Pleistoina Hypothesis

Megafaunal extinction is a reference to how large animals such as the woolly mammoth became extinct, especially in North America. This extinction had an effect on Paleolithic cultures at the time, because some were extremely affected by it. In fact, the Clovis culture around North America became extinct with the animals. This is important, as it showed that after the extinction, the people didn't die out, but instead they spread out, with groups hunting smaller animals or bison instead of mammoths. It helped evolve Native American cultures, as after the megafaunal phase, some of the cultures became farmers or developers of cities. (Social and

The scale and pace of change is dramatic; for example, the extinction of species is occurring at around 100-fold pre-human rates4. The population sizes of vertebrate species have, on average, declined by half over the last 45 years5. More than 2.3 million km2 of primary forest has been felled since 20006. About

S. 969). In order to prove the viability of an overkill theory, Martin constructed a model that would consider both the expanding population of an invading people and the population of megafauna that they are hunting throughout their colonization. He determined that even a very large biomass (in this case the megafauna) of 2.3 X 10^ 8 metric tons could be overkilled within just 1,000 years by a biomass of no more than 10^6 metric tons of Clovis hunters (Martin P. S. 972). Additionally, Martin argued that carnivores that Clovis hunters were not hunting such as the saber-tooth tiger would have become extinct around this time because of the removal of their herbivore prey (Grayson and Meltzer 586).

The article discussed the changes in many habitats due to anthropogenic activity. Anthropogenic is an adjective that describes changes in nature due to the people. Next, this article discussed climate change and the impact that it is having on species like clams, and fish due to ocean temperatures rising. The article also addressed carbon dating of fossils to look for cause of extinctions. Human development and agriculture have had a tremendous impact on the population of many species that are terrestrial. Deforestation is a big problem that has caused a decline in the bird species. Commercial fishing in many areas has led to a decline in fish populations. Furthermore this article

Humans played a major role in the extinction of large mammals because hunters possibly killed them off. They were also slaughtered with knives and stampeded over cliffs at that time at which their species became less and less. to extinction in a period already providing great stress due to the receding ice sheets as the last glacial maximum came to an end. Later, this would mean a lack of analogues

Megafauna simply means large animals, in which most have become extinct within the last 20 000 to 50 000 years. The extinction of megafauna was, debatably, due to climate change and human expansion. Although, Africa still retains some megafauna, such as the elephant or the rhinoceros. Australia has managed to keep many examples of relict species, some from the time of the megafauna. These include the Crocodile, Wollemi Pine and Stromatolites.

Defenders indicated that the lack of killing site was a result of the fast speed and early time of the extinction. They also called question into the plausibility of the alternative theory. Sprawling the continent for tens of million years, these animals prospered, and successfully endured all serious droughts during that time period. It would be such a coincidence for them to be exterminated almost at the same time, in different habitats ranging from the middle desert areas to the humid south-eastern, just after the point of human’s arrival. Here the author is illustrating the theory he supports through logical

My trip to the La Brea Tar Pits, taught me of the biodiversity that was within California, from the Columbian Mammoths, Shasta Ground Sloth, Dire Wolves, and Sabretooth Cats. The museum emphasized that most of the extinct animals that were on display were extinct due to climate change or hunted by the earliest tribes throughout California and North America. The museum points out that most of these animals were large, but doesn’t show the reason as to why the larger animals went extinct, but the smaller animals survived the extinction. The museum also mentions that night-stalking animals weren’t found in the pits as during the cool temperatures throughout the evening would solidify the asphalt. This extinction was known as the Pleistocene

When sometimes around twelve thousand years ago climate started to become warmer and ice started to melt, it created a great allowance for ancient hunters to reach North America. Native Americans started to hunt in the wider areas and supply their community with a lot of meat. When people started to have more food, especially meat that caused a fast growth of population. For some unknown reasons, at the same time big mammals and mastodons started to disappear from the Earth. It is a possibility that the climate warming and lack of water sources played a role of the disappearance these big animals. Lack of water put animals in the situation when survival is not possible. The climate change also made a big adjustment in human’s ration and style of life. When people started to spread to North America, they discovered a lot of new food sources like small animals, fish, different kind of nuts and berries.

Hypothesis supporting climate change as a factor in Neanderthal extinction has taken on two forms - Neanderthals inability to adapt to harsh environments and prey extinction. Traditionally, Neanderthal extinction has been contributed to sudden climate change in which the species was unable to adapt (Houldcroft & Underdown 2015). Despite the fact that Neanderthal fossil exhibit ecomorphological characteristics that suggest they were adapted to colder ‘ice age’ environments; there is considerable evidence that supports the hypothesis that climatic changes are responsible for their sudden disappearance (Rae et al 2011; Stewart 2005). Neanderthal species were unlike any

But, this book has 13 chapters each explaining evidence of extinction, theories, or animals that had been extinct. Animals that were talked about included the Great Auks and Mammoths. Reasons for the extinctions were the obvious ones such as hunting and global warming.

Dinosaur extinction: An analysis of events and theories that possibly led to the dinosaurs' demise.

It’s clear that a great extinction is coming from the evidence of the destruction of other species around us. The choices made by the human race have too often negatively affected the surrounding species. Tracy Wilson, the site director for HowStuffWorks.com, in an article for Animal Planet, states that

However, such mass extinction opens up speciation – when new species are developed. After the K-Pg extinction, new groups of organisms were on the rise. Giant boid snakes (12 – 15 meters) began appearing on land and the teleost fish (diverse class of ray-finned fish) filled marine niches left vacant. Most significantly, “Paleocene mammals would spread and evolve into the many ecological niches left open by the extinction of the dinosaurs,” (“Cretaceous: Extinction of the Dinosaurs”).

They say as mammals continued to evolve, they drove the dinosaurs into extinction (“What Killed the Dinosaurs”). “Not only did mammals likely compete with dinosaurs for resources, many species survived the end-Cretaceous extinction and subsequently came to dominate Earth.” (“What Killed the Dinosaurs?”). This is primarily because the early mammals were a lot smaller than the mammals that exist today. “Some of the world's earliest mammals were the multituberculates, a group of small rodent like animals that first emerged on Earth about 165 million years ago.” (Welsh, Jennifer). Scientists predict that any mass extinction event that caused animals to go extinct affected larger animals than it did the smaller animals, such as mammals ("Dinosaurs Became Extinct 'due to Laying Eggs'"). Mammals remained small for almost 100 million years, while they out competed small and baby dinosaurs for food, shelter and resources until they were extinct. Once the dinosaurs were out of the way mammals were able to evolve and grow large in size like the mammals that exist today today (LiveScience). Fossil evidence sheds some light on this theory as well. Fossils of mammals believed to date back to about eighty five million years ago show that mammals began to change rapidly and grow. “This matches up with other mammal groups, including recently discovered species from the Late Cretaceous (between 100 million and 65 million years ago) showing highly specialized