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.