Origins of Life on Earth

SC.912.L.15.8

Describe the scientific explanations of the origin of life on Earth.

Source: http://satirizingscientism.blogspot.com/2013/05/creation-of-life-la-campbells-la-blake.html.

What do I need to know?

Students will describe scientific explanations of the origin of life on Earth.

Students will identify situations or conditions contributing to the origin of life on Earth.

Theories on the Origin of Life on Earth

•Extraterrestrial theory: The first life or building blocks of life arrived came to Earth on asteroids or meteors that collided with Earth’s surface.•Primordial ooze/Ancient soup theory: The mixing of chemicals in the atmosphere and oceans and the energy in lightning led to the formation of organic compounds (nucleic acids, proteins, lipids). These compounds eventually gave rise to the first life on Earth First proposed by Oparin and Haldane independently.

Source:http://www.fromquarkstoquasars.com/abiogenesis-theory-origins-life/

Theories on the Origin of Life on Earth

•Guiding Questions:1) What is the scientific evidence used to describe the formation of life on earth2) What was the significance of the Miller-Urey Experiment?3) What are some of the major transition in that have occurred in living things?4) What does molecular evidence suggest about living things?

Testing the Ancient Soup Theory

•Stanley Miller and Harold Urey conducted a famous experiment in which they mimic the conditions of Earth’s early atmosphere in a closed container. They then added an electric spark to mimic lighting. They found amino acids and other simple organic compounds had formed. This supported the idea that life could of formed from the synthesis of organic compounds (ancient soup theory).

Endosymbiotic Theory

•Endosymbioitc theory: Proposed by Lynn Margulis, this theory describe the formation of the eukaryotic cell. It proposes that the eukaryotic cell is a result of the combination of multiple prokaryotic cells that had formed a symbiotic relationship.

Endosymbiotic Theory

•Guiding Questions:

1) What the types of cells seen in living things?

2) What does endosymbiosis suggest?

3) What evidence is used to support endosymbiosis?

Conditions of early earth•Early earth was very hot, evaporating the liquid water into the atmosphere. However, as the earth cooled, gravity-trapped water vapor condensed, fell as rain, and did not boil away but remained impounded in pools that became lakes and oceans. It was also believed that tectonic activity caused many volcanic eruptions at that time. From present-day volcanoes, we know that when they erupt, they release carbon dioxide, nitrogen, and a host of non-oxygen gases. In addition, with no protecting atmosphere, the earth was constantly bombarded with meteorites and other space debris still in circulation from the big bang. From current astronomical research, we know that meteorites can carry ice and other compounds, including carbon-based compounds. Researchers believe, therefore, that early Earth's atmosphere consisted of water vapor, carbon dioxide, carbon monoxide, hydrogen, nitrogen, ammonia, and methane.

Read more: Origin of Life: Early Earth Environment | Infoplease.com http://www.infoplease.com/cig/biology/early-earth-environment.html#ixzz36uOKdDU9

Source: http://motherboard.vice.com/blog/scientists-are-cracking-the-primordial-soup-mystery

Show What You Know One of the accepted scientific theories

describing the origin of life on Earth is known as chemical evolution. According to this theory, which of the following events would need to occur first for life to evolve?

A. onset of photosynthesis

B. origin of genetic material

C. synthesis of organic molecules

D. formation of the plasma membrane

Show What You Know The endosymbiotic theory proposes that eukaryotic cells

arose from living communities formed by the merging of prokaryotic organisms and their hosts. Which of the following is the best evidence to support the endosymbiotic theory?

A. Mitochondria and chloroplasts contain DNA similar to bacterial DNA.

B. Both prokaryotic and eukaryotic organisms require oxygen in order to use energy.

C. Bacteria, mitochondria, and chloroplasts all divide by mitosis, while the cells containing them divide by binary fission.

D. Bacteria and mitochondria contain many features that are similar to each other but different from those of

chloroplasts.

Show What You Know According the the hypothesis of Oparin and

the subsequent experiments of Miller and Urey, which of the following situations contributed to the origin of life on Earth?

A. Organic compounds formed frommeteorites that had fallen to Earth.

B. Cells evolved in an environment lacking oxygen.

C. Organic compounds formed from gases available in the atmosphere.

D. Cells evolved from large prokaryoticcells that engulfed smaller prokaryotic cells.

Show What You Know According the the hypothesis of Oparin and the

subsequent experiments of Miller and Urey, which of the following situations contributed to the origin of life on Earth?

A. Organic compounds formed from meteorites that had fallen to Earth.

B. Cells evolved in an environment lacking oxygen.

C. Organic compounds formed from gases available in the atmosphere.

D. Cells evolved from large prokaryotic cells that engulfed smaller prokaryotic cells.