The Cambrian Explosion

The 13

periods are: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Mesozoic, Triassic,

Jurassic, Cretaceous, Paleogene , Neogene, and Quaternary.

1.

The Cambrian, the first period of the Paleozoic Era, began approximately 570 million years ago and ended 510 million years ago. During this period, the land subsided, and most of the Northern Hemisphere was submerged by seawater. The biota consisted mainly of invertebrates, especially trilobites and lower brachiopods, while red and green algae flourished. Cambrian is the Latin name for Wales, UK, where the strata of this period were first discovered.

2. The

Ordovician, the second period of the Paleozoic Era, began approximately 510 million years ago and ended 438 million years ago. During this period, the rocks consisted of limestone and shale. The biota consisted mainly of trilobites, graptolites, and brachiopods, with the appearance of tegu and corals. Algae flourished. The Ordovician is named after the ancient Ordovician tribe of North Wales, UK.

3. The Silurian Period

, the third period of the Paleozoic Era, began approximately 438 million years ago and ended 410 million years ago. During this period, the Earth's crust was relatively stable, but there was intense orogenic activity at the end. Brachiopods and corals flourished, trilobites and graptolites remained abundant, jawless animals developed, and primitive fish appeared in the later stages. Primitive terrestrial plants, psilocybines, appeared at the end. The Silurian Period is named after the ancient Silurians who lived in southwest Wales, England.

4. The Devonian

Period, the fourth period of the Paleozoic Era, began approximately 410 million years ago and ended 355 million years ago. In the early stages of this period, the sea receded, accumulating later sediments. Later, the sea submerged the land, forming sediments rich in organic matter, resulting in rocks that are mostly sandstone and shale. Brachiopods and corals developed, and insects and primitive amphibians were also found, in addition to primitive pyrethroids. Fish developed, and ferns and primitive gymnosperms appeared. The Devonian Period is named after Devonshire, England.

5. The Carboniferous period,

the fifth period of the Paleozoic Era, began approximately 355 million years ago and ended 290 million years ago. During this period, the climate was warm and humid, and tall, dense vegetation was buried underground, carbonizing and metamorphosing to form coal seams, hence the name. Rocks were mostly limestone, shale, and sandstone. Amphibians appeared among the animals, and ferns and conifers appeared among the plants.

6. The Permian

period, the sixth and last period of the Paleozoic Era, began approximately 290 million years ago and ended 250 million years ago. During this period, intense tectonic movements occurred in the Earth's crust. In Germany, the stratigraphy of this period is clearly dichotomous, hence the name. Ammonites and primitive reptiles among the animals, and conifers and cycads among the plants, developed during this period.

7.

The second era of the Phanerozoic Eon. Divided into the Triassic, Jurassic, and Cretaceous periods. Began approximately 250 million years ago and ended approximately 65 million years ago. The dominant animals during this period were reptiles, with dinosaurs flourishing and mammals and birds beginning to appear. Invertebrates were mainly ammonites and belemnites. Plants were primarily ginkgo, cycads, and conifers.

8.

The first period of the Mesozoic Era, the Triassic Period, began approximately 250 million years ago and ended approximately 205 million years ago. During this period, geological changes were relatively minor, and rocks were mostly sandstone and limestone. It is named after the fact that the strata of this period were initially divided into upper, middle, and lower parts in Germany. Animals included cephalopods, crustaceans, fish, amphibians, and reptiles. Plants were mainly cycads, conifers, ginkgo, horsetails, and ferns.

9. The Jurassic

period, the second period of the Mesozoic Era, began approximately 205 million years ago and ended 135 million years ago. This period was characterized by orogenic movements and intense volcanic activity. It is named after the Jura Mountains on the border of France and Switzerland. Reptiles were highly developed, and giant dinosaurs, flying dragons, and Archaeopteryx appeared. Cycads and ginkgo trees were the most abundant plants.

10. The Cretaceous

period, the third period of the Mesozoic Era, began approximately 135 million years ago and ended 65 million years ago. It is named after the predominantly chalk strata of western Europe. Orogenic movements were extremely intense during this period, and many mountain ranges in China were formed during this time. Dinosaurs were the most abundant animal species, but gradually became extinct towards the end. Fish and birds were highly developed, and mammals began to appear. Angiosperms appeared. Flowering plants were abundant, and tropical plants and broad-leaved trees also appeared.

11. The Paleogene, the first period of the Cenozoic Era

(formerly known as the Early Tertiary or Paleogene), began approximately 65 million years ago and ended 23 million years ago. During this period, mammals, in addition to those living on land, included flying bats and swimming whales. Angiosperms flourished. The Paleogene can be divided into the Paleocene, Eocene, and Oligocene epochs, with the corresponding strata called the Paleocene, Eocene, and Oligocene series.

12. The

Neogene, the second period of the Cenozoic Era (formerly known as the Late Tertiary or Neogene), began approximately 23 million years ago and ended 1.6 million years ago. During this period, mammals continued to evolve, gradually increasing in size. Some ancient types became extinct. Higher plants were not significantly different from modern ones, while lower plants, such as diatoms, were abundant. The Neogene can be divided into the Miocene and Pliocene epochs, with the corresponding strata called the Miocene and Pliocene series.

13. The Quaternary Period

, the third and last period of the Cenozoic Era, is also the last period in the geological timescale. It began approximately 1.6 million years ago and continues to this day. During this period, multiple glacial periods occurred, and the Earth's crust and flora and fauna began to resemble modern forms. Early human ancestors (such as Peking Man and Neanderthals) began to appear. The Quaternary Period can be divided into the Pleistocene (Early Pleistocene, Middle Pleistocene, Late Pleistocene) and the Holocene, with the corresponding strata called the Pleistocene Series (Lower Pleistocene, Middle Pleistocene, Upper Pleistocene) and the Holocene Series.

URL 1:https://www.sexlove5.com/htmlBlog/113195.html

URL 2:/Blog.aspx?id=113195&aspx=1

Previous Page : Exotic

Next Page : Women are all promiscuous

增加

comment Open a new window to view comments

Contact Information

The Cambrian Explosion

comment Open a new window to view comments