Frog Eggs

How it all begins... Below is a shot of some cascade frog eggs sitting in a subalpine wetland in Washington.

The location that eggs are deposited in the wetland determines how quickly they develop. Embryo development is temperature dependent, warmer conditions mean faster development. Eggs deposited in the deeper, cooler part of a wetland will develop more slowly than those deposited in the sun-warmed shallows of the wetland. Quick development is important to successful reproduction because a temporary wetland may dry up completely before the embryos develop into frogs capable of moving out of the water. If the wetland dries up before the frogs have developed, they die. If the eggs are laid in water that is very warm, but too shallow, the eggs may dry out as the wetland looses volume.

So it's a balance. Eggs can't be deposited too deep or too shallow. Warmer is better, but drying out is not good. It's kind of like a game of bocce ball, the closer you get to the target (faster development) the better, but as soon as you go over it you loose the game (eggs dry up).