Why are fossils related to the Great flood?
You must all have heard about the Great flood that swept across the earth in ancient time. Many people believe that thousands of animals that were swept away by the flood, eventually become fossils. It is true that condition during the were ideal ‘fossilizing’ millions of animals, plants, and even dinosaurs. In fact, thousands of dinosaur bones can be found where they were washed together by violent flood waters and buried under mud sand and rock. Many of the animal were torn apart and their bones broken jumbled up . The mud and sands hundred like concrete to form the great layers of fossils rock we find today. Quick flood burial would be the only way that so many dinosaurs and other things could have become fossilized in the way scientists have found them.
Animals and plants will fossilize only if they are buried quickly and deeply before predators decay and weather destroy them most scientists do not support this theory but there are some scientists today who are seeking evidence to support it.
Why is the Vendian period important?
The vendian period began about 650 million years ago and ended about 543 million year ago with the beginning of the Cambrian period .
The vendian is when the earliest know animals evolved . this included soft bodied malty cellular animals like sponges and worms. During the vendian the continents had merged into a single super continent called rodinia. In the 20 century macroscopic fossils of soft bodied animals , algae, and fossils Bactria have been found in rock attributed to the vendian period in few localities around the world. The vendian the also known as the ediacaran or as the Proterozoic.
Why is the Precambrian period extremely significant ?
The Precambrian period spans a long period of earth’s history. It starts with the planet’s creation about 4.5 billion years ago and ends with the emergence of complex multicelled life-forms almost four billion year later. It is extremely significant because it is earliest of the geologic ages which are marked by different layers of sedimentary rock. Laid down over million of years, these rock layer contain a permanent record of the earth ‘s past, including fossilized remains of plants and animals breed when the sediments where formed.
The Precambrian is divided into two parts the Archean time , and Proterozoic era. There may not have been many different forms life,s but very important changes were taking place during the Precambrian . The earth was formed , and it,s outer covering cooled and hardened into a crust. The hot molten in sides of earth leaked out at weak places in crust to form volcanoes. The cloud formed by the volcanoes caused use amounts of rain to fall, and oceans were created .
The first life formed. The oceans were like thick soup and their chemistry made them the perfect place of life to begin. The first one celled organisms formed during the Precambrian ear. They had and important job to do. They helped make the air and water around the earth full of oxygen. Once their was plenty of oxygen, new life could form this life would have many cells which would evolve into different kind of animals. All of the important work the cambrian period made the earth ready for what would come next.
What are metazoans?
Metazoans were the first multi-cellular animals. They could move, respond to their environment, and feed on other organisms. They developed organs, a nervous system. Sensory organs, and a brain which led to the development of intelligence. The earliest forms were flat bodied, like today’s flat worms. Direct fossils of metazoans from later periods have been found. These are fossils of animals that live in the sea and seabed, 680 to 570 million ago. These fossils bear some resemblance to the bodies of some of today’s invertebrates, including some type of jellyfish. These fossils are amongst the earliest discovered of distinct forms of animal life.
What is Cambrian Period?
The Cambrian period latest for nearly 53 million Years, from 543 million Years ago. Until 490 million Year ago. The continent were still forming, but were mostly barren rocks. The land had no plant an animal life on it yet. During the Cambrian period, there was an explosion of life forms. Most of these were in the water. Many animals with no backbones lived in the shallow seas.
The most plentiful species during this period were trilobites. The species got its name from the three lobes in the in the hard skin. The trilobite was also one of first animals to have eyesight. There were plenty of other species living during the Cambrian period also. Molluscs, worms, sponges and echinoderms filled the Cambrian seas. The plants of the Cambrian were mostly simple, one-celled algae.
The Cambrian period ended in a mass extinction. Advancing glaciers would have lowered the temperature of the shallow seas where seas were so many species lived. Changes in the temperature and the amount of oxygen in the water, would have meant the end of any species that could not adapt.
Why was there an explosion of life during the Cambrian period?
The Cambrian period marks an important point in the history of life on Earth. It is the time when most of the major groups of animals first appear in fossil record. This event is sometimes called the ‘Cambrian explosion’, because of the relatively short time over which many life forms appeared. Many reasons have been suggested for this explosion. The is that the increase in oxygen levels in atmosphere led to the evolution of more complex body structures.
Moreover, many species become extinct at the end of the vendian period, and this allowed new life forms to develop. It is also thought that a change in the ocean chemistry made possible the development of hard body part such as teeth and skeletons. Animals could now swim, burrow, defend themselves, hide, and hunt. However, the was still the centre of activity.
Why is Jean Baptiste de Lamarck a key figure in the history of evolution?
Jean Baptiste Lamarck was a French scientist who developed a theory of evolution at the beginning of the 19TH century. His theory involved to ideas. The first was the law of use and disuse, which stated that a characteristic which is used more and more by an organism becomes bigger and stronger, and one that is not used, eventually disappears . The second low was the low of inheritance of acquired characteristic. It stated that any feature of an organism that is improved through use, is passed to its offspring.
However,Lamarck’s theory cannot account for all the observations made about life on Earth. For instance, his theory would predict that all organisms gradually become complex, and simple organisms disappear. But we know that this is not the case, and that simple organisms still exist. So Today, Lamarck’s theory is largely ignored.