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Measuring Biodiversity
Measuring Biodiversity

Learning Objectives

At the end of this lab, students should know...

What is biodiversity?

Biodiversity is defined as the variability among living organisms in an ecosystem.

What are alpha, beta, and gamma diversities?

Alpha-diversity (α) refers to the number of species in an area. Beta-diversity (β) compares two different areas and it is the sum of species unique to each area. Gamma-diversity (γ) is the number of species in many areas combined into a region.

What are the richness and evenness of an ecosystem?

The richness of an ecosystem is the total number of distinct species within a local community. Evenness refers to the equality of the proportion of each species within an area or community.

How do ecologists assess the species in an ecological system?

Ecologists use sampling tools called quadrats. A quadrat is simply a frame with a known internal area. They may also systematically sample by using transect tapes. Transects are stretched across the field. Then, quadrats are placed along the transect at regular intervals. This method is semi-random and ensures ample coverage of sampling across the entire field to estimate its biodiversity.

What are some of the reasons to maintain ecological diversity?

If species are lost, the ecosystem may collapse. If the ecosystem collapses, the services that it provides to humans will be lost as well. A highly diverse community is less likely to collapse due to functional redundancy. Moreover, a significant number of medicines that we now synthesize were once isolated from animals, plants, fungi, and bacteria, underscoring the importance of maintaining diversity of organisms for development of novel therapies.

List of Materials

  • Hula hoops
  • Rope (6x 20-feet long)
  • Small paper bags
  • Plastic beads (50x10 colors)
    5 sets

Lab Prep

  1. Quadrats and Transects Preparation
    • Start by tying a knot at the beginning, end and every 5 feet of six 20-foot pieces of rope.
    • Then, identify three outdoor areas near the classroom, each containing a variety of at least four plant species. NOTE: Surprisingly, grassy areas often contain at least four plant species. Although most plants in these areas will be of a single grass species, there are usually many weeds, such as clovers or dandelions mixed in. Therefore, a well-kept grassy area without shade, a well-kept grassy area with shade, for example under a tree, and a weedy field could be used for the three different habitats that they students will be moving between.
    • Place two ropes parallel to each other within each of the habitats. It does not matter which direction the ropes face as long as the entire length of rope is within each area and a hula hoop can be placed on either side of the ropes within the habitat.
    • Finally, back in the lab set out enough plant identification guides for each student group to have at least one.
    • Also set out enough hula hoops so that each group has one to use as a sampling quadrat.
  2. Diversity Lab Simulation Preparation
    • Before beginning the species accumulation curves and richness evenness activity, place 50 colored beads into one paper bag. The bag should contain 15 black beads, 10 purple beads, 8 red beads, 5 green beads, 3 blue beads, 3 yellow beads, 2 pink beads, 2 brown beads, 1 orange bead and 1 white bead.
    • Label this bag Community A.
    • Then, add five beads of each color to the second bag and mark this bag Community B.


JoVE Lab Lab: 21 Prep

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