Some Animals Are More Equal than Others: Keystone Species and Trophic Cascades

preview_player
Показать описание
The short film opens with two questions: “So what determines how many species live in a given place? Or how many individuals of the species can live somewhere?”

The research that provided answers to these questions was set in motion by key experiments by ecologists Robert Paine and James Estes. Robert Paine’s starfish exclusion experiments on the coast of Washington state showed that removing starfish from this marine ecosystem has a big impact on the population sizes of other species, establishing the starfish as a keystone species. James Estes and colleague John Palmisano discovered that the kelp forest ecosystems of the North Pacific are regulated by the presence or absence of sea otters, which feed on sea urchins that consume kelp. These direct and indirect effects of sea otters on other species describe a trophic cascade. These early studies were the inspiration for hundreds of investigations on other keystone species and trophic cascades, as well as ongoing studies into the regulation of population sizes and species numbers.
Рекомендации по теме
Комментарии
Автор

Me: *looking at starfish* are you a keystone specie?

Starfish: no this is Patrick

merubindono
Автор

3:37 green world hypothesis (def.)
13:40 trophic cascades (def.)

지젤-bi
Автор

this homework at home is not the move anymore

kylap
Автор

anyone else looking through the comments procrastinating your work?

annika
Автор

i spent 20 minutes reading the comments and forgot to watch the video

cececramer
Автор

Watch at 1.75 or 2x speed. It's gonna help you a lot if you're doing this for school ;)

ramennoodles
Автор

He looked so proud of him self when he said "I changed the nature of the system"

MrAshton
Автор

Sean and these Biointeractive pieces are amongst the best quality anywhere. So well done.

Leoneidas
Автор

ecologist Robert Paine has passed away on June 13, 2016. This is around seven weeks after this video was posted. Rest in peace, star thrower 😔

dannylim
Автор

As a former student of Dr. Estes’ wife, I was very familiar of their orca research (although in 2001 the phrase “trophic cascade” was not used).

christophercook
Автор

With All honestly, I am glad to be watching these videos, as they are quite informal, I enjoy watching them repeatedly, & I somehow do not grow bored of any of the videos! They work well as video assignments, as long as the right questions are asked!

YoungSinger
Автор

It makes me feel despair that so many people have lost or never had a connection to Nature. While this video has lots of facts that are “dry” relative to the experience of being in Nature. The research does provide clues on how to reverse losses of endangered species.

VW
Автор

Wait so one man killed an entire ecosystem right?

SHZpai
Автор

Bro this virus and staying home is getting to my head

samisgit
Автор

Wonderful - clear and easy to understand for my 5th grade students, yet full of profound information from two wonderful scientists. Great film. The students were absolutely fascinated.

carrieannnaumoff
Автор

I love hhmi biointeractive, I wish I had them on TV when I was growing up. I was fortunate to have Eyewitness (shows and books). Happy to have these videos now!

cassied
Автор

Leopold described the trophic cascade in his essay "Thinking Like a Mountain" before any of this work was done. What is impressive, is how well Paine and Este's work empirically validates Leopold's anecdotal description.

WilsonRobertB
Автор

i forgot that it was homework, mindblowing as hell. ecology and nature just too beautiful to handle

IchaMufti
Автор

I wish all my ecology lessons were this interesting. Why can't they be??

kCuFfication
Автор

The answers to some questions
Green World Hypothesis: The world is green because predators keep herbivores in check.

Keystone Species: a animal that were removed from a ecosystem would effect on the ecosystem as a whole

Trophic Cascades: Trophic cascade is when you have an apex predator controlling the distribution of resources, and they lead to these cascades of indirect effects lots and lots of indirect effects

Hypothesis and Experimentation: Killer whales eat otters. a place called Clam Lagoon. It provided us a site that orcas could not get to. We had no problem catching about 30 animals in two or three Days. And the fact that that little population did not decline when everything else did the orcas

coolestone