Sapiens 4 -- The "Human Flood" leads to mass extinctions

See also these transcripts, posted by someone else who took Dr. Yuval Noah Harari's Coursera course.

Lesson 04 - part 1 -- Soon after the Cognitive Revolution, Sapiens became the most important factor in the ecology of planet Earth, long before the agricultural revolution when the spread beyond Eurasia (where all other humans had existed) and caused extinctions, "the first significant mark that Homo sapiens left on planet Earth."

• 45k ago -- Sapiens reached Australia:  analogous to 1492 with Columbus or 1969 moon landing
• How did they cross the huge expanse of sea?
• Ancient Indonesians became advance seafarers:  a unique case whereby a land creature becomes a sea creature within only hundreds of years (unlike millions as with dolphins) and without changing its body
• "the moment that Homo sapiens climbed from the middle to the top rung of the food chain and became the deadliest specie in the annals of plant earth."
• Within a few thousand years, 23 of 24 large animals in Australia were extinct (like the Diprotodon or giant koala).  4 different explanations for how we managed to do this.

Lesson 04 - part 2 -- "The American Blitzkrieg" = An even bigger ecological disaster in America 16k years ago (14,000 BCE)

• "This spread of humans across America, testifies to the incomparable ingenuity and unsurpassed adaptability of our species of Homo sapiens. No other animal had ever moved into such a huge variety of radically different habitats so quickly without undergoing any significant genetic mutation and evolution."
• Animals that were there when Sapiens first arrived but who later became extinct in the Americas:  camels, horses, saber-tooth tiger, giant ground sloth, giant rodents, American elephants, etc.  Within a few thousand years after Sapiens' arrival, these creatures had disappeared.
• We are the deadliest specie ever:  "At the time of the cognitive revolution planet Earth was home to about 200 genera of large terrestrial mammals, mammals weighing more than 50 kilograms. At the time of the agriculture revolution, only about 100 genera survived."
• The next wave of extinction is happening now to sea creatures, which have long managed -- until about 300 years ago -- to avoid the effects of Sapiens until now.