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Carrying Capacity
The carrying capacity of an ecosystem is the maximum population size of a biological species that can be sustained by that specific environment, given the food, habitat, water, and other resources available. The carrying capacity is defined as the environment's maximal load, which in population ecology corresponds to the population equilibrium, when the number of deaths in a population equals the number of births (as well as immigration and emigration). Carrying capacity of the environment implies that the resources extraction is not above the rate of regeneration of the resources and the wastes generated are within the assimilating capacity of the environment. The effect of carrying capacity on population dynamics is modelled with a logistic function. Carrying capacity is applied to the maximum population an environment can support in ecology, agriculture and fisheries. The term carrying capacity had been applied to a few different processes in the past before finally being appl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecosystem
An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and energy flows. Ecosystems are controlled by external and internal Environmental factor, factors. External factors—including climate—control the ecosystem's structure, but are not influenced by it. By contrast, internal factors control and are controlled by ecosystem processes; these include decomposition, the types of species present, root competition, shading, disturbance, and succession. While external factors generally determine which Resource (biology), resource inputs an ecosystem has, their availability within the ecosystem is controlled by internal factors. Ecosystems are wikt:dynamic, dynamic, subject to periodic disturbances and always in the process of recovering from past disturbances. The tendency of an ecosystem to remain clo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biosphere
The biosphere (), also called the ecosphere (), is the worldwide sum of all ecosystems. It can also be termed the zone of life on the Earth. The biosphere (which is technically a spherical shell) is virtually a closed system with regard to matter,"Biosphere" in ''The Columbia Encyclopedia'', 6th ed. (2004) Columbia University Press. with minimal inputs and outputs. Regarding , it is an open system, with capturing |
Raymond Pearl
Raymond Pearl (June 3, 1879 – November 17, 1940) was an American biologist, regarded as one of the founders of biogerontology. He spent most of his career at Johns Hopkins University in Baltimore. Pearl was a prolific writer of academic books, papers and articles, as well as a committed populariser and communicator of science. At his death, 841 publications were listed against his name. An early eugenicist, he eventually became an important critic of eugenics. He also advanced the concept of carrying capacity, although he didn't use the term, and was a Malthusian concerned with resource limits. He was a critic of mass consumption. Early life Pearl was born into an upper-middle-class family on June 3, 1879, in Farmington, New Hampshire, the son of Ida May (McDuffee) and Frank Pearl. At an early age, Pearl was exposed to the classics. His parents and grandparents wanted him to study Greek and Latin. However, when he attended Dartmouth College at 16 years old, he became fascina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biostatistics
Biostatistics (also known as biometry) is a branch of statistics that applies statistical methods to a wide range of topics in biology. It encompasses the design of biological experiments, the collection and analysis of data from those experiments and the interpretation of the results. History Biostatistics and genetics Biostatistical modeling forms an important part of numerous modern biological theories. Genetics studies, since its beginning, used statistical concepts to understand observed experimental results. Some genetics scientists even contributed with statistical advances with the development of methods and tools. Gregor Mendel started the genetics studies investigating genetics segregation patterns in families of peas and used statistics to explain the collected data. In the early 1900s, after the rediscovery of Mendel's Mendelian inheritance work, there were gaps in understanding between genetics and evolutionary Darwinism. Francis Galton tried to expand Mendel's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eugenicist
Eugenics is a set of largely discredited beliefs and practices that aim to improve the genetics, genetic quality of a human population. Historically, eugenicists have attempted to alter the frequency of various human Phenotype, phenotypes by inhibiting the fertility of those considered inferior, or promoting that of those considered superior. The contemporary history of eugenics began in the late 19th century, when a popular eugenics movement emerged in the United Kingdom, and then spread to many countries, including the United States, Canada, Australia, and most European countries (e.g. State Institute for Racial Biology, Sweden and Nazi eugenics, Germany). In this period, people from across the political spectrum espoused eugenics. Many countries adopted eugenic policies intended to improve the quality of their populations. Historically, the idea of ''eugenics'' has been used to argue for a broad array of practices ranging from prenatal care for mothers deemed genetically ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neo-Malthusians
Malthusianism is a theory that population growth is potentially exponential, according to the Malthusian growth model, while the growth of the food supply or other resources is linear growth, linear, which eventually reduces living standards to the point of triggering a depopulation, population decline. This event, called a Malthusian catastrophe (also known as a Malthusian trap, population trap, Malthusian check, Malthusian snatch, Malthusian crisis, Point of Crisis, or Malthusian crunch) has been predicted to occur if population growth overshoot (population), outpaces agriculture, agricultural Production (economics), production, thereby causing famine or war. According to this theory, poverty and economic inequality, inequality will increase as the price of assets and scarce commodities goes up due to fierce competition for these dwindling resources. This increased level of poverty eventually causes depopulation by decreasing birth rates. If asset prices keep increasing, social un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Livestock
Livestock are the Domestication, domesticated animals that are raised in an Agriculture, agricultural setting to provide labour and produce diversified products for consumption such as meat, Egg as food, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to animals which are raised for consumption, and sometimes used to refer solely to farmed ruminants, such as cattle, sheep, and goats. The breeding, maintenance, slaughter and general subjugation of livestock called ''animal husbandry'', is a part of modern agriculture and has been practiced in many cultures since humanity's transition to farming from hunter-gatherer lifestyles. Animal husbandry practices have varied widely across cultures and periods. It continues to play a major economic and cultural role in numerous communities. Livestock farming practices have largely shifted to intensive animal farming. Intensive animal farming increases the yield of the various commercial outputs, but also nega ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
US Senate
The United States Senate is a chamber of the bicameral United States Congress; it is the upper house, with the U.S. House of Representatives being the lower house. Together, the Senate and House have the authority under Article One of the U.S. Constitution to pass or defeat federal legislation. The Senate also has exclusive power to confirm U.S. presidential appointments, to approve or reject treaties, and to convict or exonerate impeachment cases brought by the House. The Senate and the House provide a check and balance on the powers of the executive and judicial branches of government. The composition and powers of the Senate are established in Article One of the U.S. Constitution, which has been in continuous effect since March 4, 1789. Each of the 50 states is represented by two senators who serve staggered six-year terms. In total, the Senate consists of 100 members. From its inception in 1789 until 1913, senators were appointed by the state legislature o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
US Secretary Of State
The United States secretary of state (SecState) is a member of the executive branch of the federal government of the United States and the head of the U.S. Department of State. The secretary of state serves as the principal advisor to the president of the United States on all foreign affairs matters. The secretary carries out the president's foreign policies through the U.S Department of State, which includes the Foreign Service, Civil Service, and U.S. Agency for International Development. The office holder is the second-highest-ranking member of the president's cabinet, after the vice president, and ranks fourth in the presidential line of succession; first amongst cabinet secretaries. Created in 1789 with Thomas Jefferson as its first office holder, the secretary of state represents the United States to foreign countries, and is therefore considered analogous to a secretary or minister of foreign affairs in other countries. The secretary of state is nominated by the pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shipping
Freight transport, also referred to as freight forwarding, is the physical process of transporting commodities and merchandise goods and cargo. The term shipping originally referred to transport by sea but in American English, it has been extended to refer to transport by land or air (International English: "carriage") as well. "Logistics", a term borrowed from the military environment, is also used in the same sense. History Prehistoric Era Initial human civilization relied heavily on domesticated animals, such as horses, camels, and donkeys, to transport their goods. The invention of the wheel in Mesopotamia in 5000BC improved this efficiency by allowing for carts and carriages to be created, which animals could pull. Classical Era Romans The Romans built a vast network of roads, which facilitated trade across the numerous cities in its empire. Silk Road Transport along the silk road, a land-based route, was generally done through caravans, equipped ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre François Verhulst
Pierre François Verhulst (28 October 1804, in Brussels – 15 February 1849, in Brussels) was a Belgian mathematician and a doctor in number theory from the University of Ghent in 1825. He is best known for the logistic growth model. Logistic equation Verhulst developed the logistic function in a series of three papers between 1838 and 1847, based on research on modeling population growth that he conducted in the mid 1830s, under the guidance of Adolphe Quetelet; see for details. Verhulst published in the equation: : \frac = rN - \alpha N^2 where ''N''(''t'') represents number of individuals at time ''t'', ''r'' the intrinsic growth rate, and ''\alpha'' is the density-dependent crowding effect (also known as intraspecific competition). In this equation, the population equilibrium (sometimes referred to as the carrying capacity, ''K''), N^*, is : N^* = \frac . In he named the solution the logistic curve. Later, Raymond Pearl and Lowell Reed popularized the equatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematical model, models, and mathematics#Calculus and analysis, change. History One of the earliest known mathematicians was Thales of Miletus (); he has been hailed as the first true mathematician and the first known individual to whom a mathematical discovery has been attributed. He is credited with the first use of deductive reasoning applied to geometry, by deriving four corollaries to Thales's theorem. The number of known mathematicians grew when Pythagoras of Samos () established the Pythagorean school, whose doctrine it was that mathematics ruled the universe and whose motto was "All is number". It was the Pythagoreans who coined the term "mathematics", and with whom the study of mathematics for its own sake begins. The first woman math ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
