Cenozoic in the context of "Evolution of tetrapods"

The Last Glacial Period (LGP), also known as the last glacial cycle, occurred from the end of the Last Interglacial to the beginning of the Holocene, c. 115,000 – c. 11,700 years ago, and thus corresponds to most of the timespan of the Late Pleistocene. It thus formed the most recent period of what is colloquially known as the "Ice Age".

The LGP is part of a larger sequence of glacial and interglacial periods known as the Quaternary glaciation which started around 2,588,000 years ago and is ongoing. The glaciation and the current Quaternary Period both began with the formation of the Arctic ice cap. The Antarctic ice sheet began to form earlier, at about 34 Mya (million years ago), in the mid-Cenozoic (Eocene–Oligocene extinction event), and the term Late Cenozoic Ice Age is used to include this early phase with the current glaciation. The previous ice age within the Quaternary is the Penultimate Glacial Period, which ended about 128,000 years ago, was more severe than the Last Glacial Period in some areas such as Britain, but less severe in others.

Albania is mostly mountainous, with the first alpine regions forming towards the end of the Jurassic period. During the Cenozoic era, the malformation of the Albanides accelerated, causing the subterranean landscape to take its present form. The average altitude of the country is 714 m (2,343 ft), almost three times that of Europe. Its highest summits are situated in the Albanian Alps and the eastern mountain range, with Korab being the highest peak, at 2,764 m (9,068 ft) above sea level.

The country's geography is unique due to its location and varied relief, with landscapes ranging from mediterranean in the west to a more continental influence in the east and mountainous terrain in the interior and east. This combination of plains, hills and mountains has resulted in a diverse range of geographical features, extending horizontally and vertically. However, this complexity has made regionalization challenging, as different authors have used alternating criteria and methods. In the 1920s, Herbert Louis proposed a scheme that divided Albania into two large regions: Inner Albania and Coastal Albania, each with specific subdivisions. His scheme was widely used until 1964, when it was to be replaced by Pandi Geço's proposed scheme which divided the country into four physiographic regions, listed as follows: Albanian Alps, Central Mountain Region, Southern Mountain Region, Albanian Coastal Lowlands and its hills. By 1990, Geço's scheme was improved through further research and consideration of ecological concerns, recapping all regions into 67 constituent subunits.

The Pliocene ( /ˈplaɪ.əsiːn, ˈplaɪ.oʊ-/ PLY-ə-seen, PLY-oh-; also Pleiocene) is the epoch in the geologic time scale that extends from 5.33 to 2.58 million years ago (Ma). It is the second and most recent epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch. Prior to the 2009 revision of the geologic time scale, which placed the four most recent major glaciations entirely within the Pleistocene, the Pliocene also included the Gelasian Stage, which lasted from 2.59 to 1.81 Ma, and is now included in the Pleistocene. The name comes from Ancient Greek πλείων (pleíōn), meaning "most", and καινός (kainós), meaning "new, recent".

As with other older geologic periods, the geological strata that define the start and end are well-identified but the exact dates of the start and end of the epoch are slightly uncertain. The boundaries defining the Pliocene are not set at an easily identified worldwide event but rather at regional boundaries between the warmer Miocene and the relatively cooler Pleistocene. The upper boundary was set at the start of the Pleistocene glaciations.

Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term petroleum refers both to naturally occurring unprocessed crude oil, as well as to petroleum products that consist of refined crude oil.

Petroleum is a fossil fuel formed over millions of years from anaerobic decay of organic materials from buried prehistoric organisms, particularly planktons and algae. It is estimated that 70% of the world's oil deposits were formed during the Mesozoic, 20% were formed in the Cenozoic, and only 10% were formed in the Paleozoic. Conventional reserves of petroleum are primarily recovered by drilling, which is done after a study of the relevant structural geology, analysis of the sedimentary basin, and characterization of the petroleum reservoir. There are also unconventional reserves such as oil sands and oil shale which are recovered by other means such as fracking.

Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about 3 millimetres (1⁄8 inch) long, are usually dark in color, and have bodies that are "flattened" sideways or narrow, enabling them to move through their hosts' fur or feathers. They lack wings; their hind legs are extremely well adapted for jumping. Their claws keep them from being dislodged, and their mouthparts are adapted for piercing skin and sucking blood. Some species can leap 50 times their body length, a feat second only to jumps made by another group of insects, the superfamily of froghoppers. Flea larvae are worm-like, with no limbs; they have chewing mouthparts and feed on organic debris left on their hosts' skin.

Genetic evidence indicates that fleas are a specialised lineage of parasitic scorpionflies (Mecoptera) sensu lato, most closely related to the family Nannochoristidae. The earliest known fleas lived in the Middle Jurassic; modern-looking forms appeared in the Cenozoic. Fleas probably originated on mammals first and expanded their reach to birds. Each species of flea specializes, more or less, on one species of host: many species of flea never breed on any other host; some are less selective. Some families of fleas are exclusive to a single host group; for example, the Malacopsyllidae are found only on armadillos, the Ischnopsyllidae only on bats, and the Chimaeropsyllidae only on elephant shrews.

The Quaternary (/kwəˈtɜːrnəri/ kwə-TUR-nər-ee, US also /ˈkwɒtərnɛri/ KWOT-ər-nerr-ee) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the Phanerozoic eon. It follows the Neogene Period and spans from 2.6 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene (2.6 million years ago to 12 thousand years ago) and the Holocene (12 thousand years ago to today); a proposed third epoch, the Anthropocene, was rejected in 2024 by IUGS, the governing body of the ICS.

The Quaternary is typically defined by the Quaternary glaciation, the cyclic growth and decay of continental ice sheets related to the Milankovitch cycles and the associated climate and environmental changes that they caused.

The Central American Seaway (also known as the Panamanic Seaway, Inter-American Seaway and Proto-Caribbean Seaway) was a prehistoric body of water that once connected the Pacific Ocean to the Atlantic Ocean, separating North America from South America. It formed during the Jurassic (200–154 Ma) during the initial breakup of the supercontinent Pangaea into Laurasia and Gondwana, forming a mediterranean sea between the Panthalassia and Tethys Ocean, and finally closed when the Isthmus of Panama was formed by volcanic activity in the late Pliocene (2.76–2.54 Ma). The modern-day remnants of the seaway are the Gulf of Mexico, Caribbean Sea and the Central Atlantic region around the Sargasso Sea.

The closure of the Central American Seaway had tremendous effects on oceanic circulation and the biogeography of the adjacent seas, isolating many species and triggering speciation and diversification of tropical and sub-tropical marine fauna. The inflow of nutrient-rich water of deep Pacific origin into the Caribbean was blocked and so local species had to adapt to an environment of lower productivity. It had an even larger impact on terrestrial life. The seaway had isolated South America for much of the Cenozoic, which allowed the evolution of a wholly unique diverse mammalian fauna there. When it closed, a faunal exchange with North America ensued and led to the extinction of many of the native South American forms.

The Great American Biotic Interchange (commonly abbreviated as GABI), also known as the Great American Interchange and the Great American Faunal Interchange, was an important late Cenozoic paleozoogeographic biotic interchange event in which land and freshwater fauna migrated from North America to South America via Central America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor, forming a land bridge between the previously separated continents. Although earlier dispersals had occurred, probably over water, the migration accelerated dramatically about 2.7 million years (Ma) ago during the Piacenzian age. It resulted from the joining of the Neotropic (roughly South American) and Nearctic (roughly North American) biogeographic realms definitively to form the Americas. The interchange is visible from observation of both biostratigraphy and nature (neontology). Its most dramatic effect is on the zoogeography of mammals, but it also gave an opportunity for reptiles, amphibians, arthropods, weak-flying or flightless birds, and even freshwater fish to migrate. Coastal and marine biota were affected in the opposite manner; the formation of the Central American Isthmus caused what has been termed the Great American Schism, with significant diversification and extinction occurring as a result of the isolation of the Caribbean from the Pacific.

The occurrence of the interchange was first discussed in 1876 by the "father of biogeography", Alfred Russel Wallace. Wallace had spent five years exploring and collecting specimens in the Amazon basin. Others who made significant contributions to understanding the event in the century that followed include Florentino Ameghino, W. D. Matthew, W. B. Scott, Bryan Patterson, George Gaylord Simpson and S. David Webb. The Pliocene timing of the formation of the connection between North and South America was discussed in 1910 by Henry Fairfield Osborn.