Lecture 1: Course Overview and Introduction to Concepts of LIFE Course

Course Requirements:

Biology 2107K is an Introductory level Lecture and Laboratory series...for Biology Majors

Participation in both the lecture and the laboratory is expected.

Biology Majors: (a) become familiar with the biology web page, (b) be aware of advisement and course issues (they change), (c) don't leave things to the last minute.......

The Lecture: Attendance in lecture is "expected"...... 

Don't be fooled by the lecture notes being on the web....  If you are expecting to be absent for an extended period of time, make preparations with one of your colleagues; a quick email to me to that effect would also be considered a "common courtesy".

Associated Laboratories: Unlike their associate lectures, attendance at every lab session is MANDATORY.  To ensure this, quizzes will be given at the beginning of each lab session -so don't be late.

Be aware THERE ARE NO MAKEUP LABS.

Yes, Laboratories begin this week.

Please be sure to obtain a copy of the Biology 2107 Laboratory Schedule, Syllabus and Policy Sheets.

Laboratory Sections Corresponding to this Lecture Series:

Title/ Course Number  
Date
Time
Location
BIOL 2107K-040/ 11517
Tuesday
5:00 –7:30 pm
NSC-334
BIOL 2107K-050/ 12980
Monday
5:00 – 7:30 pm 
NSC-334
BIOL 2107K-045/ 13657
Thursday
4:00 –6:30 pm
NSC-334

 

Course objectives:

to cultivate an understanding of the biological sciences and the scientific method,
to begin to study central ideas in metabolism, evolutionary-, cellular- micro- and molecular- biology,
to acquire (and use) the vocabulary (jargon), necessary for informed discussion on some biological topics,
to gain experience collecting and analyzing data.
to begin to put bio-ethical, medical, bio-economical and environmental issues into a "plausible",
biological and scientific context.

     ........in essence, to enable you to become a Biology "apprentice".

Student responsibilities:

Attendance, Courtesy and Preparation (preparation in advance of lecture is Highly recommended), Review your own notes -text (where appropriate), Study (?) ... and ask questions

So, as the course text suggests......we are here to investigate Life !

Given the immense scientific focus over the last decade or so of the landing of robotic rovers on Mars.... -tewlve years ago this month and the ongoing exploration of the planet -as well as the more recent excitement of finding "organic compounds" on the surface (2012).... it might be appropriate to begin a discussion with regard to this very important enterprise on the surface of this desolate, forsaken planet, currently about 47 million miles away.

  ........and to ask why did we go there?

 

............what is Life?

In the early 1960's, James Lovelock was invited by NASA to participate in the scientific research for evidence of life on Mars. His job was to design instruments, capable of detecting the presence of life, which could be sent on a spacecraft to Mars. This wasn't straightf orward, since it was hard to know what to test for: any life forms on Mars may be radically different from those on Earth.

This led him to think about what constitutes life, and how it can be detected. He decided that the most general characteristic of life was that it takes in energy and matter and discards waste products. He also reasoned that organisms would use the planet's atmosphere as a medium for this cyclic exchange, just as we breathe in oxygen and expel carbon dioxide. He speculated that life would therefore leave a detectable chemical signature on the Martian atmosphere. Maybe it could be detected from Earth, so it wouldn't even be necessary to send a spaceship.            

David Orrell         

......................When you consider the tasks of the twin rovers "Spirit" and "Opportunity" and the more recent "Curiosity", the question, as to "what is 'Life'?", is not such a straight forward question, after all?

.............................................

Some Classical definitions of Life...... -online Merriam-Webster Dictionary, life defines "life" as “an organismic state characterized by capacity for metabolism, growth, reaction to stimuli, and reproduction.”

 

Group Responses......of non-biologists from a Perspectives course that I gave a few years ago.

Ability to Reproduce (self perpetuate)
Inherent Existence of "Purpose"
"Will" to Survive
Response to [external] Stimuli
Inherent Organization
As yet Unknown Features?
Complexity
Ability to Grow
Intelligence
Ability to Track/Monitor Time
Non-Spontaneous
Awareness of "Being" or Consciousness
           

 

If we can't even agree on how to address the question as it stands (or at least "pidgeonhole" or catagorize LIFE), can we at least identify some characteristics or concepts that we hope might encompass all or some of the "known" living, Life forms?

.... and then study them.

Some texts try to categorize these "life forms" as having various potentials........ "to reproduce", "to grow" and "to evolve". 

.....crystals can reproduce, mountains and landscapes can grow, the earth has "evolved".

So what, or how, would we define a Life form?

But, why limit ourselves to only one simple definition? 

Why not make a composite of some -if not a number- of these definitions?

1) Living things need to take in energy
2) Living things get rid of waste
3) Living things grow and develop
4) Living things respond to their environment
5) Living things reproduce and pass their traits onto their offspring
6) Over time, living things evolve (change slowly) in response to their environment

But we end up with the same problem as before...

Why is this question so hard?

Because, for every hard, fast and simple definition of "Life" that we can come up with, we can probably come up with a variety of seemingly analogous systems/objects that one could normally identify as being "inanimate" or (as John Cleese might say..). "bereft of life", and we end up arguing along with Supreme Court Associate Justice, Justice Stewart Potter in trying to wrestle with the "definition" of obscenity, circa 1964 and use the argument "but I know it when I see it..

 

Many living things can be made up of a lot of "dead" material.........

Similarly, some seemingly living things may not actually be....."ALIVE"... .

Wendell Stanley, 1946... no metabolism of their own.... More recently, however, viruses fall ill.....and potentially acquire their own immune system. So, are they alive?

 

So, LIFE is what makes Biology so interesting... and so broad in scope such that it simultaneously dfferentiates itself from the rest of the Natural Sciences while at the same time incorporates many aspects of that are inherent within these oth natural sciences.

As such, whatever these "life forms" are, our experience has taught us that -in order to exist- they must stay within the bounds of scientific laws that have been established for the physical and chemical world.....?

Which begs the next question........What is a "Scientific Law"? 

 

A Law is a descriptive generalization about how some aspect of the natural world behaves under stated circumstances.

 

Let's take another tack.....Where, can Life NOT exist……?

Within a state of "chaos" or entropy, or in a vacuum

Potentially, therefore, a prerequisite for Life is........, an "organization" that is able to harness the laws of the physical world, allowing "life" (whatever it is) to perpetuate, and -at the very least- reproduce itself.

So, what are the minimal requirements for life to exist?

hint:


"Good fences make good neighbours"

 Robert Frost in "Mending Wall"

 

While this was written as a tongue in cheek commentary on our apparently inherent conditioning to rebuild our fences, defining ourselves by the "fences" that we build and rebuild, maybe it goes deeper than that, may be....

 

"The molecules and cells that form our tissues are continually removed and replaced;

it is the maintenance of pattern and architecture, I reasoned, that we call life."


Donald Ingber SCI American, Jan. 1998.

 

Indeed, among all the potential variables on living organisms, one critical factor, that is paramount to ALL living organisms is that they are all boundered by a well defined, specific and reproducible boundary, or fence.  Minimally, therefore, we can say that "Life is organized".

As a result of what we have discussed thus far I would venture to suggest some additional, important aspects/requirements of living organisms:

(a) Living organisms exist, subject to the laws of chemistry and physics,

(b) the very act of living requires energy.  But according to the "laws of physics.....energy can neither be created nor destroyed", so......

(c) to survive -at least in our world- living organisms use organic atoms..."C H O N P S" to effectively cycle and recycle the available energy (in all its forms).... at the energetic expense of the local environment. Life is the ultimate capitalist.

(d) Paradoxically, therefore, as a consequence of ALL these "requirements", a single living organism cannot exist -by itself (?).

 

We will come back to each of these aspects again and again throughout the course, but for now, because you might not have thought about them for a while, let me re-aquaint you with the basic "building blocks" of Life, and how these building blocks potentially interact and "reproduce" themselves in living systems.

The Biochemistry of Living forms.

Organic matter: Carbon, Hydrogen, Oxygen,…(C H O N P S)......and the importance of driving on the "right" side of the road, or even- the importance of .... a good "hand shake"!!!!

handshake2     handshake2     handshake2

Just like humans, molecules have a potential "mirror image" or chirality. While most non-living molecules are racemic mixtures of either form, living organims have developed a homochirality "rule" to allow for the formation of more complex, intricate structures that are Stereo specific.... L-amino acids and D-Sugars

The organinc chemist William Bonner spent 25 (he claimed "wasted") years trying to find a non-biological origin for these dominance of these biologically relevant forms.

Nucleic acids: merely different storage materials of reproducible ribbons of "order" that provide the "blue print" for the maintenance of the living structure.

            

Protein:polymers of amino acids that are assembled into a chain in a manner that is determined by the blue print. And once assembled provides a function. Once the function is achieved, the protein is then recycled into its constituent parts, only to be "re-constructed" under the direction of the message written in the mRNA.

  

Sugars, Polysaccharides and Fats: paradoxically, though essential for life to exist, these are the transient, and yet stable forms of all living organisms.

    

One of the curiousities about Life, is that it requires an inherent, sustainable form of energy to maintain it's existence. 

The currency? One particular nucleotide, ATP!!!

The Biochemist's perspective on "Life" can be appreciated as being a series of "cycles", Carbon, Nitrogen, Sulphur with a few requisite metals thrown in for good measure...

 


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