|
OVERVIEW OF THE COURSE:
a.k.a. INTEGRATIVE BIOLOGY from GENES TO ENVIRONMENT
TEXTBOOK:
ANIMAL
PHYSIOLOGY
by Sherwood, Klandorf, Yancey; 2nd ed., 2013
(Cengage):
Physiology is the study of biological function. Many people
automatically think this is the study of discrete organ systems
and how they work. Indeed, most textbooks are organized around
such systems -- Nervous System, Respiratory System, etc. However,
this can be a misleading approach. First, physiology is concerned
with function at all levels, from the molecular to the ecological;
indeed there are subfields called molecular, cellular,
developmental, ecological physiology in addition to the
traditional organ-based areas such as Cardiovascular Physiology.
Second, there are no separate independent systems in an organism;
all have multiple functions that interact with many or most
others. For example, the skin is called the "Integumentary System"
in most texts, but it is an organ involved in thermoregulation,
immunity, reproduction via sexual signaling, excretion and
salt/water balance. Or take the heart--it's not simply a
circulatory pump, but also has a gland that regulates salt and
blood pressure. Third, functions begin at the micromolecular level
and build through a hierarchy to the whole organism. Understanding
of an organism's functions, therefore, requires an ability to
think across artificial boundaries from the molecular level to the
"big picture" level of the whole being. For this reason,
Physiology is often called the integrative biological science.
Today Biology is being revolutionized by rapid advances in
molecular biology and genomics. Often this information is
reductionistic, with little biological integration--for example,
the publication of a gene's DNA code without knowledge of how that
gene operates in an organism. James Schafer, President of the
American Physiological Society, has declared that
"...physiologists must play a central role in integrating
information obtained at the molecular and cellular levels into a
fuller understanding of function at higher levels of
organization." (The Physiologist v.39:41, 1996).
At the international level, physiologists and their societies are
calling for integrative research and teaching. This course
recognizes this. Themes are whole-body functions with traditional
organ systems within those; we examine those functions from the
molecular/genetic level on up. While most Physiology textbooks
take a reductionistic organ-systems approach, I have recently
co-authored a textbook which uses an integrative systems approach.
For example, a chapter on Fluid Balance integrates the regulation
of water, salts and wastes using the brain, hormones, the kidney,
the lungs, the skin, and the intestines.
Secondary Theme: EVOLUTION. Organisms are the product of
millions of years of evolution. Indeed, as Ernst Mayr, a primary
developer of the modern theory of evolution, points out, all
biological phenomena must be considered from two levels of
explanation:
1. Proximate = mechanistic function “as is”; “how does it work”
analysis. E.g., the human spine is stiffly-jointed, slightly
flexible support for the middle and upper body, made of bone,
cartilage, etc.
2. Evolutionary = historical/selective reason; “why did it end up
this particular way” analysis. E.g., the vertebrate spine first
evolved in proto-fishes as a flexible attachment for swimming
muscles.
One consequence is that bodies are not always logically designed,
but are the product of historical compromises. Just look at all
the mild to severe spinal problems humans have from our recent
evolution into an upright stance. Indeed, illogical flaws are
regarded by some as the most powerful evidence for evolution.
This explanatory duality has often profound implications for
understanding of anatomy and physiology, yet in the past it has
often been ignored. Now, a revolution called evolutionary
physiology (or Darwinian medicine) is re-evaluating many of
current biological and medical dogmas. We will have many readings
and lecture topics on this.
3. There is also a separate type of explanation, the teleological,
which describes a feature's purpose ("what is it good for?"). So
you may see three levels of analysis, the "how, why and what for"
to explain a biological feature. Teleology is a dangerous
approach; SEE THE TEXT Chap. 1 for more about this and other
explanations.
|
