Table of Contents
For Students
life: Media
biology
Videos
Learn what defines an organism and consider two candidates for the title of world's...
Video: Encyclopædia Britannica, Inc.
A survey of the largest known single living organisms on Earth, which includes representatives...
Video: © MinuteEarth (A Britannica Publishing Partner)
Learn about carbon and how it forms the basis of life.
Video: © American Chemical Society (A Britannica Publishing Partner)
Images
A herd of African elephants (Loxodonta africana) drinking from the Chobe...
© nicolamargaret—iStock/Getty Images
Scanning electron micrograph of Streptococcus pyogenes, associated with...
National Institute of Allergy and Infectious Diseases
Mangroves (Rhizophora apiculata) at low tide on the coast of Thailand.
C.B. Frith/Bruce Coleman Inc.
Bald eagle perching on a snag in Kenai, Alaska.
© MorningDewPhotography—iStock/Getty Images
Active traps of the Venus flytrap (Dionaea muscipula), a carnivorous plant....
© Robert and Linda Mitchell
The initial proposal of the structure of DNA by James Watson and Francis Crick, which...
Encyclopædia Britannica, Inc.
Carbon is transported in various forms through the atmosphere, the hydrosphere, and...
Encyclopædia Britannica, Inc.
Intrinsic proteins penetrate and bind tightly to the lipid bilayer, which is made...
Encyclopædia Britannica, Inc.
Over hundreds of millions of years, life spread through the seas and over Earth's...
Encyclopædia Britannica, Inc.
DNA in the cell nucleus carries a genetic code, which consists of sequences of adenine...
Encyclopædia Britannica, Inc.
Two αβ dimers combine to form the complete hemoglobin molecule. Each heme group contains...
Encyclopædia Britannica, Inc.
The process of food capture in different animal species.
Encyclopædia Britannica, Inc.
Pathway of carbon dioxide fixation and reduction in photosynthesis, the Calvin cycle....
Encyclopædia Britannica, Inc.
The three processes of ATP production include glycolysis, the tricarboxylic acid...
Encyclopædia Britannica, Inc.
(1) The sperm release enzymes that help disperse the corona radiata and bind to the...
© Merriam-Webster Inc.
The Whittaker five-kingdom classification of life.
Encyclopædia Britannica, Inc.
Cyanobacteria in a hot spring at Yellowstone National Park, Wyoming.
© Brad Pict/Fotolia
General Grant tree, a giant sequoia (Sequoiadendron giganteum), among the...
© Gene Ahrens/Bruce Coleman Inc.
Arctic tern (Sterna paradisaea). It breeds in the southerly reaches of the...
© Index Open
An evening primrose (Oenothera biennis) seen (top) in visible light and...
Thomas Eisner
Silkworm moths (Bombyx mori) mating on cocoons.
Stephen Dalton—NHPA/Encyclopædia Britannica, Inc.
The geologic time scale from 650 million years ago to the present, showing major...
Encyclopædia Britannica, Inc.
Parallel evolution of marsupial mammals in Australia and placental mammals on other...
Encyclopædia Britannica, Inc.
The stratigraphic chart of geologic time.
Encyclopædia Britannica, Inc. Source: International Commission on Stratigraphy (ICS)
Living stromatolites in Hamelin Pool of Shark Bay, Western Australia.
© Ikonya/Shutterstock.com
Spriggina fossil from the Ediacaran Period, found in the Ediacara Hills...
Courtesy, University of California Museum of Paleontology, www.ucmp.berkeley.edu
The Creation of Adam, detail of the ceiling fresco by Michelangelo, 1508–12;...
SuperStock
Photograph of Jupiter taken by Voyager 1 on February 1, 1979, at a range of 32.7...
NASA/JPL
Figure 4: Important events in the history of life.
Encyclopædia Britannica, Inc.
The tree of life according to the three-domain system of biological classification.
Encyclopædia Britannica, Inc.
Interactives
Discover how old Earth is and discover the timing of important events in Earth's...
Encyclopædia Britannica, Inc.
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