Download NOTES Classification

Ch. 17 Organizing Life’s Diversity
Biologists have identified and named around 1.3 million species so far, and
believe there to be up to 6 -7 million species yet to be discovered!
KINGDOM
Bacteria....................................
Protoctists (algae, protozoa, etc).........
Animals, vertebrates.......................
Animals, invertebrates..................
Fungi......................................
Plants....................................
# OF SPECIES
4,000
80,000
52,000
1,272,000
72,000
270,000
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Total number of described species... 1,750,000
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Possible # of unknown species:..... 14,000,000
From the United Nations publication: UNEP-WCMC (2000). Global Biodiversity: Earth's living resources in the 21st
century. Cambridge, World Conservation Press.
Taxonomy – Science and study of classifying organisms. It provides a common,
universal scientific language. Taxonomy considers not only physical structure,
but also genetics.
Taxonomists – Scientists that study the classification of organisms.
Classification – placing of information or objects into groups based on certain
similarities.
Aristotle- (384 - 322 BC Greek philosopher) classified organisms into plants
and animals and subdivided plants into herbs, shrubs and trees. He grouped
animals according to their habitat and physical differences.
problem: did not group organisms according to their evolutionary history –
so birds, bats and flying insects were all grouped together.
Linnaeus- (1700s Swedish botanist) – developed the system we use today.
 Based on physical and structural similarities.
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Groupings revealed relationships between organisms.
Came up with the two word system we use today for naming organisms –
binomial nomenclature
Why do scientists need a naming system?
 Common names are NOT the same. In UK, buzzards are considered
hawks and in the US they are considered vultures.
 Scientists around the world use the same name!
 Biologists can clearly communicate with each other, eliminating confusion.
binomial nomenclature  first word = genus – a group of closely related different species
 second word = species (specific epithet) – organisms with similar
characteristics that can breed with each other and produce fertile
offspring.
The genus and species (specific epithet) together make the scientific name of the
species
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Homo sapiens (humans),
Canis lupus (wolf),
Uncia uncia (snow leopard),
 Felis catus - _____________________
 Canis familiaris - ___________________
Genus Ursus contains many closely related species of bears (black
bear, polar bear, grizzly bear).
Ursus arctos - _________________________
Ursus maritimus - _______________________
Ursus americanus - ______________________
 RULES for writing names:
(This is very important! From this point forward, I will subtract points if
the scientific name is written incorrectly!)
1. In print the name should be italicized and when handwritten needs to be
underlined.
2. The first letter of the genus is Upper case and the specific epithet
(species) is lower case.
3. Can be abbreviated. i.e. C. lupus
4. scientific names are in Latin – no longer used in conversation so will not
change
Linnaeus’s system of classification consists of levels, each level is
called a taxon (singular) or taxa (plural)
Organisms are ranked from broad characteristics to specific.
Taxa
ANIMALS:
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Examples:
PLANTS:
Domain
Kingdom
Division
Class
Order
Family
Genus
Species
Zebra:
Eukarya
Animalia
Chordata
Mammalia
Perissodactyla
Equidae
Equus
E. zebra
Gray wolf:
Eukarya
Animalia
Chordata
Mammalia
Carnivora
Canidae
Canis
C. lupus
Ponderosa pine:
Eukarya
Plantae
Pinophyta
Pinopsida
Pinales
Pinaceae
Pinus
P. ponderosa
As you move up taxa from Species to Kingdom, the groups become larger and
organisms are less related.
As you move down taxa from Kingdom to Species, the groups become smaller
and increasingly more related.
Kingdoms contain different Phyla, Phyla contain different Classes, …
3 DOMAINS(Domains categorized by cell type and structure):
-BACTERIA-
-ARCHAEA-
-PROTISTA-
1. Domain: BACTERIA:
Kingdom – Bacteria
 prokaryotes
 live in most habitats except extreme ones
 ex. strep throat, pneumonia (however most are harmless, some
helpful)
 microscopic, unicellular
 lack distinct membrane bound organelles
 Can be heterotrophs or autotrophs (producers)
 oldest fossils are 3.4 by old
2. Domain: ARCHAEA (1990) (unicellular prokaryotes):
(more ancient than prokaryotes but more closely related to eukaryotic ancestors)
Kingdom – Archaea
 Can be heterotrophs or autotrophs (producers)
 live in extreme environments (swamps, deep ocean vents, hot
springs)
 ribosomal RNA, cell walls and membranes
 several hundred species
3. Domain: EUKARYOTES:
Kingdom - Protista
 producers
 lacks complex organ systems
 lives in moist environments
 can be unicellular or multicellular
 can be plantlike autotrophs or animal-like heterotrophs
-FUNGI-
-PLANTAE-
-ANIMALIA-
Kingdom - Fungi (earth’s decomposers – over 50,000 species)
 heterotrophs
 do not move from place to place
 can be unicellular or multicellular
 absorb nutrients from organic materials in the environment –
NOT producers
Kingdom - Plantae (more than 250,000 species)
 producers
 multicellular
 photosynthetic
 do not move from place to place
 contain chloroplasts and have cell walls composed of cellulose
 organized into tissues and organ systems
Kingdom - Animalia
 multicellular
 heterotrophs
 can move from place to place
 no cell walls
 organized into tissues and organ systems
Evolutionary relationships are determined by:
1. Structural similarities
2. Breeding behavior
3. Geographical distribution
4. Chromosome comparisons
5. Biochemistry
Characters - inherited features that vary among species. Used for classification.
a. morphological - homologous structures indicate descent
from a common ancestor
b. biochemical – DNA and RNA
Phylogeny – evolutionary history of a species
Cladistics – system of classification that groups organisms together by shared
characteristics.
Models:
a. Cladogram – model of phylogeny of a species
b. fanlike