In the first part of this lab we will be modeling selection on a population of birds (predators) and insects (prey) in their natural environment. This environment can change drastically depending on the amount of rainfall they get in any given season. 

There are four different insect types, each with a specifically different color:

• Beanus blackialis with its distinct black color

• Beanus mottlopia with its distinct mottled or brown with white spots color

• Beanus greenilia with its distinct green color

• Beanus whitolia with its distinct white color

There are also four different bird types, each with a specifically different beak structure:

• Forcepoides tweezeralis with its distinct tweezer-like structure

• Forcepoides flatalia with its distinct flat and straight structure

• Plierpoides needlesis with its distinct strong needle nose structure

• Plierpoides bluntilias with its distinct strong blunt structure

In this section of the laboratory, we will determine if the predators, environment, or an interaction of the two can change the distribution of the insect population in their environment. We will start by breaking up into groups of four.  Once the groups have been established I will set up the environment and assign you your beak type (in this lab I play the role of the Great Omnipotent Dictator or "GOD" for short). Each group will then count out 50 of each type of bean and give them to GOD. GOD will mix them in a large cup and distribute them over the environment. One member from each team will serve as the first predator and take a side along one side of the environmental square. With your "beak" and cup your duty is to collect as many "insects" as you can in one minute. All predators will "feed" at the same time on my command. Predators must cleanly lift the insect and place them in their cups. No scooping of insects is allowed.  Each minute of feeding will equate to one year of natural feeding. At the end of the minute, each team will need to calculate the number and type of "kills" they got from that round. These values will be listed on the table up on the board and in your lab tables below. "T" stands for Total insects started with, "K" stands for number killed, and "S" stands for the number of survivors, "O" stands for off-spring. We will then calculate the number of each type of insect left in our environment and allow every two to have 1 offspring. Once this value is calculated we need to count that many beans and add them to the environment. In the first round, each predator will be allowed to have one offspring.

For example:

All groups count out 50 of each bean. If your group "killed" 10 black beans, then you put a "10" under the "K" column. They subtract the "K" value from the "T" value to get the "S" value or number of survivors. Now every 2 survivors gets to have 1 off-spring, so divide the S value by 2 to get the "O" value or number of offspring. Now add the "S" and "O" values together to get the "T" value for the next year. Once this is done, start counting out 60 beans to give to GOD, and so on.

This process will continue for four rounds or four years of natural selection. At the end of the four rounds we will clean up and calculate the results. Each of you will need to have the results from all of the groups. As a laboratory homework assignment, I want each person to generate a graph or graphs that represents the data and a one-page typed summary of the results of this exercise. The graphs can be based on any predator, any prey, or any combination of the two. Your write-up should discuss which specific predators and prey did better or worse and explain why this occurred the way it did. This write-up will be due at the beginning of the next lab.  Happy hunting.

Predator: Forcepoides tweezeralis

Predator: Forcepoides flatalia

Predator: Plierpoides needlesis

Predator: Plierpoides bluntilias

Understand the basic concepts of Macroevolution or how life began on earth.

In the second section of the laboratory, we will be watching a video on Macroevolution. At the end of the video we will discuss the video as a class.

rmorrissette@palomar.edu