Reptiles of northern eurasia pdf

You can edit reptiles of northern eurasia pdf timeline. Please use the preview button before saving. An approximate timescale of key Mesozoic events.

Axis scale: millions of years ago. The Mesozoic was a time of significant tectonic, climate and evolutionary activity. The climate of the Mesozoic was varied, alternating between warming and cooling periods. Overall, however, the Earth was hotter than it is today. Late Triassic and became the dominant terrestrial vertebrates early in the Jurassic, occupying this position for about 135 million years until their demise at the end of the Cretaceous. The Triassic ranges roughly from 252 million to 201 million years ago. It has three major epochs: the Early Triassic, the Middle Triassic and the Late Triassic.

The Middle Triassic spans roughly from 247 million to 237 million years ago. Algae, sponge, corals, and crustaceans all had recovered, and the reptiles began to get bigger and bigger. Meanwhile, on land, pine forests flourished, as did groups of insects like mosquitoes and fruit flies. The first ancient crocodilians evolved, which sparked competition with the large amphibians that had since ruled the freshwater world.

It has three major epochs: the Early Triassic, the Early Jurassic spans from 200 million years to 175 million years ago. Broad interchange between the tetrapod fauna of the Old World continents resulted in the wide distribution during the Late Permian and Early Triassic of common or closely related forms, archosaurs rise to rule the world. The world was very tropical. The Jurassic ranges from 200 million years to 145 million years ago and features 3 major epochs: The Early Jurassic — quantitative models have also been unable to recreate the flatness of the Cretaceous temperature gradient. And as a result, late Cretaceous declined for poorly understood reasons, alexander Kaiser and John M.

The Late Triassic spans roughly from 237 million to 201 million years ago. The Jurassic ranges from 200 million years to 145 million years ago and features 3 major epochs: The Early Jurassic, the Middle Jurassic, and the Late Jurassic. The Early Jurassic spans from 200 million years to 175 million years ago. The climate was much more humid than the Triassic, and as a result, the world was very tropical. The first true crocodiles evolved, pushing out the large amphibians to near extinction. All-in-all, archosaurs rise to rule the world. The Middle Jurassic spans from 175 million to 163 million years ago.

This epoch was the peak of the reptiles. The Late Jurassic spans from 163 million to 145 million years ago. The increase in sea-levels opened up the Atlantic sea way which would continue to get larger over time. The divided world would give opportunity for the diversification of new dinosaurs. The Cretaceous is the longest period in the Mesozoic, but has only two epochs: the Early Cretaceous, and the Late Cretaceous. The Early Cretaceous spans from 145 million to 100 million years ago. The Late Cretaceous spans from 100 million to 66 million years ago.

Eventually, tropics were restricted to the equator and areas beyond the tropic lines featured extreme seasonal changes in weather. Flowering plants, possibly appearing as far back as the Triassic, became truly dominant for the first time. Late Cretaceous declined for poorly understood reasons, though this might be due to fossil record bias as their diversity seems to be much higher than previously thought. Everything over 10 kilograms became extinct. The age of the dinosaurs was over.

Paleozoic, Mesozoic tectonic deformation was comparatively mild. Siberian cratons under the Pacific Ocean. By the end of the era, the continents had rifted into nearly their present form. Low sea levels may have also exacerbated temperature extremes. Triassic was punctuated by episodes of increased rainfall. Temperatures continued to increase and began to stabilize. The climate of the Cretaceous is less certain and more widely disputed.

Not all of the data support these hypotheses, however. Quantitative models have also been unable to recreate the flatness of the Cretaceous temperature gradient. Conifers were the dominant terrestrial plants for most of the Mesozoic. Schizeales, a fern order, were skewed to the Northern Hemisphere in the Mesozoic, but are now better represented in the Southern Hemisphere. The climatic changes of the late Jurassic and Cretaceous provided for further adaptive radiation. However, all major insect mouth parts preceded angiosperms and insect diversification actually slowed when they arrived, so their anatomy originally must have been suited for some other purpose.

Peter Roach, James Hartmann and Jane Setter, eds. Gradstein F, Ogg J, Smith A. Triassic climates — State of the art and perspectives”. See the dotted line in Fig. Harrison, Alexander Kaiser and John M.

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