Classification
 Biodiversity – the variety of organisms in an ecosystem.
 10,000,000+ species known to exist today.
 Possibly 30,000,000+ species of insects alone.
 Relationship between organisms determined by:
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Evolutionary relationship
Biochemistry
Behavior
Developmental stages
Classification
 8 Levels of classification in modern system.
 There used to be 5 levels in the original Linnaeus system
 Each level is called a taxon and can change as more information
becomes available.
 Can be used to classify all BUT asexually reproducing species
1. Domain (largest category, organisms are least similar)
2. Kingdom
3. Phylum
4. Class
5. Order
6. Family
7. Genus (smallest category, organisms most similar)
8. Species (down to a single organism!)
Saying for remembering this is?
Which is more closely related to the …
Domain – broadest level, includes 3 lineages:
1. Archaea: similar to Bacteria, but inhabit extreme hostile
environments (hot springs, deep-sea thermal vents, salty
lake, no O2). “Ancient”
2. Bacteria: unicellular prokaryotic organisms. Lack
organelles and nucleus. Has a cell wall.
3. Eukarya: multicellular eukaryotic organisms. Has
organelles and a nucleus.
“True nucleus”.
Kingdoms
 6 different kingdoms in modern system
 Used to be 5 because …
 Archaebacteria & Eubacteria used to be 1 kingdom
known as Monera.
6 Kingdoms
Kingdom
Eubacteria
Bacteria
Archaebacteria
Bacteria
Protista
1 cell organisms with nucleus
Fungi
Yeasts, molds, mushrooms (Do Not make own
food like plants)
Plantae
All Plants
Animalia
All Animals
Kingdom Archaea (Domain Archaea)
•Prokaryotic – no nucleus or membrane bound organelles
•Used to be in Kingdom Monera with bacteria
•Unicellular and microscopic
•Live in extreme environments (Salty lakes and boiling hot
springs)
Kingdom Bacteria (Domain Bacteria)
•Prokaryotic – no nucleus or membrane bound
organelles
•Used to be in Kingdom Monera with archaea
•Unicellular and microscopic
•Can be a PRODUCER
•Normal bacteria
•GRAM STAIN
Used to differentiate between
different types of bacteria
(Gram + or Gram -)
•FACT
Penicillin kills bacteria by stopping
their production of their cell walls
Kingdom Protista (Domain Eukarya)
•Eukaryotic – nucleus and membrane bound organelles
•Diverse collection of mostly single celled organisms
•Can be “animal like” or “plant like”
•Algae is an example of plant like (is autotrophic –
photosynthesis) – these are PRODUCERS
•Animal like protists are called protozoans
•Recent evidence suggests this kingdom should be split
into multiple kingdoms
Kingdom Fungi (Domain Eukarya)
•Eukaryotic - nucleus and membrane bound organelles
•Multicellular
•Includes mushrooms, molds, yeasts
Mode of nutrition
Heterotrophic - Mostly decomposers (break down remains of
dead organism and organic wastes, such as leaf litter and animal
feces, and absorb the nutrients into their cells)
**Additional Info about the
Kingdom Fungi not on note
handout
• Produce spores that can survive for very long
periods of time in unfavorable conditions and will
wait to sprout until conditions are favorable for
the adult fungi to survive
• Have a branching network called hyphae that work
with their roots to digest the surface they are
growing off of
• Have a cell wall NOT composed of cellulose
• Some of them can produce toxic chemicals
Kindgom Plantae (Domain Eukarya)
•Eukaryotic - nucleus and membrane bound organelles
•Multicellular
•Plants
•Nonmotile
•Special Organelles (that animals don’t have) – 1) Cell walls made of
cellulose, 2)Chloroplast, 3)Central vacuoles
Mode of Nutrition
Autotrophic - Produce own food through photosynthesis
Kingdom Animalia (Domain Eukarya)
•Eukaryotic - nucleus and membrane bound organelles
animals
•Multicellular
•Motile
•Lack rigid cell walls, chloroplasts, and central vacuoles
Mode of nutrition
Heterotrophic – eat different organisms for food
VIRUSES
•Viruses are considered NON-LIVING because
they are not made of cells.
•So, what kingdom would they be classified in?
More facts about viruses:
•Require a host to reproduce
•Made only of protein and DNA
•No known cures for human viruses. If you get one,
you will have it for life.
Taxonomy – science classifying organisms.
(Systematics is classifying organisms based off of their
evolutionary history)
 Aristotle (about 2,400 years ago)
 1st scientist to classify organisms
 Only two groups (plant & animal) based on habitat and stem
structure.
 Common names & long descriptions
 Carolus Linnaeus (year 1735)
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“father of modern taxonomy”
Based on structural similarities.
Originally has 5 levels of classification.
Used 2 name naming system (binomial nomenclature)
Binomial nomenclature – 2 name naming
system.
 “Genus & species”
 First word capitalized, second word not.
 Always italicized or underlined.
 Always in Latin because…
 Dead language (not subject to change in meaning “slang”)
 It is universal
 Example: Homo sapien or Homo sapien
Dichotomous key
 "divided into two choices“
 looks at the similarities and
differences
 leads the user to the organism’s name
MONEY TAXONOMIC KEY
1 A. Metal....................................................go to 2
1 B. Paper....................................................go to 5
2 A. Brown (copper)........................................penny
2 B. Silver....................................................go to 3
3 A. Smooth edge...........................................nickel.
3 B. Ridges around the edge...............................go to 4
4 A. Torch on back..........................................dime
4 B. Eagle on back...........................................quarter
5 A. Number 1 in the corners...............................$1 bill
5 B. Number 2 in the corners...............................$2 bill
Problems with Taxonomy
 Classifying species into higher taxa is useful, but
ultimately arbitrary
 Higher classification levels are defined by various
morphological characteristics instead of measurable
differences that could be used to apply to an entire
taxon level
 Therefore, many biologists now propose that
classification be based solely off the evolutionary history
of an organisms
Classifying organisms based on
Evolution
 Phylogeny – the evolutionary relationship between
organisms.
 Cladogram / Phylogenetic Tree- looks like family tree,
used to show evolutionary history of organisms
 Evidence of shared ancestry:
 Fossil records
 Homologous features
 Embryological evidence
 Analogous structures - traits that have similar use, but different
structure. Due to structure being used in similar way
 Homologous structures – traits that have similar structure, but
have different uses. Due to common ancestry.
Cladistics (Cladograms)
 Organisms are grouped into clades
 A clade is a group of species that includes an ancestral
species and all of its descendants
 Based on a new trait developing and being passed
down to descendants
 Groups of organisms that share these new traits are
more closely related to each other than to groups who
only have ancestral traits
Making Cladograms / Phylogenetic
Trees
 Shared derived characters – new traits that are
shared by a group
 These shared derived characters distinguish between
clades and are “branches” in the tree of life (and
branches in cladograms)
 Shared ancestral characters – original traits present
in ancestral groups
Making Cladograms /
Phylogenetic Trees – Character
Tables
 Character Table - Table used to generate phylogenetic
trees by comparing characteristics as species.
 Each new character represents the divergence of two
groups from a common ancestor (one without the
new characteristic and one with it) and thus shows
the order in which new traits evolved
 Ingroup – group of taxa that is actually being analyzed
 Outgroup – species or group of species that is known to have
diverged before the lineage that contains the groups we are
studying
hagfish
perch
salamander
lizard
pigeon
mouse
chimp
Fur;
mammary
glands
0
0
0
0
0
1
1
Feathers
0
0
0
0
1
0
0
Claws or
nails
0
0
0
1
1
1
1
Lungs
0
0
1
1
1
1
1
Jaws
0
1
1
1
1
1
1
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Classification