What is the difference between top-down and bottom-up control on a ecosystem?

Question

what is the difference between top-down and bottom-up control on a ecosystem and what are some of the pros and cons for each one

Answer 1

Top down control refers to when a top predator controls the structure/population dynamics of the ecosystem. ( cit.)

Bottom up control in ecosystems refers to ecosystems in which the nutrient supply and productivity and type of primary producers (plants and phytoplankton) control the ecosystem structure. ( cit.)

See "Ecological" ( incl.some examples for pro/con )

http://www.answers.com/topic/top-down-an...

and this site:

http://books.google.de/books?id=Y19ZuVNd...