Population Pressure
sort by: Relevancy | Title | Rating try advanced search for more options
-
Hunter-gatherer populations were much less dense than later agriculturalists. The variety of their food supply protected them from crop failures and their sparseness reduced the spread of infectious diseases. Hunter-gatherers were healthier and worked less than early agriculturalists. Why didn't their numbers increase up to the same level of Malthusian misery? Their numbers may have been limited by violence between groups. Agriculture is...more
-
August 9, 2007 presentation by Russ Altman for the Stanford University Office of Science Outreach's Summer Science Lecture Series. There are a number of causes for variation in drug response across the population, but differences in genetics are an important factor. Russ Altman, Professor & Chair of Bioengineering and Professor of Genetics and Medicine, discusses how variations in genetics can alter the "typical" response as well as...more
-
Media and the Fertility Transition in Developing Countries (Guest Lecture by William Ryerson)
Yale / Biology
Guest lecturer William Ryerson is President of the Population Media Center which produces radio and TV serial dramas in developing countries that aim to effect behavior change on women's status, family planning and AIDS. Working with governments and in-country media professionals, these melodramas run for hundreds of episodes and are watched by millions. Careful research shows major changes in audience knowledge, attitudes and practices.
-
Geography is very important in ecology. Two major systems have been designed to model this, island biogeography and metapopulations. The idea of metapopulations is more recent, and has emerged as the dominant theory. Metapopulations are populations in multiple neighboring areas. The population of a species in any individual area may go extinct, but the metapopulation still survives. The theory of metapopulations has gained momentum in...more
-
Professor Sylvia Ceyer continues her discussion on chemical equilibrium and external effects such as a change in volume, adding inert gas, and a change in temperature. Parameters are set for maximizing the yield of a reaction, and the Principle of Le Chatelier's is returned to. Hemoglobin is used as an example involved in a series of equilibrium reactions in response to oxygen pressure.
-
April 20, 2009 - Leonard Susskind explains how to calculate and define pressure, explores the formulas some of applications of Helm-Holtz free energy, and discusses the importance of the partition function.
-
Introduction to Evolution, Variation in a Population and Natural Selection
Khan Academy / Philosophy
Introduction to evolution, variation in a population and natural selection.
-
Variance of a population.
-
Young explains how he was able to overcome the pressure of being compared to legendary 49ers quarterback Joe Montana. The best strategy, he notes, was to focus on finding out how good he could get, not how much better he could be than Montana. This helped him move in the right direction and got his career going as well. Later on, he became known as the fiery leader of the 49ers.
-
The growth of populations is held in check by several factors. These can include predators, food and other resources, and density. Population density affects growth rate by determining how likely is it that an organism will interact with a member of its own species compared to an organism of a different species. Population growth studies rely on the mathematics of logs and exponents.
-
In this lecture, bound and unbound orbits are discussed. Professor Lewin begins with a description of escape velocity, or the minimum speed required to escape the gravitational pull. Various sources of energy, energy storage, energy conversion, and the world's energy consumption are discussed. Power, or the rate at which a force does work on an object, is central to the conversation. Professor Lewin concludes with a few words on global...more
-
Concepts covered in this lecture include gases and incompressible liquids, Pascal's Principle, hydrostatic and barometric pressure. Professor Lewins concludes with a discussion of overpressure in our lungs. The lung capacity, our ability to overcome hydrostatic pressure, is measured with a manometer. This is related to how deep snorkeling works, and why scuba-divers use pressurized air tanks. Professor Lewin demonstrates that by blowing...more
