Population dynamic theory of size
... cycles with a period approximately that of the total juvenile period. This shows that the combination of densitydependent cannibalistic mortality and a time delay is sufficient to produce population cycles (see also Hastings & Costantino 1987, 1991). Similarly, in the agestructured model of Diekmann ...
... cycles with a period approximately that of the total juvenile period. This shows that the combination of densitydependent cannibalistic mortality and a time delay is sufficient to produce population cycles (see also Hastings & Costantino 1987, 1991). Similarly, in the agestructured model of Diekmann ...
population
... • From counts of these individuals, researchers estimate the total number of individuals in the population. – The mark-recapture method assumes that each marked individual has the same probability of being trapped as each unmarked individual. – This may not be a safe assumption because trapped indiv ...
... • From counts of these individuals, researchers estimate the total number of individuals in the population. – The mark-recapture method assumes that each marked individual has the same probability of being trapped as each unmarked individual. – This may not be a safe assumption because trapped indiv ...
Vancouver Island Marmot Population and Habitat Viability
... females, and their offspring from different years. They are obligate herbivores and burrow dwellers, hibernating from late September/early October until late April/early May of the following year. Young are born in the burrows in early June, with pups emerging from the burrows for the first time in ...
... females, and their offspring from different years. They are obligate herbivores and burrow dwellers, hibernating from late September/early October until late April/early May of the following year. Young are born in the burrows in early June, with pups emerging from the burrows for the first time in ...
Problem: American Elk - The International Mathematical Modeling
... population dynamics in GSMNP over a 10 year period (2001-2011). Using this data and our own analysis we were able to establish birth and death rates for the introduced elk population and thus project the future survivability and sustainability of this population. Incorporating further constants incl ...
... population dynamics in GSMNP over a 10 year period (2001-2011). Using this data and our own analysis we were able to establish birth and death rates for the introduced elk population and thus project the future survivability and sustainability of this population. Incorporating further constants incl ...
Allee Effects
... Evidence for Demographic Allee Effects Demographic Allee effects have been harder to demonstrate. Two reasons for this include: 1. Allee effects in one component of fitness may be offset at low density by increases in other components of fitness, such as decreased competition for resources; 2. Natur ...
... Evidence for Demographic Allee Effects Demographic Allee effects have been harder to demonstrate. Two reasons for this include: 1. Allee effects in one component of fitness may be offset at low density by increases in other components of fitness, such as decreased competition for resources; 2. Natur ...
What limits the Serengeti zebra population?
... (Spinage 1972), while the Serengeti population may have declined slightly between 1961 (n=179,000, Sinclair and Norton-Griffiths 1979) and 1996 (n=150,834, Moehlman 2002). For Serengeti plains zebra, no individually based estimates of foal and yearling survival are available. As these vary widely bo ...
... (Spinage 1972), while the Serengeti population may have declined slightly between 1961 (n=179,000, Sinclair and Norton-Griffiths 1979) and 1996 (n=150,834, Moehlman 2002). For Serengeti plains zebra, no individually based estimates of foal and yearling survival are available. As these vary widely bo ...
practice populations test (with answers)
... 7. Mark-recapture sampling is a method commonly used to determine the population size of which of the following? a. fish d. small rodents b. polar bears e. all of the above c. migrating ducks 8. Which of the following is not an assumption made when mark-recapture sampling is used? a. the population ...
... 7. Mark-recapture sampling is a method commonly used to determine the population size of which of the following? a. fish d. small rodents b. polar bears e. all of the above c. migrating ducks 8. Which of the following is not an assumption made when mark-recapture sampling is used? a. the population ...
carrying capacity: a critique of the concept al~ its usefulness
... densities limited by social constraints; and "security density" describing population densities limited by disease, predation or parasitism . The above classifications are discussed briefly in the following sections, highlighting the differences between them. Equivalent biological terms have been pl ...
... densities limited by social constraints; and "security density" describing population densities limited by disease, predation or parasitism . The above classifications are discussed briefly in the following sections, highlighting the differences between them. Equivalent biological terms have been pl ...
Unit 30D Population and Community Dynamics
... Populations are the functioning units of individual species. Individuals within a population vary due to their genetic diversity and the demands of their environment, and interact with each other in many ways. Many populations together make up an ecological community, in which each population intera ...
... Populations are the functioning units of individual species. Individuals within a population vary due to their genetic diversity and the demands of their environment, and interact with each other in many ways. Many populations together make up an ecological community, in which each population intera ...
From arctic lemmings to adaptive dynamics
... We shall examine the impact of Charles S. Elton’s 1924 article on periodic fluctuations in animal populations on the development of modern population ecology. We argue that his impact has been substantial and that during the past 75 years of research on multi-annual periodic fluctuations in numbers ...
... We shall examine the impact of Charles S. Elton’s 1924 article on periodic fluctuations in animal populations on the development of modern population ecology. We argue that his impact has been substantial and that during the past 75 years of research on multi-annual periodic fluctuations in numbers ...
View or download: Introduction, methods, results
... Models were deterministic and made no allowance for natural variation in vital rates over time (i.e. stochastic models). Reproductive success is the most well documented aspect of petrel and shearwater biology that demonstrates this natural variation, typically showing wide ...
... Models were deterministic and made no allowance for natural variation in vital rates over time (i.e. stochastic models). Reproductive success is the most well documented aspect of petrel and shearwater biology that demonstrates this natural variation, typically showing wide ...
Hixon, M. A., P. W. Pacala, and S. A. Sandin. 2002. Population
... Abstract. By definition, a population is regulated if it persists for many generations with fluctuations bounded above zero with high probability. Regulation thus requires density-dependent negative feedback whereby the population has a propensity to increase when small and decrease when large. Ulti ...
... Abstract. By definition, a population is regulated if it persists for many generations with fluctuations bounded above zero with high probability. Regulation thus requires density-dependent negative feedback whereby the population has a propensity to increase when small and decrease when large. Ulti ...
1 Vole population dynamics: factors affecting amplitudes of
... proposed seasonal changes in demographic variables, especially reproduction, to be responsible for seasonal patterns in population density. ...
... proposed seasonal changes in demographic variables, especially reproduction, to be responsible for seasonal patterns in population density. ...
Population Growth and Interactions
... rain have created ideal growing conditions for flies and mosquitoes. These biting insects have short life cycles, so their populations grow rapidly. The bison have shed their protective winter coats, leaving their skin bare and vulnerable to the insects, which are out for blood and may carry disease ...
... rain have created ideal growing conditions for flies and mosquitoes. These biting insects have short life cycles, so their populations grow rapidly. The bison have shed their protective winter coats, leaving their skin bare and vulnerable to the insects, which are out for blood and may carry disease ...
Interactions of Life Practice Test 2011 Answer Section
... d. how it obtains shelter ____ 26. Which of the following conditions tends to increase the size of a population? a. births exceed deaths c. movements out of an area exceed movements into the area b. population size exceeds carrying capacity d. severe drought ...
... d. how it obtains shelter ____ 26. Which of the following conditions tends to increase the size of a population? a. births exceed deaths c. movements out of an area exceed movements into the area b. population size exceeds carrying capacity d. severe drought ...
Populations - Lyndhurst School
... determines whether the size of the population increases, decreases, or stays the same. Hydrilla populations in their native habitats tend to stay more or less the same size over time. These populations have a growth rate of around zero. In other words, they neither increase nor decrease in size. The ...
... determines whether the size of the population increases, decreases, or stays the same. Hydrilla populations in their native habitats tend to stay more or less the same size over time. These populations have a growth rate of around zero. In other words, they neither increase nor decrease in size. The ...
Populations - Lyndhurst School
... determines whether the size of the population increases, decreases, or stays the same. Hydrilla populations in their native habitats tend to stay more or less the same size over time. These populations have a growth rate of around zero. In other words, they neither increase nor decrease in size. The ...
... determines whether the size of the population increases, decreases, or stays the same. Hydrilla populations in their native habitats tend to stay more or less the same size over time. These populations have a growth rate of around zero. In other words, they neither increase nor decrease in size. The ...
Density dependence in ungulates: a review of causes, and concepts
... population dynamics can be affected strongly by intraspecific competition, which changes in relation to the ecological carrying capacity (K) of the environment—a topic we will return to later. A characteristic growth curve of numbers over time for these large mammals in a constant environment would ...
... population dynamics can be affected strongly by intraspecific competition, which changes in relation to the ecological carrying capacity (K) of the environment—a topic we will return to later. A characteristic growth curve of numbers over time for these large mammals in a constant environment would ...
(1999) Consequences of the Allee effect for behaviour, ecology and
... a situation that might arise in a flock of another species, where collective vigilance shows little increase above a small number of birds, but in flocks below that size, mortality due to predation is almost 100%). ...
... a situation that might arise in a flock of another species, where collective vigilance shows little increase above a small number of birds, but in flocks below that size, mortality due to predation is almost 100%). ...
Population Ecology
... • Density-dependent birth and death rates are an example of negative feedback that regulates population growth – They are affected by many factors, such as competition for resources, territoriality, disease, predation, accumulation of toxic wastes, and ...
... • Density-dependent birth and death rates are an example of negative feedback that regulates population growth – They are affected by many factors, such as competition for resources, territoriality, disease, predation, accumulation of toxic wastes, and ...
Limitation of population recovery - Cooperative Institute for the North
... Long-lived species have low population growth rates resulting from their life histories (late recruitment, low fertility and high adult survival, Stearns 1992). Therefore, for such species, recovery can be slow, resulting in a greater risk of extinction. If the traits most likely to influence recov ...
... Long-lived species have low population growth rates resulting from their life histories (late recruitment, low fertility and high adult survival, Stearns 1992). Therefore, for such species, recovery can be slow, resulting in a greater risk of extinction. If the traits most likely to influence recov ...
The influence of top-down, bottom-up and abiotic factors on the moose
... set of models being considered. By definition, the best model has a !AICC of zero, and models with !AICC " 2 are generally considered worthy of consideration. For all models, the response variable was log-transformed growth rate of moose (rt). That is, rt = mt#1 $ mt , where mt is the natural logari ...
... set of models being considered. By definition, the best model has a !AICC of zero, and models with !AICC " 2 are generally considered worthy of consideration. For all models, the response variable was log-transformed growth rate of moose (rt). That is, rt = mt#1 $ mt , where mt is the natural logari ...
Population growth rate and its determinants
... carrying capacity, population growth rate is positive and the population increases towards carrying capacity; conversely when density is above carrying capacity, population growth rate is negative and the population declines. In this way population density is controlled by the mechanism of the negat ...
... carrying capacity, population growth rate is positive and the population increases towards carrying capacity; conversely when density is above carrying capacity, population growth rate is negative and the population declines. In this way population density is controlled by the mechanism of the negat ...
population
... Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings ...
... Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings ...
population
... Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings ...
... Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings ...
World population
In demographics and general statistics, the term world population refers to the total number of living humans on Earth. The United States Census Bureau estimates that the world population exceeded 7 billion on March 12, 2012. According to a separate estimate by the United Nations Population Fund, it reached this milestone on October 31, 2011. In July 2015, the Population Division of the United Nations Department of Economic and Social Affairs estimated the world population at approximately 7.3 billion.The world population has experienced continuous growth since the end of the Great Famine and the Black Death in 1350, when it was near 370 million. The highest growth rates – global population increases above 1.8% per year – occurred briefly during the 1950s, and for longer during the 1960s and 1970s. The global growth rate peaked at 2.2% in 1963, and has declined to 1.1% as of 2012. Total annual births were highest in the late 1980s at about 139 million, and are now expected to remain essentially constant at their 2011 level of 135 million, while deaths number 56 million per year, and are expected to increase to 80 million per year by 2040.The 2012 UN projections show a continued increase in population in the near future with a steady decline in population growth rate; the global population is expected to reach between 8.3 and 10.9 billion by 2050. 2003 UN Population Division population projections for the year 2150 range between 3.2 and 24.8 billion. One of many independent mathematical models supports the lower estimate, while a 2014 estimate forecasts between 9.3 and 12.6 billion in 2100, and continued growth thereafter. Some analysts have questioned the sustainability of further world population growth, highlighting the growing pressures on the environment, global food supplies, and energy resources.Various scholarly estimates have been made of the total number of humans who have ever lived, giving figures ranging from approximately 100 billion to 115 billion.