5. Structure: Energy, matter, systems
Image: Prehistoric hand prints found in caves that go back 40,000 years ago.
Slide 1: Although Earth was formed with an astonishing number of elements that life would require to emerge, how physics and chemistry crossed the threshold into forms of life, is still not known. Our humanoid branch showed only about 6 Million YA, and modern Homo-Sapiens did not fully evolutive until approximately 250,000 years ago.
Slide 2: The iconic Blue Dot photograph; you live here.
Slide 3: Carl Sagan's poetic quote still gives me goosebumps.
Slide 4: Earth in its first Billion-year existence before the improbable event of single-celled life emerged.
Slide 5: Single-Celled life continued for the next 2.5 Billion Years.
Slide 6: Earth Freezes over.
Slide 7: In the Carboniferous Period (350-300 MYA). This was a period when the earth had a warm and humid climate. Tropical plants flourished over the entire surface of the planet. Eventually, geological changes covered up those forests, which concentrated and stored the "energy" these plants had captured from the sun. Today they are in the form of coal and oil; they contain more than 50 million years of the sun's energy. (Coal was not found to be useful until the 1750s when it began to be burned to produce heat to run steam engines invented to pump the water out of coal mines.)
Slide 8: This timeline shows our arrival as fully formed Homo Sapiens approximately 250,000 YA.
Slide 9: The blue planet as we know it today
Slide 10: Fire: Homo Sapiens evolved from Homo Erectus, who seem to be the first creature to control and use fire for hunting and cooking approximately 400,000 YA. Homo Erectus evolved roughly 1.8 million to 300,000 years ago, (some isolated divergent populations may have survived until 50,000 years ago). By using fire to cook food, Homo Erectus this act concentrated nutrients, which made it possible for Homo Sapiens to evolve to have smaller stomachs, smaller teeth, and a larger brain (Wrangham, 2009). All Human Beings are creatures who are dependent on fire to survive.
Slide 10: Human Migrations out of Africa, first following the trails of Homo erectus than expanding to all the contenents.
Slide 11: A major cosmic impact, circa 10,835 BCE, triggered the Younger Dryas (YD) climate shift, which seems to have resulted in megafaunal extinctions and including the extinction of many large animal species during a mini ice age that lasted more than 1,000 years. The Prehistoric Cave Paintings from 40,000 Years Ago came to an end around the time of the YD impact.
Slide 12: The importance of hands: The evolution of human Hands from making tools and gestures, may have led to the invention of language in homo erectus and homo sapiens. The images of hands in caves.
Slide 13: While it is not clear if the Neolithic Era, which began around 10,000 BCE, should be regarded as an Agricultural Revolution (Scott, 2018, Graeber, 2021), although human beings began to cluster together in small cities, although rarely with fortifications. Human beings mostly traveled in bands or tribes, they began to trade, domesticate animals, and farm on a seasonal basis, and store food. Various forms of governing involved hierarchies or loose confederacies. These beginnings of "civilization" took many forms, it was a period of social experimentation (Scott 2018).
Slide 14: The first writing systems emerged approximately 3,500 BCE. The first uses of writing seemed to evolve to keep track of inventory, writing was transformational in that laws could be made public, myths could be shared, and our stories could be told; writing began to change how we lived.
Slide 15: Early towns.
Slide 16: Writing allowed greater communication, which meant that people could influence others at a distance.
Slide 17: Our contemporary era cannot be separated from the many ways we have explored living and governing each other, the domestication of animals and the development of agriculture, writing systems, and more recently the discovery in the 1750s that fossil fuels (coal and oil) contained 50,000 years of "free energy" stored in compressed carbon deposits 350 million years ago. We are only now learning the cost of releasing this energy into the atmosphere.
Slide 18: An image of the complexity of our era: Robert Frank photographed a rack of dinner place mats in a gas station at Hoover Dam?