Processes of Evolution & Genetics Part 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 inheritance 1.Describe the link between meiosis and Mendelian genetics 2.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 Thought Pre-Darwinian Views ___________ _____________________ Earth is ___________ _________________(4 th century) _________________of organisms from _________ _____________________ – closer to ________, greater excellence

History of Evolutionary Thought Precursors to the Theory of Evolution 5 scholars & their contributions ScholarsBrief Summary of Contribution Charles Lyell‘Principles of Geology’ Uniformitarianism Georges CurvierSaw potential of fossils Catastrophism Carolus Linnaeus‘Father of Taxonomy’ Thomas Malthus‘An Essay on the Principles of Population’ Jean-Baptiste LamarckInheritance of Acquired Characteristics Transformational evolution

History of Evolutionary Thought Charles Lyell ( ) __________________ ___________________ 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 ( ) Developed __________________ Species, genus, class, order, kingdom Binomial Nomenclature Genus, species Example: ___________

History of Evolutionary Thought Thomas Malthus ( ) “An Essay on the Principles of Population” _____________________________ Inspired Darwin ____________________________ ______________________________

History of Evolutionary Thought Jean-Baptiste Lamarck ( ) Inheritance of __________________ ______________________________ Central idea: When life forms reproduce, _____ ______________________________________ Changed in form over time for _________________ Now know: Mechanism is _____________ Offspring _________________________

Development of Natural Selection Charles Darwin Using Mathus’ essay and Lyell’s uniformitarian view, combined with his own observations on biological variation and sexual reproduction, _______________ _________________

Development of Natural Selection Charles Darwin _______________________ Natural selection explains _________________ Shifts in traits in response to ___________________ Descent ___________________ Similar traits indicate _________________ ______________________ ________________________ Affects individual’s _____________________________ Transmitted ___________________________________

Development of Natural Selection Key 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 Action Panda’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 19 th and early 20 th 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 F 1 generation __________ Genotype: ________ Phenotype: _______

Mendel’s Experiments What happened when Mendel crossed F 1 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: F 1 Generation Offspring of F 1 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: