STUDY of LIFE (Biology 150 - University of Miami)
Course is divided into
(3) parts:
- 1) Cellular & Molecular Biology
- 2) Cell Reproduction & Genetics
- 3) Homeostasis & Physiology (some examples)
FIRST PART of our study will be...- " a Journey thru the COSMOS of the CELL "
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Modern Biology is often
described
as...
the MOLECULAR BIOLOGY
(BIOCHEMISTRY) of the CELL
- modern Biology commonly uses a different approach
- than you may used before for studying Biology -
- more common approach has been to look at DIVERSITY...
- the
kinds of plants &
animals known to exist -
whole of biology is a counterpoint of two themes:
astonishing variety in individual particulars (species);
astonishing consistency in fundamental mechanisms. -
Bil 150's current approach to modern biology is to stress...
- of Biology.
- In my opinion,
- there are 3 UNIFYING CONCEPTS,
-
which stress the UNITY
of LIFE...
[ Campbell describes 10 themes ]
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1. CELL THEORY
2. EVOLUTION
3. BIOENERGETICS (energy transformation)
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1.
CELL THEORY |
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Tenets of the Cell
theory
-
Universal Features of Cells on Earth
- all known living things (systems) are composed of cells
- cells
arise only from other pre-existing cells
(not by
Spontaneous Generation)
(see experiments of Redi and Pasteur* experiments*) - all energy flow (metabolism & biochemistry) of life occurs within cells
- all living cells on Earth store their hereditary information in DNA molecules - (for use by subsequent generations) - copied by templated polymerization.
-
Some important facts about cells (virtual cells - Kyrk's Cell Animations):
- their diversity : - many sizes, shapes, & types [165+ in humans] no two alike NAS-6
- their similarity: - have same basic structural plan
- surrounded by cell membrane
- contain nuclei (bacteria = genophore = area of DNA)
- similar sub-cell parts (ORGANELLES)
- all contain
universal properties of all cells*
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2.
EVOLUTION..."Descent with modification"
"Nothing in biology makes sense except in the light of evolution"
Theodor Dobzhansky (1973) in Amer. Bio Teacher 35:125-129
simply... Evolution is a
change in natural/physical characteristics of a population over time
In 1858
Charles
Darwin &
Alfred Russell Wallace
present papers to
Linnaean Society
with 2 important new hypotheses about biological
PATTERNS in the natural
world.
... all
species (past & present) are related by descent from
common ancestor
... hypothesized
all species come from preexisting species & they
change through time
- individuals in a
population vary in hereditable traits...(look around class)
- this accounts for the
diversity
we see in biology...
-
living things
change gradually
over time to become new forms...
- from one form ------------------> to another form
-
(one
SPECIES) --------> (New
SPECIES)
Darwin proposed a PROCESS (mechanism) for this (PATTERN) descent & change...
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MECHANISM - is via NATURAL SELECTION (SURVIVAL of FITTEST)
- individuals in a population vary in hereditable traits...
- some traits help individuals survive better or reproduce more.
- Natural Selection picks those individuals better fit to specific environment...
only those with superior traits (physical, behavioral, biochemical)
are more likely to SURVIVE and REPRODUCE...
passing their traits onto their progeny more efficiently
- over time... a whole population's characteristics can change
see an example of natural selection with a predation model*
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Examples of
SELECTION:
Artificial
Selection.... examples
in
Cabbage Plants*...
broccoli, cauliflower, Brussels sprouts, cabbage, kale, and
collard greens are all derived from
Wild Mustard plants
horticulturalists
SELECT* wild mustards with large buds =
Brussels sprouts
Natural
Selection.... examples
case
study 1* - Peter & Rosemary Grant & medium ground
finch
case study2
- feeding
preferences of different predators does cause changes in guppy
populations favoring long-term evolutionary changes by natural selection
David
Reznick (UCR) & John Endler (UCSB) - Trinidadian guppies
experimental design and results*
Student Media - Process of Science:
Selection or How environment affects
populations*
UNITY... Comes from fact that all living things
changed,
§
a theory
evolved by same rules, the
Laws of
Evolution
Evolution of Humankind
Tree of life*view
@ home
e3
3.
BIOENERGETICS
-
(science of
EQUILIBRIUM THERMODYNAMICS)...
science
of energy flow and transformation
within, through, and between organisms...
"cells do not produce energy - they consume
energy"
- UNITY comes from the fact that the mechanisms of
- energy change and flow are NOT different
- among different life forms, but are the SAME
- METABOLIC PATHWAYS - chemical reactions that produce useable cell energy
- ... pathways used by cells are all the same in bacteria, plants and animals.
- glycolysis, Krebs's cycle,
oxidative phosphorylation, &
photosynthesis ARE UNIVERSAL
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Unity...chemical reactions of life are the same in bacteria, plants, animals
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| the CELL is FUNCTIONAL UNIT of LIFE & of all known LIVING SYSTEMS |
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| CELL THEORY is to BIOLOGY as ATOMIC THEORY is to PHYSICS |
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| Definitions of a Cell : A particular organization of matter, bounded by a selectively permeable membrane, that is capable of self-reproduction, without the presence of other living organism. (eliminates viruses). |
"Living organisms are composed of inanimate molecules... and nothing is alive in a cell except the whole of it?" Matrin Olomucki (1993) The chemistry of life. NY, McGraw Hill |
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