Interpreting Fossil Assemblages
Summary
This assignment is a synthesis of many of the skills learned throughout the course from taxonomic identification to paleoecological interpretations.
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Context
Audience
This is an upper level majors course with a sed/strat prerequisite
Skills and concepts that students must have mastered
This is the last lab assigned in the course so students should be able to identify fossils to the generic level using appropriate resources, determine age ranges, interpret lithology, taphonomic grade, and paleoecological implications of a community assemblage.
How the activity is situated in the course
This is the culminating lab assignment.
Goals
Content/concepts goals for this activity
The goal of this assignment is to give students the opportunity to synthesize many of the skills they have used independently in individual lab exercises and make interpretations of depositional settings and paleocommunities.
Higher order thinking skills goals for this activity
This requries detailed observation and synthesizing a number of different lines of data that they may not have seen together before. I am also fairly hands off on this assignment-available for questions, certainly-but I try and make it self guided. They have to approach a sample and figure out what to do with it.
Other skills goals for this activity
Identifying many of these organisms to the lowest taxonomic level possible requires the use of a range of different resources for which they must know how to work their way around.
Description of the activity/assignment
Students are provided several fossiliferous samples to analyze in detail. I provide more than they need to snalyze so everyone in the class can be working. I give a range of specimens of different geologic ages, diversities, abundances, taxonomic compositions, depositional environments and taphonomic grades. The goal is for the students to identify all of the different fossil types to the lowest taxonomic level. I provide some that are well preserved and some that are highly fragmented making identification difficult. Next, students are tasked with assigning an age range of the sample by combining the age ranges of individual taxa, and make taphonomic descriptions and paleoecological analyses.
Determining whether students have met the goals
Their grade is largely based on how well they can recognize all of the data available from each individual specimen. They are also expected to recognize the variability between samples. Interpretations that are consistent with the data provided are considered appropriate.
More information about assessment tools and techniques.Teaching materials and tips
- Activity Description/Assignment: Interpretation of Fossil Assemblages (Microsoft Word 2007 (.docx) 115kB Aug2 09)
- Instructor information for Interpreting Fossil Assemblages: I really want them to be able to recognize the limitations of the fossil record as well as the richness of information available from fossils. To this end I try to highlight the variability in the fossil record. You can choose any type of sample you like, but I like to use a range (some well preserved, some poorly preserved, some high diversity, some low diversity, some high energy, some low energy, some straightforward, some more tricky). Although I have abundant Ordovician and Devonian samples, I would ideally like to use samples from a range of time intervals. Students at the end of a paleontology course should be able to estimate the relative age of a fossiliferous sample, and then support it in the literature.
I provided 6 samples and had them complete descriptions for any 5 they liked because there were only 5 students the last time I ran this exercise. You can provide more to accommodate more students or to make it more comprehensive, but I found a lot of time is spent pouring over the treatise to identify the taxa, so you might want to make this a more than one lab period exercise. They end up spending a lot of time outside of lab (which I think is fine for a final lab assignment), but know that they need access to samples.
For the final assessment where they are called upon to defend their interpretation against my questions such as:
- How did you decide what species-what characters?
- How do you know it is shallow, deep, etc. ?
- What does your diversity data tell you?
- How would you change your interpretations if the surrounding lithology were different?
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