Chapter 14: Lessons from the Past, Lessons for the Future
How SuccessfulAre We?
- There are currently 6.7 billion human beings living on earth
- Humans have been on the scene for between 200.000 and 400.000 years
- Homo sapiens is one of approximately 1.4 million living species currently known to
science; our immediate predecessor, Homo erectus, existed for over 1.5 million years.
Humans and the Impact of Culture
- Around 15.000 ya, some human groups began to settle down and abandon their nomadic
- Exposure to infectious disease was one of the earliest cracks in the harmonious
relationship between humans and cultural innovation.
- Only about 1/5 of the earth’s original forests remain intact today
- Most highly prized wood—Lebanese cedar which was cut and shipped throughout the
eastern Mediterranean (deforestation was so complete that only small patches of trees
- The collapse of the Maya civilization of southern Mexico, Honduras, El Salvador, and
Guatemala around 1.100 ya was at least partly due to climate change (warming), over-
cultivation, and depletion of nutrient-poor tropical soils.
- By examining Inka agricultural fields, terracing, and irrigation, archeologist Clark
Erickson (1998) was able to reveal the ancient technique and duplicate many of the same
Neolithic- the period during which humans began to domesticate plants and animals; also
associated with increased sedentism. Dates for the Neolithic vary from region to region,
depending on when domestication occurred.
Mesolithic- the period preceding the Neolithic, during which humans increasingly exploited
smaller animals, increased the variety of tools they used, and became somewhat less nomadic.
The Loss of Biodiversity
- Biodiversity is the totality of all living things, from bacteria and fungi to trees and
humans; this not only refers to species but also to individuals and the various genetic
combinations they represent, as well as to entire ecosystems.
- The geological record indicates that in the last 570 million years, there have been at least
15 mass extinction events, two of which altered all of the earth’s ecosystems; the third
major extinction event is occurring now.
- Until recently, the most important cause of extinction has been habitat reduction which is
a direct result of the burgeoning human population and the resulting need for building
materials, grazing and agricultural land, and living areas.
- By the year 2022, half the world’s remaining rain forests will be gone if destruction
continues at its present rate
Holocene- the most recent epoch of the Cenozoic; following the Pleistocene, it is estimated to
have begun 10.000 years ago 2
Megafaunal- referring to megafauna, extremely large animals such as elephants; the term is
usually used in reference to the