Name: ______________________________
Virtual Lab: Fertilization and Development
Spawning and Fertilizing In Sea Urchins
Visit http://tinyurl.com/vurchin to answer the following questions about sea urchin
fertilization and development.
What varies between urchin species’ reproduction?
List 2 species of sea urchin:
What 2 sex organs release gametes (sex cells)?
Why do egg sizes vary between a human, sea urchin, and bird?
PART 2:
What tool is used to pick up very small amounts of a substance? ___________________
Compare the size of the urchin egg and sperm by viewing both under the microscope. Make a prediction
as to why this size difference occurs.
What precautions are taken during the lab to ensure the egg and sperm are viable and there is no
contamination?
Name: ______________________________
Virtual Lab: Fertilization and Development
Are sea urchin eggs fertilized internally or externally? Explain how you know using evidence from the
lab
PART 3:
Draw a diagram of urchin fertilization. Be sure to label the egg, sperm, and fertilization envelope.
Click on Embryogenesis to hatching in the side bar to answer the following:
As the cell divides from 1 to 2 to 4 to 8 etc, what process is it undergoing? (hint: pause the video after
the 2 cells division)
What is special about the morula stage?
Sea urchins and humans share similar characteristics of embryonic development. What does this tell you
about the 2 species?
What shape do cells form during the early blastula stage?
What is the function of the hatching enzyme in sea urchins?
What are the function of the embryo’s cilia during hatching?