Evolution and Domestication
Origin, divergence
Earliest life may have
originated in the water, and for billions of
years life diversified there.
The land (and air) was
conquered, first by microorganisms, and then,
about 400 million years ago, by fungi, land plants, and insects.
Vertebrates may have come on board about 300 mya.
Continental
drift has changed the
configuration of the earth throughout this
period. Here
is an animated view of this process, which took millions of
years, and continues today.
By the time (65 mya)
grasslands and large mammals had started to
evolve, the world
was beginning to look as
it does today, except that North and South
America still were separate, Eurasia was covered by high seas, and
India had not yet collided with Eurasia to form the Himalayas.
Here
is the story of human origin and migration as currently understood from
genetic data. Starting from Africa, about 60,000 years ago, human
beings spread across the world, colonizing Europe and Asia by about
40,000 years ago and the Americas by about 20,000 years ago.
After the last ice age
(18,000 years ago) they started domestication animals and plants in
the Fertile
Crescent (SW Asia).
There may have been at least 6
independent origins of agriculture across the world, and around eight
centers of origin for crop plants.
Why
did not agriculture originate and spread from more places? Here
is one explanation: Hawkes
argues that some plants evolve to avoid being eaten to extinction by
producing vast quantities of edible seeds, but mainly in disturbed
areas around human settlements. In other words, these 'weedy' plants,
which could not compete with other vegetation, co-evolved with human
beings, and ended up being consciously domesticated by them.
Here,
Diamond argues that the geography and climate in around the centre of
agriculture in SW Asia allowed migration and easy establishment
of grain crops and domestic animals along a band of temperate latitudes
in Eurasia. On the other hand, migration was generally only
possible in a N-W direction in Africa and the Americas, and climate
prevented easy diffusion of crop along the longitudes. Thus, potatoes
from S. America did not reach the north, nor did the sunflower from N
America reach the south until modern times.
Trade Connections, Convergence
By about 4000-3500 BCE, the basis of modern, city culture was in
place in many places. There is evidence for trade links between Turkey,
Iran,
Syria and the Levant around that time.
Trade between India and Egypt (Ramses II 1304 -1237 BCE): Land? Sea?
Land routes within India 300 BCE
Ancient Sea Route 250 BCE-250 CE
Silk Route 206 BCE (Chinese control)-220 CE: China to Europe and India
100 BCE Egypt under Rome; 1 CE Silk in Rome
Salt Timbuktu 300 CE
Land and Sea Routes, 800 CE
Ancient
Maps And Corn Help Track The Migrations Of Indigenous people