Sea to Shore Summary

What does it mean to be alive? How did the first cells form, and what traits did these earliest cells possess? How do living things function in varied environments? In this scenario, students are asked to consider what constitutes life, its origins, and the evidence needed to demonstrate that something is alive. Students are introduced to the molecules common to all living things, and the structure and function of cells. Students make observations of animal body shape, and apply knowledge of gradients and chemical activity to develop a working hypothesis about the ratio of surface area-to-volume, and its impact on homeostasis, metabolism and ultimately, survival. Instructors could use examples from extreme environments or journeys to other planets as contexts for this investigation and guide student inquiry.

Life Learning Outcomes
  1. List and explain the characteristics of life.
  2. Use these characteristics of life to distinguish between living and nonliving things.
  3. Define homeostasis, and describe its importance to maintaining life.
  4. Compare and contrast the biological/medical, legal, and ethical definitions of life and death, and discuss the importance of defining life and death.

 

Chemistry Learning Outcomes
  1. Explain why water is essential to life and how the characteristics of polarity and hydrogen bonding are important for this role.
  2. Identify the four macromolecules, and define their roles/functions in a cell.
  3. Explain the difference between ionic, covalent, and hydrogen bonds, and identify the relative strength of each type of bond.
  4. Predict which type of bond would be formed between two (or more) atoms.
  5. Describe the relationship between monomers and polymers, and give examples for each type of biological macromolecule listed below:
    1. Proteins
    2. Nucleic acids (RNA, DNA)
    3. Carbohydrates
  6. Explain what an enzyme is and how it influences the rate of biological reactions.
  7. Define active site and its role in enzyme function.
  8. Describe and predict how environmental conditions (e.g., temperature and pH) can influence protein structure and the shape of the active site of an enzyme.

 

Cell Learning Outcomes
  1. Identify the function of cell components, especially:
    1. Nucleus
    2. Mitochondria
    3. Chloroplasts
    4. Ribosomes
    5. Rough and Smooth Endoplasmic Reticulum
    6. Vesicles
    7. Golgi
    8. Cell Membrane
    9. Cytoplasm
    10. Cell Wall
    11. Vacuoles
  2. Identify which cell components are found in:
    1. all cells
    2. prokaryotes (Eubacteria, Archaea)
    3. eukaryotes
      1. Animals
      2. Plants
      3. Protists
      4. Fungi
  3. Predict the organismal group to which an unknown cell might belong from a description of its components.
  4. Predict the possible functions of an unknown cell depending on its components.
  5. Predict the abundance of particular organelles depending on a cell’s functions.

 

Ratio of surface area-to-volume (SA/V) Learning Outcomes
  1. Calculate the ratio of surface area-to-volume of an object, and explain why the ratio decreases as objects get larger and increases as objects get smaller.
  2. Explain how the ratio of surface area-to-volume plays a role in regulating:
    1. Rates of diffusion and osmosis
    2. Gas exchange
    3. Body temperature
  3. Given environmental conditions, predict the SA/V ratio that would be selected by natural selection, and explain how this could be a mechanism of evolution.

 

Gradients Learning Outcomes
  1. Explain what a gradient is and the role of gradients in:
    1. Homeostasis
    2. Thermoregulation
    3. Osmoregulation
    4. Chemical reactions associated with metabolism
  2. Identify whether a chemical or energy gradient exists in new situations
  3. Indicate the direction of energy or material movement under different conditions such as:
    1. Chemical concentrations
    2. Temperature
    3. Permeability of membranes
  4. Indicate the relative rate of energy or material movement under different conditions including:
    1. chemical concentrations
    2. temperature
    3. permeability of membranes
    4. varied shape (surface-to-volume ratio)

 

Membrane Transport Learning Outcomes
  1. Identify the components of cell membranes, and explain how the arrangement of components makes the membrane semi-permeable.
  2. Explain how processes of transport work including:
    1. Diffusion
      1. Passive
      2. Facilitated
    2. Osmosis
      1. Passive
      2. Facilitated
    3. Active transport
  3. Define the following terms, and explain how they relate to the movement of materials across a membrane:
    1. Isotonic
    2. Hypotonic
    3. Hypertonic
  4. Explain how larger objects/molecules cross membranes by exocytosis, endocytosis, and phagocytosis, and predict when each of these transport mechanisms is used.
  5. Predict how the following conditions affect membrane transport:
    1. gradient conditions
    2. temperature
    3. ATP availability
    4. changes in permeability
    5. molecule size, charge, or polarity

 

Thermoregulation Learning Outcomes
  1. Apply the terms endotherm, ectotherm, poikilotherm/heterotherm, and homeotherm to organisms
  2. Identify organisms as endotherms, ectotherms, poikilotherms/heterotherms, and homeotherms based on
    1. physical characteristics
    2. behavior
    3. metabolic changes
    4. membership in taxonomic groups (birds, mammals, etc.)
    5. changes in body temperature measurements
  3. Predict the effect of varying environmental temperatures on an organism’s behavioral or metabolic responses including:
    1. enzyme activity
    2. locomotion
    3. body temperature
  4. Interpret data/graphs as they relate to the effect of varying environmental temperatures on an organism’s behavioral or metabolic responses including:
    1. enzyme activity
    2. locomotion
    3. body temperature
  5. Design or critique simple experiments to test the effect of varying environmental temperatures on an organism’s behavioral or metabolic responses including:
    1. enzyme activity
    2. locomotion
    3. body temperature
  6. Explain how various temperature regulation methods serve to heat or cool an organism including:
    1. avoidance
    2. altering metabolic rate
    3. behaviorally adjusting posture, ratio of surface area-to-volume, and location
    4. explain how ratio of surface area-to-volume is involved in heat retention or loss
  7. Explain why organisms thermoregulate.
  8. Explain mechanisms of heat generation at the cellular level

 

Osmoregulation Learning Outcomes
  1. Explain why organisms osmoregulate.
  2. For different habitats (ocean, freshwater, on land, etc.), predict whether ions or water need to be conserved.
  3. Describe how organisms osmoregulate in different habitats, on the:
    1. cellular level, using active and passive transport across membranes
    2. individual organism level, in terms of inputs and outputs
  4. Compare and contrast how organisms osmoregulate in different habitats.

Lecture Materials

Lab Materials

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

Sea to Shore Lab: Thermoregulation

Why are animals shaped differently in cooler climates than in warmer ones?

Overview

The purpose of this lab is to get students relating surface area/volume ratio to the way in which an animal thermoregulates (by using modeling clay).  At the conclusion of this investigation, students should also be writing a better lab report, able to produce a XY scatter plot with a trendline, and perform a simple statistical test. They will be using modeling clay to simulate body shapes, and temp probes to monitor any changes.  They may craft any shape they like, provided that 1. They can calculate the SA/V ratio of the shape, and 2. They can accurately record its temp with the probe (shapes like a long cylinder or flattened box do not work well as there is little clay surrounding the temp probe).

Outcomes:  Inquiry 4, Inquiry 5, Inquiry 6, Inquiry 7, Inquiry 8; SA/V 1; Gradients 1, Gradients 2, Gradients 3, Gradients 4; Thermoregulation 1, Thermoregulation 6

Materials (Per lab group)

Shaw, T.J. & French, D.P. (2018). Authentic Research in Introductory Biology, 2018 ed. Fountainhead, Fort Worth.

Assessments

PreLab

Quiz

Keys and additional instructor-only notes (you will be asked to sign into a Google account and request access to view instructor materials)

Lab report rubric

Sea to Shore Lab: Diffusion

Why is diffusion through a membrane sometimes faster?

Overview

This lab should help students understand the extremely important role of gradients. Focus on the idea that gradients occur whenever there is a concentration difference from high to low. Gradients do not just occur in liquids there can be gradients in temperature, Na and K ions, smoke, perfume, people, etc.

Students should be familiar with the terms solute, solvent, hyper-and hypotonic. Osmosis refers to the movement of water and dialysis typically to the movement of solute. Students may or may not comprehend the concept of ion, but you can simply leave it as a charged atom or particle or molecule. Unfortunately, if they don’t have some clue about ions or at least that NaCl becomes Na+ and Cl- when dissolved, the understanding what conductivity tells them is difficult. The pre-lab explains it, but be prepared.

Outcomes:  Inquiry 4, Inquiry 5, Inquiry 6, Inquiry 7, Inquiry 8; SA/V 1, SA/V 2; Gradients 1, Gradients 2, Gradients 3, Gradients 4; Membrane Transport 2, Membrane Transport 3, Membrane Transport 5

Materials

Per lab group

Shaw, T.J. & French, D.P. (2018). Authentic Research in Introductory Biology, 2018 ed. Fountainhead, Fort Worth.

Assessments

PreLab Activity

Quiz

Keys and additional instructor-only notes (you will be asked to sign into a Google account and request access to view instructor materials)

Lab report rubric

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).

Defining life and death in different ways

Objective:  Life 4

  1. Group discussion or short lecture about the Charlie Gard (baby in the UK with mitochondrial depletion syndrome), to illustrate the many ways life can be defined, and the importance of these different definitions. (Life 4)

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 MoleculesIn 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

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

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 EcstasyThis 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)