Learning Objectives:
- Understand normal Brine Shrimp development.
- Understand the effects of alcohol of Brine Shrimp hatching.
- Record and interpret data.
• In the next two labs we will be looking at the effects of various environmental conditions on embryonic development.
• In the this lab we will look at the effects of varying alcohol concentration has on the development of Brine shrimp embryos.
• In the next lab we will look at the effects that varying the pH of water that amphibian eggs are developing in has on them.
• We will look at the effects the varying alcohol concentrations has on the ability of Brine Shrimp eggs to hatch.
• Keep in mind that a blood alcohol concentration of 0.01% - 0.09% is considered under he influence. A blood alcohol concentration of 0.1 or above is considered legally drunk.
• It is important to understand normal development if we wish to identify any effects the varying concentration of alcohol has on the development of Brine Shrimp.
• Since we will be looking at the effects of varying pH on amphibian development next week, we will spend some time this week modeling the early cleavage divisions that occur in a very specific pattern in amphibian embryos.
Brine shrimp (Aetemia) are commonly known of as "Sea Monkeys". Maybe you had a kit and grew some as a child. Maybe you have a fish tank and use them as fresh food for your fish!
• Figure 4.1 A shows many of these tiny Brine shrimp in a small aquarium.
• Figure 4.1 B is a magnified image of a single Brine shrimp.).
• Brine Shrimp are classroom-friendly crustaceans whose development is relatively quick and easy to see.
• Under ideal conditions, female brine shrimp can produce eggs that hatch soon after emerging from the ovisac to produce live young.
• When environmental conditions become less than ideal, such as high salinity or food shortage, the female responds by producing dormant cysts, which are encased embryos that cease development and enter a state, called diapause, until conditions are again favorable (Figure 4.2).
• The dormant cysts can remain viable for years if kept in a dry, oxygen-free environment.
• We will be using brine shrimp that have been kept in the dormant cyst stage.
• Once the cysts are incubated in saltwater, the embryos quickly resume their development by hatching from the cysts.
• After the cysts open the brine shrimp remains attached to the cyst shell surrounded by a hatching membrane. This stage is known as the umbrella stage.
• The hatching membrane remains attached to the cyst for a number of hours until the young brine shrimp, known as a Nauplius, emerges.
• During the first larval stage. The Nauplius subsist on yolk reserves until it molts.
• During the second larval stage, the Nauplius begins to feed on algal cells.
• The Nauplius will go through approximately 15 molting stages before reaching adulthood in 2-3 weeks.
• Since Brine Shrimp develop externally in a marine environment they are susceptible to the influences of many environmental toxins, such as alcohol, acid rain and many other common substances.
• Toxins often impair or impede the hatching process.
• Given the relatively short development time from cyst to Nauplius (15-20 hours), the use of brine shrimp in this study is a fast and easy way to observe some of the effects of environmental toxins on development.
• We will be using them to determine the effects of varying alcohol concentration on their ability to hatch.