The Paleozoic Era (from the Greek palaios (παλαιός), "old" and zoe (ζωή), "life", meaning "ancient life") is the earliest of three geologic eras of the Phanerozoic Eon, spanning from roughly 542 to 251 million years ago (ICS, 2004). It is the longest of the Phanerozoic eras, and is subdivided into six geologic periods (from oldest to youngest): the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian. The Paleozoic comes after the Neoproterozoic era of the Proterozoic eon, and is followed by the Mesozoic era.

The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian Period witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion, in which most modern phyla first appeared. Fish, arthropods, amphibians and reptiles all evolved during the Paleozoic. Life began in the ocean but eventually transitioned onto land, and by the late Paleozoic, it was dominated by various forms of organisms. Great forests of primitive plants covered the continents, many of which formed the coal beds of Europe and eastern North America. Towards the end of the era, large, sophisticated reptiles were dominant and the first modern plants (conifers) appeared.

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.