Sea urchin on the left and mammal on the right. What you usually have to do is set cultures up at different times, including the day before. This lesson is often done when mitosis and meiosis are discussed. Comparing the steps leading up to first division in sea urchins and onion root tip can help students see the differences between plant and animal cell division. Normal Fertilization Normal Early Blastula Pluteus at 5 days Students should keep careful records of when each of the recognizable development steps occurs.
Detailed drawings are very helpful.
If you are lucky enough to have two species or two different temperature environments, students can compare stages and rates of development. Compare the rates of survival at each of the stages. The lab is very different from the open ocean. The process of development is VERY complex with lots of possibilities for things to go wrong. This is a group assignment.