Science Serving Maryland's Coasts

The Life Cycle of the Oyster

Explanation

The sequential development and rapid changes in the early life of the oyster are the emphasis of this activity. The activity introduces new terms for specific stages of larval development and emphasizes the age, size, and characteristics of each stage. Although modeled on the traditional "cut-and-paste" format, students must use logical reasoning and background information to puzzle out the proper chronological order of the diagrams and labels. (Lesson Time: 30 to 45 minutes)

Objectives: 

1. Understand the basic stages of development in the oyster's life cycle, from larvae to adult.
2. Identify the names of important larval stages, sizes in microns, and key features of each stage.
3. Analyze information and search for trends in data.
4. See clear diagrams, photographs, and computer images of microscopic larvae.

Lesson Materials: 

Student Activity Handouts:
The Oyster's Lifecycle
Flow Chart
Lifecycle Diagrams
Labels
Teacher Key

Alternate Activity: "An Oyster's Life" published by Sea Grant

Supplementary Resource: Horn Point Laboratory's Oyster Hatchery

Procedures: 

Introductory Set:
1.  Introduce this activity by explaining that oysters begin life as microscopic life forms called larvae and that they are way too small to see with your eyes. Explain that as a larva (singular) grows and develops, it passes through distinct "stages," just as people change from infants, to babies, to small children, to teenagers ... etc.
2.  Students will learn the names and characteristics of these stages. If computer video projection equipment is available, show 10 second clips to give a clear visual idea of what larvae look like. For example, "Swarming video clip" (larvae moving amongst grains of sand) and "Settling video clip" (a "pediveliger"-stage oyster larva using its foot to attach) from the website of Horn Point Laboratory, University of Maryland Center for Environmental Science, http://hatchery.hpl.umces.edu/​.
 
Flow Chart:
1.  Have students review the activity handout ("The Oyster’s Life Cycle") and carefully read the background information.
2.  Distribute two cut-out pages, scissors, and glue stick. From the cut-out pages, students remove the diagrams and labels by cutting along the black lines.
3.  Allow students to devise their own methods for arranging the information in the proper order on the Flow Chart. (See Teacher Key for notes and an organized table of lifecycle information).
4.  All informational pieces should be "dry fit" before being permanently glued down. The instructor could adjust the difficulty of the activity by adding or removing "set" information from the Flow Chart. (Lesson Time: 30 to 45 minutes)
 
Alternative Lesson:
If time is extremely limited (Lesson Time: 15 minutes), use the Introductory Set above but substitute "An Oyster's Life", a Maryland Sea Grant activity published by the Maryland Department of Natural Resources (download from Lesson Materials.) Answers: (1) Egg, (2) Spermatazoa, (3) Fertilized egg, (4) Embryo, (5) Free-swimming larvae, (6) Cilia, (7) Pseudopod, (8) Spat, (9) Adult oysters, (10) Bonus: "clutch."

References: 

Web site for Horn Point Laboratory Oyster Hatchery, video clips, https://www.umces.edu/hpl.

"An Oyster's Life" game (available under Lesson Materials) appears in the the 2003 Maryland Bay Game booklet, published by the Maryland Department of Natural Resources. Contact the Maryland DNR Public Communication Office at http://www.dnr.state.md.us

Maryland State Standards: 

1.5.5

The student will create and/or interpret graphics (scale drawings, photographs, digital images, field of view, etc.).

1.5.7

The student will use, explain, and/or construct various classification systems.

3.2.1

The student will explain processes and the function of related structures found in unicellular and multicellular organisms.