Classification - Identifying and Grouping Organisms

TY Biology

Learning Objectives

• Identify the Domains and Kingdoms of Life

• Know who Carolus Linnaeus was and his contribution to classification

• Understand what is meant by a Dichotomous key.

• Create a simple dichotomous key to identify insects

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• Broadest, most inclusive taxon

• The three domain system was proposed by Carl Woesein 1990 following extensive research and is based on differentiating organisms using the molecule ribosomal RNA. His methods have become the standard approach used to identify and classify all organisms,

• Archaea and Bacteria are unicellular prokaryotes (no nucleus or membrane-bound organelles)

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

Domains

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Domain ARCHAEAKingdom – 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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Extremophiles

An extremophile is an organism that thrives under "extreme" conditions.

• Halophiles are organisms that thrive in very high concentrations of salt. The name comes from the Greek for "salt-loving“

• Methanogens produce methane from the reaction of hydrogen and carbon dioxide.

• Acidophiles thrive in acidic environments with pH values (1 to 5) including sulfuric pools and geysers and even our own stomachs.

• Thermophiles have optimal growth temperatures between 60 and 108 oCincluding shallow terrestrial hot springs, hydrothermal vent systems and deep sea hydrothermal vents.

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Domain BacteriaKingdom – EUBACTERIA

• Some may cause DISEASE

• Found in ALL HABITATS except harsh ones

• Important decomposers for environment

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

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Protista

Most are unicellular

Some are multicellular

Some are autotrophic, while others are heterotrophic

•Aquatic

Fungi

Multicellular, except yeast

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

Cell walls made of chitin

Plantae

Multicellular

Autotrophic

Absorb sunlight to make glucose –Photosynthesis

Cell walls made of cellulose

Animalia

Multicellular

Ingestiveheterotrophs (consume food & digest it inside their bodies)

Feed on plants or animals

Domain Eukarya Divided into four Kingdoms

Car0lus Linnaeus

• There are millions of species on Earth to name and organize without getting confused required a system?

• Today we still use a system developed in the 1700s by Carolus Linnaeus a Swedish botanist.

• During his lifetime, Linnaeus collected around 40,000 specimens of plants, animals, and shells.

• He believed it was important to have a standard way of grouping and naming species.

• In 1735, he published his first edition of Systema Naturae (The System of Nature), which was a small pamphlet explaining his new system of the classification of nature.

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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

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

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Binomial nomenclatureThe scientific system of naminganorganism using two terms, thefirst being the genus and the second the species.

Genus species•Latin or Greek

•Italicized in print

•Capitalize genus, but NOT species

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Turdus migratoriusAmerican Robin

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Genus -a group of organisms with common characteristics

Species -

• a group of organisms

• capable of interbreeding and

• producing fertile offspring.

Coyote Wolf

Jackal

Classification levels

All living things have both a Common and Latin name (made up of their Genus and Species)

Grey WolfCanis Lupus

DogCanis lupus familiaris

Dichotomous Key

• "Dichotomous" means "divided into two parts". Therefore, dichotomous keys always give two choices in each step.

• A dichotomous key is a tool that allows the user to determine the identity of items in the natural world, such as insects, trees, reptiles, rocks etc…

• Keys consist of a series of choices that lead the user to the correct name of a given item.

A tree that looses its leaves in winter

Leaves edges are lobed

Leaf edges are toothed

Leaflets emerge from a central point

Leaflets emerge in opposite pairs

Oak BeechHorse

ChestnutAsh

Single Leaves Leaves divided into leaflets

Sphynrna mokarran

Daisy