MODERN BOTANY - P. RAVEN - 1990

Class="center">Era¹

Period¹

Epoch¹

Life Forms

Climate and Major Geological Events

Cenozoic

(65)

Quaternary (2)

Tertiary (65)

Recent, or Holocene (0.01) Pleistocene (2)

Pliocene (5.1)

Miocene (24.6)

Oligocene (38)

Eocene (54.9)

Paleocene (65)

Age of humans. Extinction of many large mammals and birds

Aridification, desert formation; climates become diverse. First appearance of Australopithecines

Spread of grasslands as forests shrink. Herbaceous mammals, higher primates

Herbivorous mammals, ape-like primates; appearance of many modern plant genera

Widespread adaptive radiation of mammals and birds; beginning of grassland formation

Early insectivorous mammals and primates

Fluctuations from cold to mild. More than two dozen glacial advances and retreats, final uplift of many mountain ranges

Colder. Intensive mountain-building processes; extensive glaciation in the Northern Hemisphere. Uplift of the Isthmus of Panama, connecting North and South America

Temperate. Extensive glaciation begins again in the Southern Hemisphere

Uplift of the Alps and Himalayas. South America separates from Antarctica. Volcanoes in the Rocky Mountains

Mild to distinctly tropical. Australia separates from Antarctica; Hindustan connects with Asia

Mild to cool. Extensive shallow continental seas largely disappear

Mesozoic (248)

Cretaceous (144)

Jurassic (213)

Triassic (248)

Appearance and dominance of many groups of angiosperms and insects. Age of reptiles. Dinosaur extinction at the end of the period

Gymnosperms, especially cycads. Appearance of birds

Forests of gymnosperms and ferns. Appearance of dinosaurs and mammals

Climate universally tropical or subtropical. Africa and South America separate

Mild. Lowland continents with vast areas covered by seas

Mountainous continents joined into a supercontinent. Extensive arid regions

Paleozoic (590)

Permian (286)

Carboniferous: Pennsylvanian (320) and Mississippian (360) subperiods

Devonian (408)

Silurian (438)

Ordovician (505)

Cambrian (590)

Appearance of conifers, cycads, and ginkgos; earlier types of forests disappear. Increasing diversity of reptiles

Amphibians move onto land; forests appear and become dominant. Emergence of insects and reptiles. Age of amphibians

Age of Fishes. Spread of land plants; extinction of primitive vascular plants

The period begins with an intensive organismal extinction. First fossil plants. First jawed fishes

The period begins with the first large-scale organismal extinction. Oldest fossil crustaceans. Increased diversity of Mollusks. Possible migration of plants onto land. First Fungi

Emergence of external skeletons in animals. Explosive evolution of phyla and divisions. Appearance of Chordates.

Extensive glaciation in the Southern Hemisphere. Uplift of the Appalachians. Widespread aridity

Warm, with minor seasonal fluctuations; lowland, swampy land; formation of coal deposits

Most of the continents covered by seas, mountains are rare

Mild. Continents mostly flat

Mild. Shallow seas, continents mostly flat; seas cover a significant part of the modern USA

Mild. Territories of modern continents occupied by vast seas

Precambrian

(4500)

Origin of life (at least 3.5 billion years ago), eukaryotes (at least 1.5 billion years ago), Multicellular animals (about 700 million years ago)

Formation of the Earth's crust and the onset of continental drift