Search results
Results from the WOW.Com Content Network
Classical antiquity – Broad term for a long period of cultural history centered on the Mediterranean Sea, comprising the interlocking civilizations of ancient Greece and ancient Rome, collectively known as the Greco-Roman world. It is the period in which Greek and Roman society flourished and wielded great influence throughout Europe, North ...
At long irregular intervals, Earth's biosphere suffers a catastrophic die-off, a mass extinction, [9] often comprising an accumulation of smaller extinction events over a relatively brief period. [10] The first known mass extinction was the Great Oxidation Event 2.4 billion years ago, which killed most of the planet's obligate anaerobes.
The recovery interval after the anoxic event's conclusion features an abundance of Planolites and is characterised overall by a high degree of bioturbation. [126] At the time, there were also peak abundances of the green algal groups Botryococcus and prasinophytes, coincident with pelagic sedimentation. The abundances of these algal groups are ...
c. 298.9 ± 0.15 Ma – End of Carboniferous and beginning of Permian Period. By this time, all continents have fused into the supercontinent of Pangaea. Seed plants and conifers diversify along with temnospondyls and pelycosaurs. c. 296 Ma – Oldest known octopus fossil. c. 295 Ma – Dimetrodon evolves. c. 295 Ma – First beetles appear. [28]
The geologic time scale is a way of representing deep time based on events that have occurred throughout Earth's history, a time span of about 4.54 ± 0.05 Ga (4.54 billion years). [3] It chronologically organises strata, and subsequently time, by observing fundamental changes in stratigraphy that correspond to major geological or ...
The Miocene Epoch spans from 23.03 to 5.333 million years ago and is a period in which grasses spread further, dominating a large portion of the world, at the expense of forests. Kelp forests evolved, encouraging the evolution of new species, such as sea otters. During this time, Perissodactyla thrived, and evolved into many different varieties.
This second, follow-on event is known as the oxygen catastrophe, which some geologists believe triggered the Huronian glaciation. [ 2 ] [ 3 ] Since the time period from 2,420 Ma to 2,250 Ma is well-defined by the lower edge of iron-deposition layers, an alternative period named the Oxygenian , based on stratigraphy instead of chronometry, was ...
Many crown node eukaryotes (from which the modern-day eukaryotic lineages would have arisen) have been approximately dated to around the time of the Paleoproterozoic Era. [12] [13] [14] While there is some debate as to the exact time at which eukaryotes evolved, [15] [16] current understanding places it somewhere in this era.