Why would it be important to understand what controls the number and types of species in an ecosystem? •THERE’S ALSO OTHER QUESTIONS IN THE PIC (if you could answer them it would be appreciated)

The short film Some Animals Are More Equal than Others: Trophic Cascades and Keystone Species opens by asking

two fundamental questions in ecology: “What determines how many species live in a given place? Or how large

can each population grow?” The film then describes the pioneering experiments by Robert Paine and James Estes,

in the 1960s and 1970s, which started to address them. Paine’s experiments on the coast of Washington state

showed that the starfish is a keystone species, having a disproportionately large impact on its ecosystem relative

to its abundance. Estes and colleague John Palmisano discovered that the kelp forests of the North Pacific are

indirectly regulated by sea otters, which feed on sea urchins that consume kelp. The presence or absence of sea

otters causes a cascade of direct and indirect effects down the food chain, which in turn affect the structure of

the ecosystem. These early experiments inspired countless others on keystone species and trophic cascades in

ecosystems throughout the world.

Explanation:

HAND TYPED!!