Ecological disasters such as the destruction of rainforests

Large dams have harmed Siberia's delicate ecological balance.

Witnesses put him at the Goldman ecological conference.

Mark, can you tell us what an ecological niche is?

The species of moa that are currently recognized occupied ecological niches customarily filled elsewhere by large mammalian browsing herbivores.

The story of moa species and their demise raises ecological issues on the vulnerability of species to human-caused changes - including altered vegetative cover of the landscape, change in the physical environment, and modification of the flora and fauna of a region by eliminating some species and introducing others.

Furthermore, a species-rich ecosystem is more likely to have species with similar ecological functions, so that if a species is lost from an ecosystem, another species, probably a competitor, is likely to flourish and occupy its functional role.

But I haven't read about any major ecological problems.

What ecological pressures might have caused fishes to gradually abandon their watery habitat and become increasingly land-dwelling creatures?

You might think of it as…um…as a…a kind of ecological vacuum.

They adapted to survive in their particular ecological niche, their…their position within a particular ecosystem.

And what adaptive radiation is: an evolutionary process by which a parent species rapidly undergoes changes resulting in various new species in order to fill multiple ecological niches.

In popular language this was the era “when dinosaurs ruled Earth,” when a wide variety of reptile species occupying many ecological niches.

Prairie farmers also introduced new crops that were not part of the earlier ecological system, notably wheat, along with fruits and vegetables.

The physical structure of species competing for resources in the same ecological niche tends to gradually evolve in ways that allow them to occupy different niches.

The other is to restore some of the evolutionary and ecological potential that has been lost in North America.

Finally, younger ecologists have found ecological problems involving behavior and life-history adaptations more attractive than measuring physical constants.

Biological hypotheses include ecological changes brought about by the evolution of cooperation between insects and flowering plants or of bottom-feeding predators in the oceans.

To understand the ancient Mayan people who lived in the area that is today southern Mexico and Central America and the ecological difficulties they faced,one must first consider their environment, which we think of as "jungle" or "tropical rainforest."  

So, basic ecological principles imply a strong tendency within pastoralist lifeways toward nomadism (a mobile lifestyle).

So, it is no accident that with the appearance of pastoralist societies there appear large areas that share similar cultural, ecological, and even linguistic features.

Female Professor: So, um, continuing our discussion of ecological systems, whole systems, the main thing to keep in mind here is the inter-relationships.

Ecological groups say that nothing is being done to tackle the problem.