The Cambrian is the first geological period of the Paleozoic Era, lasting from 542 ± 0.3 to 488.3 ± 1.7 million years ago (mya) (ICS, 2004); it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's Cambrian rocks are best exposed. The Cambrian is unique in its unusually high proportion of lagerstätten. These are sites of exceptional preservation, where 'soft' parts of organisms are preserved as well as their more resistant shells. This means that our understanding of the Cambrian biology surpasses that of some later periods.

The Cambrian Period marked a profound change in life on Earth; prior to the Cambrian, living organisms on the whole were small, unicellular and simple. Complex, multicellular organisms gradually became more common in the millions of years immediately preceding the Cambrian, but it was not until this period that mineralised – hence readily fossilised – organisms became common. The rapid diversification of lifeforms in the Cambrian, known as the Cambrian explosion, produced the first representatives of many modern phyla, representing the evolutionary stems of modern groups of species, such as the arthropods. While diverse life forms prospered in the oceans, the land was comparatively barren – with nothing more complex than a microbial soil crust. Most of the continents probably resembled deserts.^{[citation needed]} Shallow seas flanked the margins of several continents created during the breakup of the supercontinent Pannotia.The seas were relatively warm, and polar ice was absent for much of the period.

Sir David Frederick Attenborough ( /ˈætənbərə/) OM, CH, CVO, CBE, FRS, FZS, FSA (born 8 May 1926) is a British broadcaster and naturalist.

His career as the face and voice of natural history programmes has endured for more than 50 years. He is best known for writing and presenting the nine Life series, in conjunction with the BBC Natural History Unit, which collectively form a comprehensive survey of all life on the planet. He is also a former senior manager at the BBC, having served as controller of BBC Two and director of programming for BBC Television in the 1960s and 1970s.

Attenborough is widely considered a national treasure in Britain, although he himself does not care for the term. He is a younger brother of director, producer and actor Richard Attenborough.

Attenborough was born in Isleworth, west London, but grew up in College House on the campus of the University College, Leicester, where his father, Frederick, was principal. He is the middle of three sons (his elder brother, Richard, became an actor and his younger brother, John, an executive at Italian car manufacturer Alfa Romeo). During World War II his parents also adopted two Jewish refugee girls from Europe.

Paul Zachary "PZ" Myers (born March 9, 1957) is an American scientist and biology professor at the University of Minnesota Morris (UMM) and the author of the Pharyngula science blog, hosted on both the Science Blogs and Freethought Blogs blog networks. He is currently an associate professor of biology at UMM, works with zebrafish in the field of evolutionary developmental biology (evo-devo), and also cultivates an interest in cephalopods. He has published numerous research papers in Nature and other notable scientific journals.

He is a public critic of intelligent design (ID) and of the creationist movement in general and is an activist in the American creation–evolution controversy. He is widely regarded as a confrontationalist.

In 2006, the journal Nature listed his blog, Pharyngula, as the top-ranked blog written by a scientist. Additionally, PZ Myers was the recipient of the Humanist of the Year award in 2009, and the International Humanist Award in 2011.

Asteroid 153298 Paulmyers is named in his honor.

Ryan Thomas Gosling (born November 12, 1980) is a Canadian actor and musician. He began his career as a child star on the Disney Channel's Mickey Mouse Club (1993–95) and went on to appear in other family entertainment programs including Are You Afraid of the Dark? (1995), Goosebumps (1996), Breaker High (1997–98) and Young Hercules (1998–99). His first serious role was as a Jewish neo-Nazi in The Believer (2001), and he then built a reputation for playing misfits in independent films such as Murder by Numbers (2002), The Slaughter Rule (2002), The United States of Leland (2003) and Stay (2005).

Gosling came to the attention of a wider audience in 2004 with a leading role in the romantic drama The Notebook, for which he won four Teen Choice Awards and an MTV Movie Award. His performance as a drug-addicted teacher in Half Nelson (2006) was nominated for an Academy Award and his performance as a socially inept loner in Lars and the Real Girl (2007) was nominated for a Golden Globe Award. In 2007, he starred in the courtroom thriller Fracture.