NAME: _____________________ DATE: ______________ PERIOD: _____

Answer questions as best you can. You may use the back for drawings (label with question #).

1) What are eggs? Point out some of the differences between a human egg and a chicken egg.

2) Why does an egg need a sperm in order to divide and grow?

3) Draw an egg and a sperm keeping their sizes relative.

4) How can you tell when an egg has been fertilized?

5) Is an egg a cell? If so, how is it different from other cells? If not, what is another name for it?

6) Why can't sperm fertilize eggs from other species? Or can they? Give examples if you think they can.

7) Make a quick sketch of a sea urchin.

8) Where do sea urchins live?

9) What do sea urchins and humans have in common?

10) Do sea urchins mate?

11) How can you tell a female urchin from a male urchin?

12) Draw an unfertilized sea urchin egg and a fertilized sea urchin egg (zygote).

13) Draw a sea urchin embryo at the gut forming stage (gastrula).

14) Draw a sea urchin embryo at the feeding stage (pluteus).

15) Why does an urchin embryo have to develop so quickly?

16) Why can a human embryo take it's time?

17) Why do so many researchers use sea urchins to answer their scientific questions?

18) What is an experiment?

19) What is an experimental control?

20) What makes "scientific illustration" different from ordinary drawing?