Population Selection
Population Selection - Related Videos
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Large-scale Reconstructions and Independent, Unbiased Clustering Based on Morphological Metrics to Classify Neurons in Selective Populations
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Cited by 3 •
2017
This protocol describes large-scale reconstructions of selective neuronal populations, labeled following retrograde infection with a modified rabies virus expressing fluorescent markers, and independent, unbiased cluster analyses that enable comprehensive characterization of morphological metrics among distinct neuronal subclasses.
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Population Growth - Student Protocol
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2019
Exponential Population Growth Model ExpandNOTE: In these experiments you will use computer software to simulate different types of growth models. HYPOTHESES: The experimental hypothesis might be that if we increase either R, the reproductive rate or the initial population size, NT, that this will increase the population size after 10 generations in an exponential growth model compared to unmanipulated control populations. The null hypothesis may be that populations of different R and initial...
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Population Growth - Concepts
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2019
Population Models An ecological population is a group of individuals of a single species living in an area at the same time. To persist, a population must either grow or maintain its size. Population ecology is the study of how population size and age distribution change over time through interactions with other species and the environment as well as with individuals of their own species. A particularly important feature that is studied by ecologists is the rate at which a population grows or...
06:48
Natural Selection - Concepts
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2019
Fitness Widespread variation of phenotypes in natural populations provides the raw material for evolution, which is the change in the inherited traits of populations over successive generations. Natural selection is one of the main mechanisms of evolution and requires variable traits to be heritable and associated with differential survival and/or reproductive success. Phenotypes that correlate with greater success will have more offspring that survive to reproduce in the next generation, and...
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Artificial Selection - Concepts
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2019
Natural Selection and Adaptive Evolution In natural settings, adaptive evolution takes place by natural selection, a process in which differences in traits lead to differences in survival and reproductive success between individuals. This happens because individuals with certain phenotypes have a higher probability of survival and/or produce more surviving offspring than individuals with other phenotypes. A classic example of this was demonstrated by Rosemary and Peter Grant studying the...
FAQs
Population selection affects statistical validity by determining whether estimates and hypothesis tests apply to the intended group. If the chosen observations do not align with the research question, results may describe a different population than the one researchers want to understand. That mismatch can weaken interpretation and restrict generalizability, even when the calculations are performed correctly.
A sampling frame is the operational list or source from which observations are selected. Its contents should correspond to the target population’s stated characteristics, geographic limits, time period, and eligibility rules. Missing or ineligible units can make the selected sample systematically different from the intended population, producing selection bias and reducing confidence in broader conclusions.
Geographic and time boundaries determine the scope of the conclusions drawn from a study. A population limited to a particular place or period may differ from one defined more broadly, so changing those boundaries changes which observations are eligible and who the findings describe. Stating them explicitly helps keep the selected observations aligned with the research question.
Before selecting observations, researchers should translate the research question into specific characteristics, geographic or time boundaries, and eligibility criteria. These specifications clarify which units belong in the target population and which do not. They also provide a basis for checking whether the sampling frame can support the intended selection, reducing ambiguity and helping the resulting analysis answer the original question.
A sampling frame connects the conceptual target population to the units that can actually be selected. Researchers use it to identify observations that meet the stated criteria within the chosen boundaries. If the frame includes units outside those rules or leaves relevant units out, the study may suffer selection bias, and its estimates may not generalize to the intended population.
It is particularly important whenever a study uses a sample to draw conclusions about a larger group, including surveys, experiments, and public health studies. In these settings, the population rules determine whether estimates and hypothesis tests address the intended group. Clear selection also helps readers judge how far the findings can reasonably be generalized.
The clearest warning is a mismatch between the population described by the study and the population implied by its eligibility rules or sampling frame. Such a mismatch can introduce selection bias, distort the relevance of estimates or hypothesis tests, and limit generalizability. Researchers should therefore interpret findings within the population actually represented by the selection process.