Plankton Introduction

Today students got new seats and started a new unit on Plants, Plankton, and Biomes. This is probably our longest and most difficult unit because of the large amount of information that needs to be learned and applied.

We started class with a discussion about phytoplankton (cyanobacteria pictured above) and its importance to the ocean and to the world. Phytoplankton are responsible for feeding most of the creatures that live away from the shore and they are important for adding oxygen both to the water and to the atmosphere.

We are learning about plankton! Plankton include organisms that drift through the seas that cannot swim and do not attach to the bottom. Plankton can be classified a variety of ways.

The first way is to classify them by size. Microplankton and nannoplankton require a microscope if you want to see them because they are so tiny. Macroplankton are small, but you can see them without a microscope. Megaplankton are big enough to pick up and include things like jellies.

Another easy way to classify plankton is into plants and animals. Phytoplankton are tiny plants that photosynthesize and make their own food. Zooplankton (belong in the the zoo) and are animal plankton.

Plankton can also be classified as holo- plankton and mero- plankton. Holo- plankton are plankton for their whole lives (forever) and meroplankton are only plankton for part of their lives. The meroplankton may be plankton when they are eggs, larvae, juveniles, all of those stages, or only some of those stages. Most of the invertebrates and fish in the ocean spend some time in their life as a plankton because it allows them to spread around the ocean and find new places to live. This photo is a meroplankton snail larvae that grows into a poisonous cone snail. Part of its body hardens in to the shell it carries for the rest of its life. This is my favorite website about plankton and it is where all my photos come from. Check out the other types of meroplankton.

Students have drawn their own plankton, tried to match meroplankton to the adult forms, and are currently designing plankton to compete in the Plankton Grand Prix - where the object is to sink slowly.