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Life on Earth



Bee on flower
Click on image for full size (85K jpeg)
Image courtesy of Corel Photography
Between 2 and 3 million species are currently known on Earth and new species are being discovered every day. From tiny yeasts to starfish to blue whales, the diversity of life is pretty awesome! Some forms of life on Earth survive in truly harsh environments, environments which might be compared to those of other planets. With so many kinds of living things, how can we ever make sense of it all?

Scientists have organized living things into groups according to how closely they are related. The smallest groups are called "species" which represent one kind of living thing. The largest groups are called "kingdoms". All living things on Earth are classified into five Kingdoms:
Kingdom Monera -- the bacteria
Kingdom Protista -- the protists
Kingdom Fungi -- the fungi
Kingdom Plantae -- the plants
Kingdom Animalia -- the animals


Image archive

Learn about ocean life!

Exploratour: Life on Earth

Exploratour: Life in the Solar System

Exploratour: NASA's exploration for life

Terrestrial Life



Bee on flower
Click on image for full size (85K jpeg)
Image courtesy of Corel Photography
It is estimated that between 2-3 million species are currently known to inhabit Earth and new species are being discovered every day. From tiny yeasts to starfish to blue whales, life's diversity is truly impressive! Some forms of life on Earth survive in truly harsh environments, environments which might be compared to those of other planets. With such a diversity of life on Earth, how does one go about making sense of it all?

Scientists organize "species" (a unique type of organism) into groups of increasing size according to how closely they are related. Very closely related "species" belong to the same "genus". Closely related "genera" are grouped into the same "family", and so on. From smallest to largest, the names of these groups are: Species, Genus, Family, Order, Class, Phylum (or Division), and Kingdom.

Currently, all of life is classified into one of five Kingdoms:
Kingdom Monera -- the bacteria
Kingdom Protista -- the protists
Kingdom Fungi -- the fungi
Kingdom Plantae -- the plants
Kingdom Animalia -- the animals


Image archive

Learn about ocean life!

Exploratour: Life on Earth

Exploratour: Life in the Solar System

Exploratour: NASA's exploration for life

Terrestrial Life



Bee on flower
Click on image for full size (85K jpeg)
Image courtesy of Corel Photography
It is estimated that between 2-3 million species are currently known to inhabit Earth and new species are being discovered every day. From single-celled yeasts to starfish to blue whales, life's diversity is truly impressive! Some forms of life on Earth survive in truly harsh environments, environments which might be compared to those of other planets.

Carl von Linne (also known as Carolus Linnaeus, 1707-1778), a botanist from Sweden, devised a system of binomial nomenclature to name and identify each species (type of organism) as being unique from every other. "Binomial" refers to the fact that each species' name is in two parts. The first part of the name refers to the "Genus", or group of organisms to which the given organism is very closely related. The second part of the name identifies the "Species".

Very closely related "species" are said to belong to the same "genus". Closely related "genera" are grouped in to the same "family", and so on. From smallest to largest, the names of these groups are: Species, Genus, Family, Order, Class, Phylum (or Division), and Kingdom.

Currently, all of life is classified into one of five Kingdoms:
Kingdom Monera -- the bacteria
Kingdom Protista -- the protists
Kingdom Fungi -- the fungi
Kingdom Plantae -- the plants
Kingdom Animalia -- the animals


Image archive

Learn about ocean life!

Exploratour: Life on Earth

Exploratour: Life in the Solar System

Exploratour: NASA's exploration for life



Last modified January 11, 1999 by the Windows Team

The source of this material is Windows to the Universe, at http://www.windows.ucar.edu/ at the University Corporation for Atmospheric Research (UCAR). ©1995-1999, 2000 The Regents of the University of Michigan; ©2000-05 University Corporation for Atmospheric Research. All Rights Reserved. Site policies and disclaimer