Summary and Critique

“A minority disputes this theory, arguing that other events-such as volcanic eruptions, sea-level changes or a series of impacts-were to blame for the spectacular loss of species that occurred at the transition between the Cretaceous and Tertiary periods…”

Summary and Critique of Twilight of the Mammoths: Ice Age Extinctions and the Rewilding of America

The first example of human manipulation of changes within the biosphere is through expansion. The rapid growth of the population has led to expansion in development; the need for more space is causing strain on other living organisms such as plants and animals. Human procurement of forest, grass, and wetlands has weighed on the animal population heavily. As a result of this domination, animals have lost areas they use to thrive in, causing migration and in more serious cases extinction. Animals are a prevalent source of protein for humans, and when a species is threatened by extinction, it not only disrupts the balance of the ecosystem, but it also disrupts the food chain. The more resources that are required to sustain human life, the bigger the need to migrate to surrounding areas in a short period of time (Haines).

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

Major problems arise from Martin's theory. Thirty-three large mammal extinctions occurred around the time of Clovis occupation, yet only two, the mammoth and the mastodon, have ever been associated with human sustenance, and even those only appear at 14 of 76 early Palaeoindian

There have been five major mass extinction on earth triggered by a distinguishable event, but in The Sixth Extinction: An Unnatural History, Elizabeth Kolbert writes of the narrative of the sixth extinction caused directly by human impact. The book identifies the effects of human activity on how, over humans history on earth, the natural world has been affected. Every environmental impact stems into three basic groups of global problems to nature: Pollution, Habitat loss and Invasive Species. Kolbert explains that each impact can be traced back to one source, human industrial development. With each impact various types of life in the natural world are affected. Deforestation, urbanization, and sea level rise contribute to habitat loss worldwide. When humans began to travel they also brought invasive species and disease along with them; as boats only became bigger more and more invasive species travel. This reverse engineering of the planet species, brings new species that don’t have any natural predators, thus having an easier time driving native species out to endangerment or extinction. The different outcomes that come from human pollution is separated throughout the book, but the idea remains constant; with the development of human culture, pollution has drastically impacted a vast extent of species habitats and their environment.

Neanderthals and modern humans coexisted for well over 100,000 years.  Then suddenly Homo neandertalensis began to die out and surrender the earth to Homo sapiens.  Paleontologists and anthropologists have entertained several possibilities to the causes of this event: interbreeding among Neanderthals and humans, competition for natural resources, and Darwin’s theory of “survival of the fittest.”  What the real cause has been has plagued scientists for years. Now, due to an international research team from Germany, those possibilities have been even further deduced, making it easier to pinpoint the exact reason Homo neandertalensis became extinct.

These humans used complex hunting tools and techniques to stalk and kill the targeted pray. The precise planning that went into hunting large game consisted of technological advances in the production of tools used to kill, and the cooperation of a group to obtain the game. The adoption of hunting strategies presented humans with daily reliable access to essential proteins and other micronutrients. The animals also proved to be easier to digest and contained more calories, which gave humans more energy to continue hunting these large

The Paleocene-Eocene Thermal Maximum was a period of time around the Paleocene-Eocene boundary during which the Earth experienced a significant rise in temperature. As we discussed in class January 27-February 3, the PETM period conveniently coincides with primate evolution and dispersal worldwide. This period of thermal increase is important to primate evolution because this rise in temperature worldwide created an ideal, survivable environment for primates globally. This rise in temperature encouraged primates to expand their territories into areas not previously inhabitable, such as the Arctic Circle. Additionally, I believe that the PETM may have encouraged primates to evolve into broader adaptive radii in order to exploit more tropical food sources and landscapes. In general, it is acknowledged that the PETM allowed primates to become more pervasive worldwide.

While it is important to understand the significance of each hypothesis, the questions surrounding the Neanderthal extinction takes on assorted factors that are not mutually exclusive. Numerous studies have been conducted focusing exclusively on climate, competition or disease as a function of Neanderthal extinction. However, conflicting conclusion suggest that there are several factors involved that overlap and/ or arising from one another. This paper will attempt to better understand how climate, competition, and disease might operate together to account for Neanderthal extinction. First by summarizing each argument of the three arguments and identifying the potential implications for father research. Secondly, aim to develop a framework that will include the most relevant hypothesis.

In a summary, Kolbert explains the extinctions of a variety of different major animal species that became extinct. She also explains that if trends in the environment continue that the biggest extinction in history will occur soon. If global warming, deforestation, and glaciers continue to melt she says that more and more species will continue to become extinct. She explains how humans need to be more conservative and careful with what they’re doing to prevent extinction.

Several different hypotheses have been formulated to explain the extinction of Neanderthals, from climate changes to intoxication from cave-associated contaminants like smoke, from cannibalism to diseases (Herrera et al., 2009). It is only certain that Neanderthals disappeared from fossil record after the arrival of modern humans, around 40,000 years in Asia, and 10,000-15,000 years in Europe (Shreeve, 1995). Fossil evidence shows the presence of modern humans in Middle East from 130,000 to 75,000 years ago, in the same areas where Neanderthals retreated between 65,000 and 47,000 years ago (Mellars, 2004).

Bill Freedmen, author of “Endangered Species—Human Causes Of Extinction and Endangerment” notes, “scientists approximate that present extinction rates are 1,000 to 10,000 times higher than the average natural extinction rate.” These distressing numbers should be acted upon to save the endangered species and avoid the catastrophic change to this planet if these species were to become extinct. In order to produce change, people need to recognize that habitat loss, climate change, and poaching are all factors in why our animal species are going extinct.

There is evidence to suggest that Homo neanderthalensis and Homo sapiens had coexisted for approximately 35-40,000 years, (Fagan 2010) from around 60,000 years ago to 25,000 years ago when they finally went extinct (Gibbon 2001). Anthropologists are still uncertain what the cause of their extinction was. This paper will analyze three main theories of Neanderthal extinction. The first theory is the competition theory, which claims that the Homo sapiens and Neanderthals had to compete for resources, ultimately leading to their demise. The second theory I will discuss is the climate change theory, which claims that Homo sapiens lived while Neanderthals died because they were better adapted to the climate. The last theory I will discuss is

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