Planet Earth - Mesozoic Era - Parish Notices

The Mesozoic Era ran from 251 to 65.5 million years ago, it has been split up into three periods - these being the Triassic, the Jurassic and the Cretaceous. These will be covered in greater detail in their own entries in this blog.

Planet Earth - Permian Period

The Permian Period ran from 299 to 251 million years ago. Details to come...

Planet Earth - Carboniferous Period

The Carboniferous Period ran from 359 to 299 million years ago. Details to come...

Planet Earth - Devonian Period

The Devonian Period ran from 416 to 359 million years ago. Details to come...

Planet Earth - Silurian Period

The Silurian Period ran from 444 to 416 million years ago. Details to come...

Planet Earth - Ordovician Period

The Ordovician Period spanned from 488 to 444 million years ago. The biodiversity of the marine life continued to expand, especially in the shallower seas where organisms that used calcium carbonate in their shell, with such appearances of arthropods and molluscs. The period also saw the first vertebrate (species with a back bone) family start, namely the fish and some with jaws that evolved in the latter part of the period.  

There were higher sea levels in the Ordovician and at the start period, from around 480 MYA, the climate was very hot due to high carbon dioxide levels within the atmosphere - an early example of the Greenhouse Effect - which led to a potential sea temperature of 45 degrees Centigrade. These levels of water temperature may sound wonderful but it reduced the biodiversity of the more complex (multi-cellular) organisms.

By 460 MYA, the sea temperature had reduced to the types of temperature found in the current equatorial seas. The shallower seas became more inhabited by organisms that exploited the calcium carbonate present in the sea to provide more elaborate shells and body parts. Just think of that, the next time you see a crab, lobster or oyster in the fishmongers.

The marine faunal (means animals) life of this period included some communities of suspension feeders in tiers, which led to the basis of a food chain that still exist today. It is thought that the diversity of marine faunal organisms that share similar characteristics increased fourfold (Dixon, Dougal; et al. (2001) Atlas of Life on Earth. New York: Barnes & Noble Books pp 87)  as well as an increase in filter feeder organisms. The creatures that were typical of the Cambrian period - the archaeocyathids, the eocrinoids, the inarticulate brachiopods, the trilobites were succeeded by the articulate brachipods, the cephalopods and the crinoids by the middle of the Ordovician period. It was also a good time to start scuba diving, if such a thing had been invented, as coral species that create reef-like structures were taking advantage of the calcium carbonate in the water.

But life on the land was restricted to the bryophytes and a few fungal structures (Arbuscular mycorrhiza) that made nutrients more readily available to plant cells - there have been fossils found of hyphae and spores from around 460 MYA.

Planet Earth - Cambrian Period

The Cambrian Period ran from 542 to 488 million years ago. Not literally ran. The period is the first period of the Paleozoic Era. The best place to look at Cambrian rock examples is in wales, the Latin for Wales being Cambria. This is also where Alec Amos, past Whatlington village members, moved to after leaving the village. He and his wife worked hard especially for the village hall and he was the originator of the Whatlington Duck Race at the Village Fete on the River Line.

Back to the Cambrian rocks and due to their age and their structure being altered through metamorphic movements, it is quite hard to comprehend their specific geographic reconstructions. However, it is purported that Pannotia, a super continent, was breaking up early in the Cambrian period with other smaller land masses (Baltic, Laurentian and Siberia) having calved from Gondwana's super continent. It is thought that most land masses were in the southern hemisphere in the early Cambrian with a slow migration of continents towards the northern hemisphere during the latter part of the Cambrian period.

The land was mainly desert-like with potential microbial mats of algae, fungi and lichens. However, with the reduction in the quantity of sea ice in the Cambrian period, there was a rise in the sea levels and thus shallower seas formed around the edges of the land masses.  This period saw an increase in aquatic biodiversity, despite the disappearance of of animals that relied upon microbial mats on the sea floor. These mats were destroyed by the increase presence of burrowing animals. The greater an animal's ability to adapt increases its success to taking over a new ecological niche. Similar to business today.

There is evidence for species becoming more mineralised. The process through which an organic substance becomes impregnated by inorganic substances - for example a bacterium may use the organic part of matter thus leaving the waste minerals within the body. This process aided the preservation of fossilised records of life. However at this time, the mineralised species were found at the benthic level of the sea, the lowest part of the sea, in the water column and the Cambrian fauna lived on or above the sea bed.