OVERPOPULATION

CENOZOIC ERA

  

CENOZOIC ERA

                                                    Is an Era of eon Phanerozoic


PERIOD: Tertiary and Quaternary


________________________________________________________________________________
                                                                    TERTIARY PERIOD

TERTIARY - PALEOGENE:   Paleocene Epoch   (marcela), 

Paleocene Epoch

• Paleocene Epoch, also spelled Palaeocene Epoch, first major worldwide division of rocks and time of the Paleogene Period, spanning the interval between 66 million and 56 million years ago. The most complete picture of Paleocene terrestrial life and environments is afforded by the rock record of North America

The Paleocene is subdivided into three ages and their corresponding rock stages: the Danian, Selandian, and Thanetian.

• The die-off of the dinosaurs in the prior mass extinction left unfilled ecological niches worldwide, and the name "Paleocene" comes from Greek and refers to the "old(er) (paleo)–new (ceno)" fauna that arose during the epoch, prior to the emergence of modern mammalian orders in the Eocene. The Paleocene provided the foundation for today, including the appearance of primate-like mammals.

Paleocene climate

• According to the science of paleoclimatology, the early Paleocene is considered to have been slightly cooler than the preceding Cretaceous, though temperatures rose again late in the epoch. The climate was warm and humid worldwide, with subtropical vegetation growing in Greenland and Patagonia. The poles were cool and temperate, North America, Europe, Australia, and southern South America were warm and temperate; tropical climates characterized equatorial areas, and north and south of the Equator, climates were hot and arid (Scotese 2002).

Paleocene flora

• Pine trees appeared during the Paleocene Epoch and avian species flourished and diversified.
• the Paleocene is marked by the development of modern plant species. Cacti and palm trees appeared. Paleocene and later plant fossils are generally attributed to modern genera, or to closely related taxa.
• Flowering plants (angiosperms), first seen in the Cretaceous, continued to develop and proliferate, coevolving with the insects that fed on these plants and pollinated them.
  

Paleocene fauna

• Paleocene animals, especially mammals, are lacking or rare or are only of late Paleocene age. Prominent faunal remains of the late Paleocene Epoch are known from the regions of Cernay, France; Gashato, Mongolia; and the Chico River of Patagonian Argentina.
  
  
• the complete absence of dinosaurs and other reptilian groups that were dominant during the preceding Cretaceous Period. 
• Paleocene mammals included Cretaceous species such as opossum-like marsupials and, especially, the archaic and unusual multituberculates—herbivorous animals that had teeth very similar in some respects to those of the later, more advanced rodents. 
•  Primates became more abundant in the middle Paleocene; they displayed characteristics intermediate between the insectivores and the lemurs, especially in their dental anatomy.
• mammals had evolved and widely populated the changing continental land-masses long before the Paleocene Epoch, the reduction in predator species allowed land mammals to dominate and thrive—eventually setting the stage from the evolutionof homo sapiens (humans). Pine trees appeared during the Paleocene Epoch and avian species flourished and diversified.
• Mammals of the Paleocene include:
  • Monotremes. Three species of monotremes are represented in modern times: The duck-billed platypus, and two species of Echidnas. Monotrematum sudamericanum lived during the Paleocene.
  • Marsupials. A number of marsupials are represented in modern times, such as the kangaroos, which are characterized by giving birth to embryonic babies, who crawl into the mother's pouch and suckle until they are developed. The Pucadelphys andinus is a Paleocene example of a marsupial.
  • Multituberculates. This is the only major branch of mammals to go extinct. This rodent-like grouping includes the Paleocene Ptilodus.
  • Placentals. This grouping of mammals became the most diverse and the most successful. Members include hoofed ungulates, primates, and carnivores, such as the Paleocene mesonychid.
  • 
    

Birds

Birds began to diversify during the epoch, occupying new niches. Most modern bird types had appeared by mid-Cenozoic, including perching birds, cranes, hawks, pelicans, herons, owls, ducks, pigeons, loons, and woodpeckers.

Large, carnivorous, flightless birds (also called Terror Birds) have been found in late Paleocene fossils, including the fearsome Gastornisin Europe.

 ________________________________________________________________________________

Eocene Epoch (Patricia),

_________________________________________________________________________________

Oligocene Epoch (Laura)

Third period of the Tertiary Age. It extended for 14 million years (38 - 24 million years).

 Its name means "small life"

Beginning of the formation of the mountain range of the Alps and the Apennines.

 Mammals dominated life on Earth. The camels are extinguished in America. Migrations of Oreodontes 

in this period the freezing of the earth begins

________________________________________________________________________________

TERTIARY - NEOGENE:    
Is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period 23.03 million years ago (Mya) to the beginning of the present Quaternary Period 2.58 Mya. The Neogene is sub-divided into two epochs, the earlier Miocene and the later Pliocene. Some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the Quaternary.

TERTIARY - NEOGENE:    MIOCENE EPOCH (ANDRES)

Do you remember the name of this character?

The earth went from the Oligocene through the Miocene and into the Pliocene, with the climate slowly cooling towards a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regional boundaries between the warmer Oligocene and the cooler Pliocene Epoch.

The apes arose and diversified during the Miocene, * becoming widespread in the Old World*. By the end of this epoch*, the ancestors of humans* had split away from the ancestors of the chimpanzees* to follow their own evolutionary path* (Approximately between 7.5 to 5.6 million years ago)*. As in the Oligocene before it*, grasslands continued to expand* and forests to dwindle in extent*. In the Miocene seas*, kelp forests made their first appearance* and soon became one of Earth's most productive ecosystems. 

 


The plants and animals of the Miocene* were fairly modern*. Mammals and birds were well-established*. Whales, seals, and kelp spread*. The Miocene is of particular interest to geologists and palaeoclimatologists* as major phases of the Himalayan orogeny* had occurred during the Miocene*, affecting monsoonal patterns in Asia*, which were interlinked with glaciations in the northern hemisphere.

Questions 

What scientific, named  the Miocene?

__________________________________________________________________________________

                                                     Pliocene Epoch (adriana)

 

The Pliocene Epoch is the epoch in the geologic timescale that extends from 5.333 million to 2.58 million years. 


In the official timescale of the International Commission on Stratigraphy, the Pliocene is subdivided into two stages. From youngest to oldest they are:

- Piacenziam (3.600 - 2.58 Ma)
-  Zanclean (5.333 - 3600 Ma)

The Pliocene world looked very similar to Earth today as North and South America had been drifting ever closer and the gap between them was sealed in this epoch.

At the start of the Pliocene, over 5 million years ago, the north polar ice cap came and went with the seasons and with fluctuations in climate.

However, as the world cooled in the late Pliocene, ice at the North Pole became permanent and grassland and tundra thrived. The human lineage split away from the chimpanzees' early on in the epoch.

The change to a cooler, dry, seasonal climate had considerable impacts on Pliocene vegetation, reducing tropical species worldwide. Tropical forests were limited to a tight band around the equator, and deserts appeared in Asia and Africa.

Both marine and continental faunas were essentially modern, although continental faunas were a bit more primitive than today. The first recognizable hominins, the australopithecines, appeared in the Pliocene.


                                                              QUATERNARY PERIOD

________________________________________________________________________________

PLEISTOCENE EPOCH : (Luz enith)

The quaternary period began 2.6 million years ago and extends into the present. The quaternary 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. This period is divided into two epochs: the Pleistocene (2.588 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today). The informal term "Late Quaternary" refers to the past 0.5–1.0 million years. https://en.wikipedia.org/wiki/Quaternary

THE PLEISTOCENE: Often colloquially referred to as the Ice Age, is the geological epoch which lasted frim about 2,588,000 to 11,700 years ago, spanning the world´s most recent period of repeated glaciations. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The Pleistocene  is divided into four stages or ages, the Gelasian, Calambrian, Ionian and Tarantian. https://en.wikipedia.org/wiki/Pleistocene

Imagen 1: Pleistocene map

Pleistocene climate was marked by repeated glacial cycles in which continental glaciers pushed to the 40th parallel in some places. It is estimated that, at maximum glacial extent, 30% of the Earth's surface was covered by ice. In addition, a zone of permafrost stretched southward from the edge of the glacial sheet, a few hundred kilometres in North America, and several hundred in Eurasia.

Imagen 2: The largest land mammals of the Pleistocene

One of the largest land mammals of the Pleistocene, was the Mamut,on the time period that spanned from 2.6 million to 11,700 years ago.* Pleistocene biotas were extremely close to modern ones — many genera and even species of Pleistocene conifers, mosses, flowering plants, insects, mollusks, birds, mammals, and others survive to this day. Yet the Pleistocene was also characterized by the presence of distinctive large land mammals and birds.

Mammoths and their cousins the mastodons, longhorned bison, saber-toothed cats, giant ground sloths, and many other large mammals characterized Pleistocene habitats in North America, Asia, and Europe. Native horses and camels galloped across the plains of North America. Great teratorn birds with 25-foot wingspans stalked prey. Around the end of the Pleistocene, all these creatures went extinct.

Imagen 3: The largest land animals of the Pleistocene

The Pleistocene also saw the evolution and expansion of our own species, Homo sapiens, and by the close of the Pleistocene, humans had spread through most of the world. According to a controversial theory first proposed in the 1960s, human hunting around the close of the Pleistocene caused or contributed to the extinction of many of the Pleistocene large mammals. It is true that the extinction of large animals on different continents appears to correlate with the arrival of humans, but questions remain as to whether early human hunters were sufficiently numerous and technologically advanced to wipe out whole species. It has also been hypothesized that some disease wiped out species after species in the Pleistocene.

________________________________________________________________________________

HOLOCENE EPOCH : (Gloria Nancy)

Holocene. 

melting began, raising sea levels, flooding large areas of land and widening the continental shelf. Humans began to organize into social groups that concentrated on "cities." It was also called Age of Civilization

3.     Another name for the Holocene that is sometimes used is the Anthropogene, the "Age of Man." This is somewhat misleading: humans of our own subspecies, Homo sapiens, had evolved and dispersed all over the world well before the start of the Holocene. Yet the Holocene has witnessed all of humanity's recorded history and the rise and fall of all its civilizations. Humanity has greatly influenced the Holocene environment; while all organisms influence their environments to some degree, few have ever changed the globe as much, or as fast, as our species is doing. The vast majority of scientists agree that human activity is responsible for "global warming," an observed increase in mean global temperatures that is still going on. Habitat destruction, pollution, and other factors are causing an ongoing mass extinction of plant and animal species; according to some projections, 20% of all plant and animal species on Earth will be extinct within the next 25 years.

Yet the Holocene has also seen the great development of human knowledge and technology, which can be used — and are being used — to understand the changes that we see, to predict their effects, and to stop or ameliorate the damage they may do to the Earth and to us. Paleontologists are part of this effort to understand global change. Since many fossils provide data on climates and environments of the past, paleontologists are contributing to our understanding of how future environmental change will affect the Earth's life.

3.     The Holocene ( /ˈhɒləˌsiːn, ˈhoʊ-/)^[1][2] is the geological epoch that began after the Pleistocene^[3] at approximately 11,700 years before present.^[4] The Holocene is part of the Quaternary period. Its name comes from the Ancient Greek words ὅλος (holos, whole or entire) and καινός (kainos, new), meaning "entirely recent".^[5] It has been identified with the current warm period, known as MIS 1, and is considered by some to be an interglacial period.

4.      

The Holocene encompasses the growth and impacts of the human species worldwide, including all its written history, development of major civilizations, and overall significant transition toward urban living in the present. Human impacts on modern-era Earth and its ecosystems may be considered of global significance for future evolution of living species, including approximately synchronous lithospheric evidence, or more recently atmospheric evidence of human impacts. The International Commission on Stratigraphy Subcommission on Quaternary Stratigraphy’s working group on the 'Anthropocene' (coined by Paul Crutzen and Eugene Stoermer in 2000) note this term is used to denote the present time interval in which many geologically significant conditions and processes have been profoundly altered by human activities. The 'Anthropocene' is not a formally defined geological unit.^[6]

____________________________________________________________________________