Is sexual reproduction in yeast isogamous or anisogamous

[tomsecret]

also what is an example of an organism inferred to have evolved from igonamy to anisogamy besides sperm and egg? is yeast an example of this??

 

[spockjones20]

According to wikipedia it is isogamous. Here is the link, look under "biological types."
http://en.wikipedia.org/wiki/Isogamy
As for the evolutionary question, I have no idea. Sorry.