The Triassic It is the first geological division of the Mesozoic Era, with an approximate duration of 50 million years. It was a period of transition on the planet, since it began with the Permian - Triassic mass extinction process, by which the environmental conditions of the planet were greatly affected..
During the Triassic there was a transformation in which the Earth acquired the conditions for life to diversify. It represents, from the biological point of view, the moment in which dinosaurs, the dominant species, originated for the next 165 million years or so. For this and other reasons, the Triassic has been a very interesting period for specialists as an object of study.
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The Triassic period lasted for about 50 million years. It began 251 million years ago and ended approximately 201 million years ago..
During this period, cracks began to appear at various sites on the supercontinent Pangea. This caused that this land mass began to fragment and later, in other periods, give rise to the continents.
The Triassic was the period in which the dinosaurs began their hegemony over the planet. These reptiles conquered the terrestrial, aquatic and aerial environments. There were herbivores and carnivores, which were great predators.
At the end of the Triassic period, a mass extinction process took place, known as the Triassic - Jurassic mass extinction. Specialists in the area have classified this event as a process of a minor category, compared to other extinctions that occurred in different geological periods..
During this process, a large number of terrestrial and marine species disappeared from the planet. This allowed dinosaurs to assume the dominant role in the following period..
The Triassic period is divided into three epochs: Lower Triassic (early), Middle Triassic, and Upper Triassic (late). Likewise, these times are divided into ages (7 in total).
During the Triassic period, all the supercontinents that existed in previous periods were united, forming a single land mass known as Pangea..
In the Triassic period its fragmentation process began, which would extend throughout the Mesozoic Era until giving rise to the continents as they are known today. It is important to note that two areas or zones were clearly distinguished in the Pangea: Laurasia, to the north of the continent, and Gondwana to the south..
Gondwana comprised the territories that currently correspond to Antarctica, Africa, South America, Australia, and India. While Laurasia was made up of what today corresponds to Asia, Europe and North America.
The rupture of the Pangea was started almost simultaneously by fissures that arose at various points. Fissures began to form in northern Africa, central Europe, and far eastern North America.
Regarding the bodies of water that could be observed during the Triassic period, there were only two:
During this period three layers of rock were deposited. This is where the name of the period comes from, since the prefix "tri" means three.
Those three layers of rocks are known by the names of Bunter, Muschelkalk and Keuper.
Here it is important to remember that at the end of the previous period (Permian) and the beginning of this, a process of extinction occurred, caused by environmental modifications of the planet. In this sense, at the beginning of the period the climatic conditions were a bit hostile. However, little by little they stabilized.
The planet's climate during the Triassic period was quite particular. In the previous period, the Permian, the climate was very humid, however, in the Triassic, environmental temperatures were gradually rising to even reach much higher values than those that exist today..
Because the Pangea was extremely large, there was no influence of water in the interior lands, so the climate there was very dry and arid. On the contrary, in the places near the coasts the climate was quite humid. It could even be considered tropical.
Likewise, according to the fossil records collected, during the Triassic period there was no ice at the poles, on the contrary, the climate in these places was humid and temperate..
These climatic characteristics allowed diverse forms of life to flourish in certain places, both plants and animals..
On the dividing line between the previous period, the Permian, and the Triassic, the most devastating mass extinction process that the planet has experienced occurred, as it resulted in the disappearance of 95% of living species.
It can be affirmed then that the Triassic represented something like a restart in the development of life on the planet, since the few species that managed to survive extinction had to adapt to the conditions.
Despite everything, they were able to adapt very well and the different forms of life experienced great diversification..
In the Triassic, plants formed large forests, while in relation to the zoological part, dinosaurs began to dominate the planet, in all existing habitats: land, air and sea..
A large number of plant species became extinct at the beginning of the Triassic period, due to the fact that the environmental conditions were not the most suitable and suitable for them.
The plants that were maintained and diversified in this period were mainly gymnosperms, known as bare-seeded plants. Within this group, the conifers and cycads stand out. Likewise, there were representatives of the gingko genus and ferns.
Conifers are a type of plant that has a woody, thick and quite resistant stem. Its leaves are evergreen and generally monoecious, which means that both the male and female reproductive organs are found in the same individual..
The seeds of conifers are housed within a structure known as cones. Externally, this plant has a pyramidal shape.
These plants have a woody stem that does not have any type of ramifications. The leaves, of the pinnate type, are located at the apical end of the plant, arranged as a tuft.
Similarly, these plants are dioecious, that is, there are male and female individuals. Male cells are generated in structures known as microsporophils and female cells do so in structures called megasporophils.
This type of plant was abundant during this period. They were dioecious plants, with separate male and female flowers. Its leaves had a lobed or divided blade. Of this group only a single species survives to this day, the Ginkgo biloba.
These plants are vascular (they have xylem and phloem) and belong to the group of pteridophytes. Their main characteristic is that they do not produce seeds or flowers..
Reproduction is through spores. These are stored in structures that are found on the lower edge of the leaves, known as sori.
The most representative terrestrial fauna of the Triassic period was made up of two groups: mammalian reptiles (Therapsids) and dinosaurs.
Regarding the aquatic ecosystem, invertebrates continued to be the most abundant forms of life, although some species of marine reptiles also appeared that in later periods would dominate the seas..
In the air some reptiles began to be observed that thanks to certain anatomical adaptations were able to adapt to flying.
This group is called therapsids. In their physical appearance, these animals looked like a hybrid between dog and lizard. They were quadrupeds, their limbs were a bit long and their tails short.
Their teeth had specific shapes according to the function they fulfilled in food. The first to appear were herbivores and later the carnivores did..
Within the group of therapsids, the most prominent were the cynodonts and dicynodonts. The importance of therapsids lies in the fact that, according to the studies carried out, they were the direct ancestors of the mammals that are known today.
Dinosaurs are believed to have appeared well into the Triassic period. The most representative groups of dinosaurs were the prosauropods and theropods.
They were animals of great volume, which had a very long neck (not as long as that of the herbivores of the Jurassic). Their forelimbs were less developed than their hindquarters..
There is still some controversy as to whether they were bipeds or quadrupeds. Within this group of animals were:
They were a group of carnivorous dinosaurs. Its main characteristics include that they were bipedal, their front limbs were very poorly developed and their size was very varied..
There were some small ones whose size did not exceed one meter, while others were very large, up to 12 meters. These include:
Aquatic invertebrates were represented by mollusks, such as some species of gastropods, cephalopods, and bivalves. Likewise, some forms of corals developed on the seabed, which were very similar to those that can be observed today..
Within this group, the following stood out:
In the Triassic there was a group of reptiles that developed membranes that extended from their trunk to their upper extremities. These allowed them to glide and fly.
This group became known as the Pterosaurs. These were oviparous and had an elongated beak. Likewise, they were carnivorous. They were of different sizes; very small and very large, like the famous Quetzalcoaltlus.
The Triassic period was divided into three epochs: lower or early, middle and upper or late.
It was the first division of the period, immediately after the Permian. It lasted for approximately 5 million years. It was divided into two ages:
Intermediate division of the Triassic period. It began 245 million years ago and ended approximately 228 million years ago. In turn, it was divided into two ages:
It was the last division of the Triassic period. It spanned 36 million years. It was divided into three ages:
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