“Globally, however, infectious... ... middle of paper ... ...tists concluded that ocean warming and acidification are the two greatest global threats that leads species to extinction. Human activity is the third reason that leads them into fatal and death of species. Human activity was involved in the past five great mass extinctions and they were related directly or indirectly. The directly of human activity that leads to extinction are habitat change, destruction, overexploitation of species, the spread of aggressive species and genes, pollution and climate change as humans use mainly all the earths lands for construction and they get advantage on fresh water rivers and limit natural rivers and unfortunate that drives species into massive fatal. While humans’ burn fossil fuels, the carbon dioxide have risen to their highest levels all over these years and that leads to global warming, rising sea levels and climate change.
This paper examines the relationship between natural catastrophes and mass extinctions and their impact on vertebrate evolution. Natural catastrophes have a major influence on the likelihood of extinction. The largest mass extinctions are linked to these catastrophes and often reconstruct the biosphere. Therefore eliminate some species, while also allowing previously minor groups to survive and diversify. This involves extinction of certain groups based on certain parameters like body size and rate of life history.
Many species perished in that extinction. Today evidence for this extinction can be seen in the fossil record. Biological, botanical and geological evidence at the Cretaceous – Tertiary Boundary show that some enormous event occurred that caused mass extinction of life on the Earth. Controversy about the cause of the K-T extinction exists with two main theories currently being in favour. One theory is called Intrinsic Gradualism and believes the cause of the K-T Extinction was a slow and gradual Earth generated event, caused by intense volcanic activity and the effect of plate tectonics.
Our world is a great incubator of life, however it likes to go through periods of change where only those ready to adapt will survive. Five times already, our planet has gone through periods of mass species extinction, forcing those who want to survive to adapt and overcome. We are now facing a sixth major extinction, one not caused by a force of nature, but caused by a single species. We will take a look into the first five major extinction and then delve into the one that is ongoing right now. The first major mass extinction occurred approximately 440 mya, and is known as the Ordovician–Silurian extinction event.
Something happened sixty-five million years ago, at the end of the Cretaceous period that was so devastating that it altered the course of life on earth. Extinction is easily defined: the birth rate fails to keep up with the death rate. However, the definition does not answer the question about the nature or causes of extinction. Since so many different causes of death of the dinosaur arose, paleontologists generally divide extinction into two main types. The first is called background extinction, or the isolated extinction of a species due to a variety of cause.
The planet earth is a complex environment in which various organisms have cycled through their time of existence for millions of years. All species that have lived are destined for extinction at some point in time, and this is a natural process and cycle. Mass extinctions are this process at an extreme rate. In fact, many scientists today suspect that earth is on the verge of the sixth mass extinction. In order to better analyze this, one must understand what a mass extinction is, the history of mass extinctions, the evidence that earth is nearing the next extinction, and how humans are affecting the extinction.
Habitat destruction, deforestation, ozone depletion, global warming, and poaching. These actions and ecological happenings are creating a world where animals are going extinct at rapid rates. Our world is on the brink of what scientists believe is the sixth mass extinction. Unlike the five previous mass extinction, the latest one killing a majority of the dinosaurs, the main causes for this current extinction are anthropogenic reasons, not natural events. Scientists calculate that without humans about one to five species would die a year, which is considered the background rate of extinction.
The first one would be the rising of the sea level (1.8mm/per year 1960-1983 and 3.1mm/year afer that time ) and tropical happened because of climate change , which cause the loss of wetland , low-lying island and coastal ecosystems . The climate change also lead to the increasing of global average temperature , about 2oC so it is hard for animals to adapt these changes . As the results , a lot of species will become extinct . Morover , a lot of areas were highly vulnerable like Great Barrier Reef , the Australia Alps , the Queensland Wet Tropics , Kakadu wetland ,ect. with switches in genetic composition , changesd some birds’ migration patterns , altered life cycles of some species and ruduced the reduction rat of other ,ect.
The first is called background extinctions, isolated extinctions of species due to a variety of causes. Included is out competition, depletion of resources in a habitat, changes in climate, the development or destruction of a mountain range, river channel migration, the eruption of a volcano, the drying of a lake, or the destruction of a forest, grassland, or wetland habitat. The second type of extinction is called mass extinctions. Large numbers of species go extinct; many types of species go extinct; the effects must be global, and the effects must occur in a geologically short period of time.1 The dinosaur could not have lived for ever. No creatures, no plants, no tiny bacteria are forever, not even Homo sapiens.
Any animal unable to adapt to these new changes will go extinct. The polar bear is one of those species that is very close to this tragic consequence. Another thing that global warming will affect is disease. As the temperature rises by 1°F a century, the insects carrying disease will roam north bringing it with them (Mixit Productions website design , 2011). This could result in plagues and a higher death count to common diseases.