Thermoregulation 7 – Integrating Biology & Inquiry Skills

Outcomes: Gradients 2Identify whether a chemical or energy gradient exists in new situations, Gradients 3Indicate the direction of energy or material movement under different conditions such as: A) Chemical concentrations B) Temperature C) Permeability of membranes, Gradients 4Indicate the relative rate of energy or material movement under different conditions including: A) chemical concentrations B) temperature C) permeability of membranes D) varied shape (surface-to-volume ratio); Membrane Transport 2Explain how processes of transport work including: A) Diffusion i) Passive ii) Facilitated B) Osmosis i) Passive ii) Facilitated C) Active transport, Membrane Transport 3Define the following terms, and explain how they relate to the movement of materials across a membrane: A) Isotonic B) Hypotonic C) Hypertonic, Membrane Transport 4Explain how larger objects/molecules cross membranes by exocytosis, endocytosis, and phagocytosis, and predict when each of these transport mechanisms is used., Membrane Transport 5Predict how the following conditions affect membrane transport: A) gradient conditions B) temperature C) ATP availability D) changes in permeability E) molecule size, charge, or polarity; Thermoregulation 7Explain why organisms thermoregulate.

Prerequisite objective: Membrane Transport 1Identify the components of cell membranes, and explain how the arrangement of components makes the membrane semi-permeable.

Ask students to work in groups to complete a table to compare and contrast modes of transport. (Membrane Transport 2Explain how processes of transport work including: A) Diffusion i) Passive ii) Facilitated B) Osmosis i) Passive ii) Facilitated C) Active transport)

	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 3Indicate the direction of energy or material movement under different conditions such as: A) Chemical concentrations B) Temperature C) Permeability of membranes, Gradients 4Indicate the relative rate of energy or material movement under different conditions including: A) chemical concentrations B) temperature C) permeability of membranes D) varied shape (surface-to-volume ratio), Membrane Transport 3Define the following terms, and explain how they relate to the movement of materials across a membrane: A) Isotonic B) Hypotonic C) Hypertonic, Membrane Transport 5Predict how the following conditions affect membrane transport: A) gradient conditions B) temperature C) ATP availability D) changes in permeability E) molecule size, charge, or polarity)

(Gradients 4Indicate the relative rate of energy or material movement under different conditions including: A) chemical concentrations B) temperature C) permeability of membranes D) varied shape (surface-to-volume ratio), Membrane Transport 5Predict how the following conditions affect membrane transport: A) gradient conditions B) temperature C) ATP availability D) changes in permeability E) molecule size, charge, or polarity) 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 7Explain why organisms thermoregulate.: enzymes work best at a narrow temperature range.

Gradients and membrane transport visual aids from ibis_curriculum

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 2Explain how processes of transport work including: A) Diffusion i) Passive ii) Facilitated B) Osmosis i) Passive ii) Facilitated C) Active transport, Membrane Transport 3Define the following terms, and explain how they relate to the movement of materials across a membrane: A) Isotonic B) Hypotonic C) Hypertonic)
- 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 2Explain how processes of transport work including: A) Diffusion i) Passive ii) Facilitated B) Osmosis i) Passive ii) Facilitated C) Active transport, Membrane Transport 3Define the following terms, and explain how they relate to the movement of materials across a membrane: A) Isotonic B) Hypotonic C) Hypertonic)
- 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 1Identify the components of cell membranes, and explain how the arrangement of components makes the membrane semi-permeable., Membrane Transport 2Explain how processes of transport work including: A) Diffusion i) Passive ii) Facilitated B) Osmosis i) Passive ii) Facilitated C) Active transport, Membrane Transport 4Explain how larger objects/molecules cross membranes by exocytosis, endocytosis, and phagocytosis, and predict when each of these transport mechanisms is used.)

Outcomes: Gradients 1Explain what a gradient is and the role of gradients in: A) Homeostasis B) Thermoregulation C) Osmoregulation D) Chemical reactions associated with metabolism, Gradients 2Identify whether a chemical or energy gradient exists in new situations, Gradients 3Indicate the direction of energy or material movement under different conditions such as: A) Chemical concentrations B) Temperature C) Permeability of membranes, Gradients 4Indicate the relative rate of energy or material movement under different conditions including: A) chemical concentrations B) temperature C) permeability of membranes D) varied shape (surface-to-volume ratio); Thermoregulation 1Apply the terms endotherm, ectotherm, poikilotherm/heterotherm, and homeotherm to organisms, Thermoregulation 2Identify organisms as endotherms, ectotherms, poikilotherms/heterotherms, and homeotherms based on: A) physical characteristics B) behavior C) metabolic changes D) membership in taxonomic groups (birds, mammals, etc.) E) changes in body temperature measurements, Thermoregulation 3Predict the effect of varying environmental temperatures on an organism's behavioral or metabolic responses including: A) enzyme activity B) locomotion C) body temperature, Thermoregulation 4Interpret data/graphs as they relate to the effect of varying environmental temperatures on an organism's behavioral or metabolic responses including: enzyme activity
locomotion
body temperature
, Thermoregulation 5Design or critique simple experiments to test the effect of varying environmental temperatures on an organism's behavioral or metabolic responses including: A) enzyme activity B) locomotion C) body temperature, Thermoregulation 6Explain how various temperature regulation methods serve to heat or cool an organism including: A) avoidance B) altering metabolic rate C) behaviorally adjusting posture, ratio of surface area-to-volume, and location D) explain how ratio of surface area-to-volume is involved in heat retention or loss, Thermoregulation 7Explain why organisms thermoregulate., Thermoregulation 8Explain mechanisms of heat generation at the cellular level.

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.

Visual aids for thermoregulation and ratio of surface area to-volume from ibis_curriculum

Ask students to work in groups to research and find organisms to complete this table:

	Poikilotherm	Homeotherm
Endotherm
Ectotherm

(Thermoregulation 1Apply the terms endotherm, ectotherm, poikilotherm/heterotherm, and homeotherm to organisms, Thermoregulation 2Identify organisms as endotherms, ectotherms, poikilotherms/heterotherms, and homeotherms based on: A) physical characteristics B) behavior C) metabolic changes D) membership in taxonomic groups (birds, mammals, etc.) E) changes in body temperature measurements)

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

Tag: Thermoregulation 7

Gradients and Membrane Transport

Thermoregulation and ratio of surface area-to-volume