A Roy society survives by feeding off the Biv society, this can be from Roy invading Biv wealthy areas to plunder which imposes their philosophy on them. It can also be by trading with them, this is Biv imposing their philosophy on Roy. R prey such as gazelles can be chaotic and overeat Biv vegetation causing their ecosystem to collapse, an R society of nomadic farmers might cut down so much forest to grow crops that the ecosystem is damaged. For example this can cause the soil to be lost by trying to farm on hills, the rain washes it into the valleys as the Romans found when farming in Libya. The chaos R and B farmers can wreak on the environment is usually quenched by the randomness of V plants to absorb this damage. For example plants that are overeaten tend to evolve defenses like poison and thorns to survive. When the tastiest plants are eaten the more unpleasant ones are all that remain, this acts as a ceiling on the R chaos of feeding so their population might collapse rather than destroying more of the plants. Then after this collapse into starvation or moving elsewhere the Biv plants re establish themselves beinging the colors into balance again.
The
city states of the ancient Mayan empire flourished in southern Mexico
and northern Central America for about six centuries. Then, around A.D.
900, Mayan civilization disintegrated.
Two new studies examine the reasons for thecollapse of the Mayan culture, finding the Mayans themselves contributed to the downfall of the empire.
Scientists have found that drought played a key role,
but the Mayans appear to have exacerbated the problem by cutting down
the jungle canopy to make way for cities and crops, according to
researchers who used climate-model simulations to see how much
deforestation aggravated the drought.
"We're
not saying deforestation explains the entire drought, but it does
explain a substantial portion of the overall drying that is thought to
have occurred," said the study's lead author, Benjamin Cook, a climate
modeler at Columbia University's Lamont-Doherty Earth Observatory and
the NASA Goddard Institute for Space Studies, in a statement. [ Dry and Dying: Images of Drought ]
Using
climate-model simulations, he and his colleagues examined how much the
switch from forest to crops, such as corn, would alter climate. Their
results, detailed online in the journal Geophysical Research Letters,
suggested that whendeforestation was
at its maximum, it could account for up to 60 percent of the drying.
(The switch from trees to corn reduces the amount of water transferred
from the soil to the atmosphere, which reduces rainfall.)
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