Species Migration Quotes

I think humans are migratory animals.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand. It has been said that astronomy is a humbling and character-building experience..... To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known.

Sometime during the many millions of years that have elapsed since mammalian faunas came into existence, some sort of island crossed from West Africa to South America.

The chance of any species reaching and then surviving on an island as distant as one of the Hawaiian chain is infinitesimal, but despite the extraordinary odds, plants and seeds found their way ashore, carried by the tide or blown by trade winds, inside birds or in their feathers, in the branches of trees and in the jetsam of sunken ships.

Living in an entirely different physical as well as biotic environment, such a population would have unique opportunities to enter new niches and to select novel adaptive pathways.

Several times in Earth's history, rapid global warming occurred, apparently spurred by amplifying feedbacks. In each case, more than half of plant and animal species became extinct. New species came into being over tens and hundreds of thousands of years. But these are time scales and generations that we cannot imagine.

A refuge is supposed to prevent what? The genes from flowing out of sight? This refuge idea won't stop insects from moving across boundaries. That's absurd.

Moreover, all our knowledge of organic remains teaches us, that species have a definite existence, and a centralization in geological time as well as in geographical space, and that no species is repeated in time.

It's our human nature to explore. Tens of thousands of years ago, our species walked out of Africa, traveling far and wide across the entire planet, from the Arctic to the tip of Tierra Del Fuego, making us the most geographically diversified species on Earth.

Eurasia's main axis is east/west, whereas the main axis of the Americas is north/south. Eurasia's east/west axis meant that species domesticated in one part of Eurasia could easily spread thousands of miles at the same latitude, encountering the same day-length and climate to which they were already adapted.

Land bridges were everywhere during the extinction, many species were spreading, and there were many diseases.