What are the effects of temperature on the mitosis of sea urchin eggs?

Answer 1

Most of the mitosis cycles after fertilization are dramatically affected by temperature. A decrease of ten degrees celcius can quadruple the amount of time each division cycle requires. This is a pretty well-known effect.

There's at least one study which suggests that immediately after fertilization there is a very brief period when temperature is of less significance. There's a link to the paper below, if you're interested. It only lasts a few minutes and the authors thought it was due to initial activation of the egg.

Hope that helps!