Biophysical Field Methods

Using the physics of heat and water to study the thermal ecology of animals and plants in the wild.

Biophysical field methods online offers a practical approach to biophysical ecology, which applies physical concepts, principles and techniques to the interpretation of animal-environment interactions. These include how physical laws, such as the laws of thermodynamics, affect the abundance and distribution of animals and plants, the nature of microclimate, the ecological niche, and the integration of physiology and evolutionary ecology.

With specific ecological questions in mind, we aim to teach practical methods for reliably measuring temperature and humidity and their physical drivers in the field. Temperature and humidity are commonly reported in field studies, but they are usually measured with little attention to the physical principles that make the measurements meaningful and reliable. Without such attention, the results can be worse than meaningless: they can be misleading.

The course is composed of seven lessons, each subdivided into several sections. The first third of the course deals with the physics of heat: energy, temperature, the differences between them and how biological systems are constrained by the laws of thermodynamics. Next the course delves into the physics of water, its colligative properties, and the energetics of phase changes from ice to liquid water and liquid water to water vapor. Then, the course focuses on the physics of water potential. All these concepts are tied together through their common currency—energy—and are demonstrated with several examples of how these concepts properly applied can lead to a deeper understanding of the organism and its environment.

What are the requirements?

• Since during the material of the course includes a deal of physics, chemistry and biology, knowledge of at least high school mathematics, physics and chemistry will smooth your way. Your other need is motivation. Since during the material of the course includes a deal of physics, chemistry and biology, knowledge of at least high school mathematics, physics and chemistry will smooth your way. Your other need is motivation.
• A basic knowledge of physics, biology and mathematics through algebra. High school level is adequate, introductory college level is preferable.
• Drive, motivation and curiosity.

What am I going to get from this course?

• Over 45 lectures and 6.5 hours of content!
• Learn practical methods for reliably measuring temperature and humidity and their physical drivers in the field.
• Learn about calibration and ways you can improvise meaningful calibrations of your instruments under field situations.
• Learn about the concept of the operative temperature, and how this can be applied to ecologically meaningful measurements of the operative temperature.
• Learn how ecologically meaningful measurements of operative temperature can be made in field situations.
• Measure environmental temperature in a physically meaningful way.
• Learn about the concept of humidity, what relative humidity is compared to absolute humidity, and the relationship of humiditiy to liquid water in the environment.
• Learn about the concept of the water potential, the various types of water potential and how these influence the movements of liquid water in soils.
• Learn about the relationship between humidity and water potential, and to understand the physical principles underlying the phase relationships between vapor phase and liquid phase water.
• Learn how the colligative properties of water affect the water vapor pressure, and how these influence both humidity and the water potential.
• Learn how to apply these practical methods to specific ecological questions.
• Understand what the water vapor pressure is compared to the partial pressure of water vapor and how these relate to the concept of humidity.
• See these concepts demonstrated in model experiments under field conditions in Namibia.

What is the target audience?

• Undergraduates in biology, ecology, zoology, botany.
• Graduate students in biology, ecology, zoology and botany who are looking to improve their planning and execution of their research projects.
• Professional scientists who are seeking a better understanding of the physical meaning of environmental temperature and moisture.
• Anyone interested in gaining a deeper understanding of environmental temperature, environmental moisture, humidity, and how water moves in soils.

Curriculum
Section 1: Energy, temperature and work
Lecture 1 Introduction to heat and temperature 02:32
Lecture 2 Temperature and heat 03:48
Temperature and heat. After viewing this lecture you should know the difference between temperature and heat and how they are related.

Lecture 3 Introduction Text
After reading "Scientific writing instructions" you should have a good idea of the level of writing that will be required of you.

Lecture 4 The three laws of thermodynamics 05:16
The three fundamental laws of thermodynamics made simple

Lecture 5 Temperature scales 08:02
Temperature scales, Fahrenheit, Celsius and thermodynamic (absolute). How temperature scale endpoints came about.

Lecture 6 Specific heat and thermal capacity 16:31
How to explicitly associate temperature to heat through knowledge of the specific heat of a material and thermal capacitance of an object.

Lecture 7 Latent heat of vaporization 08:45
Latent heat of vaporization and what happens when water changes from liquid to gas and vice versa.

Lecture 8 Energy, work and power 03:07
The relations between heat, work and power: energy economies.
Section 2: Energy and temperature lifestyles
Lecture 9 Energy and temperature lifestyles 02:04
This lecture deals with the importance of temperature for animals in their environment. By the end of the lecture you should understand the difference between endothermic and ectothermic animals and why, although far more expensive in terms of energy and water, endothermy is a viable lifestyle. The lecture also introduces energy budgets and the "operative temperature" concept.
Lecture 10 The thermal energy budget 03:36
Definition of the operative temperature and how it relates to the first law of thermodynamics. Also, the mechanisms of heat transfer between animals and their physical environment and the energy balance equation.

Lecture 11 Energy lifestyles 08:23
Energy lifestyles –Here you will learn about ectothermic animals as energy misers and endothermic animals as energy wastrels andhow the body temperatures and energy budgets of the two groups differ because of their different lifestyles. The effects of body size on energy use are also discussed.

Lecture 12 Temperature life styles 04:07
Temperature life styles – This section is about how animals manage their body temperature. Here, we more closely examine how the energy budgets of endothermic and ectothermic animals differ and you will be introduced to the term "heterothermy".
Lecture 13 Modes of heat exchange 12:15
In this section, modes of heat exchange are discussed and by its end you will have learned about heat exchange through radiation, convection and conduction.

Section 3: The operative temperature
Lecture 14 The operative temperature. Introduction 00:56
Lecture 15 Why operative temperature is not the same as air temperature 04:19
We will now go the next step and in this lesson you will learn to measure the operative temperature on "animals" of different sizes and colors. You will learn how the operative temperature is affected by radiation and convection and why small animals are coupled to convection, whereas large ones are radiation-coupled.

Lecture 16 Making a meteorological shelter 11:55
Since air temperature and operative temperature are different, in the first part of this lesson, you will learn a standard way of measuring air temperature in a meteorological shield.
Lecture 17 Size, shape and operative temperature 09:58
In this section we'll will teach you about the effects of body size, shape and color on the operative temperature. You will learn a simple way for estimating surface area of animals and then learn to write an energy balance equation, taking into account convection and solving for radiation. The result will be an equation for the operative temperature T<sub style="">e</sub>.You will learn in some depth about the relationships and importance of volume and surface area and the terms radiation- and convection coupled.

Lecture 18 Measuring operative temperature: size and color 14:06
Here you will learn how to measure operative temperature and about how operative temperature changes under natural conditions. You will also learn to build simplified operative temperate thermometers from scratch, including making your own thermocouples. Finally, you will see a demonstration of how what you have built can be used.
Lecture 19 Operative temperature: size and color results 06:06
In this section you will learn how to collect data and analyze the data collected from the black and white models of spherical animals. Also you will learn to compare among the models and draw some conclusions about the differences among them.
Lecture 20 Measuring operative temperature: shape 06:31
In this section you will learn the effects of a shape closer to that of a real animal on its operative temperature. Obviously, the operative temperature of a sphere will be the same whichever side of it faces the sun. Not so for a flat leaf or a cylindrically shaped form. You will learn that a leaf's or a cylinder's operative temperature depends very much on which side of it faces the sun and that the area of the portion facing the sun can be viewed, and, if you like, measured as the objects silhouette.
Section 4: Operative temperature in the real world
Lecture 21 Operative temperature in the real world 03:24
This lesson will take you from models of animals studied und quite controlled conditions to learning how to measure operative temperatures under field conditions, where there are a wide variety of microclimates that an animal can occupy in a given habitat. You will also learn the utility of measuring the operative temperature of an animal (or plant). But before you can go out and measure these variables, you will learn how to calibrate your measuring devices. You will see three demonstrations of how microclimates can be used by animals and plants to their own ends.

Lecture 22 Calibration basics 11:45
In this lesson you will learn the principles of calibration of temperature measurement devices and how you might increase your confidence in the measurements you make by good practice. You will also become familiar with iButton data loggers.
Lecture 23 Calibration results 11:11
After you have learned the process of calibrating iButtons, the next step is to analyze the data you collected and to prepare correction equations for your individual instruments.
Lecture 24 Microclimates 16:44
In this section you will learn how microclimates vary in habitats and affect the operative temperatures of plants and animals. You will also learn how to characterize the thermal environment of a habitat using animal proxy models and calibrated iButtons.
Lecture 25 Operative temperature of armored crickets 12:35
Here you will learn how to explain the daily pattern of behavior of an ectothermic animal by following its operative temperature.

Lecture 26 Microenvironments of Welwitschia leaves 11:25
Leaves also have operative temperatures, but, by contrast to the animal models you have learned about till now, in this section you will learn how plants, in this case a very interesting species, may affect its own microclimate.
Section 5: Water
Lecture 27 Water 02:42
This lesson is about water. Like temperature, water and its relations with the environment and its effects are not always immediately obvious. You will learn about the basic physics of water, in its different phases, and how that relates to animals and plants in their diverse environments.
Lecture 28 The colligative properties of water 08:23
Water has what are called colligative properties. These, the reduction of freezing point, the elevation of boiling point, the reduction of vapor pressure, and osmotic pressure, all depend on the concentration of solute molecules (or dissociated ions) in solution. In this section you will learn about these properties and their relationships with the environments in which animals and plants live.

Lecture 29 Humidity and vapor phase water 12:57
This section will introduce you to water vapor in the air and its relations with water in the liquid phase. You will learn how to correctly describe water in these two phases and the basic physical principles of evaporation and condensation.

Lecture 30 Psychrometry 11:21
In this section you will learn the principles of measuring absolute and relative humidity in the air. You will learn to use a sling psychrometer and a psychrometric chart.
Lecture 31 Temperature and relative humidity 10:37
Here you will learn about the relationship between temperature and relative humidity and how relative humidity is a misleading measure. You will also learn about the use of a specialized iButton data logger called a Hygrochron to follow absolute and relative humidity over a 24 hour period.

Section 6: The water potential
Lecture 32 The water potential 01:57
This lesson continues the examination of water and its properties and focuses on the water potential and the principles of how water moves in the environment. Also, you will learn what relative humidity can actually tell you about the environment.
Lecture 33 Introduction to the water potential 14:20
In this section the term water potential you will be introduced and what are the causes of water movement, gravity, pressure, matric potential and osmotic pressure. You will learn how to express all these forces in the common language of energy.
Lecture 34 Water potential in soils 11:35
This section deals with water potential in soils. You will learn how water actually moves through soils as a function of the interactions between the different forms of water potential.

Lecture 35 The Hele-Shaw cell 17:06
Here you will learn how water potential can be measured in the soil with a Hele-Shaw cell that can be simply and cheaply constructed and used to measure the effects of gravity and matric potentials on water movement in in sand.
Lecture 36 Water potential and relative humidity 06:21
In this part you will learn about the association between water potential and relative humidity and that water potential is the capacity to do work. Finally, you will learn about the water potential of air, what the measure of relative humidity is good for, and how water moves up in tall trees.

Section 7: Water potential and relative humidity in the real world
Lecture 37 Water potential and relative humidity in the real world 02:04
This lesson shows how all of what you have learned about water, its properties and water potential can teach you about what is happening in real environments. You will learn to put theory to practice with three examples, one involving evaporation from the surfaces of frogs; one about water potentials in soils, and finally one involving lichens in the fog desert of western Namibia.
Lecture 38 Humidity and microclimate 1 16:13
In this section you will first review what you have learned about relative humidity then how to make molds of animals whose evaporative water loss you wish to study. That will lead you to the next section where you will learn to use the molds evaluate evaporation in several microhabitats.

Lecture 39 Humidity and microclimate 2 16:46
In this section we will learn to use the models we made to measure what is the daily variation in mass loss (evaporation) over time in different microhabitats. And we will learn what effect color has or hasn't on the rate of evaporation from our plaster models.
Lecture 40 Measuring the water potential 14:01
Here you will learn to measure water potential in the soil around a termite mound with a gypsum sensor and how to analyze these data using those from a previous project.

Lecture 41 Water potential around termite mounds 12:44
Based on the method learned in section 7.3., you will learn to analyze soil water potentials around a termite mound using data collected a few years ago when these mounds were being extensively studied. You will also learn what termite mounds are all about.

Lecture 42 Lichens and air-borne water 06:17
In this section you will learn about the biology of lichens. Lichens are a diverse group of symbiotic organisms that live in profusion on the seemingly arid gravel planes the Namib Atlantic coast.
Lecture 43 Lichen diversity 1 13:17
Lichens are able to harvest water from the fog that regularly rolls in from the coat. In this section you will learn about their incredible diversity and how they respond to the presence of water.
Lecture 44 Lichen diversity 2 12:20
In this final section you will learn about the responses of lichens to dew after learning how dew forms in response to changes in rock surface temperature. Also, about how lichens hang on to the water the extract from the foggy air or from dew.
Section 8: Wrapping it up
Lecture 45 Wrapping it up 03:33







For More Rare Movies Check out my blog!

No Mirrors Please