Introduction

In this module, we will explore the diversity within the plant and animal kingdoms. For each kingdom, begin with the basic concept of “What is a plant?” and “What is an animal?” What traits define these categories of life?

Begin by defining animal. While there is a lot of diversity within this category of life, and you will read about the nine phyla that fall under this category and the unique characteristics for each phyla, you should start by identifying what these organisms have in common. What must each have to remain under the classification “animal”. As you work through the nine phyla, think about the progression of characteristics from one organism to the next. Compare their mode of reproduction, the way they obtain nutrients, and how they expel waste.

One concept that links this module to the last (Diversity of Life I) is the idea that all cells/ organisms need nutrients and make waste. Let’s look at two types of heterotrophs, one from this module (animals) and one from last module (fungi). Both organisms must obtain their food from another source and cannot make their own food. Animals will consume/ take food into the body where digestive enzymes will break down the organic macromolecules which make up the food source into monomers inside the body and then transport the breakdown products to nourish the cells of the body (monomers that we have discussed: sugar, amino acids, etc.).

Fungi are also heterotrophs and unable to make their own food. Rather than ingest complex food molecules and digest within the body, they release digestive enzymes outside of the body and then absorb the broken down products. In both cases, the multicellular organism is breaking down a polymer and obtaining the nutrients (monomers) of the breakdown process. In one case, this is happening within the body and in the other outside of the body ¹ .