The Main Themes of Microbiology (ch.1 PP

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Dec 14, 2012 (4 years and 10 months ago)

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THE MAIN THEMES OF
MICROBIOLOGY


Chapter 1

The Scope of Microbiology


Microbes are
ubiquitous
: ~found
everywhere


Examples


Hydrothermal vents


Polar ice caps


Toxic waste dumps






questional.com

MRSA





Estimates of the total number of microbial cells on Earth is
on the order of 5 x 10
30

cells.



Some estimate there are 8 to 10 million microbial species




Microbiology:

area of
biology that deals with
microscopic organisms


Microscopic:

“small to
see” (often needing a
microscope)


Microbe:

literally
meaning “small life”

mcdaid
-
science.wikispaces.com

Bacillus
anthracis




Because microorganisms are central to the very
functioning of the biosphere, the science of microbiology
is at the foundation of all the biological sciences.


Several major groups of microorganisms this course will
study:


Bacteria


Viruses


Fungi


Protozoa


Algae


Helminths (parasitic worms)



Virus

guardian.co.uk

Fungi

greendump.net

Protozoa

mdmedicine.wordpress.com

Algae

celsias.com

helminths

microscopesblog.com

Major Fields of Microbiology (
table 1.1)


Immunology:

studies protective substances and
reactions caused by invading microbes


Biotechnology:

studies any process that harnesses the
actions of living things to create a product


Epidemiology:

monitor and control the spread of
diseases in communities


Genetic Engineering:
deliberate alterations of the
genetic makeup of organisms (rapidly expanding field)


Food and aquatic microbiology:

examine the ecological
and practical roles of microbes in food and water



Agricultural Microbiology:

relationships between
microbes and domesticated plants and animals

Microbial Origins


The fossil record shows bacterialike cells that existed at
least 3.5 billion years ago!



These simple cells were the dominant forms of life for an
approximated 2 billion years.



These simple cells lacked many complex internal
structures, including the nucleus.



These simple cells were
prokaryotic:

cells that lack a
nucleus.

Microbial origins cont.


Around 1.8 million
years ago, a more
complex cell
containing a nucleus
appeared



Eukaryotic:

cell that
contains a nucleus

Microbial Involvement in Energy and
Nutrient Flow




Microorganisms change the chemical and physical
properties of their habitats through such activities as the
removal of nutrients from the environment and the
excretion of waste products.


Microbes are essential
in the flow of energy
and food through
Earth’s ecosystem



photosynthesis
:
light
-
fueled conversion
of carbon dioxide to
organic material, as
well as the formation of
oxygen


Photosynthetic
microorganisms
provided early Earth
with Oxygen



Today these microbes
still provide 50% of
Earth’s photosynthesis

t
opnews.in


Decomposition
: the breakdown of dead matter and
wastes into simple compounds that can be directed back
into the natural cycle of living things



Microbes are the main forces that drive the structure and
content of the soil, water, and atmosphere



Significant proportion of greenhouse gases are produced by
microbes


~50% of microbe species live exist underground, acting as a major
driving force in weathering, mineral extraction, and soil formation


Bacteria are essential for the function of higher level plants and
animals.

Taxonomy: Organizing, Classifying, and
Naming Microorganisms



Nomenclature: a system
of naming



Around for over 250
years,
taxonomy

is the
formal system for
organizing, classifying,
and naming living things.



Carl Linnaeus created
the basic rules for
modern taxonomy (taxa)

The Main Role of Taxonomy is…


Classification:

orderly arrangement of organisms into
groups indicating evolutionary relationships and history



Formation of
Nomenclature:

the process of assigning
names to the various taxonomic rankings of species



Identification:

the process of
determinging

and
recordign

the traits of organisms to enable their placement in an
overall taxonomic scheme.

Levels of Classification


Main
Taxa

(groups) in classification are organized into
descending ranks called a
hierarchy.




Domain

(category based on cell type)


Kingdom


Phylum


Class


Order


Family


Genus


species


Each domain can be
subdivided into a series
of kingdoms, each
kingdom is made of
several phyla, each
phyla of several classes,
classes of orders, and
so on.



Each
decent in the
category represents a
closer relationship
among the species
within
.

Assigning Names


Binomial system of nomenclature
: method of assigning
the scientific name of a species



This is always the combination of the genus name
followed by the species name.


First letter of genus name is always capitalized


First letter of species name is always lowercased


Both words are always italicized


Examples:


Staphylococcus
aureus


Lactobacillus
sanfrancisco

Origin and Evolution of
Microbs



Phylogeny:

relatedness between groups of living things




Different methods are used to create a taxonomy of
biological species


Morphology (structure)


Physiology (function)


Genetics (inheritance)



The underlying theme of all taxonomy is
evolution
:




living things change gradually through hundreds of years and that
these evolvements result in structural and function changes
through many generations.



Founded on two preconceptions:


All new species originate from preexisting species


Closely related organisms have similar features because they have
evolved from common ancestors



Universal Tree(s) of life



Three Major Domains:



Archaea


Bacteria


Eukarya

Whittaker system of classification

Woese
-
Fox system


Overarching methods of classification are always
changing



NOTE
: viruses are not included in any of the classification
or evolutionary schemes


Viruses are not CELLS!