But first, a very quick cartoon show.

The Fossil Record

Nature of fossils

Archaeopteryx Lucy Ida Famous Fossils

Distribution of fossils RELATIVE AGE

Distribution of fossils LAW OF SUPERPOSITION

Distribution of fossils ABSOLUTE AGE

W HEN SCIENTISTS USE RADIOMETRIC DATING, THEY USE A MASS SPECTROMETER TO ANALYZE THE ISOTOPES PRESENT IN THE MATERIAL, BOTH OF THE OLD MATERIAL AND OF THE NEW, DECAYED ISOTOPE. U SING THE KNOWN HALF - LIFE OF MATERIALS ( FOR EXAMPLE, THE HALF - LIFE OF CARBON -14 IS 6,000 YEARS ), SCIENTISTS CAN COMPARE HOW MUCH OF EACH TYPE OF ISOTOPE ( THE ORIGINAL ISOTOPE, KNOWN AS THE PARENT, AND THE DECAYED ISOTOPE, KNOWN AS THE DAUGHTER ISOTOPE ) IS PRESENT IN THE MATERIAL. U SING THIS INFORMATION, HIGHLY ACCURATE DATING CAN BE ESTABLISHED FOR EVEN VERY OLD OBJECTS. R EAD MORE : H OW D OES R ADIOMETRIC D ATING W ORK ? | E H OW. COM HTTP :// WWW. EHOW. COM / HOW - DOES _ _ RADIOMETRIC - DATING - WORK _. HTML # IXZZ 1EL XI K T 6DH OW D OES R ADIOMETRIC D ATING W ORK ? | E H OW. COM HTTP :// WWW. EHOW. COM / HOW - DOES _ _ RADIOMETRIC - DATING - WORK _. HTML # IXZZ 1EL XI K T 6D

Absolute Aging

Distribution of fossils SUCCESSION OF FORMS

Extinction

Distribution of fossils MASS EXTINCTION

K-T

K-TPermian

VIDEO dramatization

immediate 6 months 10 years 50 years 65 million years

Video

MODERN BIOLOGY CHAPTER 15.2

Lamarcks Explanation FIRST TO PROPOSE A UNIFYING THEORY ABOUT SPECIES MODIFICATION –SIMILAR SPECIES DESCENDED FROM A COMMON ANCESTOR –RELATED FOSSILS TO EXTANT ORGANISMS BASED ON PHYSICAL CHARS.

Lamarcks Explanation

Lamarcks Problem –ACQUIRED TRAIT –FIERCELY ATTACKED, PRIMARILY BY SCIENTISTS WHO WERE VIOLENTLY OPPOSED TO THE IDEA OF EVOLUTION

The beginning of modern evolutionary thought NATURAL SELECTION: ORGANISMS BEST SUITED TO THEIR ENVIRONMENTS ARE BETTER ABLE TO SURVIVE AND THEREFORE REPRODUCE MORE, LEAVING MORE OFFSPRING POPULATION: A GROUP OF INTERBREEDING INDIVIDUALS WITHIN A SPECIES

Charles Darwin BORN IN 1809 MEDICAL SCHOOL AND CLERICAL SCHOOL H.M.S. BEAGLE

A 5-Year Tour

Darwins Beginnings Analysis of Darwin's data –Returned to England in October, 1836 with thousands of specimens, each carefully documented –13 similar, but distinctly different species of finches Young islands

The Finches Similar but not the sameSimilar but not the same Identify the islandIdentify the island

Darwins Beginnings Publication –Wallaces move –On the Origin of Species By Means of Natural Selection Was published in 1858 Sold out on its first day

Darwins theories Evolution: defined by Darwin as descent with modification –Newer forms are refined forms of earlier fossils –All must have developed from a few common ancestors –Accounts for the similarities in organisms in a geographical area and the fossils found there

Darwins theories Natural selection: defined by Darwin as the means of evolution –Competition –Some individuals are better able to survive –Eventually the frequency of that trait changes in the population

Lamarck v. Darwin

Darwins theories Survival of the fittest –Not always true –Fitness means ability to reproduce, not healthiest –Oversimplification

Evolution A CHANGE IN THE FREQUENCY OF ALLELES WITHIN A POPULATION OVER GENERATIONS

Requirements for natural selection If these are present, selection will occur. –Differential selection –Variation –Heritability

Evidence of Evolution Homologous structures –Same origin; different function

Evidence of Evolution Analogous structures –Same function, different origin

Evidence of Evolution Vestigial structures –Left-overs

Evidence of Evolution Macromolecule comparison –All organisms have the same dna structure and the same amino acids –Many related organisms have very similar proteins

Patterns of evolution CO-EVOLUTION

Patterns of evolution Convergent evolution –Different origins similar characteristics –Similar environment similar solution

Patterns of evolution Divergent evolution –Similar background –Different environment; different solution –Adaptive radiation

Patterns of evolution Divergent evolution –Speciation –Artificial selection

… when the last individual of a race of living things breathes no more, another heaven and another earth must pass before such a one can be again." --William Beebe