- 1 week - Suggested for 1st lab experience
PRIMARY LABS - 2 weeks +
This is a list of labs extending the sea urchin experience over a longer more rigorous time frame. If you have trouble getting and keeping sea urchins, you are probably better off just doing the CORE LAB and maybe the SPERM EXPERIMENTS lab.
- Gametes - Looks at the gametes of the sea urchin and relates them to our own gametes in terms of size and characteristics. Detailed instructions on spawning animals, collecting and storing gametes for future work. Includes sources for sea urchins.
- Fertilization - Sea urchin sperm are added to sea urchin eggs and the early steps of development are observed and discussed
- Development - Latter stages of development are observed, from 2 cell to pluteus.
- Experiments - Environmental effects of temperature, light, pH, oxygen and toxins are looked at in relation to fertilization and development of the sea urchin.
- Sperm Experiments - Sea urchin sperm keep very easily in a refrigerator. This allows students to do multiple experiments over several days.
- PUSH lab - is a set of guided experiments, based on the above ideas. [greater details and directions presented]. Because these labs are "cookbooked", they do not promote inquiry or critical thinking as much as the two experiments sections above.
These are ideas that go beyond the one period classroom experience. Some could be appropriate for special interest students, others for science fair projects, etc. Each web page shows a new skill or method and suggestions for new investigations. [Listed in order of increasing difficulty] see also the Scientific Method.
- Shaking - simulating wave action on young embryos.
- Ultraviolet Light Effects - UV causes damage to genetic and protein material in the eggs and sperm. How much does it take and what is affected?
- Modified Seawater Formulations - What are the effects of varying formulas on fertilization and development? What happens when the MAGNESIUM is left out? CALCIUM? SODIUM?
- Osmotic vs. Ionic - Is it the ions in the seawater or the osmotic pressure that is important for fertilization and normal development?
- Artificial Activation - Shown are several ways to "activate" the egg without a sperm. Are males needed at all?
- Carnoy's Fixative - This fixative is used to preserve detail for later examination of embryos. Fixatives work by selective extraction and preservation. What can you see in the fixed developing embryo you could not see in the live ones?
- Isolating the Mitotic Apparatus - Illustrates mechanisms for removing the plasma membrane and other cell components to enhance viewing of microtubules, chromosomes and centrosomes in the dividing cell.
- Gamete Storage - Gamete Storage - Whereas we can keep cow and sheep gametes and embryos for years, at best we can keep sea urchin gametes for only a few weeks. But even this is an improvement over the past, where urchin eggs essentially had to be fertilized when fresh.
- Egyptian Project Page - see how above principles have actually been applied in a real research project.