by Lordo » Wed Dec 22, 2021 1:39 pm
140 million years ago - Around this time, placental mammals split from their cousins the marsupials. These mammals, like the modern kangaroo, that give birth when their young are still very small, but nourish them in a pouch for the first few weeks or months of their lives.
131 million years ago - Eoconfuciusornis, a bird rather more advanced than Archaeopteryx, lives in China.
130 million years ago - The first flowering plants emerge, following a period of rapid evolution.
105-85 million years ago - The placental mammals split into their four major groups: the laurasiatheres (a hugely diverse group including all the hoofed mammals, whales, bats, and dogs), euarchontoglires (primates, rodents and others), Xenarthra (including anteaters and armadillos) and afrotheres (elephants, aardvarks and others). Quite how these splits occurred is unclear at present.
100 million years ago - The Cretaceous dinosaurs reach their peak in size. The giant sauropod Argentinosaurus, believed to be the largest land animal in Earth’s history, lives around this time.
93 million years ago - The oceans become starved of oxygen. Twenty-seven per cent of marine invertebrates are wiped out.
75 million years ago - The ancestors of modern primates split from the ancestors of modern rodents and lagomorphs (rabbits, hares and pikas). The rodents go on to be astonishingly successful, eventually making up around 40 per cent of modern mammal species.
70 million years ago - Grasses evolve – though it will be several million years before the vast open grasslands appear.
65 million years ago - The Cretaceous-Tertiary (K/T) extinction wipes out a swathe of species, including all the giant reptiles: the dinosaurs, pterosaurs, ichthyosaurs and plesiosaurs. The ammonites are also wiped out. The extinction clears the way for the mammals, which go on to dominate the planet.
63 million years ago - The primates split into two groups, known as the haplorrhines (dry-nosed primates) and the strepsirrhines (wet-nosed primates). The strepsirrhines eventually become the modern lemurs and aye-ayes, while the haplorrhines develop into monkeys and apes – and humans.
58 million years ago - The tarsier, a primate with enormous eyes to help it see at night, splits from the rest of the haplorrhines: the first to do so.
55 million years ago - The Palaeocene/Eocene extinction. A sudden rise in greenhouse gases sends temperatures soaring and transforms the planet, wiping out many species in the depths of the sea – though sparing species in shallow seas and on land.
50 million years ago - Artiodactyls, which look like a cross between a wolf and a tapir, begin evolving into whales.