How Did The Ice Ages Affect Animal Life During The Cenozoic Era?

3rd era of the Phanerozoic Eon (66 million years agone to present)

Cenozoic
66.0 – 0 Ma Pha. Proterozoic Archean Had'n
Rock deposits from the Cenozoic Era (Torre Sant'Andrea, Salento, Italy)
Chronology
−70 — – −65 — – −lx — – −55 — – −50 — – −45 — – −40 — – −35 — – −30 — – −25 — – −20 — – −15 — – −x — – −5 — – 0 — P h a northward e r o z o i c Mesozoic C e n o z o i c Quaternary Paleogene Neogene An approximate timescale of the Cenozoic. Axis scale: millions of years ago.
Etymology
Name formality	Formal
Nickname(s)	Age of Mammals
Usage information
Angelic trunk	Earth
Regional usage	Global (ICS)
Time scale(southward) used	ICS Fourth dimension Scale
Definition
Chronological unit	Era
Stratigraphic unit	Erathem
Time bridge formality	Formal
Lower boundary definition	Iridium enriched layer associated with a major meteorite bear upon and subsequent Chiliad-Pg extinction outcome.
Lower boundary GSSP	El Kef Department, El Kef, Tunisia 36°09′xiii″Due north eight°38′55″E  /  36.1537°N eight.6486°E  / 36.1537; 8.6486
GSSP ratified	1991
Upper purlieus definition	N/A
Upper boundary GSSP	Due north/A
GSSP ratified	Due north/A

The Cenozoic ( Run across-nə-ZOH-ik, SEN-ə-;^{[one] [ii]} lit. 'new life') is Globe's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the electric current configuration of continents. It is the latest of three geological eras since complex life evolved, preceded past the Mesozoic and Paleozoic. It started with the Cretaceous–Paleogene extinction event, when many species, including the not-avian dinosaurs, became extinct in an outcome attributed by nigh experts to the impact of a large asteroid or other celestial torso, the Chicxulub impactor.

The Cenozoic is also known as the Age of Mammals because the terrestrial animals that dominated both hemispheres were mammals – the eutherians (placentals) in the northern hemisphere and the metatherians (marsupials, at present mainly restricted to Australia) in the southern hemisphere. The extinction of many groups immune mammals and birds to greatly diversify so that big mammals and birds dominated life on Earth. The continents too moved into their electric current positions during this era.

The climate during the early on Cenozoic was warmer than today, particularly during the Paleocene–Eocene Thermal Maximum. Notwithstanding, the Eocene to Oligocene transition and the Quaternary glaciation stale and cooled Globe.

Nomenclature [edit]

Cenozoic derives from the Greek words kainós (καινός 'new') and zōḗ (ζωή 'life').^[3] The name was proposed in 1840 past the British geologist John Phillips (1800–1874), who originally spelled it Kainozoic.^{[4] [5] [6]} The era is also known as the Cænozoic, Caenozoic, or Cainozoic ().^{[seven] [8]}

In name, the Cenozoic (lit. 'new life') is comparable to the preceding Mesozoic ('middle life') and Paleozoic ('one-time life') Eras, likewise as to the Proterozoic ('earlier life') Eon.

Divisions [edit]

The Cenozoic is divided into three periods: the Paleogene, Neogene, and Quaternary; and seven epochs: the Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, and Holocene. The Quaternary Period was officially recognized by the International Commission on Stratigraphy in June 2009.^[9] In 2004, the Tertiary Period was officially replaced past the Paleogene and Neogene Periods. The common utilize of epochs during the Cenozoic helps paleontologists better organize and group the many pregnant events that occurred during this insufficiently brusque interval of time. Noesis of this era is more detailed than any other era considering of the relatively young, well-preserved rocks associated with it.

Paleogene [edit]

The Paleogene spans from the extinction of not-avian dinosaurs, 66 million years ago, to the dawn of the Neogene, 23.03 million years ago. It features 3 epochs: the Paleocene, Eocene and Oligocene.

The Paleocene Epoch lasted from 66 million to 56 meg years agone. Mod placental mammals originated during this fourth dimension.^[10] The devastation of the K–Pg extinction outcome included the extinction of big herbivores, which permitted the spread of dense but usually species-poor forests.^{[11] [12]} The Early Paleocene saw the recovery of Earth. The continents began to take their mod shape, but all the continents and the subcontinent of India were separated from each other. Afro-Eurasia was separated by the Tethys Sea, and the Americas were separated by the strait of Panama, equally the isthmus had not yet formed. This epoch featured a general warming tendency, with jungles somewhen reaching the poles. The oceans were dominated by sharks^[13] as the large reptiles that had in one case predominated were extinct. Archaic mammals filled the earth such as creodonts (extinct carnivores, unrelated to existing Carnivora).

The Eocene Epoch ranged from 56 one thousand thousand years to 33.9 million years ago. In the Early-Eocene, species living in dense forest were unable to evolve into larger forms, as in the Paleocene. All known mammals were nether ten kilograms.^[xiv] Amongst them were early primates, whales and horses forth with many other early forms of mammals. At the tiptop of the food chains were huge birds, such equally Paracrax. The temperature was 30 degrees Celsius with niggling temperature slope from pole to pole. In the Mid-Eocene, the Circumpolar-Antarctic current between Commonwealth of australia and Antarctica formed. This disrupted sea currents worldwide and as a event caused a global cooling effect, shrinking the jungles. This allowed mammals to grow to mammoth proportions, such every bit whales which, past that time, had become near fully aquatic. Mammals like Andrewsarchus were at the pinnacle of the nutrient-chain. The Late Eocene saw the rebirth of seasons, which caused the expansion of savanna-like areas, along with the evolution of grass.^{[15] [sixteen]} The end of the Eocene was marked by the Eocene-Oligocene extinction event, the European face of which is known as the Grande Coupure.

The Oligocene Epoch spans from 33.ix million to 23.03 1000000 years ago. The Oligocene featured the expansion of grass which had led to many new species to evolve, including the kickoff elephants, cats, dogs, marsupials and many other species still prevalent today. Many other species of plants evolved in this period too. A cooling period featuring seasonal rains was still in effect. Mammals notwithstanding continued to abound larger and larger.^[17]

Neogene [edit]

The Neogene spans from 23.03 million to 2.58 1000000 years ago. It features 2 epochs: the Miocene, and the Pliocene.^[18]

The Miocene Epoch spans from 23.03 to 5.333 million years ago and is a menses in which grass spread farther, dominating a big portion of the world, at the expense of forests. Kelp forests evolved, encouraging the development of new species, such as sea otters. During this time, perissodactyla thrived, and evolved into many dissimilar varieties. Apes evolved into 30 species. The Tethys Ocean finally closed with the creation of the Arabian Peninsula, leaving simply remnants equally the Black, Red, Mediterranean and Caspian Seas. This increased aridity. Many new plants evolved: 95% of mod seed plants evolved in the mid-Miocene.^[nineteen]

The Pliocene Epoch lasted from 5.333 to ii.58 million years agone. The Pliocene featured dramatic climatic changes, which ultimately led to modern species of flora and brute. The Mediterranean Sea stale up for several 1000000 years (because the water ice ages reduced sea levels, disconnecting the Atlantic from the Mediterranean, and evaporation rates exceeded inflow from rivers). Australopithecus evolved in Africa, beginning the human branch. The isthmus of Panama formed, and animals migrated between North and S America during the great American interchange, wreaking havoc on local ecologies. Climatic changes brought: savannas that are nonetheless continuing to spread beyond the world; Indian monsoons; deserts in fundamental Asia; and the ancestry of the Sahara desert. The globe map has not changed much since, save for changes brought nigh past the glaciations of the Quaternary, such as the Great Lakes, Hudson Bay, and the Baltic sea.^{[20] [21]}

Quaternary [edit]

The Fourth spans from 2.58 meg years ago to present day, and is the shortest geological period in the Phanerozoic Eon. Information technology features modern animals, and dramatic changes in the climate. It is divided into ii epochs: the Pleistocene and the Holocene.

The Pleistocene lasted from 2.58 million to 11,700 years ago. This epoch was marked past ice ages equally a consequence of the cooling trend that started in the Mid-Eocene. There were at least four split glaciation periods marked past the advance of ice caps every bit far southward as 40° Due north in mountainous areas. Meanwhile, Africa experienced a tendency of desiccation which resulted in the cosmos of the Sahara, Namib, and Kalahari deserts. Many animals evolved including mammoths, behemothic basis sloths, dire wolves, saber-toothed cats, and most famously Homo sapiens. 100,000 years agone marked the end of one of the worst droughts in Africa, and led to the expansion of primitive humans. As the Pleistocene drew to a close, a major extinction wiped out much of the world'southward megafauna, including some of the hominid species, such as Neanderthals. All the continents were affected, but Africa to a lesser extent. Information technology withal retains many large animals, such as hippos.^[22]

The Holocene began eleven,700 years ago and lasts to the present mean solar day. All recorded history and "the Human history" lies within the boundaries of the Holocene Epoch.^[23] Human activity is blamed for a mass extinction that began roughly 10,000 years ago, though the species becoming extinct have only been recorded since the Industrial Revolution. This is sometimes referred to every bit the "6th Extinction". Information technology is often cited that over 322 recorded species take become extinct due to human being activity since the Industrial Revolution,^{[24] [25]} merely the rate may be as high as 500 vertebrate species alone, the majority of which have occurred after 1900.^[26]

Tectonics [edit]

Geologically, the Cenozoic is the era when the continents moved into their electric current positions. Australia-New Guinea, having split from Pangea during the early on Cretaceous, drifted north and, eventually, collided with Southward-due east Asia; Antarctica moved into its current position over the S Pole; the Atlantic Body of water widened and, later in the era (two.8 one thousand thousand years ago), South America became attached to North America with the isthmus of Panama.

Republic of india collided with Asia 55 to 45 million years ago creating the Himalayas; Arabia collided with Eurasia, endmost the Tethys Bounding main and creating the Zagros Mountains, around 35 million years ago.^[27]

The break-up of Gondwana in Tardily Cretaceous and Cenozoic times led to a shift in the river courses of various big African rivers including the Congo, Niger, Nile, Orangish, Limpopo and Zambezi.^[28]

Climate [edit]

In the Cretaceous, the climate was hot and humid with lush forests at the poles, there was no permanent ice and sea levels were around 300 metres college than today. This connected for the get-go 10 1000000 years of the Paleocene, culminating in the Paleocene–Eocene Thermal Maximum about 55.5 million years ago. Around 50 million years ago Globe entered a catamenia of long term cooling. This was mainly due to the collision of Republic of india with Eurasia, which caused the ascension of the Himalayas: the upraised rocks eroded and reacted with CO₂ in the air, causing a long-term reduction in the proportion of this greenhouse gas in the atmosphere. Around 35 1000000 years agone permanent ice began to build up on Antarctica.^[29] The cooling trend connected in the Miocene, with relatively short warmer periods. When S America became attached to North America creating the Isthmus of Panama around 2.viii million years agone, the Arctic region cooled due to the strengthening of the Humboldt and Gulf Stream currents,^[30] eventually leading to the glaciations of the Quaternary water ice age, the current interglacial of which is the Holocene Epoch. Contempo analysis of the geomagnetic reversal frequency, oxygen isotope record, and tectonic plate subduction charge per unit, which are indicators of the changes in the oestrus flux at the core mantle boundary, climate and plate tectonic activity, shows that all these changes indicate similar rhythms on million years' timescale in the Cenozoic Era occurring with the common fundamental periodicity of ~13 Myr during almost of the time.^[31]

Life [edit]

Early on in the Cenozoic, following the K-Pg event, the planet was dominated by relatively small fauna, including pocket-size mammals, birds, reptiles, and amphibians. From a geological perspective, it did not take long for mammals and birds to greatly diversify in the absenteeism of the dinosaurs that had dominated during the Mesozoic. Some flightless birds grew larger than humans. These species are sometimes referred to as "terror birds," and were formidable predators. Mammals came to occupy almost every available niche (both marine and terrestrial), and some also grew very large, attaining sizes non seen in virtually of today'southward terrestrial mammals.

During the Cenozoic, mammals proliferated from a few modest, simple, generalized forms into a diverse drove of terrestrial, marine, and flight animals, giving this menstruation its other proper name, the Age of Mammals. The Cenozoic is just every bit much the historic period of savannas, the historic period of co-dependent flowering plants and insects, and the age of birds.^[32] Grass also played a very important role in this era, shaping the evolution of the birds and mammals that fed on it. One grouping that diversified significantly in the Cenozoic too were the snakes. Evolving in the Cenozoic, the variety of snakes increased tremendously, resulting in many colubrids, following the evolution of their electric current primary prey source, the rodents.

In the earlier part of the Cenozoic, the world was dominated by the gastornithid birds, terrestrial crocodiles like Pristichampsus, and a handful of archaic large mammal groups like uintatheres, mesonychids, and pantodonts. But every bit the forests began to recede and the climate began to cool, other mammals took over.

The Cenozoic is full of mammals both strange and familiar, including chalicotheres, creodonts, whales, primates, entelodonts, saber-toothed cats, mastodons and mammoths, 3-toed horses, giant rhinoceros like Indricotherium, the rhinoceros-similar brontotheres, various bizarre groups of mammals from South America, such as the vaguely elephant-like pyrotheres and the dog-similar marsupial relatives called borhyaenids and the monotremes and marsupials of Australia.

Meet also [edit]

• Cretaceous–Paleogene boundary (K–T boundary)
• Geologic time scale
• Late Cenozoic Ice Age

References [edit]

1. ^ "Cenozoic". Lexico U.k. English Dictionary. Oxford University Press. northward.d.
2. ^ "Cenozoic". Merriam-Webster Lexicon.
3. ^ "Cenozoic". Online Etymology Lexicon.
4. ^ Phillips, John (1840). "Palæozoic series". Penny Cyclopaedia of the Gild for the Diffusion of Useful Knowledge. Vol. 17. London, England: Charles Knight and Co. pp. 153–154. From pp. 153–154: "As many systems or combinations of organic forms as are clearly traceable in the stratified crust of the world, so many respective terms (as Palæozoic, Mesozoic, Kainozoic, &c.) may be fabricated, ... "
5. ^ Wilmarth, Mary Grace (1925). Bulletin 769: The Geologic Fourth dimension Classification of the Usa Geological Survey Compared With Other Classifications, accompanied by the original definitions of era, menstruation and epoch terms. Washington, D.C., U.S.A.: U.S. Government Press Office. p. eight.
6. ^ The development of the spelling of "Cenozoic" is reviewed in:
   • Harland, W. Brian; Armstrong, Richard L.; Cox, Allen Five.; Craig, Lorraine Due east.; Smith, David Grand.; Smith, Alan G. (1990). "The Chronostratic Scale". A Geologic Time Scale 1989. Cambridge, England, U.K.: Cambridge University Press. p. 31. ISBN9780521387651.
   Although John Phillips originally spelled it as "Kainozoic" in 1840, he spelled it "Cainozoic" a year later:
   • Phillips, John (1841). Figures and Descriptions of the Palæozoic Fossils of Cornwall, Devon, and West Somerset; ... London, England, U.Thousand.: Longman, Dark-brown, Green, & Longmans. p. 160.
7. ^ "Cainozoic". Dictionary.com Unabridged (Online). n.d.
8. ^ "Cainozoic". Oxford English Dictionary (2nd ed.). 1989.
9. ^ Gibbard, P. 50.; Caput, K. J.; Walker, M. J. C. (2010). "Formal ratification of the Quaternary System/Period and the Pleistocene Series/Epoch with a base at 2.58 Ma". Journal of Quaternary Science. 25 (2): 96–102. Bibcode:2010JQS....25...96G. doi:10.1002/jqs.1338.
10. ^ O'Leary, Maureen A.; Bloch, Jonathan I.; Flynn, John J.; Gaudin, Timothy J.; Giallombardo, Andres; Giannini, Norberto P.; Goldberg, Suzann Fifty.; Kraatz, Brian P.; Luo, Zhe-Eleven; Meng, Jin; Ni, Michael J.; Novacek, Fernando A.; Perini, Zachary Southward.; Randall, Guillermo; Rougier, Eric J.; Sargis, Mary T.; Silcox, Nancy b.; Simmons, Micelle; Spaulding, Paul M.; Velazco, Marcelo; Weksler, John r.; Wible, Andrea L.; Cirranello, A. 50. (8 February 2013). "The Placental Mammal Antecedent and the Mail–K-Pg Radiations of Placentals". Science. 339 (6120): 662–667. Bibcode:2013Sci...339..662O. doi:10.1126/scientific discipline.1229237. hdl:11336/7302. PMID 23393258. S2CID 206544776.
11. ^ Williams, C. J.; LePage, B. A.; Johnson, A. H.; Vann, D. R. (2009). "Structure, Biomass, and Productivity of a Late Paleocene Arctic Forest". Proceedings of the University of Natural Sciences of Philadelphia. 158 (1): 107–127. doi:ten.1635/053.158.0106. S2CID 130110536.
12. ^ Johnson, Kirk R.; Ellis, Beth (28 June 2002). "A Tropical Rainforest in Colorado 1.4 1000000 Years Later the Cretaceous-Tertiary Boundary". Science. 296 (5577): 2379–2383. doi:10.1126/scientific discipline.1072102.
13. ^ Purple Tyrrell Museum (28 March 2012), Lamniform sharks: 110 one thousand thousand years of ocean supremacy, archived from the original on 7 August 2013, retrieved 12 July 2017
14. ^ University of California. "Eocene Epoch". University of California.
15. ^ University of California. "Eocene Climate". University of California.
16. ^ National Geographic Society (24 January 2017). "Eocene". National Geographic.
17. ^ Academy of California. "Oligocene". Academy of California.
18. ^ Encyclopædia Britannica. "Neogene". Encyclopædia Britannica.
19. ^ Academy of California. "Miocene". Academy of California.
20. ^ University of California. "Pliocene". University of California.
21. ^ Jonathan Adams. "Pliocene climate". Oak Ridge National Library. Archived from the original on 25 February 2015.
22. ^ Academy of California. "Pleistocene". University of California. Archived from the original on 24 Baronial 2014. Retrieved 25 Apr 2015.
23. ^ University of California. "Holocene". University of California.
24. ^ Scientific American. "Sixth Extinction extinctions". Scientific American.
25. ^ IUCN (3 Nov 2009). "Sixth Extinction". IUCN.
26. ^ Ceballos et al. (2015) (2015). "Accelerated modern man–induced species losses: Entering the sixth mass extinction". Science Advances. 1 (five): e1400253. Bibcode:2015SciA....1E0253C. doi:10.1126/sciadv.1400253. PMC4640606. PMID 26601195.
27. ^ Allen, 1000. B.; Armstrong, H. A. (2008). "Arabia-Eurasia collision and the forcing of mid Cenozoic global cooling" (PDF). Palaeogeography, Palaeoclimatology, Palaeoecology. 265 (1–ii): 52–58. Bibcode:2008PPP...265...52A. doi:10.1016/j.palaeo.2008.04.021.
28. ^ Goudie, A.S. (2005). "The drainage of Africa since the Cretaceous". Geomorphology. 67 (3–four): 437–456. Bibcode:2005Geomo..67..437G. doi:ten.1016/j.geomorph.2004.11.008.
29. ^ Dartnell, Lewis (2018). Origins:How the Globe Made Us. London, Britain: Bodley Head. pp. ix–10, twoscore. ISBN978-1-8479-2435-3.
30. ^ "How the Isthmus of Panama Put Ice in the Arctic". Oceanus Magazine.
31. ^ Chen, J.; Kravchinsky, 5.A.; Liu, 10. (2015). "The 13 million year Cenozoic pulse of the World". Earth and Planetary Scientific discipline Messages. 431: 256–263. Bibcode:2015E&PSL.431..256C. doi:10.1016/j.epsl.2015.09.033.
32. ^ "The Cenozoic Era".

Further reading [edit]

• Prothero, Donald R. (2006). Subsequently the Dinosaurs: The Age of Mammals. Bloomington, Indiana: Indiana University Press. ISBN978-0-253-34733-half-dozen.

External links [edit]

Wikimedia Commons has media related to Cenozoic.

• Western Australian Museum – The Age of the Mammals
• Cenozoic (chronostratigraphy scale)

Source: https://en.wikipedia.org/wiki/Cenozoic

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