Fundamentals of Genetics Chapter 9. Mendel’s Legacy Section 9.1.
Evolution and Genetics Unit 2. Outline Evolution: Theory and Fact Genetics ◦Mendel’s Experiments...
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Transcript of Evolution and Genetics Unit 2. Outline Evolution: Theory and Fact Genetics ◦Mendel’s Experiments...
Outline
Evolution: Theory and Fact Genetics
◦ Mendel’s Experiments◦ Independent Assortment and Recombination
Biochemical or Molecular Genetics◦ Cell division◦ Crossing over◦ Mutation
Population Genetics and Mechanism of Genetic Evolution◦ Natural selection◦ Random Genetic Drift◦ Gene flow
The Modern Synthesis◦ Punctuated Equilibrium
Evolution
What are some ways we adapt to our environment?
What ways are cultural and what ways are biological?
Evolution
Originally, believed humans came from the story of Genesis from the Bible◦ Creationism◦ Characteristics of life
forms could not change◦ Biblical scholars James
Usher and John Lightfoot traced creation to October, 23, 4004 B.C. at 9AM
Activity Time
In your table groups, read through the Biblical account of creation
Is this a scientific theory? Why or why not?
Evolution
Carolus Linnaeus developed the first comprehensive taxonomy (classification)◦Grouped life forms on
basis of similarities and differences in their physical characteristics
Evolution
Fossil discoveries in 18th and 19th centuries started to raise doubts about creationism
Modified explanation combining creationism and catastrophism arose◦ Fires, floods, and other
catastrophes had destroyed ancient species
◦ After each destructive event, God created again
Theory and Fact
Alternative to creationism and catastrophism was transformism or evolution◦ Species arise through a
long and gradual process of transformation or descent with modification
◦ Charles Darwin best known
Theory and Fact
Charles Darwin influenced by Sir Charles Lyell, father of geology◦ Introduced idea of
uniformitarianism Natural forces at work
today also explain past events
Cast doubt on theory that Earth was only 6,000 years old
Darwin applied to living things
Theory and Fact
Darwin offered theoretical framework for understanding evolution
Proposed the theory of evolution with natural selection as the mechanism to explain diversity, origin, and similarities◦ Theory is a set of ideas
formulated by reasoning from a known factor to explain sometimes.
Natural selection is the selection of favored forms through differential reproduction
Genetics
Genetics: science that emerged after Darwin that helps us understand the causes of biological variation
DNA molecules make up genes and chromosomes which are basic hereditary units
Mutations in DNA provide much of the variety on which natural selection operates
Mendelian genetics studies ways chromosomes transit genetic material through generations
Biochemical genetics examines structure, function, and changes in DNA
Population genetics investigates natural selection and other causes of genetic variation, stability, and change in breeding population
STOP – Activity Time
You will be put into 3 groupsEach group will be given a different topic – Mendelian
genetics, biochemical genetics, and population genetics
You will look over the information and create a summary of the important points
You will then teach those points to the rest of the class
Everyone will record their notes on the provided graphic organizer
You will only be given today and some time tomorrow to do this
Modern Synthesis
Today’s view on evolution is known as the “modern synthesis”◦ Combination of Darwin’s theory
of evolution and Mendel’s genetic discoveries
◦ Microevolution – genetic changes over few, several, or many generations but without speciation
◦ Macroevolution – refers to larger-scale or more significant changes in a population or species, usually over a long time period which results in speciation Speciation – the divergence of
one ancestral species into two or more descendent species
Punctuated Equilibrium
Model of evolution that points to the fact that long periods of stability may be interrupted by evolutionary leaps◦ Could be caused by
extinction of another species followed by invasion by another Example: Sea species dies
out because water dries up, while a closely related species survives in deeper waters. Later, when water levels rise again, protected species goes to first area