scholarly journals The past and future human impact on mammalian diversity

2020 ◽  
Vol 6 (36) ◽  
pp. eabb2313 ◽  
Author(s):  
Tobias Andermann ◽  
Søren Faurby ◽  
Samuel T. Turvey ◽  
Alexandre Antonelli ◽  
Daniele Silvestro
Keyword(s):  
Human Impact ◽  
Fossil Record ◽  
Human Population ◽  
Biodiversity Crisis ◽  
The Past ◽  
Extinction Rates ◽  
Current Trends ◽  
Predictive Methods ◽  
Near Future ◽  
Better Than

To understand the current biodiversity crisis, it is crucial to determine how humans have affected biodiversity in the past. However, the extent of human involvement in species extinctions from the Late Pleistocene onward remains contentious. Here, we apply Bayesian models to the fossil record to estimate how mammalian extinction rates have changed over the past 126,000 years, inferring specific times of rate increases. We specifically test the hypothesis of human-caused extinctions by using posterior predictive methods. We find that human population size is able to predict past extinctions with 96% accuracy. Predictors based on past climate, in contrast, perform no better than expected by chance, suggesting that climate had a negligible impact on global mammal extinctions. Based on current trends, we predict for the near future a rate escalation of unprecedented magnitude. Our results provide a comprehensive assessment of the human impact on past and predicted future extinctions of mammals.

3. Extinction in the past

2019 ◽  
pp. 33-50
Author(s):  
Paul B. Wignall
Keyword(s):  
Fossil Record ◽  
The Past ◽  
Extinction Rates ◽  
History Of ◽  
Extinction Events

Despite the less-than-perfect nature of the fossil record, it still provides a unique window on the history of life, and reveals that there have been dramatic fluctuations in extinction intensities since complex life evolved around 600 million years ago. ‘Extinction in the past’ considers Jack Sepkoski’s database compiled in the 1980s, and his series of highly informative charts showing both diversity and extinction rates since the start of the Cambrian Period 541 million years ago. The calculation of extinction rates and the improved dating of extinction events are discussed, along with the extinction trends that can be observed. Fossils also provide valuable evidence on the nature of selection during extinction.

Extinction, the Causes of Extinction and the Conservation of Biodiversity

2008 ◽  
Vol 3 (3) ◽  
pp. 166-173 ◽  
Author(s):  
Hisashi Nagata ◽  
Keyword(s):  
Global Warming ◽  
Theoretical Background ◽  
Natural Process ◽  
Habitat Destruction ◽  
Mass Extinctions ◽  
Species Extinction ◽  
Biodiversity Crisis ◽  
The Past ◽  
Extinction Rates ◽  
Conservation Of Biodiversity

Over 25% of species are currently categorized as threatened. Extinction is a natural process in organism evolution, and 99% of all organisms that have thus far existed are already extinct. Current extinction rates, however, is progressing at least 2,500 times faster than in the past. Ongoing extinction is so fast, in fact, that organisms may not be able to adapt environment and to evolve. Current biodiversity crisis is called “sixth extinction” because it is severer than five geological mass extinctions. Habitat destruction, overexploitation, and invasion of species through human activities are currently the major causes of species extinction. Global warming is also expected to pose a considerable threat to Earth’s organisms. I briefly review the nature of species extinction, its processes, causes, theoretical background, and ongoing threats.

2. Extinction today and efforts to stop it

2019 ◽  
pp. 18-32
Author(s):  
Paul B. Wignall
Keyword(s):  
Big Five ◽  
Food Chain ◽  
Fossil Record ◽  
Abundant Species ◽  
Marine Conservation ◽  
Mass Extinctions ◽  
Species Extinction ◽  
The Past ◽  
Extinction Rates

The fossil record shows that life has experienced five major mass extinctions. A sixth catastrophe may be underway. Past mass extinctions were geologically short-lived intense crises that affected animals and plants in all environments. They removed the dominant and abundant species, leaving ecological voids to be filled by groups that were often rare or insignificant beforehand. Uniquely, the big five also saw the collapse of the base of the food chain in the oceans. The current extinction crisis does not yet have any of these attributes, but there are concerns over rising species extinction rates. ‘Extinction today and efforts to stop it’ compares current extinction rates with those of the past, and considers different terrestrial and marine conservation approaches.

scholarly journals History is written by the victors: the effect of the push of the past on the fossil record

2017 ◽  
Author(s):  
Graham E. Budd ◽  
Richard P. Mann
Keyword(s):  
Fossil Record ◽  
Molecular Clocks ◽  
Phenotypic Evolution ◽  
Mass Extinctions ◽  
The Past ◽  
Extinction Rates ◽  
The Mean ◽  
Birth Death

AbstractPhylogenies may be modelled using “birth-death” models for speciation and extinction, but even when a homogeneous rate of diversification is used, survivorship biases can generate remarkable rate heterogeneities through time. One such bias has been termed the “push of the past”, by which the length of time a clade has survived is conditioned on the rate of diversification that happened to pertain at its origin. This creates the illusion of a secular rate slow-down through time that is, rather, a reversion to the mean. Here we model the controls on the push of the past, and the effect it has on clade origination times, and show that it largely depends on underlying extinction rates. An extra effect increasing early rates of lineage generation is also seen in large clades. These biases are important but relatively neglected influences on many aspects of diversification patterns, such as diversification spikes after mass extinctions and at the origins of clades; they also influence rates of fossilisation, changes in rates of phenotypic evolution and even molecular clocks. These inevitable features of surviving and/or large clades should thus not be generalised to the diversification process as a whole without additional study of small and extinct clades.

Letters to the Editor

PEDIATRICS ◽  
1967 ◽  
Vol 39 (6) ◽  
pp. 945-946
Author(s):  
ARTHUR J. Moss
Keyword(s):  
Gestational Age ◽  
Letters To The Editor ◽  
The Past ◽  
Near Future ◽  
Better Than

The Editor always jealous of those who know their ovine fetuses and newborns so much better than we know our human ones (yet not quite willing to exchange), received the following comment from Dr. Moss: There is no question that the points made by Dr. Alexander are both important and well taken. We recognize that a record of mating dates is the best means of estimating gestational age, and members of our faculty have negotiated in the past with members of the Davis Campus in attempts to obtain these services. Unfortunately, this was never achieved. However, other means for provision of this service are currently being explored, and, hopefully, it will be forthcoming in the near future.

Implementasi Algoritma Hamming Distance dan Brute Force dalam Mendeteksi Kemiripan Source Code Bahasa Pemrograman C

2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Andreas Budiman ◽  
Dennis Gunawan ◽  
Seng Hansun
Keyword(s):  
College Presidents ◽  
Hamming Distance ◽  
Source Code ◽  
Structural Type ◽  
Brute Force ◽  
Important Thing ◽  
The Past ◽  
Index Terms ◽  
Better Than

Plagiarism is a behavior that causes violence of copyrights. Survey shows 55% of college presidents say that plagiarism in students’ papers has increased over the past 10 years. Therefore, an application for detecting plagiarism is needed, especially for teachers. This plagiarism checker application is made by using Visual C# 2010. The plagiarism checker uses hamming distance algorithm for matching line code of the source code. This algorithm works by matching the same length string of the code programs. Thus, it needs brute will be matched with hamming distance. Another important thing for detecting plagiarism is the preprocessing, which is used to help the algorithm for detecting plagiarized source code. This paper shows that the application works good in detecting plagiarism, the hamming distance algorithm and brute force algorithm works better than levenstein distance algorithm for detecting structural type of plagiarism and this thesis also shows that the preprocessing could help the application to increase its percentage and its accuracy. Index Terms—Brute Force, Hamming Distance, Plagiarisme, Preprocessing.

Understanding Molecular Process and Chemotherapeutics for the Management of Breast Cancer.

2020 ◽  
Vol 14 ◽  
Author(s):  
Abhishek Kumar ◽  
Neeraj Masand ◽  
Vaishali M. Patil
Keyword(s):  
Breast Cancer ◽  
Molecular Mechanisms ◽  
Molecular Targets ◽  
Molecular Classification ◽  
Neoplastic Disease ◽  
Molecular Process ◽  
The Past ◽  
Anti Cancer ◽  
Molecular Etiology ◽  
Near Future

Abstract: Breast cancer is the most common and highly heterogeneous neoplastic disease comprised of several subtypes with distinct molecular etiology and clinical behaviours. The mortality observed over the past few decades and the failure in eradicating the disease is due to the lack of specific etiology, molecular mechanisms involved in initiation and progression of breast cancer. Understanding of the molecular classes of breast cancer may also lead to new biological insights and eventually to better therapies. The promising therapeutic targets and novel anti-cancer approaches emerging from these molecular targets that could be applied clinically in the near future are being highlighted. In addition, this review discusses some of the details of current molecular classification and available chemotherapeutics

Ways of Being and Time

2017 ◽  
Author(s):  
Kris McDaniel
Keyword(s):  
Being And Time ◽  
Present Moment ◽  
Ontological Pluralism ◽  
The Past ◽  
Mode Of Being ◽  
Ways Of Being ◽  
Better Than

This chapter develops a version of ontological pluralism that respects two common intuitions about time: that the present moment is metaphysically distinguished but not in such a way that the past is unreal. The version of ontological pluralism developed—presentist existential pluralism (PEP)—embraces two modes of being, the mode of being that present objects enjoy and the mode of being that past objects enjoy. The author argues that this view fares at least as well, and probably better, than other views in which the present is metaphysically distinguished. The chapter also introduces another form of ontological superiority called “levels of being.”

Patents for Critical Pharmaceuticals: The AZT Case

1991 ◽  
Vol 17 (1-2) ◽  
pp. 145-180
Author(s):  
Evan Ackiron
Keyword(s):  
The United States ◽  
Incentive System ◽  
The Public ◽  
Incentive Programs ◽  
The Past ◽  
Research And Innovation ◽  
Monopoly Pricing ◽  
Conflicting Interests ◽  
Necessary Evil ◽  
Near Future

Patents and other statutory types of market protections are used in the United States to promote scientific research and innovation. This incentive is especially important in research intensive fields such as the pharmaceutical industry. Unfortunately, these same protections often result in higher monopoly pricing once a successful product is brought to market. Usually this consequence is viewed as the necessary evil of an incentive system that encourages costly research and development by promising large rewards to the successful inventor. However, in the case of the AIDS drug Zidovudine (AZT), the high prices charged by the pharmaceutical company owning the drug have led to public outcry and a re-examination of government incentive systems.This Note traces the evolution of these incentive programs — the patent system, and, to a lesser extent, the orphan drug program — and details the conflicting interests involved in their development. It then demonstrates how the AZT problem brings the interest of providing inventors with incentives for risky innovative efforts into a sharp collision with the ultimate goal of such systems: ensuring that the public has access to the resulting products at a reasonable price. Finally, the Note describes how Congress and the courts have attempted to resolve these problems in the past, and how they might best try to solve the AZT problem in the near future.

Sign in / Sign up

Export Citation Format

Share Document