Food Webs

Trophic cascades, food web theory, and the keystone species concept are illustrated by connecting thestudents themselves into a food web. Each student represents a species in a given trophic level, and a ball of yarn is passed through the levels to represent the flow of energy through that system. System stability and the role of specifically local species in the under-studied, Missouri glade habitat, introduce the students to the species that exist, and are restricted to, the threatened prairie glades. There is ample time for discussion and pre- and post-food web activity about related topics.

Food_Webs.doc


Fossil Formation

Students will learn about the Law of Superposition and create their own stratigraphic columns using sand, salt, soil, and gummy bears. They will use what they learn from this activity to interpret fossil evidence from the horse and its ancestors. There are 2 different worksheets for different level students.

Fossil_Formation_TeacherHandout.docx


Homology of Forelimbs

Students will learn what homologous structures are by studying the forelimbs of various animals.Using sample, safe dissection tools, students will dissect a chicken wing that has been bleached overnight. Students will determine if the chicken wing is homologous to the forelimbs of other animals by examining and sketching the wing's underlying bone structure. Specifically, students are asked to identify the humerus, radius, and ulna of the chicken wing and compare it to pictures of homologous bone structures from whales, frogs, horses, lions, humans, and bats. In discussion, students are asked how these structures are similar and different, whether these structures are homologous in structure and/or function, and how homology is evidence for evolution.

Homology_of_Forelimbs.doc


Island Biogeography

The theory of Island Biogeography examines the factors that affect species richness, or species numbers,in isolated communities. The main principles of island biogeography, which we cover in this module, tie into important themes in ecology, evolution, and conservation. In this module, the students are actively engaged in an exercise of island colonization, with the students themselves representing species colonizing islands made by circular ropes. These concepts are used to explain numbers of species on any isolated habitat surrounded by unlike habitat, including mountaintops surrounded by lowlands, ponds surrounded by terrestrial communities, organisms themselves as islands colonized by parasites, and fragmented forest surrounded by farmland. At the end of the module, we tie previously covered concepts into broader environmental issues, such as species diversity in a fragmented landscape and how to conserve species across a network of protected reserves.

Island_Biogeography_TeacherHandout.docx


Missouri Botanical Gardens Tour

Embracing experiential learning, we tour the Missouri Botanical Climatron, the dome-shaped building housing nearly 3,000 exotic plant species. This is a unique opportunity to explore a tropical ecosystem within our very own St. Louis. Students attend each of four "learning stations" strategically placed around the Climatron. These include: (1) Evolution of Plants, (2) Adaptations, (3) Leaves and Flowers, and (4) Growth and Forms. Multiple instructors allow small groups of students to explore topics hands-on. Rather than lecturing, we use the life forms around us to cover topics such as the transition from ancient to modern plants, plant classification, how plants use resourses and the wide variety of familiar edibles. We also cover pollination, reproduction, and the basics of photosynthesis and cellular respiration. We recommend spending a three-hour period at Missouri Botanical Garden in order for us to best accommodate your students. We also strongly recommend planning this trip on a Wednesday or Saturday morning, since Garden admission is free those days. We suggest a 9-12 visit on either Wednesday or Saturday; packed or purchased lunches can be eaten after in Sassafras Cafe.

Climatron_Tour_TeacherHandout.docx


Our Adaptive Hands

First, demo instructors will discuss with students what an adaptation is, and how it differs from acclimation. With a partner, students will then learn why the human thumb is adaptive by timing how long it takes them to do a series of activities 1) while their thumbs are free and 2) while their thumbs are taped to their hands. Students will then switch roles and repeat the activities so that both students are able to try the activities. At the end of the activity, students are asked to chart the time that it took them to do the activities with and without thumbs. Discussion with demo instructors at the end may include a class comparison of timed activities, as well as a period of hypothesis-testing where students are encouraged to go around the room and test whether they can do activities without thumbs as easily as with thumbs free.

Our_Adaptive_Hands.pdf


Rope of Life

Just how old is the Earth? Students learn to think in terms of evolutionary time scales by retracing key events in the history of our planet along the Rope of Life. A rope with lines on it marking millions of years is laid out around the room, and students place note cards along the rope to guess when they think particular events occurred, such as the appearance of land plants, and the appearance of mammals. Then students will be given a new set of cards with the actual dates of the events, and will place them in the correct order. As a group, we will discuss with the students which events they had originally guessed correctly and what they were surprised about.

Rope_of_Life.doc


Ecological Interactions

The main concepts of this module are to describe the difference between mutualism, parasitism, and competition; to explain why no two species can occupy the same niche in a community; and to predict what could happen if an invasive species is introduced into an ecosystem. Students will be introduced to basic vocabulary about ecological relationships (symbiosis, mutualism, competition, parasitism, commensalism, generalists, and specialists). Then students will be split up into groups of three to do an activity that simulates these different relationships. Each student will represent a different species competing for limited food. Between rounds, students will count how much food they collected and answer questions about the various ecological interactions. After the game, students will work individuals to analyze two graphs and a cartoon.

Ecological_Interactions_TeacherHandout.doc


Natural Selection

Students will be introduced to the concepts of genetic variation and natural selection by filling out a worksheet during a class discussion. Then they will break into small groups to simulate natural selection acting on a population of black and white peppered moths in two different environments. Students will have 10 seconds to pick up as many black and white circles as they can from a piece of black construction paper. Then they will count how many of each color they caught. They will repeat activity against a white background and see which color moth will increase in frequency.

Natural_Selection_TeacherHandout.doc