Cenozoic Era Phanerozoic

1 cenozoic era

1.1 paleogene period
1.2 neogene period
1.3 quaternary period

cenozoic era

the cenozoic featured rise of mammals dominant class of animals, end of age of dinosaurs left significant evolutionary vacuums. there 3 divisions of cenozoic: paleogene, neogene , quaternary.

paleogene period

the paleogene spans extinction of dinosaurs, 66 million years ago, dawn of neogene 23 million years ago. features 3 epochs: paleocene, eocene , oligocene.

basilosaurus (a whale, despite name)

the paleocene epoch began k-t extinction event caused impact of metorite in area of present-day yucatan peninsula , caused destruction of 75% of species on earth. paleocene saw recovery of earth event. continents began take modern shape, continents (and india) separated each other. afro-eurasia separated tethys sea, , americas separated strait of panama, isthmus of panama had not yet formed. epoch featured general warming trend, , jungles reached poles. oceans dominated sharks large reptiles had once ruled became extinct. archaic mammals, such creodonts , primates evolved during mesozoic filled world. during time there no land creatures on 10 kilograms. mammals still quite small.

the eocene epoch ranged 56 million years 34 million years. in eocene, land animals small , living in cramped jungles, paleocene. none had mass on 10 kilograms. among them primates, whales , horses along many other forms of mammals. @ top of food chains huge birds, such gastornis. time in recorded history birds ruled world (excluding ancestors, dinosaurs). temperature 30 degrees celsius little temperature gradient pole pole. in middle eocene epoch, circum-antarctic current between australia , antarctica formed disrupted ocean currents worldwide, resulting in global cooling, , caused jungles shrink. allowed mammals grow; such whales mammoth proportions, were, now, aquatic. mammals andrewsarchus @ top of food-chain , sharks replaced basilosaurus, whales, rulers of seas. late eocene epoch saw rebirth of seasons, caused expansion of savanna-like areas, along evolution of grass.

the oligocene epoch spans 33 million 23 million years. oligocene featured expansion of grass had led many new species take advantage, including first elephants, cats, dogs, marsupials , many other species still prevalent today. many other species of plants evolved during epoch also, such evergreen trees. long term cooling continued , seasonal rains patterns established. mammals continued grow larger. paraceratherium, largest land mammal ever live evolved during epoch, along many other perissodactyls in event known eocene–oligocene extinction event (grand coupure).

neogene period


animals of miocene (chalicotherium, hyenadon, entelodont)

the neogene spans 23.03 million 2.58 million years ago. features 2 epochs: miocene, , pliocene.

the miocene spans 23.03 5.333 million years ago , period in grass spread further across, dominating large portion of world, diminishing forests in process. kelp forests evolved, leading evolution of new species, such sea otters. during time, perissodactyla thrived, , evolved many different varieties. alongside them apes, evolved 30 species. overall, arid , mountainous land dominated of world, did grazers. tethys sea closed creation of arabian peninsula , in wake left black, red, mediterranean , caspian seas. increased aridity. many new plants evolved, , 95% of modern seed plants evolved in mid-miocene.

the pliocene lasted 5.333 2.58 million years ago. pliocene featured dramatic climactic changes, led modern species , plants. mediterranean sea dried several million years. along these major geological events, australopithecus evolved in africa, beginning human branch. isthmus of panama formed, , animals migrated between north , south america, wreaking havoc on local ecology. climatic changes brought savannas still continuing spread across world, indian monsoons, deserts in east asia, , beginnings of sahara desert. earth s continents , seas moved present shapes. world map has not changed since, save changes brought glaciations of quaternary, such great lakes.

quaternary period

the quaternary spans 2.58 million years ago present day, , shortest geological period in phanerozoic eon. features modern animals, , dramatic changes in climate. divided 2 epochs: pleistocene , holocene.

megafauna of pleistocene (mammoths, cave lions, woolly rhino, reindeer, horses)

the pleistocene lasted 2.58 million 11,700 years ago. epoch marked ice ages result of cooling trend started in mid-eocene. there @ least 4 separate glaciation periods marked advance of ice caps far south 40 degrees n latitude in mountainous areas. meanwhile, africa experienced trend of desiccation resulted in creation of sahara, namib, , kalahari deserts. many animals evolved including mammoths, giant ground sloths, dire wolves, saber-toothed cats, , famously homo sapiens. 100,000 years ago marked end of 1 of worst droughts of africa, , led expansion of primitive man. pleistocene drew close, major extinction wiped out of world s megafauna, including of hominid species, such neanderthals. continents affected, africa lesser extent. continent retains many large animals, such hippos.

the holocene began 11,700 years ago , lasts until present day. recorded history , history of world lies within boundaries of holocene epoch. human activity blamed mass extinction began 10,000 years ago, though species becoming extinct have been recorded since industrial revolution. referred sixth extinction . more 322 species have become extinct due human activity since industrial revolution.