Taxonomy
The science of naming and classifying living things is called
taxonomy.
Common Names: Vary from place to place and from person to
person. For example a flower could have various names.
Scientific Name: These names are the same everywhere.
Binomial Nomenclature: Assigns every living organism a two-word
scientific name. The names are written in Latin and were created by
Carolus Linnacus, a Swedish botanist. For example Homo sapiens is
the scientific name for humans.
 Scientific names are always written in italics or underlined.
 Scientific name is always written with the genus name before
the species name.
 The genus name is always Capitalized.
 The species name will tell you what type of organism it is. The
genus name will be the adjective that describes the organism.
 Examples: Quercus rubra = oak red = red oak tree
Quercus alba = oak white = white oak tree
Taxonomic Categories:
 The categories range from general to specific.
 The most general category includes many different types of
organisms, while the most specific category has only one kind
of organism.
Categories:
1.
Kingdom (most general)
2.
Phyla
3.
Class
4.
Order
5.
Family
6.
Genus
7.
Species
Kings
Play
Cards
On
Fridays
Generally
Speaking
*Note: Each sub group is made up of organisms that are more alike.
Basics for Classification:
 Relatedness is the basis for classification.
 In biology, related organisms are believed to have the same or
common ancestors.
 Must go beyond outward appearances.
1.
Homologous Structures: Placed in the same categories.
Similar structures in different organisms that develop in the
same way. For example: Arm of a human and wing of a bat
have similar bones that develop in the same way.
2.
Analogous Structure: Placed in different categories.
Structures in different organisms that have similar functions
but develop in different ways. For example: Wing of a bird
and a wing of an insect.
3.
Chemical Tests:
Analyze blood. For example: Blood in whales is more
closely related to humans than to fish.
Life History of Organism:
How they develop and reproduce. For example: Whale not
closely related to fish because most fish hatch from eggs laid
by the mother. A whale develops within the mother’s body.
4.
5.
Breeding Studies:
If two (2) organisms breed and produce offspring that also
produce the same kind of offspring, they belong to the same
species.
Kingdom Monera
 Includes all prokaryotic cells such as bacteria and blue green
algae.
 Probably the biggest ecological success and still dominate the
world by:
 Their abundance
 Their distribution
 Their diversity (Approx. 4000 species known)
 Their ability to sustain life for others
 Their ability to withstand the harshest, most
severe environments
 Their size in relation to other organisms is extremely small.
Virus < Prokaryotes (1000 x larger) < Eukaryotes (1000 x larger)
 These organisms are in the kingdom because they are
prokaryotes, which mean they lack a true nucleus (no nuclear
membrane).
Bacteria:
 Are one celled organisms with a simple cell structure.
 Are the most numerous of all organisms.
 Anything that comes in contact with the air picks up bacteria,
which grow and reproduce if they have enough food.
Cell Structure:
 Cell wall with small pores and require small food molecules
(enzymes help break down larger particles).
 Some bacteria have a slimy, jelly-like layer called a capsule
outside the cell wall, which helps protect the bacteria from
chemicals in its surroundings.
 Have a cell membrane inside the cell wall which serves as a
barrier between the cell’s surroundings and its cytoplasm, the
part of the cell within the membrane.
 The membrane also helps make DNA.
 The cytoplasm is the nuclear body, which consists of the long
DNA molecule.
Four Kinds of Bacteria:
1. Round bacteria are called cocci (coccus): Grow in
clusters or in chains.
2. Rod -shaped bacteria are called bacilli (bacillus).
3. Bent - rod shapes are vibrios.
4. Spirals are called spirilla.
Movement:
 Carried by air and water.
 Some can swim by the use of flagella.
Reproduction:
 Asexually: Fission (divide in 2) and no exchange of DNA.
 Some mate and there is a transfer of DNA.
 Bacterial spores: Resistant to harsh conditions as it is protected
by several sets of membranes.
 These spores are formed on bacteria and can develop into
ordinary bacterial cells.
How Bacteria Live:
 Most are saphrophytes: Feed on dead organisms.
 Some are parasites: Obtain food from living organisms.
 Some are photosynthetic: Obtain energy needed for growth
from sunlight.
 Some are chemosynthetic: Obtain energy by breaking down
chemical substances such as asphalt, detergents, paints, paper
and pesticides.
 Either aerobes (need oxygen) or anaerobes (live without
oxygen).
How Bacteria Are Killed:
 By heat, sunlight, ultraviolet light or by chemicals such as
alcohol, chlorine and iodine.
 Penicillin kills bacteria by interfering with the development of
the cell wall.
Helpful Bacteria:
 Help to break down dead organisms into simple molecules.
 Convert nitrogen gas in the air into chemical forms that can be
used by plants and animals (found in soil and water).
 Make buttermilk, cheese, sauerkraut through fermentation.
 Used to purify water.
Harmful Bacteria:
 Disease in man and animals such as gonorrhea, pneumonia,
syphilis, whooping cough.
 May cause milk to spoil.
 Botulism: Poisoning when improperly canned.
Archaebacteria & Eubacteria:
 The kingdom is broken into two main classifications based on
what time period the organisms came into existence.
 Archaebacteria (early/ancient earth)
 Eubacteria (true bacteria)
Three Types of Archaebacteria:
 The classification Archaebacteria lived 3.5 billion years ago.
 They lived in environments that were extreme, some even
without oxygen.
 There are three distinct types of archaebacteria:
 Thermoacidophiles: Live in hot (70 – 90 degrees Celsius),
acidic environments (ph <2). Examples include hot sulfur
springs, smoldering piles of coal mining debris.
 Halophiles: Require high concentration of salt to survive.
Examples include salt brine, ocean borders, inland seas such
as the Dead Sea.
 Methanogens: Are killed by oxygen. Produce methane gas
from hydrogen and carbon dioxide. Examples include stagnant
water, hot springs, sewage treatment plants, ocean bottom,
digestive tracts of animals (cattle & humans).
Eubacteria Are A Diverse Group:
 May be aerobic or anaerobic, photosynthetic or thermophilic.
 Includes both autotrophs (produce food) and heterotrophs
(consume food).
 A gram stain can identify 2 groups of eubacteria.
 This method, named after Hans Christian Gram, distinguishes
between two kinds of bacterial cell walls.
 Bacteria is stained with a violet dye and
iodine.
 It is then rinsed in alcohol.
 Bacteria is stained again with a red dye.
 The structure of the cell wall determines the
results.
 Gram - positive eubacteria will retain the violet dye.
 Gram - negative eubacteria will shed the violet dye when rinsed
in the alcohol and retain the red dye.
Eubaceria Are Divided Into Three Main Groups:
 Mycoplasms:
 Lack a cell wall.
 Are resistant to penicillin which works by
inhibiting the growth of the cell wall.
 Most are harmless. But some cause disease
(pneumonia) in humans & cattle.
 Gram – Positive:
 Are wide spread in both soil and air.
 Some produce lactic acid and as a result are
used in making sauerkraut, buttermilk and
yogurt.
 Others are a source of antibiotics.
 Gram – Negative:
 Includes the rest of the eubacteria.
 A very diverse group.
 Many are photosynthetic, both aerobic and
anaerobic.
 Based on the pigment in the cells, eubacteria can be called:
 Green Eubacteria
 Purple Eubacteria
 Blue-Green Eubacteria (cyanobacteria)
Cyanobacteria:
 A special type of photosynthetic eubacteria which is thought to
be the bridge between Kingdom Monera and Kingdom Plantae.
 They use chlorophyll for photosynthesis and have structures
and functions similar to those of algae and plants.
 They are thought to be responsible for the oxygen revolution
that changed Earth’s atmosphere from largely carbon and
nitrogen based to oxygen based, making larger oxygen reliable
organisms, such as humans, viable to live.
 Although cyanobacteria produce their own food, many bacteria
get their energy from other organisms.
 If the food source is living, the eubacteria is considered to be
parasitic.
 If the food source is dead, the eubacteria is considered to be a
decomposer.
Eubacteria Plays an Important Role in The Nitrogen Cycle:
 The eubacteria which live in plant roots, causing them to swell
resulting in nodules, are responsible for nitrogen fixation.
 Eubacteria which are responsible for converting the ammonia to
nitrates are called nitrifying bacteria.
 Eubacteria which are responsible fro converting the remaining
nitrates to nitrogen gas, allowing it to escape into the
atmosphere, are called denitrifying bacteria.
Some Eubacteria Are Pathogens:
 Although most bacteria are harmless and often beneficial, a few
are not and are considered to be pathogens (a disease –
causing organism).
 Many plant diseases are caused by eubacteria (Fire Blight on
fruit trees).
 Human conditions caused by types of eubacteria include:









Cholera
Leprosy
Tetanus
Pneumonia
Whooping Cough
Typhoid
Toxic Shock Syndrome
Diptheria
Cavities
 Sexually transmitted diseases (STD’s) caused by eubacteria
include:
 Gonorrhea
 Syphilis
 Chlamydia
Biological Science: An Ecological Approach Textbook: Page 296