9/29 Biodiversity Lab AP - Ryan Beeler | Library

Healthy ecosystems, such as a salt marsh, temperate forest, and tropical rainforests, are complex webs of living and nonliving elements. An important measure of an ecosystem’s health is its biodiversity. The term "biodiversity" is defined in diverse ways. It may be "all living things within a given geographical area and the interrelationships among them (Audesirk & Audesirk 1996). E.O. Wilson - a brilliant man with a lot to say about diversity calls it "all of the variety of life - from the different genes at the same chromosome position within populations, up through different species of organisms, on up to different aggregations of species in ecosystems." Familiarity with the term has increased in the last couple of decades as extinction rates, driven by human activities, have reached a crisis level.

For our purposes, we will define and use this biodiversity definition. “Biodiversity is the variety of life that occurs within an ecosystem (commit this to memory)”. A population is "a group of one species that live in a particular geographic area (Campbell's, 1996)". Although it is important to view life at all structural levels, many ecologists use the "species" level of taxa (short for taxonomy) to determine the biodiversity of the system being studied. Two simple methods for describing the biodiversity are richness and abundance. Richness is defined as "the number of unique taxa (species/organisms) present". It does not give you an indication of how the population (# of each species) is distributed. In other words, a system with 100 grackles, 1 red-wing blackbird, and 1 American crow has the same biodiversity (richness value 3) as a system with 34 grackles, 34 red-wing blackbirds, and 34 American crows. Abundance (sometimes called "relative abundance") is "the number of individuals present in each taxonomic group relative to the total number of individuals" (# of individuals in each taxonomic group, population/total # of individuals from all taxonomic groups being studied X 100). It is expressed in percent. For example: # of red wing blackbirds/total # of birds in the study area X 100. Okay, lets practice.

You are Bean Counters (actually, you are ecologists studying the biodiversity in the
ecosystem defined by the volume of a cup called "bean world")

Types of beans:
Red bean
Black bean
Lentils (small flat brown circles)
Blackeye Peas
Rice
Green Peas
White Beans

Materials
Cup / Beaker (This captures a sample from the ecosystems you will observe.)
A sample of organisms from one of the ecosystems (cup A, cup B, cup C, or cup D)
The ability to count beyond 10 without your fingers.

Procedure
1. Pour (capture) beans (~30) from the ecosystem (cup)
2. Record the cup: A, B, C, or D, you took beans from (return beans to the same cup when you are done counting).
3. Record the type of beans/unique taxa and the number of individuals in each taxonomic group in table 1.
4. Calculate the total number of individuals (beans) in the community
5. What is the richness of your community?
6. Calculate the relative abundance of each taxonomic group
# of individuals in each taxonomic group / Total # of individuals in the community X 100 OR
# of individuals for each type of bean /Total # of beans X 100
7. Graph relative abundance
8. Return beans to correct cup (to live happily ever after)
9. Repeat the process with another community (cup) X 2
10. Answer questions

1

Record your data here for the first community.

1

Record your data here for the second community.

1

Record your data here for the third community.

1

Graph the first community's relative abundance.

1

Graph the second community's relative abundance.

1

Graph the third community's relative abundance.

1

Which community has the greatest richness?

1

Which bean taxa has the greatest relative abundance in each community?

1

Which bean taxa is most likely to become extinct?

1

Why? (okay, we all know the beans are safe in the cup - pretend they are subject to the forces of natural selection and the negative consequences of human activities)

1

Which community has the greatest biodiversity?

1

Why? Use richness, abundance to support your answer.

1

Urbanization is the process by which humans occupy and modify ecosystems. It is a matter of degrees, with densely populated areas representing one end of the spectrum and wilderness areas representing the other (such as Houston versus a nature preserve). How does urbanization effect habitat quality and quantity?