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| | Population density - encyclopedia article about Population density. |
 | | Population density is a common biological measurement and is often used by conservationists Conservationists are proponents or advocates of conservation, especially those who advocate the conservation of all the species in an ecosystem. | | | Population is studied in a wide variety of ways and disciplines. | | | Inbreeding often leads to reduced health and fitness (called consanguinity depression); however, livestock breeders often practice inbreeding, then cull unfit offspring, especially when they are trying to establish a new and desirable trait in their stock. |
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http://encyclopedia.thefreedictionary.com/population+density
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| | Population genetics - Encyclopedia.WorldSearch |
| | As such, it is the theory that attempts to explain such phenomena as adaptation and speciation. | | | For example, if the phenotype is almost one-to-one with genotype (sickle-cell anemia) or the time-scale is sufficiently short, the "constants" can be treated as such; however, there are many situations where it is inaccurate. | | | John Gillespie Population Genetics: A Concise Guide, Johns Hopkins Press, 1998 ISBN 0-8018-5755-4 |
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http://encyclopedia.worldsearch.com/population_genetics.htm
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| | Some Sample Size Theory |
| | When some investigators see how the sample sizes required for paired studies compared to those involving independent samples, their first thought is to drop any control group in favor of "using subjects as their own control". | | | An investigator who measured only the 50 subjects at two time points would be able to determine whether there was a change over time, but s/he would not be able to say how it compared to what would have happened over the same time period in the absence of any intervention. | | | Who wouldn't prefer to recruit 50 subjects and look at whether their cholesterol levels change over time rather than 200 subjects (100 on treatment; 100 on placebo) to see if the mean change in the treatment group is different from that in the control group? |
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http://www.tufts.edu/~gdallal/sizenotes.htm
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| | Washington State Department of Health - Assessment Guidelines: Small Numbers |
| | Questions concerning health outcomes and related health behaviors and environmental factors often are studied within small subgroups of a population. | | | The second alternative is to omit certain fields from analysis entirely. | | | Dever GA. Outcome assessment: Small area analysis and quality improvement methods. |
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http://www.doh.wa.gov/Data/Guidelines/SmallNumbers.htm
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| | Small population size - Wikipedia, the free encyclopedia |
| | The degree of homozygosity within individuals in a population; i.e. | | | Inability of the population to adapt/evolve to changing conditions, “without variability evolution is impossible” | | | Polymorphism may be particularly important at loci involved in the immune response. |
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http://en.wikipedia.org/wiki/Small_population_size
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| | BIOL115 Lecture Note Series |
| | It should be apparent that natural selection should only favor characteristics or behaviors that enhance an organism's fitness. | | | Imagine how poorly we would represent the diversity of genes and thoughts if we were to sample the student body of CSB/SJU as our indicator of the world's human diversity. | | | Nothing #2 represents what happens if the assumptions are held - no evolution occurs. |
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http://www.users.csbsju.edu/~dgbrown/BIOL115/evolmechanisms.html
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| | Determining Sample Size |
| | Another approach is to use the same sample size as those of studies similar to the one you plan. | | | Similarly, Kish (1965) says that 30 to 200 elements are sufficient when the attribute is present 20 to 80 percent of the time (i.e., the distribution approaches normality). | | | Many researchers commonly add 10% to the sample size to compensate for persons that the researcher is unable to contact. |
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http://edis.ifas.ufl.edu/PD006
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| | Population Growth |
| | A story said to have originated in Persia offers a classic example of exponential growth. | | | This way of life kept their total numbers small, probably less than 10 million. | | | Most, in fact, likely have population declines in their future. |
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http://www.prb.org/Content/NavigationMenu/PRB/Educators/Human_Population/Population_Growth/Population_Growth.htm
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| | Effective population size, Ne |
| | The harmonic mean of 123.7 contrasts with the arithmetic mean of 200. | | | Nunney, L. The effective size of a hierarchically structured population. | | | Genetically effective population size of large mammals: an assessment of estimators. |
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http://uwadmnweb.uwyo.edu/zoology/mcdonald/molmark/lectures/PopGen/PopGen5/PopGen5.html
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| | Size of population |
| | Ontogenetic niche shifts, flexible behavior and size-structured population dynamics. | | | Population Momentum and the changing health environment in India | | | Effective population size is the number of individuals in a population who contribute offspring to the next generation. |
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http://getinfoeasy.com/q/size-of-population.html
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| | Cutting Evaluation Costs by Reducing Sample Size |
| | One reason for this difference between the two studies could be the homogeneity of the subject groups. | | | In both studies, there was little or no difference in outcome when sample size was reduced from 558/552 to 174. | | | Both the above analyses showed that reducing sample size did not affect the results of the study. |
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http://www.joe.org/joe/1996february/a2.html
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| | Synthetic Theory of Evolution: Small Population Effects |
| | In other words, when a sample is very small, the probable outcome may not occur. | | | The smaller the population, the more susceptible it is to such random changes. | | | Since genetic drift is measurably effective only in small populations, it must have played a major role in the early stages of human evolution when our populations were tiny. |
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http://anthro.palomar.edu/synthetic/synth_5.htm
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| | Synthetic Theory of Evolution: Printable Crossword Puzzle (topics 1-5) |
| | The term for the modern theory of evolution being caused by a number of complex and often interacting processes. | | | Researchers in this area of study are also involved in identifying processes resulting in evolution. | | | This is essentially a combination of Darwin's concept of natural selection, Mendel's genetics, along with the facts and theories of population genetics and molecular biology. |
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http://anthro.palomar.edu/synthetic/crossword/synthetic_crossword_p_1.html
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| | Hoofbeats |
| | Small population size inevitably results in a loss of genetic variation which usually results in a loss of fitness of the population due to the increased probability of deleterious recessive genes being paired (and therefore expressed) by in breeding. | | | The high frequency of this color in the Abaco herd could make these horses a valuable study population for determination of the inheritance of the splashed white and also for identification of the gene responsible for the pattern. | | | If the molecular genetic basis of splashed white could be determined it could be developed into a diagnostic test to aid breeders interested in producing horses with this color pattern. |
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http://www.arkwild.org/hoofbeats/01_articles/ukendna.html
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| | Founder effect - Wikipedia, the free encyclopedia |
| | The result of the small number of founders is that there is a sharp loss of genetic variation compared with the parent population. | | | As a result, the new population may be distinctively different, genetically and phenotypically, from the parent population it derived from. | | | In the extreme case, a single fertilised female might arrive in a new environment. |
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http://en.wikipedia.org/wiki/Founder_effect
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| | Chapter 18 - Small population size |
| | Small populations, which result from the physical isolation of a small group of individuals from the larger group or from bottlenecks (that is, the rapid reduction of a large population) are characterized by small subsets of the original varied gene pool. | | | If the population is large, it is less likely that random fluctuations will change the allele frequencies within the population, resulting in evolutionary change. | | | Influences as simple as the accidental loss of specific individuals results in shifts away from the parental population allele frequencies (genetic drift) and increases the likelihood that evolution will occur. |
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http://w3.dwm.ks.edu.tw/bio/activelearner/18/ch18c4.html
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| | Lecture 9 Outline |
| | fixation of alleles and loss of variation within a population. | | | in normally outcrossing populations, inbreeding leads to "inbreeding depression", but not such | | | The effective population size, Ne, is what matters for evolution, and Ne < N (usually) |
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http://www.life.umd.edu/classroom/bsci370/lecture9.html
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| | Population Size and Genetic Drift |
| | This decline in heterozygosity is due to the increase in frequency of one of the alleles, which approaches fixation. | | | (i.e., the probability of either being autozygous in the present generation OR the probability that an individual comes from that fraction of the population that is already autozygous due to inbreeding in the previous generation). | | | This stochastic change in allele frequency resulting simply from the finite size of a population is called "genetic drift". |
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http://www.nyu.edu/projects/fitch/courses/evolution/html/genetic_drift.html
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| | Convergence-Time Models for the Simple Genetic Algorithm with Finite Population (ResearchIndex) |
| | The factors affecting the convergence with small population size are explained and used to construct a correct model of the variance in fitness for the OneMax problem. | | | This knowledge is included in the existing asymptotic model to derive the embedded convergence-time model. | | | A piecewise convergence-time model is derived using ideas from two existing convergence models. |
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http://citeseer.ist.psu.edu/ceroni01convergencetime.html
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| | [No title] |
| | Let's assume there are 1000 organisms in your study population. | | | could not return to the population from which they had come, what might become | | | all phenotypic traits in a single member of a study population |
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http://fig.cox.miami.edu/Faculty/Julian/microevolution1.htm
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| | Variable population size |
| | This means that genetic drift may play a much more imporant role than we might have imagined, since the effective size of a population will be more influence by times when it is small than by times when it is large. | | | So the population will behave with respect to the inbreeding associated with drift like a population a tenth of its arithmetic average size. | | | The notation for this one gets a little more complicated, but the ideas are simpler than those you just survived. |
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http://darwin.eeb.uconn.edu/eeb348/lecture-notes/drift/node13.html
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| | Hymenoxys research |
| | In theory, these small populations will be subject to ecological and genetic processes not associated with large populations, that result in losses of genetic diversity, reduced population growth and even extinction. | | | My research examined the consequences of population size on the reproductive success of the rare, self-incompatible plant Hymenoxys herbacea. | | | This will result in a decline in sexual reproductive success. |
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http://www.uoguelph.ca/botany/research/evollab/hymenox.htm
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| | [No title] |
| | them to maintain their body temperature since increased size means | | | quite large and yet their brains were the size of walnuts. | | | mammals); some were quite small, the size of chickens or small dogs. |
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http://www.american.edu/schaeff/lec19.html
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| | IngentaConnect Small effective population size in the long-toed salamander |
| | Keywords: Ambystoma">Ambystoma; effective population size; long-toed salamander; temporal method | | | for each of the six salamander populations of less than 100. | | | Small effective population size in the long-toed salamander |
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http://www.ingentaconnect.com/content/bsc/mecol/1999/00000008/00000010/art00748
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| | Audubon WatchList - Hawaii Creeper |
| | It may form small flocks (likely family groups) and may also join large mixed-species flocks after breeding. | | | Sightings in dry mamane forest suggest that the species may have seasonal movements, unless this is a very small year-round population. | | | Its population is severely threatened by habitat loss, feral pigs, and other problems. |
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http://audubon2.org/webapp/watchlist/viewSpecies.jsp?id=97
(554 words)
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| | Evolution 101: The Big Issues |
| | This is based on the model of peripatric speciation. | | | Larger population size and a stable environment make evolutionary change less likely. | | | Strong selection and rapid change: The small, isolated population experiences strong selection and rapid change because of the novel environment and small population size: The environment in the newly formed lake exerts new selection pressures on the isolated mollusks. |
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http://evolution.berkeley.edu/evosite/evo101/VIIA1bPunctuated.shtml
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| | Audubon WatchList - Black Oystercatcher |
| | Audubon's Important Bird Area program is a vital tool for the conservation of Black Oystercatcher as well as other species. | | | The species' small population size places it at risk to large-scale disturbances, such as oil spills. | | | With a relatively small population size, it is especially at risk from the effects of oil spills and other coastal pollution. |
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http://audubon2.org/webapp/watchlist/viewSpecies.jsp?id=36
(731 words)
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| | Small Effective Population Size |
| | Historical populations thought to be migratory, currently sedentary or nearly so (12-170 km). | | | Females difficult to census; researchers assume an equal sex ratio. |
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http://www.fhsu.edu/biology/rchannell/Teaching/Consbio/Projects/Matt/tsld006.htm
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| | Small population size |
| | When species have few members left, i.e., a small population size, the have extra problems in addition to the problems that caused the small population size |
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http://www.uic.edu/classes/bios/bios101/conservatio/sld016.htm
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| | Prediction Of Marker Coverage and Map Density |
| | "When a large number of markers are used in a genomic mapping experiment, map density is not limited by the number of markers, but rather by number of progeny of the mapping population. | | | "Small population size and low linkage information content can cause undetected linkage when a small number of markers are used." | | | There is a limitation on the linkage that can be resolved for a relatively small population size." |
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http://www.ndsu.edu/ndsu/abergstr/webcourses/genetics/pmc/pmc01.htm
(78 words)
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| | Small Effective Population Size |
| | Nine isolated populations occurring on islands of suitable habitat in eight states compared to one contiguous historical population. |
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http://www.fhsu.edu/biology/rchannell/Teaching/Consbio/Projects/Matt/sld004.htm
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| | [No title] |
| | Vulnerable: 1000 mature individuals OR very restricted area of occupancy ( | | | ª z ó ) ” ¨( Criterion D (Very small population size) ¡ ) ) ( ª ) ¨Ç Critically endangered: 50 mature individuals. | | | ª z ó ) ” ¨( Criterion D (Very small population size) ¡ ) ) ( ª ) ¨Ç Critically endangered: 50 mature individuals. |
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http://courses.washington.edu/fish458/lecture24.ppt
(419 words)
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| | Small population size - Wikipedia |
| | Wähle „Small population size suchen“ um nach Small population size zu suchen. | | | Ein Wörterbucheintrag zu Small population size hat seinen Platz im Wiktionary (Wiktionary). |
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http://de.wikipedia.org/wiki/Small_population_size
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