Biology Units of Study

Unit 1: Experimental Design 

Unit 2: Characteristics of Life and Classification 

Unit 3: Population Growth and Interactions

Unit 4: Evolution by Means of Natural Selection 

Unit 5: Growth and Reproduction 

Unit 6: Inheritance 

Unit 7: Energy

Biology Storyline

Storyline for a 10th grade modeling biology course

Students of a biology first course frequently arrive with little or no ability to create an experiment.  They can quote the steps of “The Scientific Method” but cannot communicate what they observe or suggest questions to test from those observations.  Because of this, we begin Modeling Biology by developing some skills in experimental design.  

In Unit 1, students observe sowbugs, goldfish, seeds, and brine shrimp in four separate activities.  They develop questions to test, collect, analyze and graph data as appropriate and discuss their findings during a whiteboard meeting.  At the end of this unit students are asked if the “things” they were observing are alive; if so, how do they know?  What criteria would they use to determine if “things” are alive? students first learn to distinguish living from nonliving things, and then are given a group of things and asked to use the established criteria to group the items into living and non-living groups. Next, they are introduced to a simple cellular model of life.  The existence of differences in the structure of these simple cells leads to the need for a system by which we can classify living things (taxonomy). The similarities and differences in structure and function are used to help students understand the diversity of life.  

In Unit 2, students start the unit with an exploration of isolated populations of Paramecium caudatum and Paramecium aurelia. They make a comparison of those populations with a mixed culture. Students then set off building a model regarding population growth, decline, and stability. They explore the interactions various groups of animals have with one another as well as their environments. 

In Unit 3, students are asked if the organisms alive today have always looked the same and if there were any organisms that might not exist on earth now.  Students are then asked what kind of factors might influence the variety of organisms. Since observing changes in a population is not feasible within the time constraints of a class, students perform a simulation in which they collect and analyze sample data, and report their findings in a whiteboard meeting.  Discussion leads to the development of a model of evolution through the process of natural selection.  The concepts of genetic drift, adaptations (physiological and behavioral), and sexual selection are also introduced.  Students are reminded that, despite the diversity in the appearance of organisms, all living things have similar needs; e.g., all organisms need to acquire and use energy.

In Unit 4, through shared observations (energy stations activity) students reach a consensus on a definition of energy.  The study of energy acquisition and use begins as a “zoom” journey from the ecosystem to the mitochondria1.  As they examine food chains and webs students notice that each organism serves as a food source.  They are then asked what is in food and an examination of organic macromolecules ensues.  As they continue to focus in on energy, students are asked how a food source becomes a macromolecule through digestion. Next, students trace the acquisition, transport, release, and elimination of the matter and energy in four different organisms (animals-earthworm, grasshopper, frog, and fetal pig). In the final steps of the journey, a fifth organism (fungi-yeast) is used to develop a model for cellular respiration. A sixth organism (plant-spinach) is used to develop a model for photosynthesis.  To summarize, students prepare whiteboards tracing the movement of matter and energy through each zoom level (ecosystem, organism and molecular) and discuss energy acquisition, storage and transfer at the various levels   Students are asked if organisms without complex systems (Kingdom Protista) have the same need to obtain, transport, release and eliminate matter and energy.  If so, how do they accomplish this?

In Unit 5, students observe single-celled organisms and determine that while they have “needs” like multicellular organisms, they do not have complex systems to address these needs. Instead, they must have smaller parts within the cell that carry out their life functions.  The question: “How are materials moved into/out of a cell?” leads to the development of a fluid mosaic model for a cell membrane that accounts for diffusion and homeostasis.  Examination of the question, “What other components make up a cell?” begins the development of a model of DNA that accounts for the synthesis of proteins. By studying the function of proteins within the cell and the role energy plays in homeostasis, students learn to describe how the cell functions as a unit. As a segue to Unit 6, students are asked what organisms do with the energy they acquire.

In Unit 6, students recall that one of the reasons organisms obtain energy is for growth. Students are asked “if you examine a plant, where would you find it to be growing?” After they decide that plants grow from tips of stems and roots, students observe the tips of onion roots and look for differences in the observed cells.  They determine that “growth” is actually accomplished by the reproduction of cells instead of cells simply getting bigger. The grouping of cells with similar structures (chromosome configurations) begins the development of the mitosis model. Manipulation of “popsicle” chromosomes helps to flesh out the concepts of independent assortment and segregation.  After first using mitosis to explain asexual reproduction, students extend the model to the manipulation of DNA in bacterial transformation and the discussion of cancer.  Students are then asked to review what they know about plant reproduction (they planted, pollinated and dried fast plant seeds during units 2-5).  Students are led, through classroom discourse and the use of the “popsicle” chromosomes, to the idea that the mitosis model will not work to explain what must happen to gametes during plant reproduction.  This discussion leads to the development of the model for meiosis.  Students are asked “Is plant reproduction asexual or sexual?” and “What is the evidence to support your answer?”

In Unit 7, students are asked to record observations of the germinated fast plant first generation (F1) seeds and whiteboard an explanation of the inheritance pattern they observed from the class data.  The question “How did the traits get passed from parent to offspring?” begins the treatment of the role meiosis plays in heredity.  Students extend the meiosis model by adding fast plant alleles to the chromosomes; by mating various combinations they develop the idea that outcomes of crosses can be predicted. Students continue to refine the model through activities and exercises that examine non-Mendelian inheritance and genetic disorders.

1 Showing the book “Zoom” by Istvan Banyai prior to beginning the energy activity sets up the discussion of examining processes at different levels. 

Biology Pacing Guide