Diversity and Classification

Taxonomy “The science of naming organisms

and assigning them to groups.”

Taxa- groups to which Linnaeus assigned organisms; taxon (singular)

The biological classification of organisms is based on a set of rules.

Classification Systems

• Why classify organisms?

• What are characteristics of a good classification system?

Connection to Natural SelectionNatural selection produces:

1. individuals that are adapted to their environment.2. and new species

This generates biodiversity.

In order to study biodiversity, scientists must organize species by classifying them into groups.

Why classify organisms?

1. Classification assigns a universally accepted species name.

2. Taxonomic groups (kingdom, phylum, etc.) have biological meaning.

Carlos Linnaeus (1707-1778)

• Swedish Botanist & “father of taxonomy”

• Systema Naturae

• Binomial nomenclature

• Genus

• specific epithet (species)

Systema Naturae

• printed in the Netherlands in 1735. It was an eleven page work.

• By the time it reached its 10th edition (1758), it classified 4,400 species of animals and 7,700 species of plants.

Binomial Nomenclature

• Latin• genus• species

• example: Homo sapiens or Homo sapiens

Biological Classification

TaxaKing- Kingdom Phillip- Phylum Came- Class Over- Order For- Family Green- Genus Spaghetti- Species

example

Biological Kingdoms

• Two Kingdoms- Linnaeus, 1758

• Three Kingdoms- Earnst Haeckel, 1866

• Five Kingdoms- Whittaker, 1869

Whittaker’s Five Kingdoms1. Monera- unicellular; bacteria and blue-green

algae (prokaryotes)

2. Protista- unicellular organisms (eukaryotes); both plant-like and animal-like forms

3. Fungi- multicellular, heterotrophs; yeasts, molds, mushrooms,

4. Plantae- multicellular, vascular plants, photosynthetic

5. Animalia- metazoans, heterotrophs

Kingdoms- present day

What is a species?

Biological Species Concept

A species is a population of organisms that actively or potentially interbreed, producing viable offspring and which remain reproductively isolated from other such populations.

How many species are there on Earth?

Currently there are about 1.4 million species described.

Current estimates of the total number of species on Earth range from 5 to 30 million (Environmental Literacy Council).

The 2005 Millennium Ecosystem Assessment notes approximately 2 million have been formally described.

Over half of all described animal species are insects, including nearly 300,000 known beetles.

Recently Extinct SpeciesDodo Bird Thylacine- “Tasmanian Wolf”

Extinction Statistics