This lesson is designed for students to learn to recognize and understand the relationships between living organisms. Students will determine that related organisms have a common ancestor and/or common traits.
Grades 6 - 12
Allow for 10-20 minutes for an introduction to the topic including new vocabulary (see below), and 30 minutes to complete the project.
Scientists have identified 1.8 million species living today. Some researchers estimate that there might be as many as 100 million! However, those species alive today are only a very small percentage of the perhaps billions of species that have lived on this Earth since life first evolved approximately four billion years ago.
Over 75% of the described living species belong to the Phylum Arthropoda, which includes such diverse organisms as lobsters, barnacles, spiders, and insects. The insects are by far the most abundant arthropods. MollusksMollusk:
A member of the phylum Mollusca; also spelled mollusc (most especially in the United Kingdom). are the most species rich group in the sea, and bivalves comprise the second largest class of mollusks. How are the many species of insects or bivalves arranged, categorized, and classified? How does the classification scheme reflect phylogenetic (evolutionary) relationships? It can be a bewildering yet extremely interesting problem. The following activity is intended to demonstrate the importance of classification through the examination of objects and the identification of common characteristics that organisms do or do not share and the way in which subgroups are created.
As an example, think of your Halloween candy. On Halloween night, after returning from trick or treating, what do you and your friends do? Many kids pour their candy out on the floor or bed, and separate the candy into piles based on how the candy items are the same, and how they are different. The chocolate goes into one pile, the Smarties™ into another, the Sugar Daddy™ into yet another pile, until all the candies are in the appropriate places. Biologists do the same thing with life forms (see also KidsBiology.com Classification of Living Things).
See also the Taxonomy Activity.