Neogene characteristics, subdivisions, flora and fauna

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Philip Kelley
Neogene characteristics, subdivisions, flora and fauna

The Neogene it was the second period of the Cenozoic Era, beginning about 23 million years ago and ending about 2.6 million years ago. It is a period in which the planet underwent a series of changes and transformations at the geological level and in biodiversity.

One of the most momentous events of this period was the appearance of the first hominids, known as Australopithecus, which represent the oldest ancestors of the Homo sapiens.

Neogene fossils. Source: Emilio J. Rodríguez Posada [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]

Article index

  • 1 Features
    • 1.1 Duration
    • 1.2 Intense geological activity
    • 1.3 Broad development of biodiversity
  • 2 Geology
    • 2.1 Continental drift
    • 2.2 Messinian salt crisis and Zanclian flood
  • 3 Climate
  • 4 Life
    • 4.1 Flora
    • 4.2 Fauna
  • 5 Subdivisions
  • 6 References

Characteristics

Duration

This period lasted from 23 million years ago to 2.6 million years ago..

Intense geological activity

During the Neogene period, the planet experienced intense geological activity, both in terms of continental drift and at sea level..

The continents continued their slow movement towards locations similar to those they currently have, while the marine currents were modified by the emergence of physical barriers, such as the isthmus of Panama..

This was a very important event that had a lot to do with the decrease in temperatures in the Atlantic Ocean..

Extensive development of biodiversity

In this period a great biodiversity of animals was observed. The groups that experienced the greatest transformation and opening are terrestrial and marine mammals, birds and reptiles..

geology

During this period there was intense activity, both from the orogenic point of view and from the point of view of continental drift..

Continental drift

Pangea

In the Neocene period the fragmentation of the Pangea continued, with the various originated fragments moving in different directions.

Throughout this period several land masses collided with southern Eurasia. Those masses were Africa (the north), Cimmeria and the one corresponding to India. In particular, the one corresponding to present-day India did not stop its drift, but continued to press against Eurasia, causing the continuous elevation of the peaks of the Himalayas..

Likewise, South America, which had separated from Gondwana and moved in a northwesterly direction, was located in a position very similar to what it currently has, below North America..

At first, both continents were separated by a small strait that communicated the waters of the Pacific Ocean with those of the Atlantic. However, during the Pliocene this communication was interrupted thanks to the emergence of a land bridge; the isthmus of Panama.

The formation of this isthmus resulted in a considerable variation in the climatic conditions of the planet, causing a cooling at both the Pacific and Atlantic oceans..

Particularly the waters of the Atlantic Ocean that were at the level of the North Pole and South Pole suffered a significant decrease in temperature, cooling rather quickly..

Similarly, during this period a very important event occurred at the level of the Mediterranean Sea; the Messinian salt crisis.

Messinian salt crisis and Zanclian flood

It was a process that originated as a consequence of the progressive isolation of the Mediterranean Sea, restricting the flow of the waters of the Atlantic Ocean. This caused the desiccation of the Mediterranean Sea, leaving in its place an immense saline.

Among the possible causes of this event, some specialists mention a drop in sea level, which caused a bridge to emerge in the space of the Strait of Gibraltar..

Others postulate the emergence of land in the strait as a possible theory. Regardless of the causes, the truth is that for a time the bed of the Mediterranean Sea was completely stripped of water.

This remained so until the Zanclian age of the Pliocene (about 5.33 million years ago). In this there was an event known as the Zancliense flood, which consisted of the entry of water from the Atlantic Ocean into the Mediterranean basin. As a consequence, the Strait of Gibraltar was formed and the Mediterranean Sea re-emerged..

Weather

The climate experienced by the planet during this period was characterized by a decrease in ambient temperatures. In the territories located in the northern hemisphere, the climate was a little warmer than that of those found in the south pole of the Earth.

Similarly, as the climate changed, so did the different ecosystems that existed. This is how large areas of forests disappeared, giving way to grasslands and savannas with herbaceous.

Also, during this period the poles of the planet were completely covered with ice. In general, the ecosystems that predominated were those that had vegetation made up of savannas, which had conifers among their representative plants..

Lifetime

During this period there was an extension of the existing forms of life from the Paleogene. The climate and the terrestrial temperatures had a wide influence in the development and establishment of the different alive beings.

Establishing a comparison between flora and fauna, the latter was the one that experienced the greatest diversification, while the flora remained somewhat stagnant.

Flora

The climate of this period, being a bit cold, limited the development of jungles or forests, and even caused the disappearance of large areas of these. Due to this, a type of plants that could adapt to a low-temperature environment flourished: herbaceous.

In fact, some specialists refer to this period as "the age of herbs." Likewise, some species of angiosperms also managed to establish and develop successfully.

Fauna

This period was characterized by a wide diversification of various groups of animals. Among these, the most recognized were reptiles, birds and mammals. Likewise, in marine ecosystems there was extensive development, especially of the group of cetaceans.

Birds

Within this group, the most prominent were the passerine birds and the so-called "birds of terror", which were located mainly in the American continent..

Representation of a "bird of terror" from Neogene. Source: McBlackneck [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]

Passerine birds are the most diverse and widest group of birds, which have managed to maintain their survival over time. They are characterized because the shape of their legs allows them to perch on the branches of the trees.

Also, because they have the ability to sing, they have complex mating rituals. They are the so-called songbirds. Well, in this period this group of birds began to gain strength and massify.

In America, mainly in South America, the fossil records bear witness to the existence of very large birds, without the ability to fly, which were great predators of their time. So much so that specialists have agreed to call them "birds of terror".

Mammals

In this period, the group of mammals underwent a wide diversification. Within these, the families Bovidae (goats, antelope, sheep) and Cervidae (deer and deer) expanded their distribution remarkably.

Likewise, large mammals, such as elephants, mammoths or rhinos, also experienced great development, although some have not managed to survive until today..

During this period there were also primates, specifically monkeys, both on the American and African continents. Each group in its respective habitat underwent certain transformations in its evolutionary process.

Similarly, in the Neogene, other mammals began to appear, such as cats and canines, hyenas and various types of bears..

Likewise, within the group of mammals, an extremely important event occurred within the evolutionary process of the human being; the emergence and development of the first hominid. This was baptized by specialists as Australopithecus and was characterized by its small size and bipedal movement.

Reptiles

From this group of living beings, frogs, toads and snakes expanded their domains, due to the great availability of food that was available. They fed mainly on insects, which were abundant.

Subdivisions

The Neogene period is divided into two very well differentiated periods:

  • Miocene: it was the first Neogene epoch, immediately after the Oligocene. It spread from about 24 million years ago to about 6 million years ago. 
  • Pliocene: second and last epoch of this period. It lasted for almost 3 million years.

References

  1. Alonso, A. (2008). The Neogene: from tectonic crises to the tranquility of shallow lakes. Guadalajara Geology.
  2. Krijgsman W. et al., 1999, Chronology, causes and progression of the Messinian salinity crisis, Nature, 400, 652-655
  3. Levin, H. (2006), The Earth Through Time, 8th ed, John Wiley & Sonc, Inc
  4. Neogene period. Retrieved from: Britannica.com
  5. Neogene period. Retrieved from: nationalgeographic.com
  6. Strauss, B. The Neogene period. Retrieved from: thoughtco.com.

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