if a population is very large or spred out,ecologists use the sampling medthod to estime the population's size
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Why do you post homework problems here?\n\nAre you so dense you can't figure this out? Or look it up? \n\nAnd you put it in EARTH SCIENCE? It has NO business being in earth science. MAYBE biology or environment and ecology?\n\nI won't dignify this with an answer. Look it up. And anyone who comes after me, please let's have some people look things up and not just post homework here. Or think for a change. What a novel concept.
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Sampling is that part of statistical practice concerned with the selection of individual observations intended to yield some knowledge about a population of concern, especially for the purposes of statistical inference. In particular, results from probability theory and statistical theory are employed to guide practice.\n\nThe sampling process consists of 5 stages:\n\nDefinition of population of concern \nSpecification of a sampling frame, a set of items or events that it is possible to measure \nSpecification of sampling method for selecting items or events from the frame \nSampling and data collecting \nReview of sampling process \n\nPopulation definition\nSuccessful statistical practice is based on focused problem definition. Typically, we seek to take action on some population, for example when a batch of material from production must be released to the customer or sentenced for scrap or rework.\n\nAlternatively, we seek knowledge about the cause system of which the population is an outcome, for example when a researcher performs an experiment on rats with the intention of gaining insights into biochemistry that can be applied for the benefit of humans. In the latter case, the population of concern can be difficult to specify, as it is in the case of measuring some physical characteristic such as the electrical conductivity of copper.\n\nHowever, in all cases, time spent in making the population of concern precise is often well spent, often because it raises many issues, ambiguities and questions that would otherwise have been overlooked at this stage.\n\n\n[edit] Sampling frame\nIn the most straightforward case, such as the sentencing of a batch of material from production (acceptance sampling by lots), it is possible to identify and measure every single item in the population and to include any one of them in our sample. However, in the more general case this is not possible. There is no way to identify all rats in the set of all rats. There is no way to identify every voter at a forthcoming election (in advance of the election).\n\nThese imprecise populations are not amenable to sampling in any of the ways below and to which we could apply statistical theory.\n\nAs a remedy, we seek a sampling frame which has the property that we can identify every single element and include any in our sample. For example, in an opinion poll, possible sampling frames include:\n\nElectoral register \nTelephone directory \nShoppers in Anytown, High Street on the Monday afternoon before the election. \nThe sampling frame must be representative of the population and this is a question outside the scope of statistical theory demanding the judgement of experts in the particular subject matter being studied. All the above frames omit some people who will vote at the next election and contain some people who will not. People not in the frame have no prospect of being sampled. Statistical theory tells us about the uncertainties in extrapolating from a sample to the frame. In extrapolating from frame to population its role is motivational and suggestive.\n\nThere is however, a strong division of views about the acceptabilty of representative sampling across different domains of study. To the philosopher, representative sampling procedure has no justification whatsoever because it is not how truth is pursued in philosophy. 'To the scientist, however, representative sampling is the only justified procedure for choosing individual objects for use as the basis of generalization, and is therefore usually the only acceptable basis for ascertaining truth'. (Andrew A. Marino) [1]. It is important to understand this difference to steer clear of confusing prescriptions found in many web pages.\n\nIn defining the frame, practical, economic, ethical and technical issues need to be addressed. The need to obtain timely results may prevent extending the frame far into the future.\n\nThe difficulties can be extreme when the population and frame are disjo
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Most systems, when left alone, will tend to come to a "steady state" or be at rest.  In the case of balancing the ecosystem, overpopulation is a situation that I tend to think would eventually be controlled by the environment.\n\nAs an example, consider bacteria and viruses for which not everyone is immune nor is there necessarily a vaccine.  The increase in population ensures: a) that there are more hosts for these agents to travel; and b) that the agent doesn't have that far to travel, so it does so quickly.  Epidemics have a way of balancing out overpopulation.\n\nIn some cases, people make the mistake of introducing some 'agents' (not necessarily viruses, but such as in a recent case with toads) into an environment in which they help control the population in one aspect, but then the agent itself overpopulates.  Eventually, as it runs out of food (unless it has several plentiful sources in the environment to which it's been transplanted) it too will experience a loss in population.
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OK.  From any given population, you can take many, many different samples of size n.  For each of those samples, you can find the mean.  So if you take 1000 samples of size 50,  Then you would have 1000 sample means.  Now each of those sample means are probably going to be different from the overall population mean, since samples are going to look different from the population.  Also, each of the 1000 sample means are going to look different from each other because the mean is coming from different samples.\n\nSo if I were to draw a histogram (hopefully you know what that is; it is a bar graph that you can use to look at the distribution of numerical data).  Anyway, if I were to draw a histogram of my 1000 sample means,  You should notice the following three things...\n\n1.  The center of your histogram should be the same as you population mean (so if the mean of the population is 20, then the histogram of my 1000 sample means should center around 20).\n\n2.  As the sample size gets larger, the spread of the histogram should get smaller (so the spread of the means of samples of size 50 would be smaller than for the means of samples of size 25).  This is because with larger samples, you would have more information about the population, and thus you should be able to get closer to the population mean.\n\n3.  As the sample size gets larger, the shape of the histogram will look more and more like a normal curve.\n\nThis is because of the Central Limit Theorem, that states that if you take a sample of size n from any population with a finite variance, the distribution of the mean of the sample would get closer and closer to a normal curve as n gets larger.  The mean of the normal would be the same as the population mean, and the standard deviation of the normal (usually called the standard error) would  be the standard deviation of the population divided by the square root of n.  Notice that as n gets larger, the standard error gets smaller, just as described before.  So typically you can approximate these histrgrams with a normal curve if n > 25.\n\nThis phenomenon is hard to describe in words alone.  Looking at pictures of these histograms that I described would help you understand it better.
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samples or sample size; usually designated "n"
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By eliminating weak individuals in the prey population and causing natural selection to play its role in population genetics.  \n\nI knows its a vague answer but  I can't remember all the fancy terminology in population ecology.
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Species are dying out all the time. And this effects the ecological balance. Therefore conservation biology can help to maintain species and prolong others lives. This is a must in research otherwise there will be nothing to research.
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to stop the population rise,
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The population of the world is subtracted by 1.
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a lot, over a  billion people
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If measured by the number of participants, it is fishing.
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Depends where you look. We don't have records long enough to look at the statistics of earthwuakes for the whole of the Earth.\n\nHowever, over time, some areas become more active and some less so.
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Ideally you would want the largest number possible. If you use too few people then there would not be enough variety in their genes.\n\nEventually the entire population's genes would be very similar and the members of the population would have similar strengths and weaknesses eg. if one member of the population is not resistant to a particular virus, then because of the genetic similarity to other members it is quite likely that the entire population would not be resistant. It would be possible for them to be wiped out by a single virus (or other threat).
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how can a goverment manage a population that exceeds 1 billion people? just because a portion of the people are doing better from the boom does not mean everyone will benifit.
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Basing this on rough statistics you'd be looking at a maximum current population of about 60 million, give or take a million.  That is of course assuming that all other aspects remain the same.
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People take over animals & plants living spaces.
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Wicked Friggin Big. ;)\n\nPopulation \nTotal (2000) 589,141 \nMetro area 5.8 million