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第III部分:种群生态学
第III部分:种群生态学

... Temperature regulation and distributions of E. farinosa and E. frutescens ...
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PVA

... simulations, tally number of extinction events) + indicates which factors are most important in declines – requires large amounts of data – not generalizable - build anew for each species ...
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... Some species need a large population density to display social interaction Threatened populations may have low reproductive success If a species has low reproductive rates, they need increased numbers to maintain the population ...
ENVIRONMENTAL SCIENCE
ENVIRONMENTAL SCIENCE

... individuals and the long-term welfare of society is the main difficulty in solving environmental problems. The “commons” of the essay was an area of land that belonged to the whole village. The short-term interest of the individual was to put as many animals on the area for grazing as possible – if ...
Unit 5
Unit 5

... 1. Define the scope of population ecology. All characteristics of population research including measuring diversity, patters of dispersion, and limiting factors. 2. Distinguish between density and dispersion. Density is the number of individual per unit area or volume and dispersion is the spacing o ...
Ecology Test *Use Answer sheet TEST A Test Number: Chapter 3, 4
Ecology Test *Use Answer sheet TEST A Test Number: Chapter 3, 4

... 1. The branch of biology dealing with interactions among organisms and between organism and their environment is a. economy b. modeling c. recycling d. ecology 2. Which of the following descriptions about the organization of an ecosystem is correct? a. communities make up species, which make up popu ...
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Unit_3_population

... Doubling Time = The amount of time it takes for a population to double in size (assuming that it’s growth rate (r) doesn’t change) Doubling time can identify a country as highly, moderate, or less developed. The shorter the doubling time the less developed the country! Formula (simplified): TD (time ...
12.2 - Demography
12.2 - Demography

... Fecundity – is the potential for a species to produce offspring in a lifetime. Generation Time - is the average time between the birth of an organism and the birth of the offspring. Sex Ratio – is the relative proportion of males and females in a population. Fecundity is the potential reproductive c ...
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... The difference between the birth rate and the death rate is the per capita growth rate r=b-d The growth equation can be rewritten as ∆N = rN or dN = rN ∆t dt Exponential growth occurs when resources are unlimited and the population is small (doesn’t happen often). The r is maximal (rmax) and it is c ...
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... In 2013, Earth Overshoot Day fell on August 20 – the day when the world has used as much of Earth’s resources as Earth can replace in one year. ...
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chapter5B - TJ

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Final Study Guide

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CP CHEMISTRY STUDY GUIDE

... BIO.B.4.2.1 Describe how energy flows through and ecosystem (food chains, food webs) BIO.B.4.2.2 Describe biotic interactions in an ecosystem (competition, predation, symbiosis) BIO.B.4.2.5 Describe the effects of limiting factors on population dynamics and potential species extinction. ...
Population Ecology
Population Ecology

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SC20F Ecology Unit Review Name: 1. Define the following terms

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Sustaining Fisheries Yields Over Evolutionary Time Scales

... lack larger and/or older individuals (2–4). This occurs not only because fishers may seek to exploit large individuals but also because regulatory measures often impose minimum size or gear regulations that ensure selective harvest of larger fish. Such harvesting practices could favor genotypes with ...
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Biodiversity, Species Interactions, and Population Control Chapter 5

...  Intrinsic rate of increase (r)= rate of population growth with unlimited resources  Individuals in populations with high r ...
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... competition • The ultimate effect of competition is a decreased contribution to the next generation; – Intraspecific competition leads to decreased rates of resource intake per individual, decreased rates of individual growth or development, or to decreases in the amounts of stored reserves; – These ...
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Ecosystems and Communities

... and abiotic factors that affect it Niche: an organism’s habitat plus its role in an ecosystem ...
REACH Populations
REACH Populations

... Which explains the high birth rate in contrast to the rapidly declining death rate during industrialization? A. The average age of marriage increasing B. Nations becoming more developed C. Increases in many areas including technological and medical innovations D. Increase in educational and employme ...
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... Answer: The ferns that grow along side the pond. • Organisms interact with both the living and the non-living portions of the ecosystem. • Ecosystems are divided into two main parts: Biotic Factors and Abiotic Factors. ...
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... Population density is the number of individuals per unit area. Population distribution is how individuals are spaced out in their range. Growth rate determines whether a population grows, shrinks, or stays the same size. Age structure is the number of males and females of each age in a population. P ...
Energy Flow
Energy Flow

... its density. These are abiotic factors in the community. Density-dependent factors or population controls have a greater affect on the population as its density increases. Infectious disease is an example of densitydependent population control. ...
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Maximum sustainable yield

In population ecology and economics, maximum sustainable yield or MSY is theoretically, the largest yield (or catch) that can be taken from a species' stock over an indefinite period. Fundamental to the notion of sustainable harvest, the concept of MSY aims to maintain the population size at the point of maximum growth rate by harvesting the individuals that would normally be added to the population, allowing the population to continue to be productive indefinitely. Under the assumption of logistic growth, resource limitation does not constrain individuals’ reproductive rates when populations are small, but because there are few individuals, the overall yield is small. At intermediate population densities, also represented by half the carrying capacity, individuals are able to breed to their maximum rate. At this point, called the maximum sustainable yield, there is a surplus of individuals that can be harvested because growth of the population is at its maximum point due to the large number of reproducing individuals. Above this point, density dependent factors increasingly limit breeding until the population reaches carrying capacity. At this point, there are no surplus individuals to be harvested and yield drops to zero. The maximum sustainable yield is usually higher than the optimum sustainable yield and maximum economic yield.MSY is extensively used for fisheries management. Unlike the logistic (Schaefer) model, MSY has been refined in most modern fisheries models and occurs at around 30% of the unexploited population size. This fraction differs among populations depending on the life history of the species and the age-specific selectivity of the fishing method.However, the approach has been widely criticized as ignoring several key factors involved in fisheries management and has led to the devastating collapse of many fisheries. As a simple calculation, it ignores the size and age of the animal being taken, its reproductive status, and it focuses solely on the species in question, ignoring the damage to the ecosystem caused by the designated level of exploitation and the issue of bycatch. Among conservation biologists it is widely regarded as dangerous and misused.
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