Raising Awareness of Botany through Forensic Analysis in the Laboratory

Bobak D. Kechavarzi* and Darrin L. RubinoBiology Department, Hanover College, Hanover, IN 47243

AbstractAbstractIn Biological education, particular fields are often underappreciated. By designing a cost-effective laboratory exercise, we present an opportunity for students at the introductory level of biology to gain further insights into various botanical topics. By utilizing the field of forensics, made popular by recent media, we have created a lab exercise to actively engage the student’s ability to critically analyze data and generate informed conclusions. Students are presented with a police report, description of the crime scene, and other botanical evidence. Evidence includes simulated stomach contents, photos of the crime scene, and swabs of clothing. Participating in the investigation familiarizes students with fruits, flowers, seeds, and plant tissues. A key feature of this design is low cost and reliance on few instruments outside of a common compound microscope. This lab is well suited for high school and introductory level classes.

Introduction•Plant blindness

•Botany is often overlooked and underappreciated•Biology teaching often largely focused on animals and humans•Misconception that botany is unimportant and boring•Illustrates viable utilization and development of botanical knowledge

•Forensics•Forensics is extremely popular•Engages students critical thinking skills•Great lure for student curiosity

Methods and Materials•Devoted two, 2 hour lab periods

•Lab 1: Basic microscopy and botanical skills•Introduction to basic plant anatomy

•Parenchyma•Schlerenchyma•Vacuoles•Plastids

•Examine student made preparations of tissues•Students made drawings of observations for use during later labs

•Lab 2: Crime scene investigation and application of skills

•Students presented with botanical evidence in phases (see sheets)

•Part 1: Crime scene photos, crime scene report, introduction to characters, case information part 1, stomach contents•Stomach contents challenged students to use microscope and slide preparation skills•Essential for cracking the case

•Conclusions made after each investigative phase

Goal: Development of new botanical lab experience

•Utilize forensics to get students excited about botany•Simultaneously develop students microscopy skills, botanical knowledge, and reasoning skills

Results•Stomach content components were easy to identify, but still engaged and challenged students microscopy skills

•Blueberry seeds easy to distinguish from other “ingested” seeds•Pear sclerids were identifiable•Tomato skin

•Scenario structure was logical and complete while still requiring student deduction

•Removal treatment study•Mean species richness

•Over a ten-fold range in richness among treatments•Pulling and raking led to the highest richness

•Mean periwinkle cover•Highest in raking, weed whacking, and control•Tarp, herbicide, herbicide+rake, and non invaded all simila

AcknowledgementsThe authors would like to thank Cliff Chapman, Ellen Herrenbruck, and the Hanover College Biology Department, STAR Grant Program, and Faculty Development Committee

Discussion•Herbicide application (as low as 1% glyphosate) leads to “brown out;” however, the mat of dead periwinkle may limit light at the soil’s surface•Methods causing scarification (raking, weed whacking, pulling) appear to increase species richness at least in the short term•Efficacy of tarp treatment on species richness and periwinkle cover will be determined in year two

•Recommendations•Best eradication technique must weigh several factors•Considering time for application, impact on species richness, and lack of reinvasion, spraying with 1% glyphosate (with adjuvant) appears to be the best treatment technique •Abandon weed whacking as a viable method

•Future work•Seed bank analysis•Track plots for many years•Analyze the amount of herbicide needed for eradication•Determine best long-term eradication method

Methods and Materials•Part 2: A break in the case!

•Stomach content analysis only provides insight to possible perpetrator not to solving the case•Additional case information is provided•New botanical evidence is provided requiring pollen analysis•Case is concluded with students deductions

•Laboratory components included the following:

•Write up of crime scene description, testimonies of individuals, overall scenario and description of events•Photos of crime scene and victim

•All of above items provided•Simulated stomach contents containing:

•Blueberries•Pears•Tomato•Popped popcorn

•Two flowers: Asiatic lily and alstroemeria •Pollen stained items: blue jeans and comforter