NATURAL SELECTION How do we organize the diversity of life?

How do we explain: great diversity of organisms? organisms that are well-adapted to their environment? similarities and relationships of organisms (all use same basic genetic information)?

Jean-Baptiste Lamarck ( ) Inheritance of Acquired Characteristics – Traits developed during your life can be given to offspring. Theory of Use and Disuse – Genetic traits can be developed. Example – Blacksmith and bigger biceps Example – Giraffe and longer neck

Problem – How do you account for any variety in giraffes? What about those who don’t have long necks? Did trees all of a sudden get taller? What if someone gets a tattoo? Loses a finger? Dyes their hair? Inheritance of Acquired Characteristics – WRONG! Traits developed during your lifetime cannot be passed on. You cannot will yourself to have new traits.

Charles Darwin ( ) Voyage of the H.M.S. Beagle – ( ) Among other observations, saw finches on the Galapagos Islands off the coast of South America. These finches had been seen nowhere else in the world, but resembled those on South American coast. How did they become so well-suited to their environment? Darwin Video –

Theory of Natural Selection 4. Differential survival and reproduction – Those that live, reproduce and pass on traits. Example #1 – Speedy Rabbits # of rabbits Slow Fast What will this graph look like if a predator is introduced into the rabbit’s habitat? 1. Genetic Variation – Each organism has unique DNA sequence and traits. 2. Overproduction of offspring – More kids are produced than can survive. 3. Struggle for existence – Kids compete for limited resources (food, shelter, mates). PBS video - natural selection (6:41)

Example #2 – Peppered moth. Two different colors – light and dark. How many moths do you see in each picture? Prior to 1850 most had light-colored wings After 1850 most had dark-colored wings. WHY?

DOES EVOLUTION HAPPEN WITHIN ONE GENERATION? EXAMPLE: A LIGHT-COLORED MOTH IS MOVED TO AN AREA WITH SOOT COVERED TREES. CAN THIS INDIVIDUAL MOTH EVOLVE?

Evidence to support Theory of Evolution and Natural Selection 1.Comparative Anatomy – Bones have similar patterns Fossil Video (7:00)

2. Molecular Biology – all organisms use same A, T, C, G, but different order. Sequence can acquire mutations which can be passed on to next generation. Mutations can result in different traits. VideoVideo – includes UW- Madison researcher, Dr. Sean Carroll (7:00)

3. Selective breeding – Humans have been performing natural selection experiments for centuries using “artificial selection”. TEOSINTE AND CORNArtificial Selection of Wild Mustard

Video Clips Classification of Species (2:09) Classification of Species (2:09) Natural Selection - Darwin (6:49) Natural Selection - Darwin (6:49) PBS - Adaptation - Hummingbirds (6:39) PBS - Adaptation - Hummingbirds (6:39) PBS - Adaptation - Mantis camouflage (:58) PBS - Adaptation - Mantis camouflage (:58) PBS - Molecular Evidence (4:47) PBS - Molecular Evidence (4:47) PBS – Salamander Migration (3:21) PBS – Salamander Migration (3:21)

Using What You Have Learned How would Darwin use his Theory of Natural Selection to explain the insect seen in this video? video