Earth’s Early Atmosphere had very little free oxygen Contain: methane, CO2, H2O, Nitrogen, Ammonia, and Carbon Monoxide Changes are constantly occurring … we notice them during volcanoes and earthquakes.

AGE OF THE EARTH 4.6 Billion yrs. PALENTOLOGIST: Study fossils to understand the Earth’s origin FOSSILS: Preserved remnant or remains of an organism that lived many years ago

Evidence of Evolution (Comparative Morphology) Science comparing the structures of living things 2 Categories Analogous Structures Homologous Structure

Evidence of Evolution (Analogous Structures) Serve the same purpose in different species but evolved independently Did not evolve from the same structures in a common ancestor pterodactlyl bird moth bat

Evidence of Evolution (Homologous Structures) Have a common origin but not necessarily a common function (these bone pattern are similar/but have different functions)

Homologous vs Analogous

Evidence of Evolution (Embryology) Study of the earliest stages of life, before birth.

Evidence of Evolution (Biochemical) Comparing genetic information (the sequence of amino acids) DNA Fingerprinting (gel electrophoresis) Ex. Hemoglobin (red blood cell protein) The amino acid sequence for this protein in humans is almost identical to the sequence in gorillas. Differ by one amino acid. In frogs, it differs by 67 amino acids. So, humans and gorillas shared a common ancestor more recently than humans and frogs.

Various Types of Fossils TRACE CAST (FILLED) MOLD (EMPTY) IMPRINTS AMBER OR ICE

OPARIN’S THEORY Suggested energy from the sun, lightning triggered chemical reactions to produce small organic molecules from the substances present in the atmosphere. The rain washed these into the ocean. Called “ORGANIC SOUP” or Primordial Soup”

MILLER AND UREY Experiment p. 382 Tested Oparin’s hypothesis by simulating the conditions of early Earth in a laboratory The experiment made a Protocell Protocell: An ordered structure, enclosed in a membrane, that carries out some life.

SEDIMENTARY ROCK Fossils are usually found Layers form over time The older the rocks the more primitive the organisms that left impressions.

HOW SCIENTIST DETERMINE AGE OF FOSSILS (1) Relative Dating (p. 372) (2) Radioactive Isotope RELATIVE DATING Undisturbed rock layers… the layers at the surface must be younger than the deeper layers. Younger rock on top.

RADIOACTIVE ISOTOPES Atoms in these isotopes are unstable They breakdown (decay) overtime giving off radiation, form a new element.

HALF-LIFE The amount of time it takes for one half of a radioactive isotope sample to break down.

UNDERSTANDING FOSSILS By studying fossil records, scientist have been able to put together an outline of earth’s history called the GEOLOGIC TIME SCALE Era: Largest division of time Period: Subdivision of an Era Extinct: Gone

GEOLOGIC TIME SCALE PRECAMBRIAN ERA THE OLDEST LIFE BEGAN---IN THE OCEANS SINGLE CELL AND SIMPLE MULTICELLULAR ORGANISMS

PALEOZOIC ERA MANY INVERTEBRATES PLANTS AND ANIMALS MOVE TO LAND

MESOZOIC ERA REPTILES AGE DINOSAURS DOMINATED THE WORLD FOR ABOUT 250 MILLION YEARS

CENOZOIC ERA ERA OF THE MAMMALS AND THE BIRDS WE LIVE IN THIS ERA!

THE ORGIN OF LIFE Spontaneous Generation (Abiogenesis): The idea that nonliving material can produce living Biogenesis: The idea that living organisms come only from other living organisms.

FAMOUS SCIENTIST Redi- Experiment using the jars and meat. (p. 380) Pasteur- Experiment using the S-Shaped Flask that remained germ free (p. 381)

ENDOSYMBIONT THEORY P. 385 Proposes that eukaryotes evolved through a symbiotic relationship between ancient prokaryotes.