What would happen if a species within a population were suddenly split into 2 groups by an earthquake creating a physical barrier like a canyon?
For this assignment, you are asked to answer this question.
What would happen if a species within a population were suddenly split into 2 groups by an earthquake that creates a physical barrier like a canyon?
I would like you to consider the question this way instead to better focus the project:
What would happen if a species of lizards were suddenly split into 2 groups by a hurricane, resulting in isolation a small group of individuals on an island far from the mainland?
Although this would be a relatively easy essay to write, you are asked to present the information as a lab report. This means you will design an experiment to test a hypothesis about speciation.
I would suggest that the easiest approach is to follow the changes in the lizards you see in the animation as the two populations become divided and then differentiate depending on the conditions in the new environment. Since you need to write this up as a lab report, you need to define an experiment.
That means you need include some observation about the species before the earthquake event (or the hurricane or flood that relocated our lizards) that separates the species into two groups, and further observation several years (or generations) after the isolation event.
What we need to consider here are the environmental conditions that lead to the change in the color of the lizards in the isolated population. This is where you will need to do a little research and some critical thinking. The lizards on the mainland are red.
They must be red for a reason that allows them to best adapted to their environment. Perhaps the soil is reddish, or perhaps the bark of trees or leaves is red, maybe there is another species of poisonous lizard that is red and our lizards mimic those. For help with these ideas look natural selection (see the section from this website on the corn snakes for info on how coloration is linked to adaptation:
http://www.realscienceprograms.com/files/webpages/cbkssprogramcontent.htm) or read about the Evolution of White Lizards at White Sands from here: http://www.nps.gov/whsa/naturescience/reptile-research.htm (choose the second pdf on the list The Evolution of White Lizards at White Sands.) mimicry is a more abstract concept, but if you are up for it, check out this description: up mimicry (http://relivearth.com/articles/nature-facts-articles/expert-mimics-in-reptile-world/).
On this website you will find a terrific description of an experiment actually performed with anole lizards that demonstrates how researchers would design and perform an experiment to test speciation and natural selection in anoles: http://www.livescience.com/18276-lizards-show-evolution.html. Likewise the description of the evolution of White Lizards at White Sands shows how researchers collect the data to study speciation and natural selection in lesser earless lizards.
Here is a copy of the instructions given to you in the lab worksheet. I have added tips, explanations and recommendations in blue.
State the purpose of the lab.
This will be one or two sentences focusing on determining if speciation occurred as a result of geographical isolation.
This is an investigation of what is currently known about the question being asked. Use background information from credible references to write a short summary about concepts in the lab. List and cite references in APA style.
Your introduction needs to describe the topic to your reader and explain the rationale behind doing the study.
Describe the scenario with the lizards. Include information about the habitat differences between the mainland and island environments that would impact adaption.
Be sure to include some background information on the topic of speciation. Here is an excellent explanation of speciation: http://evolution.berkeley.edu/evosite/evo101/VBDefiningSpeciation.shtml
A hypothesis is an educated guess. Based on what you have learned and written about in the Introduction, state what you expect to be the results of the lab procedures.
Make one sentence that can be shown to be true or false based on the results of your test. This will focus on the topic of speciation in general or on the organism you have chosen.
Geographic isolation results in speciation.
Environmental conditions lead to natural selection of coloration in lizards.
Summarize the procedures that you used in the lab. The Methods section should also state clearly how data (numbers) were collected during the lab; this will be reported in the Results/Outcome section.
This section should include the geologic event that separates the species, and the types of observations you would make. (For example, you would need to observe the soil types, foliage types, other lizard species, predators and most importantly coloration of the lizards in both areas. Then describe how you would do this. For example, to determine coloration on the lizards you may have to catch them, make your observations, then tag them and release them (so you do not count them twice). Pretend you are the researcher!
Provide here any results or data that were generated while doing the lab procedure.
Describe the characteristics of the two environments.
Explain changes to the two populations. Include measurements or numbers if you would like.
You could easily make a table such as this:
In this section, state clearly whether you obtained the expected results, and if the outcome was as expected.
Note: You can use the lab data to help you discuss the results and what you learned.
Summarize the results.
Explain how your results apply to the original question of what happens to a species separated by a geologic event that results in isolation of two groups. Here is where you apply the critical thinking and your research into natural selection, speciation and/or mimicry from the introduction to the question.
Include a statement that you accept or reject your hypothesis. Explain why.
Provide references in APA format. This includes a reference list and in-text citations for references used in the Introduction section.
If you would like to work from these notes, I have added this annotated worksheet to the instructor files for you.