Anthropology Is human extinction possible? Why does this happen? What causes a species to be extinct? Can human race prevent it? To answer these questions we must first define what extinction means, what types are there and why do they occur. As extinction is a continual product of natural selection, since the dawn of competition spawned by the first meiosis event, natural selection has altered all life on earth, precariously engaging in life experiments some that work and some that dont. Those experiments that do not work are those who have so far been extinct, and in fact 99% (Kiernan 1996:574) of all species that have ever engaged in the life battle have met their fate and are now extinct. Some people define extinction, as the disappearance of a plant or animal from the wild. Meaning that creatures surviving only in zoos or natural reserves could also be considered extinct. Other people use the terms regional extinction and local extinction to refer to the elimination of a creature from a specific geographical area but not from the whole planet Kiernan 1996: 574).
These types of extinctions are rather common and are usually caused by human intervention in the form of over hunting, introduced competitors and destruction of habitat. Another type of extinction refers to the very dynamic way nature interrelates, where the extinction of one creature can lead to the extinction of another. This phenomenon is known as co extinction. Animals in the food chain depend on other animals for food thus when one animal becomes extinct those who prayed upon it, must find other means of food if they are unable to do so their fate is surely written. Another type of extinction deals with extinction caused by evolutionary change where through the process of speciation results in the development of a new species Elliot 1998: 2931).
The Essay on Extinction and Animals
Should we keep animals in zoo? Zoos may seems like a inhumane way to keep animal... locked up. But the plus side to zoos are they help stop animals from becoming extinct. They are also used for animal research which can help repopulate some species back into the wild. For : - Zoo life does not prepare animals for the challenges of life in the wild. For example, two rare lynxes released into the ...
This type of extinction is not as devastating to the biodiversity on earth in that though we loose a species, genetic heritage of the extinct species is passed on its evolutionary descendants (Kiernan 1996: 574) thus maintaining diversity in genetic characteristics. The last and better-known type of extinction is the most devastating form of all.
In studying the fossil record scientist have found evidence of what they call Human extinctions. This type of extinction is characterized by rapid decline of biodiversity followed by periods of explosive development. At least five times in the earths geological history have there been acute mass extinctions. The most know eras of human extinction are the Ordovician, 440 million years ago; the Devonian, 365 million years ago; the Permian, 245 million years ago; the Triassic, 210 million years ago; and the Cretaceous, 65 million years ago (Freedman 1996: 1431).
The decline of diversity within a species or a taxon is so great found in these periods that such drastic decline could have not possibly been caused by genetic changes. One of the most devastating mass extinctions took place at the end of the Permian period.
This rapid extinction has been puzzling to the scientist trying to understand these phenomenon. Various explanations for such change have been proposed which has been the cause of many debates. Attempts to explain the causes of human extinction have centered on terrestrial phenomena such as sea-level changes, climatic changes, or volcanic activity. In Richard Monasterskys lifes closest call he outlines one of the leading theories behind the cause of the Permian extinction. Soda water as it harmlessly sounds suggest Monastersky along with Andrew Knoll and Richard Bambach (Monastersky 1997: 75) was the cause along with other geological events of the great Permian extinction. In this model Knoll, suggest that toxic concentrations of carbon dioxide accumulated in the deep ocean and then surged to the surface, extinguishing much of the life in the shallow seas (Monastersky 1997: 75).
The Essay on Mass Extinction Permian Layer Boundary
Extinction is, quite literally, the end of a particular evolutionary line, the end of a species, a family, or a larger group of organisms. While it may be bad news for the victims, it's a 'natural' event in the history of life on earth. Extinctions, mostly at the level of species, have been occurring constantly at a low 'background rate', usually matched by the rate at which new species appear - ...
(Most of the extinction in the Permian was of shallow sea creatures).
This theory builds upon the concept of plate tectonics, which hoarded all of the continents together earlier in the Permian. With this arrangement coupled with the absence of the polar ice caps suggest Knoll, ocean currents would have grown sluggish preventing oxygen rich water to sink to the bottom of the ocean in a process called thermohaline (Monastersky 1997: 75).
It is this process which was triggered by the onset of global cooling caused by lack of carbon dioxide in the air during this Permian which suggest knoll caused the release of toxic carbon dioxide and other gases that caused havoc on animals and plants filling the upper reaches of the ocean (Monastersky 1997: 75).
Perhaps one of the most known extinctions is the one that happened during the Cretaceous period bringing about the extinction of those great creatures we are so enthralled with: the dinosaur. This particular extinction has been the cause of much debate mainly because is the first extinction where an extraterrestrial cause may have been the culprit. The scientists were investigating how does population dynamics play a role in the possible extinction of the human race? There are various models of population growth that incorporate density dependence (Dennis and Taper 1994, Hooten 1995).
These models are mostly stochastic versions of deterministic differential equations models.
Estimation of the parameters in these models is crucial for various applied problems and management decisions. Unfortunately, the commonly available length of the time series for parameter estimation is short, in the range of 10-30 yr. Shorter time series lead to larger variability in parameter estimates. However, in many ecological situations, spatial replications are available and should be utilized (Cigliano et al. 1995, Dennis et al. 1997) to improve parameter estimation.
These spatial replications can be utilized to improve the estimators in three different ways. One can consider the spatial replications identical and independent replications of the time series and combine the information under that hypothesis. This, in effect, assumes that the phenomenon is spatially homogeneous, the environmental noise is spatially uncorrelated, and that there is no dispersal. Another approach is to assume that spatial replicates are related to each other only because they share the environment. This leads to the “joint density dependence” (JDD) model by Dennis et al. (1997), which assumes that the environmental noise is spatially correlated, but there is no immigration and emigration between the spatial locations. In this paper we explore a third approach which is to explicitly take into account the effects of dispersal in addition to the effects of shared environment.
The Essay on Jeremy clarkson Long Live Extinction
I have recently read your article ‘Stuff the Tiger – long live extinction’ and disagree strongly with the views you put forward. Your arguments are unjustified and the examples you use to demonstrate are faulty and contradicting to each other . In this article, you have mentioned how extinction doesn’t have any impact on mankind. Also, your opinions were based upon natural extinction and Darwin’s ...
There have been a number of theoretically interesting and biologically sensible models for population dynamics that explicitly accommodate spatial aspects. When the information on fluctuations in resource availability, dynamics of natural enemies and other density-dependent factors is unavailable, models with time-varying parameters and high-order lags can be used to describe the influence from these unknown density-dependent factors on population dynamics. Mathematically, a time series with dynamics described by a nonlinear stochastic dynamic function with autoregressive moving average terms can, under certain assumptions, be approximated by a linear time-varying-parameter model via standard Taylor series linearization techniquesThe structural population dynamic process developed in the study incorporates time-varying growth rate and density dependence parameters. This process also incorporates population dynamics as a function of these parameters and previous population density. A fourth class of models arises when time-varying density dependence parameters are considered. The population dynamics are termed indeterminate if the density dependence parameters take on values during the time from two or more of the following categories: b [less than] 0, b [greater than] 0, and b = 0 (Strong 1986, Brown 1989).
Little attention has been paid in the literature to the formulation of models for indeterminate density dependence.
As humans we should do everything to prevent our extinction. However, the result will depend totally us and on our actions. Words: 1 292
The Essay on Is a greying UK population a time bomb waiting to go off?
Is a greying UK population a time bomb waiting to go off? A greying population is where as more people are live longer, the average age of the population increases. There are more elderly people. The UK’s population is greying. In 2010 the average population age was 39.9 projected to increase to age 42.2 by 2035. The UK’s population is greying because of the improvement in quality of life. Life ...
Bibliography:
1) Elliot, D. K1998 Extinctions and evolutionary explosions. In Magills survey of science, edited by L, Hoopes, pp. 2931-22936. Salem press.
New Jersey. 2) Freedman, B 1996 Extinction. In The gale encyclopedia of science, edited by B, Travers, pp.1430-1434. Gale research. New York. 3) Hildebrand, A. R., and Boyton, W. V1991 Cretaceous ground zero.
Natural history 46-54. 4) Kiernan, V1996 Extinctions. In Encyclopedia of life sciences, edited by M, Cavendish , pp. 574-576. New York. 5) Monastersky, R1996 lifes closest call.
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