How did the extinction of dinosaurs allow for the evolution of more complex creatures?

Here is a List Of story Of Dinosuars from a Website HISTORY OF LIFE ON EARTH The purpose of Conservation Biology is to find ways of maintaining the high levels of biological diversity that are seen in today's world. But first, in order to appreciate that diversity, we need to understand how it has evolved, and what a complicated series of geological, climatic and biological events have led up to the present day situation. Therefore, we will review briefly the history of life on earth.

Visit the virtual Museum of Paleontology at theUniversity of California at Berkeley to find more information and illustrations regarding any of the topics or geological periods mentioned Geological Time The chart shows the life forms that have been present on the earth since Cambrian times, and whose fossils are therefore found in different layers of rocks. Each time a new layer of rock is deposited (usually by sedimentation) it is on top of the older layers, so the chart reflects this order Rise of biological diversity The history of global biological diversity is best seen in the marine animals since the ocean is where life started, and marine animals are the best represented in the fossil record. The chart in the slide show shows the number of families of marine organisms on the earth at different times in biological history See Measuring Past Biodiversity, by Jeremy B.C.Jackson and Kenneth G.Johnson.

Science 2001 September 28; 293: 2401-2404 Summary Full Text Supplemental Data Multicellular animals first appeared about 600 million years ago in the early Paleozoic and there was a rapid rise in number of families during the Cambrian and Ordovician. Diversity remained relatively constant (perhaps even declining) up until about 200 million years ago and then it rose again to its current all-time high of close to 800 families Four eras are recognized, and are characterized by typical life forms: 1. Precambrian: The origin of life 2.

Paleozoic ("Ancient Life"): The origin of plants, most invertebrate types, the first vertebrates (back-boned animals, including fishes, amphibians, and reptiles) 3. Mesozoic (the "Age of Reptiles"): The origin of flowering plants, dinosaurs, birds, and mammals 4. Cenozoic (the "Age of Mammals"): The diversification of flowering plants, insects, birds and mammals, and the appearance of humans The eras are divided into periods.

Biological diversity was dramatically depleted by five mass extinction episodes at the ends of the Ordovician, Devonian, Permian, Triassic and Cretaceous Periods. At each of these times a large fraction of existing species was wiped out, leaving the survivors to repopulate the biological world. The most famous of these was the extinction at the end of the Cretaceous because this ended the age of dinosaurs and made possible the evolution and dominance of mammals.

But it was not the most devastating of the mass extinctions. Now we will review the history of life in more detail THE DAWN OF LIFE Precambrian The origin of life: the Earth was formed about 5 billion years ago. A series of giant meteorites ("the late heavy bombardment") essentially sterilized the planet about 3.8 billion years ago.

Rocks 3.5 billion years old contain microfossils of primitive one-celled organisms without a nucleus ("prokaryotes") resembling bacteria and blue-green algae, and carbon isotope ratios characteristic of biological materials, representing the earliest clear signs of life. The first cells with a nucleus ("eukaryotes") appeared 2 billion years ago, and the first organisms made up of many cells (multicellular algae) appeared about 1.8 billion years ago In addition to prokaryotes and eukaryotes, a third major group of organisms, called Archaea consisting of about 500 species but making up about 30% of the biomass on Earth, was not discovered until 1977. They live in the most extreme environments on Earth - the hottest, coldest, and highest-pressure environments, so they are sometimes called "extremophiles".

Most of their known biomass is in the Antarctic ANCIENT LIFE (PALEOZOIC); 600-230 M.Y.B.P Cambrian After 3 billion years of very little change, all of a sudden during the Cambrian period, there was a frenzy of evolutionary innovation that generated just about all of the existing major types (phyla and classes) of marine invertebrates plus many others that no longer exist. Accurate dating methods used in 1993 (involving measurements of uranium and lead isotopes) indicate that the explosion happened during a very short period - from 533 to 525 million years ago. This is sometimes called the Cambrian explosion.

What caused it is not known - one of the most plausible suggestions is that it followed shortly after marine animals evolved protective shells and cuticles that allowed them to exploit new ecological niches. Another possibility is that more complex body organization became possible after the atmospheric oxygen reached a certain threshold Many of the important fossils telling the story of the Cambrian explosion were found in a fossil bed in the Canadian Rockies called Burgess Shale where both soft- and hard-bodied animals were buried in an underwater mudslide and preserved in water so deep and oxygen-free that they did not decompose. They are described in a book by Stephen J.

Gould called "Wonderful Life". View pictures of the actual.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.