August 22/24, 2006 First Two Class Meetings

During the first class meeting the following items were covered in addition to the syllabus (consult your notes or use a dictionary to find the meaning of the terms in bold):

Your instructor is an organismal biologist who studies bryophytes and is also a field biologist who works as a taxonomist (taxonomist - one who studies the diversity of life, including the basic task of identification of species).

One of the leading biologists of today is Alabama's own E. O. Wilson. As a Harvard biologist (now retired but very active) he works as an entomologist but is also a consummate scientist in that he has helped to establish new disciplines within biology (e.g. sociobiology). One of Dr. Wilson's conceptions is biophilia - "the connections that human beings subconsciously seek with the rest of life," an innate human tendency to focus on life. Living organisms displayed within a microaquarium were presented to elicit your reactions [pseudoscorpion].

Biophilia - is supported by the following: millions of people seek out opportunities to connect with other life forms through hunting, fishing, walking on the beach, visiting zoos, aquariums, and national parks. Many of us retain a fascination with creatures (giant water bugs, etc.) and enjoy these on an emotional level.

Creature fascination aside, biology looms large in today's society, and arguably this is

THE AGE OF BIOLOGY.

Some Issues (±controversial, w/economic impact) 

Genetic Engineering & Biotechnology
Embryonic Stem Cell Research
Gene Therapy
Gentically modified foods
Bioprospecting - the search for new antibiotics, drugs, and genes
Environmental Issues
Human Diseases
Human Population Growth
Saving our natural heritage

Some Philosophy 

Biology has altered our Zeitgeist (spirit of the age; the thought or feeling of a period of time) through knowledge of cellular physiology [example, we've learned that certain strange human behaviors aren't signs of witchcraft and devilry but are rather physiological conditions resulting in dementia, schizophrenia, or other disorders] & through knowledge of ecology (our actions on the natural world affect our future existence) and evolution by natural selection - enables us to understand biological diversity. Spirituality aside, the human species is born out of nature and we must operate within certain natural limits. Our collective mindset is that we are no longer free to conquer and dominate the natural world without thought to our own survivability given the changes we may bring to ecosystem operations that we depend upon (providing clean air and water and sustainable natural resources).

OTHER ASPECTS OF BIOLOGY

Reductionism - to reduce the whole to its parts, or to reduce complex phenomena to their working components.

Emergent properties - with each level of organization, properties emerge that cannot be predicted based on knowledge of the parts alone.

Levels of organization [see figure 1.1 in textbook]

Having become aware of reductionism and emergent properties, ponder the the following sentence from your textbook:
"Reproduction refers to actual mechanisms by which parents transmit DNA to offspring." p. 4 in textbook.  The complexity of reproductive behavior and physiology have been reduced to transmitting DNA!

How to Define Life

Living organisms are fascinating to most people. Most of us are fascinated by large, warm fuzzies (raccoons, horses, pandas) while others find delight in small wonders (small animals and plant-like algae in pond water). Whatever your taste in creature fascination, the following list of attributes apply to all organisms.  The attributes below are common to all life.

1. Living Organisms Reproduce. There are two means of reproduction, asexual and sexual. Asexual reproduction is a common and widespread phenomenon characterizing most fungi and protists and many plants and animals. Multi-cellular organisms reproduce asexually through fragmentation of the parent body & subsequent mitotic growth of the fragment that recreates a new individual that is a genetic clone of the original (recall plant cuttings from home).  The cloned cells originating from a single parent differentiate to form the tissues and organs of the new individual.  For single-celled life, cell division alone (mitosis) is the means of asexual reproduction--one cell divides into two and each goes its separate way becoming a new individual, no, or little, cell differentiation is required.  Sexual Reproduction is a bit more complex than asexual reproduction.  Sexual reproduction requires the formation of a new single-celled stage, the zygote. Two single-celled gametes unite in the process of fertilization to form the zygote. Prior to the next generation of sexually produced offspring, meiosis is required to reduce the chromosome number from the diploid to the haploid state. Thus, sexual reproduction consists of two required events: 1) meiosis, and 2) fusion of sex cells or gametes, e.g. egg & sperm, through an event called fertilization.  Chapters 7 and 8 explore reproduction and inheritance.

2.  Living Organisms are Composed of Chemicals.  Life is formed from carbon based chemicals, i.e. organic chemicals.  For example, the DNA of your genes and the amino acids of your muscle proteins are all carbon based molecules.  The chemicals that comprise life are basically the same between different organisms. Because these chemicals are dominated by Carbon, they are called organic chemicals. The same organic structure of DNA is common to all life and the same can be said of many carbohydrates, lipids, and proteins.  Chapter 2 explores these and other organic molecules in more detail.

3. Living Organisms Acquire Materials and Energy.   All organisms are made of matter, i.e. chemicals, and energy is required to assimilate these chemicals in the form of the individual.  Acquiring energy and materials is accomplished through many series of energy transformations as life transfers energy from one form to another. The chemical reactions that accomplish these energy transformations are collectively referred to as metabolism - chemical reactions within an organism that transfers energy, ex. respiration & photosynthesis.  Chapters 4, 5, & 6 explore these topics in more detail.

4. Living Organisms Sense & Respond to Environmental Stimuli. The environmental stimulus may come from outside the body (ex. touch a hot iron and you respond with quick withdrawal) or from inside the body (ex. blood sugar levels rise and insulin, which lowers blood sugar, is released in response). The state of a stable internal environment being maintained by various mechanisms is called homeostasis. 

5. Living Organisms Have the Capacity to Mutate - thanks to the slightly error prone DNA replication process, gene mutations are inevitable. Whether a mutation enjoys differential reproductive success is situational.  Our coverage of Evolution explores this topic in more detail.

6. Life exhibits organization at many levels [see Fig. 1.1]. An underlying theme in the study of biology flows from this understanding, that we can learn more about the whole by reducing it to its component parts.  This idea is known as reductionism.  Yet, we acknowledge the existence of emergent properties - properties emerge at higher levels of organization that cannot be predicted based on knowledge of the parts alone.

subatomic part. -> atom-> molecule->cell parts->tissues->organs-->organ systems---->individuals---> populations--->communities--->ecosystems

The Nature of Science

The natural sciences, apart from the humanities and social sciences, include:
physics, chemistry, astronomy, geology, and biology, of these biology is perhaps the least absolute and with less predictable outcomes.

Science, as in the natural sciences, may be defined as 1) a system of facts; 2) a process, a "way of knowing"
That process is often said to be the "scientific method."  You can read about the scientific method in your textbook and in the "why files" links (see BI 101 homepage if interested, it is not required).  Some main points concerning this method are:  hypotheses are tentative explanations in answer to some question.  The hypothesis must be testable and capable of being proven false.  Hypotheses are tested by further observation and experimentation in which predictions based on the hypothesis are tested.  Hypotheses are not proven true but rather they can be substantiated and supported.  Scientists publish the results of their studies, in part as a means to share information, but also to expose their methods and conclusions so that these can be scrutinized by fellow scientists.  Scientists are only human and mistakes and erroneous reasoning sometimes occur.  Finally, a mere hypothesis generally does not mature into a theory if supported by enough evidence.  Theories are broad in scope and many related smaller hypotheses were probably tested prior to the founding of a given theory.  Examples of biological  theories include the cell theory the the theory of evolution by means of natural selection.  Most scientists do not develop new theories.  Most spend their time gathering data and testing hypotheses.