Classification Notes

Why Do We Classify?

  • To organize/group
  • Recognize relationships
  • Study evolutionary history (phylogeny)

History of Classification

- Aristotle

•Greek philosopher

•Divided organisms into 2 groups- Plants and Animals.

•Divided animals into 3 groups according to how they moved.

–1. Walking (land)

–2. Flying (air)

–3. Swimming (water)

- Carolus Linnaeus

•Classified plants and animals according to similarities in form.

•Divided living things into one of two kingdoms,Plant or Animal.

•Divided each of the kingdoms into smaller groups called genera (genus).

•Divided each genera into smaller groups called species.

The Evolution of Our Classification System

•The Linnaean System is used by scientists all over the world, but has been expanded to include new and different living things as they are discovered. It will continue to grow as human knowledge grows.

Classification Terminology

•CLASSIFICATION –Grouping based on similarities.

•TAXONOMY – Science of classifying organisms.

•ORGANISM – Any living thing.

•BINOMIAL NOMENCLATURE –2 part Scientific Name. (Genus species)

•EVOLUTION – Species change gradually over time.

Our Current Classification System

  • The classification system in use today places each living thing into a series of specific groups based on similarities and differences in body structure, color and behavior.
  • The largest group into which any living thing can be classified is its Kingdom. Followed by . . .

Phylum

Class

Order

Family

Genus

Species

Our Hierarchical System

•Taxonomists divide organisms into a series of groups (divisions) that get more and more specific.

–Kingdom includes the largest numbers of organisms.

–Species include only one type of organism.

•Moving from kingdom to species

–groups increase in commonality and evolutionary relationships, but

decrease in size (fewer numbers).

The 5 Kingdoms

1. MoneranKingdom

•Bacteria

–Oldest living organisms

–Only seen through a microscope

–Unicellular / prokaryotes (no nucleus)

–Commonly found in the ground, water, and other living things

–Most are heterotrophs but some algae are autotrophs

- Harmful Bacteria

•In human hosts, bacteria cause diseases ex.

•Humans can be treated with antibiotics.

•Sterilization and disinfectants can help prevent infection.

- Helpful Bacteria

•Produces food- ex. yogurt, some cheeses

•Helps digest food- ex.bacteria in our digestive tracts

•Keeps the soil fertile -ex. nitrogen-fixing bacteria

- Archaebacteria

–Ancient Bacteria

–“extremophiles”

–found in harsh conditions such as volcanic vents at the bottom of the sea

- Eubacteria

–True Bacteria (bacteria found commonly in nature)

–blue-green algae

–Most bacteria are in this kingdom

2. ProtistKingdom

•“Odds and Ends” kingdom

•Any organism that is not a plant, animal, or fungus

•Mostly unicellular, some multi-cellular (algae)

•Most live in the water, some live in the body

•All are eukaryotic (have a nucleus)

- Classification of Protists

  • Protists are classified based on how they obtain food /nutrition and how they move.
  • Protozoans –Heterotrophs
  • Algae – Autotrophs
  • Fungus-Like –Heterotrophs and decomposers

3. FungusKingdom

•Examples – mushrooms, molds, yeasts and mildews.

•Most fungi are multi-cellular (yeast is unicellular).

•All fungi are eukaryotic heterotrophs.

•Fungi can be found almost everywhere on land, but only a few live in fresh water.

- The Importance of Fungi

•Decomposers

–Break down dead organisms

–Return nutrients to the ecosystems (soil and air).

•Drugs are produced

–Penicillin and other antibiotics

•Food supply

–mushrooms, truffles, morels, bubbles in bread, champagne, and beer.

  • Yeast

-Fermentation which causes bubblesand produces carbon dioxide to make bread.

-"Model organisms" for studying problems in genetics and molecular biology.

- Bad Fungi?

•Animal diseases

–Ringworm

–Athlete’s Foot

•Plant diseases

–Rusts and smuts

–Leaf, root, and stem rot

4. PlantKingdom

•multicellular

•Eukaryotes

•Autotrophs

–make food through the process of photosynthesis.

•Examples

–ferns, flowers, shrubs

–Trees

•Conifers

•Deciduous

5. Animal Kingdom

  • Heterotroph/ multi-cellular / eukaryotes

•InvertebratesNO BACKBONE

–

–Could be many!!!

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•VertebratesBACKBONE

–

–Could be many!!!

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–

* The organization of LIFE is ever changing!