Thursday, 26 January 2012

Permian Period

Permian period was a geological period which started 300 million years ago and that finished 250 million years ago. In Permian period there were important climatic changes like an inclination to tropical climates and more dry conditions. Marshes began to dry and the amphibians and plants which live there became extinguished. As a result, reptiles, mammal reptiles and the plants with seeds occupied the earth. The Permian period ended with the largest mass extinction in Earth's history, in which nearly 90% of marine species and 70% of terrestrial species died out.



Fusulinida
Fusulinida is an extinct group within the Foraminifera in which the shells are composed of tightly packed, secreted calcite. They were so abundant that they formed themselves complete calcite formations. They were a very important part of the Carboniferous and Permian periods where they are excellent fossils guides. However, they became extinguished at the end of the Permian period.


Ammonites
Ammonites are an extinct group of marine invertebrate animals within the class Cephalopoda and closer, the subclass Ammonoidea. These molluscs are more related to living coleoids like octupuses than to shelled nautiloids. They lived during the Permian period where they are excellent fossils guides, like the Fusilinida. Their shell is formed by several regions and its size can be like the wheel of a truck. Many parts of their organisms are unknown due to the fact that they are fossils but it is thought that they are similar to the ones of the coleoids. They were good swimmers and they were not in deep waters.

Ginkgo

Ginkgo, know as Maidenhair Tree, is a unique species of tree with no close living relatives. This kind of tree is widely cultivated and has many uses like in medicine or food. This kind of tree is one of the best examples of fossil guide. It lived during the Permian period. It is native from China and can live around 1000 years. Nowadays it is common in East Asia and South America. These trees can measure 25m of height. They have strong, thick branches around a central, big stem. The leaves are green in a fan shape. These trees are gymnosperms.

Dragonfly
Dragonfly is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body. Dragonflies possess six legs but most of them cannot walk well. Dragonflies are some of the fastest insects in the world. Dragonflies are predators that eat mosquitoes  and other small insects like flies, bees, ants and wasps. They are usually found around marshes, lakes, ponds, streams, and wetlands.  

Conifers

Conifers developed strongly during Permian period. This plant is a relative of the Araucaria, which can often be seen in gardens nowadays. The conifers had their first appearance in the Late Carboniferous, but they became common, and sometimes even dominant, in the Early Permian. The ferns continued their evolution like they do until now.
Chondrichthyes
The Chondrichthyes are a kind of aquatic vertebrates known as cartilaginous fishes. This is due to the fact that they skeleton is made of cartilage. They lived during the Permian period. This class is formed principally by sharks, but also by rays and chimeras. Their basic structure and many of their natural characteristics are the same from the beginning. For example, the fact that they are one of the most important predators of the sea. However, after some time they developed several characteristics like a growth of size to avoid being a prey or a development in the teeth. On the one hand, sharks had a length around 1,5m, they only had scales around their eyes and their two fins and they had problems to chew the animals. On the other hand, they were very fast fishes.


Estemmenosuchus

Estemmenosuchus is a genus of omnivorous therapsid that lived during the middle part of the Permian period. They were the biggest animals of that time and they were characterized by their peculiar horns that they used to show themselves. Their size was similar to the one of an adult bull and their horns look like the ones of an elk. They were clumsy of aspect and they had a very big skull. It is thought they had aquatic habits.

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Walchia
Walchia is a fossil of conifer, cypress-like genus. It is found in Europe and also North America. One of the most common locations of walchias is the forest located on Northumberland Strait coast at Brule, Nova Scotia where, apart from this kind of trees, many tracks of an insect called monuran can be found.


Titanophoneus

Titanophoneus was a carnivorous Therapsid (Therapsid means that comes from mammals) of the Dinocephalia group. Titanophoneus lived in the late part of the Permian period. The remains of these animals were found in Russia. An adult skull of Titanophoneus would have reached 80 cm with a heavy long snout. It had a long tail and short limbs. It had large teeth with 12 large palate incisors followed by 2 canines and various smaller back teeth; the lower plate is like the upper one but without the canine teeth.


Dimetrodon
Dimetrodon was a predatory synapsid (a synapsid is a group of animals that includes mammals and every animal more closely related to mammals) that lived during the Permian period. Dimetrodon was one of the largest land animals of its time.  Dimetrodon ate freshwater, sharks, amphibians, reptiles and other animals. Dimetrodon hunted by using his sight and smell.

By Miguel Ángel Lozano and Adrián Sánchez.

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