Evolution and GeneticsUnit 2

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