classification of life - Weeblybirdzellbiology.weebly.com/.../90700465/classification_of_life_ppt.pdfcopyright cmassengale 37. Example VERTEBRATES CICHLID -has backbone, paired appendages

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Classification

copyright cmassengale

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•There are 13 billion known species of organisms

•This is only 5% of allorganisms that ever lived!!!!!

•New organisms are still being found and identified

Species of Organisms


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What is Classification?

Classification is the arrangement of organisms into orderly groups based on their similarities

Classification is also known as taxonomy

Taxonomists are scientists that identify & name organisms


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Benefits of Classifying

•Accurately & uniformly names organisms •Prevents misnomers such as starfish & jellyfish that aren't really fish •Uses same language (Latin or some Greek) for all names

Sea”horse”??


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Confusion in Using Different Languages for Names


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Latin Names are Understood by all Taxonomists


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Early Taxonomists

•2000 years ago, Aristotle was the first taxonomist•Aristotle divided organisms into plants & animals•He subdividedthem by their habitat ---land, sea, or air dwellers


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Early Taxonomists•John Ray, a botanist, was the first to use Latin for naming•His nameswere very longdescriptions telling everything about the plant


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Carolus Linnaeus1707 – 1778

•18th century taxonomist

•Classified organisms by their structure

•Developed naming systemstill used today


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Carolus Linnaeus

•Called the “Father of Taxonomy”

•Developed the modern system of naming known as binomial nomenclature

•Two-word name (Genus & species)


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Standardized Naming

•Binomial nomenclature used

•Genus species•Latin or Greek•Italicized in print•Capitalize genus, but NOT species

•Underline when writing

Turdus migratorius

American Robincopyright cmassengale

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Binomial Nomenclature

Which TWO are more closely related?copyright cmassengale

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Rules for Naming Organisms

•The International Code for Binomial Nomenclature contains the rules for naming organisms

•All names must be approved by International Naming Congresses(International Zoological Congress)

•This prevents duplicated names


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Classification Groups

•Taxon ( taxa-plural) is a category into which related organisms are placed

•There is a hierarchy of groups (taxa) from broadest to most specific

•Domain, Kingdom, Phylum, Class, Order, Family, Genus, species


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Hierarchy-Taxonomic Groups

DomainKingdomPhylum (Division – used for plants)Class

OrderFamily

GenusSpecies

BROADEST TAXON

Most Specific


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Dumb

King

Phillip

Came

Over

For

Gooseberry

Soup!


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•Broadest, most inclusive taxon•Three domains•Archaea and Bacteria are unicellular prokaryotes (no nucleus or membrane-bound organelles)

•Eukarya are more complex and have a nucleus and membrane-bound organelles

Domains


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ARCHAEA• Kingdom - ARCHAEBACTERIA

• Probably the 1st cells to evolve• Live in HARSH environments

• Found in:–Sewage Treatment Plants (Methanogens)

–Thermal or Volcanic Vents (Thermophiles)

–Hot Springs or Geysers that are acid

–Very salty water (Dead Sea; Great Salt Lake) - Halophiles


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ARCHAEAN


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BACTERIA

•Kingdom - EUBACTERIA

•Some may cause DISEASE•Found in ALL HABITATS except harsh ones

•Important decomposers for environment

•Commercially important in making cottage cheese, yogurt, buttermilk, etc.


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Live in the intestines of animals


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Domain Eukarya is Divided into Kingdoms

•Protista (protozoans, algae…)

•Fungi (mushrooms, yeasts …)•Plantae (multicellular plants)•Animalia (multicellular animals)


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Protista

•Most are unicellular•Some are multicellular•Some are autotrophic, while others are heterotrophic•Aquatic


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Fungi•Multicellular,except yeast

•Absorptive heterotrophs(digest food outside their body & then absorb it)

•Cell walls made of chitin


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Plantae

•Multicellular•Autotrophic•Absorb sunlight to make glucose –Photosynthesis

•Cell walls made of cellulose


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Animalia

•Multicellular•Ingestive heterotrophs(consume food & digest it inside their bodies)•Feed on plantsor animals



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Taxons

•Most genera contain a number of similar species

•The genus Homo is an exception (only contains modern humans)

•Classification is based on evolutionary relationships



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Basis for Modern Taxonomy

•Homologous structures (same structure, different function)

•Similar embryo development•Molecular Similarity in DNA, RNA, or amino acid sequence of Proteins


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Homologous Structures (BONES in the FORELIMBS) shows Similarities in mammals.


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Similarities in Vertebrate Embryos


Comparing StructuresCharacter: A feature or thing we can examine or label. It is

important that the feature be heritable.

Homologous Character: Character which is shared by

taxa by descent. Exists because it existed in a common ancestor.

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Analogous Character: Shared resemblance between

characters by other means than descent, such as adaptation. This is often called a homoplastic character.


Primitive Vs. Derived CharacteristicsPrimitive Character = Plesiomorphy

A character which is in the state shared by the common ancestor of the group.

Derived Character = Apomorphy

A character in a new state, not the primitive one.

Shared Character: A character shared by all the members of the group.


ExampleVERTEBRATES

CICHLID - has backbone, paired appendages (fins), dorsal nerve cord and aorta which are shared derived characters uniting the cichlid with frogs, turtles, kangaroos, mice, and humans.

FROG - has all those plus legs.

TURTLE - has all those plus a hard shelled egg called an amniotic egg.

KANGAROO - all those plus hair, warm blood, and egg develops inside.

MOUSE - all those plus placental development

HUMAN - all those plus very large brain and loss of hair.

NOTE THAT FOR EACH SHARED DERIVED CHARACTER THERE IS A PRIMITIVE CHARACTER. For example, kangaroos, mice and humans all share having hair. The corresponding primitive character is "not having hair". Fish, frogs and turtles lack hair, but these shared primitive characters are not evidence of relationship, because many other organisms lack hair that are outside the group we are considering - clams, for example.


PhylogenyPhylogenyPhylogenyPhylogeny•a family tree for the evolutionary history of a species

•The root of the tree represents the ancestral lineage

•Tips of the branches represent descendents of the ancestor

•Movement upward shows forward motion through time

•Speciation: split in the lineage•Shown as a branching of the tree

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CladogramDiagram showing how organisms are related based on shared, derived characteristicssuch as feathers, hair, or scales


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Primate Cladogram


Phylogenic Tree Vs. Cladogram

What’s the difference?

Not much. At this level they are used fairly interchangeably.

Cladograms often emphasize derived characteristics.

Phylogenic trees sometimes emphasize phylogenic groups. Both show evolutionary relationships.



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classification of life - Weeblybirdzellbiology.weebly.com/.../90700465/classification_of_life_ppt.pdfcopyright cmassengale 37. Example VERTEBRATES CICHLID -has backbone, paired appendages