Diversity of Life

How many types of living things are on the earth? How many different varieties of life-forms can we recognize as being fundamentally different from one another? How might we categorize different life forms? The purpose of this lab is to provide you some background knowledge and experience in exploring the diversity of life. There are two parts to this lab. First you are expected to learn about the different organisms. This may require research on your part. Second, you are expected to go into a non-human dominated landscape and look for organisms that fall into the different categories.

Part 1: Defining Terms


Species is a Latin word meaning “kind” or “appearance.” No doubt, we learn to distinguish among different types of plants and animals—between cats and dogs, for instance—by their appearance. Today biologists use many aspects other than an organism’s appearance to characterize species: body functions, biochemistry, behavior, and genetic make-up. As such there are many ways to define what a species is. The most common species concept is the “biological species concept.”

Lab Question

  1. Summarize what the biological species concept states about species.


Taxonomy is the identification and classification of species. The taxonomic system developed by Linnaeus in the eighteenth century is still used today. It has two main features. First, it assigned to each species a two-part Latin name. The first word of the name is the genus to which the species belongs. The second part of the name, the specific epithet, refers to one species within the genus. For example, humans are Homo sapiens while the black rat is Rattus rattus and the Norwegian rat is Rattus norvegicus. Notice each species has its own unique name, but the two rat species have a similar genus name. This means that the two rat species are in the same genus and suggests that they are more closely related to each other than either of them are to humans which are in a different genus.

The second component of the taxonomic system developed by Linnaeus was adopting a filing system for grouping species into a hierarchy of increasingly general categories. Taxonomists place related genera in the same family, groups of related families into orders, groups of related orders into classes, classes into phyla (phylum, singular), phyla into kingdoms, and kingdoms into domains.

Today we are going to focus on three of the four kingdoms in the domain Eukarya (organisms with nuclei): kingdom Plantae, kingdom Animalia, and kingdom Fungi.

Part 2: Kingdom Plantae

Plants are multi-cellular organisms composed of cells with cell walls (made of cellulose) and chloroplasts (organelles that convert solar energy into chemical energy).

Lab Question

Describe the characteristics of each of the four main categories of plants and give one example of each.

  1. Bryophytes
  2. Seedless vascular plants
  3. Gymnosperms
  4. Angiosperms

Part 3: Kindom Animalia

Animals are multi-cellular, heterotrophic (must get their nutrition from somewhere else) organisms whose cells are not surrounded by cell walls. All animals go through a blastula stage during development. A blastula is a hollow ball of cells.

There are at least 36 different animal phyla. Here we will only concentrate on some of the more common (or well known) phyla.

Lab Question

Describe the defining characteristics for each type of animal group below and give one example of each.

  1. Porifera
  2. Cnidaria
  3. Platyhelminthes
  4. Nemadota
  5. Annelida
  6. Mollusca
  7. Arthropoda
  8. Echinodermata
  9. Chordata

Part 4: Kindom Fungi

Fungi are primarily multi-cellular heterotrophic organisms that consist of slender tube like filaments called hyphae.

There are four main fungal phyla.

Lab Question

Describe the defining characteristics for each type of fungal group below and give one example of each.

  1. Basidiomycetes
  2. Ascomycetes
  3. Zygomycetes
  4. Cytrids

Part 5: Biodiversity Hike

The final part of this lab is designed to provide exposure to the wild diversity of living organisms in your own area. Your instructor might organize a field trip for this part of the lab. If there isn’t an organized field trip, you can complete this part on your own, in any non-human dominated landscape. Your assignment is to simply spend one or two hours exploring the environment, looking for different examples of living organisms we’ve studied. Use the table below to record what you find. (Printable version here.)

Date of hike: 



Table 1: Field Notes
Organism Description? Common or rare? General habitat? Phylum/Group? Common or scientific name?

Lab Questions

  1. Do you think your list is comprehensive? (In other words, do you think there were other critters living in the habitat that you did not see?) Explain.
  2. Why do YOU think biodiversity is important?