What are the major theories explaining the disappearance of the dinosaurs? Dinosaurs lived between 230 and 65 million years ago. Dinosaurs then disappear as if they were never on earth. There are many theories in the world about the death of the dinosaurs. Archaeologist discovers the the bones of dinosaurs from different time periods.
The Oxford dictionary defines extinction in relation to biology as a species, family or a large group having no living members (Oxford, 2016). With the estimation of the four billion species that evolved on earth during its 4 billion year existence, about 99% of them now are extinct (Novacek, 2001). This displays how natural extinction is, but it is usually stabilized by speciation (Barnosky, 2011). A major extinction event is one in which many species meet their end over a short period of time, these events are grand in scale and many species of all ecological types (i.e. animals and plants, aquatic and terrestrial) all around the world are involved (Benton, 2011).
How did Dinosaurs go Extinct? Over the past few centuries or so, scientists have long endeavored to unravel the enigma surrounding the Cretaceous-Tertiary Mass Extinction, which took place 65 million years ago. This event is most notorious for the halt of existence for the dinosaurs, undeterred by the fact that nearly three fourths of all flora and fauna species subsisting on Earth went extinct. Consequently, Paleontologists have proposed a profusion of theories to decipher how the Cretaceous-Tertiary Mass Extinction transpired. However, a sheer bulk of the theories makes no sense whatsoever.
Moreover, the global warming has affected the life of other living things such as animals and plants. Also, the increasing level of temperature causes many animal species to migrate and lose their habitats like polar bears and tropical frogs. The migration of animal have been irregular and are affected by changes in the climate. Animal extinction is the most serious result of global warming. “According to the Intergovernmental Panel on (IPCC), an increase in global temperature by 1.5 to 2.5 degrees will make 40 to 70 percent species vulnerable to extinction, while a rise of about 3.5.” Next effect is more hurricanes will occur and many people and country affect as well.
These endangered animals could be completely gone if there weren't laws protecting them. MASS EXTINCTION Mass extinction is when many species of animals go extinct at the same time for a short period of time due to catastrophic events. There have been five total mass extinctions during history. Today people have done studies showing we might go to through a sixth mass extinction. All this external and internal conflict in the world could lead to the sixth extinction.
Introduction: Today it is thought that global warming is a serious problem in our society. Scientist say that global warming has caused an abundance of serious matter like polar bear population decreased and extreme weather conditions. In this essay, global warming will be discussed and the cause and effects of it, as well as to what we can do to help prevent it. Ultimately, a conclusion will be raised answering the focus question, “Will global warming be the end of the human race?” First Section: Global Warming and its Causes Global warming is an unnatural warmer of the earth. Global warming is when the average temperature of earth's atmosphere and oceans rise.
For awhile, global warming has become more recent and changing the planet and the animals behaviors. So far, “Rapid climate change is already causing problems for living creatures all over the world. One problem is that weather changes are resulting in mismatches between two species that have traditionally depended on one another,” (Nakaya). Furthermore, climate change is causing more problems, that the animals are not doing their regular jobs that they are supposed to do. In addition, animals are acting unusual by coming out of hibernation to early, polar bears are thinner and less healthy, different species are moving north to get more cooler air, and some species are breeding days before they should.
Extinction is the process of particular animal or plant species die out. After the extinction there will be no more individuals of that species alive anywhere in the World. From early ages to this point in time over 99% of all the species have gone extinct. But sometimes extinctions happen at a much faster rate than usual. For example, at the end of the Cretaceous period 65 million years ago, 6 mass extinction caused the death of many different types of animals and plants, including the dinosaurs (National Geographic).
If we do not take immediate action against this issue, the world we live in will be open to an unwanted amount of change. These changes may include the earth’s temperature becoming hotter with the addition of small islands being swallowed by the ocean. This is due to the ice caps melting which in turn is causing the sea level to rise. There will also be a rise in the amount of storms, droughts and heat waves occurring all over the world. Another factor of change that will take place will be the extinction of climate sensitive animals.
Abstract: Now a day, deforestation becomes the global concern all around the globe and affects the earth’s climate. The change of climate effect the habitat of the flora and fauna and it forced several animals to migrate from their native environment. Deforestation is simply the conversion of forest areas to non-forest areas. This illegal cutting directly impact on the food security because of the loss of biodiversity which are the main source of food for the man. Pakistan is losing forest badly due to the indiscriminate cutting, overgrazing and the poor management which are desertification increasing factors.