Tag Archives: Biology

DNA from the poop of extinct four-meter-tall birds reveals lost ecosystem

Enlarge (credit: York Museums Trust staff)

A thousand years ago, gigantic 12-foot-tall flightless birds roamed New Zealand, snacking peacefully on plants and fungi. Then humans came along. Within two hundred years, the giant moa—along with a host of their close cousins—were dead at our species’ hands.

What did the world of the moa look like? Even though New Zealand has lots of well-preserved wilderness, studying that won’t give us an answer. When a species disappears, it takes a chunk of its ecosystem with it, so understanding the ramifications of the moa extinction can help us better understand the environment that many surviving species—some of them critically endangered—evolved in.

Some important answers lie in something the moa left behind: ancient bird poop. It tells us that

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Evolution Saves Species From ‘Kill the Winner’ Disasters

At a meeting of the American Society of Naturalists in 1960, the noted British ecologist G. Evelyn Hutchinson posed what he called “the paradox of the plankton.” Look at a flask of seawater; it will be filled with diverse species of plankton, all competing for the same vital elements and nutrients. Yet natural selection implies that over time, only one species should occupy an ecological niche, a concept known as competitive exclusion. And what is true of plankton seems to be true of many protozoa, plants, birds, fish and other organisms, too. How can ecosystems routinely have so many competing species that stably coexist?

Ecologists have mulled over this vexing paradox ever since, but they have generally taken comfort in a solution known as … Read the rest