Golden Rod Gall Size
|
|
|
|||
|
The article, Just lookin' for a home. Natural History, Sept, 1998 by Arthur E. Weis, Warren G. Abrahamson, is useful supplemental reading for this lab. Natural History magazine is not currently carrying the lab on it's web site but copies can be found at various library sites where you may or may not be able to get full text access due to copyright restrictions.
Abstract This investigation examines natural selection and coevolution using goldenrod (Solidago canadensis), its stem gall insect (Eurosta solidaginis), and associated parasites, parasitoids, and predators that feed upon the stem gall insect (i.e., Eurytoma obtusiventris, Eurytoma gigantea, Mordellistena unicolor, and birds). Through measurements of gall size and an investigation of events occurring within the galls, a correlation between gall size, frequency of predation, and type of predator can be made. An analysis of histograms and data tables charted from gall measurements and frequencies of various events leads to the conclusion that parasitic organisms select goldenrod galls within specific ranges of size. A statistical analysis using standard deviation and tests of reliability also lead to the conclusion that the forces of natural selection and coevolution are operating within this stem system. Appropriate Levels Concepts taught in this investigation are appropriate for all high school biology students. The main write-up is for Regents Biology. There is an extension for AP or Honors level students. There is also a version directed at general or school group students.
Time Required Three to five lab periods are required to describe the complex ecology under study, to learn to use the Vernier calipers, to measure the galls, and analyze the gall contents. Materials Special equipment needed:
|