Million years ago in the context of "Magnoliids"

Prehistory, also called pre-literary history, is the period of human history between the first known use of stone tools by hominins c. 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared c. 5,200 years ago. It took thousands of years for writing systems to be widely adopted, with writing having spread to almost all cultures by the 19th century. The end of prehistory therefore came at different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. It is based on an old conception of history that without written records there could be no history. The most common conception today is that history is based on evidence, however the concept of prehistory has not been completely discarded.

In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and keep historical records, with their neighbours following. Most other civilizations reached their end of prehistory during the following Iron Age. The three-age division of prehistory into Stone Age, Bronze Age, and Iron Age remains in use for much of Eurasia and North Africa, but is not generally used in those parts of the world where the working of hard metals arrived abruptly from contact with Eurasian cultures, such as Oceania, Australasia, much of Sub-Saharan Africa, and parts of the Americas. With some exceptions in pre-Columbian civilizations in the Americas, these areas did not develop writing systems before the arrival of Eurasians, so their prehistory reaches into relatively recent periods; for example, 1788 is usually taken as the end of the prehistory of Australia.

The Silurian-Devonian Terrestrial Revolution, also known as the Devonian Plant Explosion (DePE) and the Devonian explosion, was a period of rapid colonization, diversification and radiation of land plants (particularly vascular plants) and fungi (especially dikaryans) on dry lands that occurred 428 to 359 million years ago (Mya) during the Silurian and Devonian periods, with the most critical phase occurring during the Late Silurian and Early Devonian.

This diversification of terrestrial photosynthetic florae had vast impacts on the biotic composition of the Earth's surface, especially upon the Earth's atmosphere by oxygenation and carbon fixation. Their roots also eroded into the rocks, creating a layer of water-holding and mineral/organic matter-rich soil on top of Earth's crust known as the pedosphere, and significantly altering the chemistry of Earth's lithosphere and hydrosphere. The floral activities following the Silurian-Devonian plant revolution also exerted significant influences on changes in the water cycle and global climate, as well as driving the biosphere by creating diverse layers of vegetations that provide both sustenance and refuge for both upland and wetland habitats, paving the way for all terrestrial and aquatic biomes that would follow.

The Devonian (/dəˈvoʊni.ən, dɛ-/ də-VOH-nee-ən, deh-) is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at 419.62 million years ago (Ma), to the beginning of the succeeding Carboniferous period at 358.86 Ma. It is the fourth period of both the Paleozoic and the Phanerozoic. It is named after Devon, South West England, where rocks from this period were first studied.

The first significant evolutionary radiation of life on land occurred during the Devonian, as free-sporing land plants (pteridophytes) began to spread across dry land, forming extensive coal forests which covered the continents. By the middle of the Devonian, several groups of vascular plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants (pteridospermatophytes) appeared. This rapid evolution and colonization process, which had begun during the Silurian, is known as the Silurian-Devonian Terrestrial Revolution. The earliest land animals, predominantly arthropods such as myriapods, arachnids and hexapods, also became well-established early in this period, after beginning their colonization of land at least from the Ordovician Period.

Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is a subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya and their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds.

Dinosaurs are varied from taxonomic, morphological and ecological standpoints. Birds, at over 11,000 living species, are among the most diverse groups of vertebrates. Using fossil evidence, paleontologists have identified over 900 distinct genera and more than 1,000 different species of non-avian dinosaurs. Dinosaurs are represented on every continent by both extant species (birds) and fossil remains. Through most of the 20th century, before birds were recognized as dinosaurs, most of the scientific community believed dinosaurs to have been sluggish and cold-blooded. Most research conducted since the 1970s, however, has indicated that dinosaurs were active animals with elevated metabolisms and numerous adaptations for social interaction. Some were herbivorous, others carnivorous. Evidence suggests that all dinosaurs were egg-laying, and that nest-building was a trait shared by many dinosaurs, both avian and non-avian.

The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.5 ± 1.0 to 143.1 ± 0.6 million years ago (Ma), which is preserved in Upper Jurassic strata.

In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age. In the past, Malm was also used to indicate the unit of geological time, but this usage is now discouraged to make a clear distinction between lithostratigraphic and geochronologic/chronostratigraphic units.

The Permian–Triassic extinction event, colloquially known as the Great Dying, was an extinction event that occurred approximately 251.9 million years ago (mya), at the boundary between the Permian and Triassic geologic periods, and with them the Paleozoic and Mesozoic eras. It is Earth's most severe known extinction event, with the extinction of 57% of biological families, 62% of genera, 81% of marine species, and 70% of terrestrial vertebrate species. It is also the greatest known mass extinction of insects. It is the greatest of the "Big Five" mass extinctions of the Phanerozoic. There is evidence for one to three distinct pulses, or phases, of extinction.

The scientific consensus is that the main cause of the extinction was the flood basalt volcanic eruptions that created the Siberian Traps, which released sulfur dioxide and carbon dioxide, resulting in euxinia (oxygen-starved, sulfurous oceans), elevated global temperatures,and acidified oceans.The level of atmospheric carbon dioxide rose from around 400 ppm to 2,500 ppm with approximately 3,900 to 12,000 gigatonnes of carbon being added to the ocean-atmosphere system during this period.