Download species - askmrlloyd

Systematics
• Branch of Biology that deals with classifying
living things both current and prehistoric.
3 components:
1. Taxonomy:
–
Branch describing and naming new taxonomic
groups (species)
2. Classification
–
Branch organizing information about organisms by
arranging them into a hierarchical system
3. Phylogenetics
–
Branch determining the evolutionary history and
relationships among the various forms of life through
time
Current
Taxonomic
Model
Domain
Kingdom
Phylum / Division
Class
Order
Family
Genus
Species
Species
The smallest group of organisms classified
• Difficult to determine the criteria for what a species
is.
– Example: is a mule it’s own species?
• A species is a population which can interbreed with
each other (share a gene pool) to produce fertile
offspring
• This makes them a distinct biological unit
• Part of the scientific name
• e.g. scientific name of human : Homo sapien
Scientific name of a cat: Felis domesticus
Genus
• Group of closely related species
• All the species in a genus share common
characteristics
– Ex: a house cat, Felis domesticus, and a mountain lion, Felis
concolor, share many similar characterisitcs, but are clearly
different organisms
Binomial
Nomenclature
• Naming system developed by Swedish botanist
Carolus Linneaus
• Each organism has a two part name
• First the genus and then the species
– Ex: Acer rubrum (red maple tree)
Acer is the genus name
rubrum is the species name
• The species name is usually a Latin word
describing a characteristic
• Notice: genus name is capitalized, species
name is not!
Family
• A family is a larger classification than genus
and groups similar genera (plural for genus)
together
– Ex: all genera of cat-like animals are grouped in the
family Felidae
– Felis, Panthers, Acinonyx
Order
• The next largest classification (taxon) groups
similar families together
– Ex: Cats (family Felidae) and Dogs (family Canidae)
are in the order Carnivora (carnivores)
Class
• Orders are grouped into classes, again based
on common characteristics
– Ex: all order of Carnivora are warm-blooded, have
body hair and produce milk, so they are placed with
the order Primates (incl. humans) in the class
Mammalia
Phylum
(Division)
• Classes are grouped into a phylum
– Ex: mammals are placed in the phylum Chordata with
birds, fish, and reptiles because they share a similar
characteristic (of nervous system development)
Cladogram
Phylogenetic
Tree
Kingdom
• Closely related Phyla are grouped into
Kingdoms
• There are six kingdoms:
– Animalia, Plantae. Fungi, Protista, Eubacteria,
Archaebacteria
Domain
• In 1990 a system of 3 Domains was introduced
– Domain Eukaraya (includes Protists, Fungi, Plantae
and Animalia Kingdoms)
– Domain Bacteria (includes Kingdom Eubacteria)
– Domain Archaea (includes Kingdom Archaebacteria)
So where
did this
system
come from?
(the history)
Aristotle (384 – 322 BCE)
• Created the first widely used system of
classification by dividing organisms into
Animals and Plants
Carolus Linnaeus (1707 – 1778)
• Developed a hierarchical categorization
system (kingdom, phylum, class, order, family,
genus, species)
• Grouped organisms based on their resemblance
to other life forms
• Developed the Binomial Nomenclature system
(still in use today)
1850’s
• Improvements in light microscope led to the
discovery of a large number of organisms
Ernst Haeckel (1866)
• Proposed 3rd Kingdom Protista which includes
all single celled organisms
1900’s
• Invention of electron microscope and
advancements in biochemistry
• Discovery of Eukaryotic and Prokaryotic cells
Robert Whitaker (1959)
• Proposed 5 kingdom system (Plants, Animals,
Fungi, Bacteria and Protists)
Carl Woese (1970’s)
• Analyzed base sequences of RNA in bacteria
and protists and suggested that bacteria should
be separated into two groups Eubacteria and
Archaebacteria
• Led to a Six Kingdom system in which
Kingdom Bacteria (Monera) was separated into
the Eubacteria and Archaebacteria kingdoms
• 1990 Woese proposed a Three Domain
scheme of clasification