Chapter1: Mystery Fossil Lab

Introduction

The fossil seen to the right was discovered in China in 2004, and was radiometrically dated to 525 million years old – the Cambrian Period.  The organism was soft bodied and about 5-10cm-long (2-4 inches).  It had a flattened body and horizontal fins which researchers think, could have been used to support it as it moved along the sea floor. It also had well developed senses, including a pair of eyes on stalks.  This organism is clearly and animal, but it does not fit easily in any known phylum of animals (alive or extinct).

Task

Use the links given in the process section to examine each phylum of the animal kingdom, write down the basic characteristics of each phylum. Based on the characteristics required for each phylum, decide if that phylum is a good match for this fossil.  If there seems to be no good fit, you may decide that we need a brand new phylum just for this creature.  Finally, write a one page letter to the editor for a scientific journal that makes an argument for what phylum you feel this fossil should be placed in. You should have a topic sentence that presents a clear scientific opinion as to which phylum this fossil belongs to.  You should also provide at least three pieces of observable evidence to support your views.   Write in third person (no I’s, you’s, or we’s).  Also, don’t forget to draw all of your evidence together in some type of conclusion.

Process

1. Use the resources listed below to research each of the animal phylum and their characteristics. Divide them up among your teammates so that you work more efficiently.For each phylum develop a list of “must haves”.  These are things that an animal must have to be included in that phylum.Artistic Sketch of the Mystery Fossil

Wikipedia (Kingdom Animalia) (see the list of animal phylum on the lower right)

Encyclopedia of Life – Animal Phylum

2. Research the major animal phylum and think about what phylums this species may belong to. Specifically pick 4 or 5 phylum that are potential groups for this extinct species.    Come up with the basic requirements that a species must have to fit into that phylum.  Next, create a list of characteristics that our mystery fossil has.  Finally, compare the two lists.

3. At this point find another group or individual to share your ideas with.  Listen to their ideas.   Use what you learn and your lists of defining characteristics to determine the best fit for the mystery fossil – which phylum does it most likely belong to.

4. Individually, write a one page letter to the editor for a scientific journal.You should have a topic sentence that presents a clear scientific opinion as to which phylum this fossil belongs to.  You should also provide at least three pieces of observable evidence to support your views.   Write in third person (no I’s, you’s, or we’s).

5. Before you turn in your work make sure to read the evaluation section and make any corrections or improvements you need to get a perfect score. Proofread closely.

Evaluation

Beginning

Developing

Accomplished

Score

Hypothesis

Letter lacks a clear topic sentence or fails to state a hypothesis about which phylum the mystery fossil belongs to. Letter includes a hypothesis but it lacks clarity or  it is illogical based on the characteristics of the  fossil or phylum described. Letter contains a clear topic sentence, expressing a logical hypothesis on which phylum the mystery fossil belongs to. /10

Factual Supports

Letter does not contain any factual supports for the group’s hypothesis,or  the supports are not based on any logical or observable characteristics of the mystery fossil. Letter contains one or two factual supports for the group’s hypothesis, or some of the supports mentioned do not match the phylum mentioned or are not based on observable characteristics of the mystery fossil. Letter contains at least three factual supports for the group’s hypothesis, based on observable characteristics of the mystery fossil and known characteristics of established animal phylum. /10

Fluency

Letter is no clear, it is disorganized, or it makes frequent use of first person words like I or we or you.  Letter lacks any vocabulary appropriate for biological classification. Letter is clear, and coherent, but it fails to use specific vocabulary appropriate to biological classification or it includes first person words like I or we or you. Letter is clear, and coherent, it uses vocabulary appropriate to biological classification and it is written in third person. /10

Conclusions

Biological classification, like all science, goes through a constant process of revision.  As new data becomes available we must revise our hypotheses.  When radically new fossils are discovered it is sometimes necessary to redefine taxonomic groups or create new ones.  There is not a right answer to this problem, but there are definitely better answers.  The idea from this webquest, the description of the fossil as well as pictures of the fossil came from an article from BBC NEWS –  Strange fossil defies grouping by Julianna Kettlewell.

 

Bonus Assignment Follow Up

Mystery Fossil #2

Artistic Rendering of Fossil #2

Animation of the fossil)
from: Gizmodo.com

The fossil above, also found in China as part of a Burgess Shale deposit.   The fossil is a 0.5—3.5 cm long tubular organism with seven or eight pairs of slender legs, each terminating with a pair of claws. Above each leg is a rigid conical spine. The ‘head’ and ‘tail’ end of the organism are difficult to identify; one end extends some distance beyond the legs and often droops down as if to reach the floor. Although some specimens display traces of a gut, the internal anatomy has not been formally described.

For ten bonus points, follow the procedures above and write a one page argument for what animal phylum mystery fossil #2 belongs to.