ___________ (___________)
• Individuals with ________________________ ______________________________________
• _________________________________• Determines whether a _____________________
• ________________________
Development of Natural Selection
____________________acts on
__________ ________, but it is the
_____________ that they are a part of that
actually ___________.
Describing Traits
• Aptation
• Adaptation
• Exaptation
Natural Selection in ActionPanda’s thumb• Lamarckian explanation
• ____________________• Darwinian explanation
• _____________________• _____________________________• Ability to ________________________________
• “The panda's "thumb" is not, __________________. It is constructed from a bone called the radial sesamoid, normally a small component of the wrist,” (Gould, 1980)
Natural Selection in Action
MENDEL’S DISCOVERIES
Early Thoughts on Heredity
• Ancient Greek Influence • Predominant belief characteristic of offspring
resulted from the blending of parental traits• _______________________________
• How hereditary information was transmitted was unknown until the late 19th and early 20th century
Mendel’s Experiments
Mendelian Trait: _______________________
Dominance and Recessiveness
• Dominant Trait: governed by an ____________ _____________________ • Dominant alleles can _____________________
• Recessive Trait: a trait ___________________
• What’s an allele?• _________________________________________
Dominance and Recessiveness
• How to recognize?• Uppercase letters refer to dominant alleles (i.e. T)• Lowercase letters refer to recessive alleles (i.e. t)
• These symbols are used to represent the genotype
• Genotype: __________________________• Phenotype: ____________________________
Mendel’s Experiments
What happened when Mendel crossed the parent generations? • Parent (TT) (tall) x Parent
(tt) (short)
• Resulting F1 generation• __________
• Genotype: ________• Phenotype: _______
Mendel’s ExperimentsWhat happened when Mendel crossed F1 hybrids? • Expression that was absent
from F1 reappeared
• Resulting F2 generation:• Genotype: ____________• Phenotype: ___________
Terms to Know• Homozygous: ______________________________
• Example: Parent Generation• All tall plants were homozygous for the dominant
allele (tall) = TT• All short plants were homozygous for the recessive
allele (short) = tt
Terms to Know
• Heterozygous: _______________________________
• Example: F1 Generation• Offspring of F1 generation were Tt had inherited one
allele from each parent plant• Possessing two different alleles at the same locus
Mendel’s Principles of Inheritance
1. Principle of Segregation• Genes ___________ (i.e. RR, or Rr, or rr)
• During _____________________________
• During fertilization, the genes are reunited and the ______________________________
• Thus, ____________________________
Explanation for Principle #1
Mendel’s Principles of Inheritance
2. Principle of Independent Assortment
• Distribution of _________________________ ___________________________________
• ______________________________________
Explanation of Principle #2
Mendelian Inheritance in Humans
• Mendelian traits (or discrete/simple traits)• Describes a characteristic influenced only at one locus • Examples:
• 1.• 2.• 3.• 4.• 5.