Category: Lecture

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Science or Not Lecture Notes and Sample Class Activities

Lecture overview

This module introduces students to scientific inquiry and data-driven thinking. Working in small groups, students evaluate various claims about things that are “scientifically proven”. They create a hypothesis and design an experiment to test these claims. Students also 1) evaluate instances in which observational experiments are necessary, 2) construct a graph from a data set, and 3) draw conclusions from the data set.

Inquiry Learning Outcomes

At the end of this module, students will be able to:

  1. Distinguish among ideas that can and cannot be tested by science; evaluate statements and determine which are scientific or and which are not scientific.
  2. Create and defend a scientific argument by identifying and evaluating valid sources of scientific evidence.
  3. Distinguish among the scientific terms: theory, hypothesis, and prediction.
  4. Construct hypotheses to explain biological phenomena:
    1. Propose hypotheses that are appropriate to the given scenario or question.
    2. Evaluate several hypotheses to select the one which best explains observations, or is best supported by data.
    3. Predict what would be most likely to occur under given experimental conditions in a test of a specific hypothesis, and justify predictions using biological concepts.
  5. Design experiments to test biological hypotheses:
    1. Identify the dependent and independent variables, and control and experimental treatments in any experiment.
    2. Identify situations in which no “control treatment” is appropriate, and design an experiment where subjects are tested more than once or the experimental treatment levels take a wide range of values.
    3. Justify the steps and procedures for an experiment.
  6. Create graphs from a data set.
    1. Decide what type of graph is the most appropriate type to display a data set.
    2. Decide to which axis each variable should be assigned in order to represent a specific hypothesis properly.
  7. Use experimental results to support or refute a hypothesis:
    1. Interpret graphs and/or raw data with respect to a hypothesis
    2. Distinguish correlation from causation, and correctly attribute phenomena to biological mechanisms.
    3. Demonstrate how to distinguish observations/data resulting from a specific cause from those caused by random chance.
    4. Explain why experimental evidence may lead to multiple interpretations, and propose ways to address this limitation (e.g., many samples should be taken, many related experiments should be performed).
  8. Interpret and communicate scientific ideas effectively
    1. Use the conventions of scientific writing, including images and graphs, e.g. in laboratory reports.
    2. Interpret and paraphrase information from valid sources, such as the textbook and the primary literature.
  9. Explain why hypotheses and even theories may be subject to revision.

Sample Class Activities

  1. Students examine a claim that is “scientifically proven”. Some examples are provided (see below), but students can also search for other claims. These claims can be used to generate class discussion about science v/s not science, where scientific information can be found, and the importance of evidence. (Inquiry 1, Inquiry 2, Inquiry 3)
  2. Students propose a hypothesis and design an experiment to test their “claim”.  Discussion of good hypotheses and experimental design can be generated by comparing hypotheses and experimental design amongst different students/groups. (Inquiry 4, Inquiry 5)
  3. Students consider an experiment on the effects of class attendance to performance in a class. This activity allows students the opportunity to compare controlled experiments to observational experiments. (Inquiry 5)
  4. Students construct a graph from hypothetical class attendance v/s class performance data.  Discussion of appropriate graph type and format can be generated by comparing graphs amongst different students/groups. (Inquiry 6)
  5. Students generate a figure caption for the graph and draw conclusions. This is a good opportunity for discussion about correlation v/s causation, multiple interpretations of data, and revision of conclusions. (Inquiry 7, Inquiry 8, Inquiry 9)
  6. Some clicker questions are provided, which can be interspersed throughout the module or given at the end as a quiz:

Access the slides here

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Sea to Shore Lecture Notes and Sample Class Activities

Students are introduced to the characteristics of life, including organization, biochemistry, and homeostasis.

There are several possible options for how to present the topics.

  1. Start with the question “Are we alone in the universe, and how will we identify life if we find it?” To begin to figure this out, we should understand the properties of life, and how it arose on earth (Topics: Life, Chemistry, Cell). The importance of water as the solvent in which life originated motivates an exploration of the range of precipitation and temperature conditions of different environments (biomes). This leads to an investigation of how life works, especially how structure relates to function across a range of conditions (Topics:  SA/V, Gradients, Membrane Transport, Thermoregulation, Osmoregulation).

 

  1. Start with the question “Is there life on Mars?” Use the question “Why is water so important in the search for signs of life on Mars?” to motivate an exploration of “Why is liquid water so important for life?” (Topics:  Life, Chemistry). A study of the Miller-Urey experiment can be used to introduce or review the elements of experimental design. From macromolecules, transition to cell structure (which are made of macromolecules; Topic: Cell). Tie back to life on Mars – “If humans visit Mars, what would we need to survive?” (Topics:  SA/V, Gradients, Membrane Transport, Thermoregulation, Osmoregulation).
  2. Start with images of terrestrial (cold vs. hot) and aquatic (fresh vs. salt? tropical vs. polar?) animals from contrasting environments. What traits do they have, and why? Differences between the pairs motivate study of homeostasis (Topics:  SA/V, Gradients, Membrane Transport, Thermoregulation, Osmoregulation). The characteristics in common lead to an exploration of the traits that are necessary for life (Topics: Life, Cell, Chemistry).

Sample Class Activities

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Identify traits of living things

Objectives:  Life 1, Life 2, Life 3; Inquiry 5, Inquiry 6, Inquiry 7

  1. Students work in teams to generate a list of traits shared by living things. Using an image of a mystery object in a box is a helpful prompt. The instructor then validates and formalizes the list to summarize the characteristics of life. (Life 1, Life 2, Life 3)

  1. Apply the list that was generated to evaluate if certain things (fire, seeds, food, amoeba, etc.) are living or not. Focus on carbon dioxide production (respiration) as a characteristic of a living thing (Life 2). Students design an experiment to determine if an item (e.g., popcorn kernels) is alive. A setup with a Vernier CO2 probe could be used in the classroom and data collected for 24 hours (minimum), or the data can be provided (Inquiry 5). Graphs can be drawn as an in class or homework assignment, or provided for interpretation (Inquiry 6, Inquiry 7). An alternate hypothesis could also be explored (that something microscopic on the item in question is alive and produces carbon dioxide), and additional experiment(s) designed to test the alternate hypothesis (Inquiry 5).

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Chemistry of life

Objectives:  Chemistry 1, Chemistry 2, Chemistry 3, Chemistry 4, Chemistry 5

  1. After a short lecture or assigned reading on macromolecules, student groups match macromolecules to these cellular functions: 
    • Hormones,
    • Energy storage,
    • Store and use genetic information,
    • Provide waterproofing,
    • Structural support,
    • Control activities of life (e.g., catalyze reactions),
    • Allows cell membranes to be selectively permeable.

Clicker questions could be used to collect student answers. Note that students often have difficulty with matching when there is not one-to-one correspondence (e.g., more than one macromolecule has more than one function). (Chemistry 2)

  1. After introducing students to macromolecules and their roles in the cell, engage students with one or more of the case studies listed below.
    • Chemistry and Macromolecules – A Curious Mission: An Analysis of Martian Molecules – In this case study, students play the role of a NASA scientist tasked with analyzing samples of atmosphere and soil collected on Mars as part of the Mars Curiosity Mission. The case study takes place in the future when samples of the Martian atmosphere and surface have been returned to Earth as part of the fictional Curiosity Mission 5. (Chemistry 1-4) 
    • Chemistry and Macromolecules: Rough Games and the Brain – investigates the role of chemical bonds, polarity, and protein structure in head injuries and concussions. (Chemistry 1-5) 
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Cell structure

Outcomes: Cell 1, Cell 2, Cell 3, Cell 4, Cell 5

  1. Water and macromolecules are needed to form cells. In small groups, students draw a typical cell from memory, including drawing and labeling all the organelles that they can. They will probably draw eukaryotic (animal) cells. If each student makes a copy, corrections and additions can be completed using textbook or other resources as an in class or homework assignment (Cell 1)
  2. Prepare several “decks” of laminated cards with an illustration of an organelle on each card for use by student teams. The image library from your text is a good source for these illustrations. Ensure that there is a card for organelles and structures from every kingdom in each deck. An example set is provided below. Ask students to come up with different systems of organizing the cards. In our experience, students will sort by clade, by structure, and by function. Students could also work in teams sorting the organelle card decks to evaluate and identify only the organelles directly involved in specific cellular functions (i.e. protein secretion, lipid production and storage). This activity could also be run “backwards” so that students are given a specific set of organelle cards representing the structure of an unknown cell with the task of determining the cell’s function. (Cell 1, Cell 2, Cell 3, Cell 4, Cell 5)

Download the cards here

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Gradients and Membrane Transport

Outcomes:  Gradients 2, Gradients 3, Gradients 4; Membrane Transport 2, Membrane Transport 3, Membrane Transport 4, Membrane Transport 5; Thermoregulation 7

Prerequisite objective:  Membrane Transport 1

  1. Ask students to work in groups to complete a table to compare and contrast modes of transport. (Membrane Transport 2)
Diffusion Facilitated diffusion Active transport
Description Passive movement of… Passive movement of… Active movement of…
Are proteins involved? (yes/no) No

Follow up with clicker questions on how gradients relate to membrane transport. (Gradients 3, Gradients 4, Membrane Transport 3, Membrane Transport 5)

  1. (Gradients 4, Membrane Transport 5) Show an image of the activity at a cell membrane, that demonstrates that there are lots of materials moving in and out of cells (see example below). Ask students to brainstorm for 3 minutes about factors that can affect how quickly this transport occurs. In our experience, the list often contains factors such as:  temperature, membrane permeability, size of chemical gradient, and sometimes cell shape. Formalize the role of cell shape with the concept of surface area-to-volume ratio. Most cells are very small to maintain high SA/V, facilitating an optimal rate of material movement. Learn.Genetics has a great demonstration of cell size and scale here. Students may or may not have identified temperature as a factor with enzymes in mind. This is also a good opportunity to address Thermoregulation 7:  enzymes work best at a narrow temperature range.

 

  1. After introducing students to gradients and membrane transport, you may want to engage them in one of the following case studies:
    • Osmosis – Agony and Ecstasy – This case follows Susan, an intern at a local hospital, who has admitted a patient she discovers has used the drug Ecstasy. The girl becomes delirious, and Susan begins to suspect that she may be suffering from water intoxication. (Membrane Transport 2, Membrane Transport 3) 
    • Osmosis – Osmosis is Serious Business! – This directed case study involves two “stories,” each one concerned with some aspect of osmosis in living cells. Part I is centered around the effects of a hypertonic environment on plant cells, while Part II focuses on the effects of a hypotonic environment on human cells. (Membrane Transport 2, Membrane Transport 3) 
    • Membrane Structure and Transport – Newsflash! Transport Proteins on Strike! – This role-play case study teaches students about plasma membrane transport and the functions of transport proteins in the phospholipid bilayer. Students act out the parts of molecules and structures in a fantastical cellular world where the unionized transport proteins have called for a work stoppage. (Membrane Transport 1, Membrane Transport 2, Membrane Transport 4)
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Thermoregulation and ratio of surface area-to-volume

Outcomes: Gradients 1, Gradients 2, Gradients 3, Gradients 4; Thermoregulation 1, Thermoregulation 2, Thermoregulation 3, Thermoregulation 4, Thermoregulation 5, Thermoregulation 6, Thermoregulation 7, Thermoregulation 8

  1. The purpose of this activity is to illustrate the important role of SA/V in maintaining gradients. Students compare how life has evolved in extreme biomes namely by comparing images of the ear size of desert and tundra dwelling animals and connecting this structure with an animal’s ability to maintain homeostasis (i.e. temperature gradients and thermoregulation).  

Engage students by showing a photo of a desert biome and a tundra biome (see below). It is important that some plants be visible in each photo (not photos of sand dunes or snowpack) to illustrate that life can exist here. Ask students to make observations and compare and contrast each biome with their neighbors/teams. Ask students “What do you think might be an obstacle to life in these biomes?” and they usually respond with “temperature extremes and lack of liquid water.” Tell students, “Let’s look at the living things that have evolved to live in these extreme biomes.”

Prepare presentation slides with images of similar tundra and desert animals side by side for comparison by students (see below). Select images that prominently display the ears and legs of each animal so that students can eventually recognize the role of the ratio of surface area-to-volume in thermoregulation. Ask students to compare and contrast the body shapes of the following animals: Arctic Hare v. Jackrabbit, Lemming v. Kangaroo rat, Arctic fox v. Kit fox. It may help to show these images repeatedly as students discuss how the body shapes differ. Students will initially describe the animals as “chunky,” “skinny,” “fluffy,” etc. You may want to point out to students that it is difficult to measure how “fluffy” an animal is, so they should try describe the animals using surface area and volume.

Students soon realize that these two measurements are linked; as volume increases so does surface area. Although some students will start referring to these measurements as a ratio, many students will need prompting to make this connection.

 

  1. Ask students to work in groups to research and find organisms to complete this table:
Poikilotherm Homeotherm
Endotherm
Ectotherm

(Thermoregulation 1, Thermoregulation 2)

  1. After students work with the concepts of gradients and membrane transport, you may want to engage them this following case study:
    • Gradients and Thermoregulation: Left out in the cold! – While backpacking in the Canadian Rockies, Joel loses his way and finds that his experience hiking and camping in his home state of Florida hasn’t prepared him for springtime weather conditions in the mountains. This case study allows students to review and integrate physiological responses to cold exposure. (Gradients 1, Gradients 2, Gradients 3, Gradients 4) 
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Thermoregulation and osmoregulation

Outcomes:  Thermoregulation 3, Thermoregulation 4, Thermoregulation 6; Osmoregulation 1, Osmoregulation 2, Osmoregulation 3, Osmoregulation 4

Prerequisite Outcomes:  Thermoregulation 1, Thermoregulation 2; Membrane Transport 3

  1. This worksheet uses graphs and tables to compare and contrast different thermoregulatory strategies to one another, and different osmoregulatory strategies to one another.
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Osmoregulation and ratio of surface area-to-volume

Outcomes: Osmoregulation 3, Osmoregulation 4

Prerequisite outcomes: Gradients 1, Gradients 3; Membrane Transport 2, Membrane Transport 3

  1. Apply the concept of the ratio of surface area-to-volume, previously considered in the context of thermoregulation, to osmoregulation using these clicker questions:

 

  1. This case study could also be used to reinforce concepts of osmoregulation
    • Osmosis – Osmosis is Serious Business! – This directed case study involves two “stories,” each one concerned with some aspect of osmosis in living cells. Part I is centered around the effects of a hypertonic environment on plant cells, while Part II focuses on the effects of a hypotonic environment on human cells. (Osmoregulation 3, Osmoregulation 4)