Unit 8: EVOLUTION! Lesson 1: How Did Life Begin on Earth?

OBJECTIVES: Summarize how the Earth’s age was determined. Describe how the chemicals of life origenated Describe how cellular organization might have begun.

When did everything star? Origin of the universe- Big Bang?? Evidence? Yes, cosmic background noise. Age of universe= billion years. Geologic time. How old is Earth? Approximately 4.6 billion years old. Many changes have occurred. How Did Life Begin on Earth?

Has Earth Changed? Yes Observe the continents- what do you notice? How Did Life Begin on Earth?

At one point all continents were together forming one large continent called.  PANGEA They Began to split –  Laurasia(north) and  Gondwanaland (south) How Did Life Begin on Earth?

Click on the play button to watch the video.

These changes on the Earth can be timed. So far scientists have NOT found a way to determine the exact age of the Earth directly from Earth rocks because Earth's oldest rocks have been recycled and destroyed by the process of plate tectonics. If there are any of Earth's primordial rocks left in their original state, they have not yet been found. How Did Life Begin on Earth?

Nevertheless, scientists have been able to determine the probable age of the Solar System and to calculate an age for the Earth by assuming that the Earth and the rest of the solid bodies in the Solar System formed at the same time and are, therefore, of the same age. How Did Life Begin on Earth?

The ages of Earth and Moon rocks and of meteorites are measured by the decay of long- lived radioactive isotopes of elements that occur naturally in rocks and minerals and that decay with half lives of 700 million to more than 100 billion years

The geological or deep time of Earth's past has been organized into various units according to events which took place in each period.deep time Different spans of time on the time scale are usually delimited by major geological or paleontological events, such as mass extinctions. paleontologicalmass extinctions

orations/tours/geotime/gtpage5.html Here is an activity that will help you understand Earth’s ‘Geologic Time Scale’ How Did Life Begin on Earth?

Now study the following diagram and answer some questions. 1.Which type of organism came first animals or plants? 2.Which type of animal came first? 3.Which type of plants came first?

4.6 bya- earth was very different Atmosphere of methane, carbon dioxide, nitrogen, water vapor, but no free oxygen Intense solar radiation, lightning, volcanic activity How did life Begin on Earth?

Miller-Urey Experiment Select the link below and then select ‘Animation’ to listen to Miller’s & Urey’s Experiment m/thelifewire/content/ch p03/0301s.swf

Miller-Urey Experiment Simulated conditions on ancient earth. Successfully synthesized amino acids. Some holes in this idea How did life Begin on Earth?

Penn State Research- very new Organic compounds have been located in material in space (comets, meteorites, clouds of gas) Membrane forming molecules have been found in some meteorites Comets/meteorites bombard earth and give rise to life????? Problem? How did life Begin on Earth?

Oparin’s Idea Revisited- By PSU More evidence shows that first organisms were thermophilic (could thrive in earth’s early state) Life arises at bottom of ocean as thermophilic microorganisms How did life Begin on Earth?

So What happened next? Several Different Theories Endosymbiotic Theory Jean Baptiste De Lamarck- Acquired Traits Charles Darwin- Natural Selection Devries Gould How did life Begin on Earth?

Watch the following 10 minutes video. NOVA: Reveling the Origins of Life How did life Begin on Earth?

A FINAL WORD most reasonable people (including the pope) understand that organisms evolve. the argument is not over “IF” it occurs, but “HOW” it occurs. belief that things change does not challenge religious belief. How did life Begin on Earth?