From Wikipedia, the free encyclopedia
Population dynamics is the branch of life sciences that studies short-term and long-term changes in the size and age composition of populations, and the biological and environmental processes influencing those changes.
Population genetics is the study of the allele frequency distribution and change under the influence of the four evolutionary forces: natural selection, genetic drift, mutation and gene flow. It also takes account of population subdivision and population structure in space.
Population dynamics is the study of marginal and long-term changes in the numbers, individual weights and age composition of individuals in one or several populations, and biological and environmental processes influencing those changes.
Population: A group of organisms, all of the same species, which occupies a particular area. Also, the total number of individuals of a species within an ecosystem, or of any group of similar individuals.
More Biology Terms ...
Population may also mean the process of populating a geographic area, as by procreation or immigration.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Population".
~ density is the relation between the number of individuals of a population and the area or volume they occupy. For example, in 2001 the human population density of the United States (according to the World Bank) was 29.
~ ecology is the study of populations and their interactions with the environment. A population is a group of individuals of a species in a particular area.
1. people inhabiting a territory, as in American ~ ...
Part of the work of forensic DNA analysis is the creation of population databases for the STR loci studied.
The factors affecting population growth, and how populations increase in numbers are important concepts in ecology as they are necessary in order to successfully study how ecosystems work.
Some populations go through repeated and regular periods of boom followed by bust.
~ structure shows different selection directions shaped ornamental peach and the edible landrace of peach ...
A ~'s gene pool is defined by its allele frequencies.
A ~ is a localized group of individuals that belong to the same species.
One definition of a species is a group of natural ~s whose individuals have the potential to interbreed and produce fertile offspring.
A population must be large enough that chance occurrences cannot significantly change allelic frequencies significantly. To better understand this point, consider the random flipping of a fair coin. The coin is as likely to land on heads as it is on tails.
~ genomics really refers to a new concept in terms of ancestry, in terms of sequencing the human genome, which really has lead to the development of spectacular technology that is helping us to now search the genome in a way that we were unable to do before.
Students of population genetics learn from their textbooks that levels of genetic diversity are determined by the rate of mutation (the number of new mutations per nucleotide site and generation) and the number of reproducing individuals in the population.
Rapid increase in population growth.
Natality rate exceeds mortality rate.
Abundant resources available. (food, water, shelter)
Diseases and predators are rare.
~s Transition Between Growth and Stability
Limits on population growth can include food supply, space, and complex interactions with other physical and biological factors (including other species).
~: A group of individuals of the same species within a given space and time.
Predaceous: Preying upon other organisms, predatory.
Predator: An animal that attacks and feeds on other animals, normally killing several individuals during its life cycle.
Type of genetic drift that occurs as the result of a ~ being drastically reduced in numbers by an event having little to do with the usual forces of natural selection.
~ density ...
~ an interbreeding group of individuals of one species occupying a defined geographic area.
predation a relationship in which one ~ within a community may capture and feed upon another ~.
~ a group of the same species of organism in the same area at the same time
(populus = the people)
Porphyria a dominant genetic inability to make porphyrin
(porphyr = purple; -ia = state of‚ condition of‚ disease) ...
~ ECOLOGY Population ecology is a science that deals with measuring changes in population size and composition and identifying the factors that cause these changes.
The study of variation in genes among a group of individuals.
Positional cloning ...
8. A population of an organism reaches steady state; which would most likely have the biggest impact on population density?
~s evolve. [evolution: a change in the gene pool] In order to understand evolution, it is necessary to view populations as a collection of individuals, each harboring a different set of traits.
Population genetics is basically genetics of the particular traits, or characters, of man, in the case of human population genetics, that then pass between generations with a particular population.
~s or species with low genetic diversity at many genes are at risk. When diversity is very low, all the individuals are nearly identical. If a new environmental pressure, such as a disease, comes along, all of the individuals within the population may get the disease and die.
A group of organisms of the same species relatively isolated from other groups of the same species. See deme.
A group of organisms belong to the same biological species, if they are capable of interbreeding to produce fertile offspring.
~ of transgenic salmon have been produced in which individuals grow rapidly
These transgenic fish could compete for food with other fish species
Cells & Molecules
Cell Division ...
~ density. Number of individuals per unit area or volume
Porifera. The phylum comprising the sponges.
~s of cells in apical meristem which reproduce much more slowly than other meristematic cells
Resistant to radiation and chemical damage
Possibly a reserve which can be called into action if the apical meristem becomes damaged
The Zone of Cell Division - Primary Meristems ...
bol.ch - Das einfach runde Partnerprogramm
Complete Biology ...
~ genetics - the study of changes in gene frequencies in ~s of organisms
Paleontology - the study of fossils and sometimes geographic evidence of prehistoric life
Pathobiology or pathology - the study of diseases, and the causes, processes, nature, and development of disease ...
~ A group of organisms of the same species inhabiting a specific geographical locality.
~ crash A sudden ~ decline caused by predation, waste accumulation, or resource depletion; also called a dieback.
~ a group of organisms, usually a group of sexual organisms that interbreed and share a gene pool, and are normally relatively isolated from other groups of the same species.
A ~ of cultured cells, of plant or animal origin, that has undergone a change allowing the cells to grow indefinitely, in contrast to a cell strain. Cell lines can result from chemical or viral transformation and are said to be immortal.
When a ~ of bacteria is subjected to an antibiotic, many bacteria are killed, but a few may have the ability to evade death. If so, this ability can be passed to later generations.
Effective ~ size (N or Ne): number of individuals contributing 'unique' chromosomes to the next generation (Nf = number of mothers in a ~; relevant in the calculation of number of generations for the fixation of a mitochondrial allele).
A ~ of genetically identical cells (or organisms).
View Dr Chromo's lecture on Cloning hosts and vectors
Related Links ...
A ~ of cells derived from a single cell and thus expected to be genetically identical. Genetic differences in a "clonal" ~ may arise from random spontaneous mutations during growth of the cells.
mixed cell ~s- expression signals: Expression
molecular motors: Nanoscience & Miniaturization
morphometry: Measurement of shape, structure and form. Used in a variety of disciplines, including environmental studies, geology, imaging and cell biology.
Clone - A ~ of cells descended by mitotic division from a single ancestral cell, or a ~ of genetically identical organisms asexually propagated from a single individual.
Commensal. ~s of house mice that depend upon human-built habitats or food production for survival.
Compensatory genes. One or more genes that compensate for gain or loss of function of another gene, including transgene, thereby influencing phenotype.
The group of related organisms used in constructing a genetic map. (ORNL)
See: genetic marker (ORNL)
Also known as Filtering.
Other ecologists are more interested in how organisms of the same species interact with each other in ~s. Still others spend their days examining how whole ~s interact with other ~s in a community.
The occurrence in a ~ (or among ~s) of several phenotypic forms associated with alleles of one gene or homologs of one chromosome. See genetic polymorphism.
The total dry weight of all organisms in a particular sample, ~, or area. Bioremediation. The use of microorganisms to remedy environmental problems. See Bioaugmentation, Bioenrichment. Biotechnology.
Genetic variation -- a phenotypic variance of a trait in a ~ attributed to genetic heterogeneity. Genome -- all of the genes carried by a single gamete; the DNA content of an individual, which includes all 44 autosomes, 2 sex chromosomes, and the mitochondrial DNA.
Gene flowChanges in gene frequencies that occur over long periods of time due to migration in which different ~s interbreed. An example is the transfer of genes between racial groups, e.g., the "white" genes of the Duffy blood group system (Fya Fyb) have an increased frequency in U.S.
Allele Frequencies Term used to characterize genetic variation of a species ~. Allelic dropout Failure to detect an allele within a sample or failure to amplify an allele during PCR.
Allele frequency — The proportion of chromosomes in a ~ harboring a specific genetic variant. "Minor allele frequency" typically refers to the less common variant at a biallelic single nucleotide polymorphism.
sutchuenensis community, niche and interspecific relationships of main ~s, natural regeneration and the cone characteristics and cutting propagation of the species were studied. The main results are as the following.
It comes about when sub ~s of a species are separated geographically (geographical isolation) or are prevented from engaging in sexual reproduction (sexual isolation) and upon later reunion, they can no longer interbreed.
These traits must confer a reproductive advantage to the members of the ~, in order for them to become more common. The ability of bacteria to develop resistance to antibiotics is an example of natural selection.
Stabilizing occurs when natural selection favors average individuals in a ~. Can reduce variations in ~. EX: average sized spiders will have a better chance of survival because large spiders are easy for predators to spot and small spiders can hide from predators.
Differential displayA form of RT-PCR in which primers are used to select a subset of the total mRNA ~. This allows comparison of mRNAs from different cells. leading to identification of those mRNAs which are expressed only in certain situations e.g. after stimulation.
It is also about molecules, genes, mutations, ~s, and sex in living organisms. All of these things are primary sources of data about evolutionary processes that occur when organisms try to survive and reproduce.
They control or check the ~ of herbivore species from getting overpopulated.
Carnivores are predators and catch prey.
Carnivores that feed on insects are called insectivore whereas that feeding on fishes are called piscivores.
A food staple for much of the world’s ~, rice comes in different varieties. Two strains were sequenced in 2002, the japonica (popular in Japan) and the indica (grown in China). An international consortium is working on a third rice genome sequence that will be the gold standard.
Though widespread familiarity with the flu makes it seem relatively benign to much of the general ~, the virus can be devastating.
Ecology: abiotic, biodiversity, ecological succession, ecology, nitrogen cycle, transpiration, biotic, competition, biome, ~ model, aggregation, behavior, ~ density, biological sucession, colonial organism, dispersion, dynamic equilibrium, exponential growth, homeostasis, ...
Within a ~, the measure of how much of the variation of a particular phenotype is due to environmental factors (as opposed to variations in genotype - see genetic variance). An example might be the height of a plant as determined by such factors as nutrition or damage during development.
Polymorphic A term formulated by ~ geneticists to describe loci at which there are two or more alleles that are each present at a frequency of at least one percent in a ~ of animals.
This it is a very important task because we are able to know the behavior or functioning of each ~ when it faces to other individuals from other ~s or communities and how the ~s or the specific sectors of the biosphere are affected and/or benefited by that behavior or ...
random genetic drift Term used to refer to changes, from one generation to the next, in the ~ frequency of an allele or trait due to random deviation from the ~ frequencies expected on the basis of pre-existing frequencies.
3. What would eventually happen to the ~ of the beans that "survived" the worst? Why?
4. Which bean "survived" the best on the black background? Was it the same or different than the bean that "survived" the best on the green background? Why do you think this is so? Explain.
Penetrance: The percentage of individuals in a ~ that actually exhibit the (mutant) phenotype even though they carry the mutation
Expression: This refers to the consistency of the mutation. Basically even though the mutation penetrates it may have variable degrees of expression.
Species or ~s that occur in geographically separate areas.
A polyploid originating through the addition of unlike chromosome sets, often in conjunction with hybridization between two species.
Genetic Distance: various statistics for measuring the 'genetic distance' between subgroups or ~s.
- The movement of genes from one ~ to another by way of interbreeding of individuals in the two ~s
- Determining the relative locations of genes on a chromosome.
control action threshold. Pest ~ level at which treatment is necessary to prevent economic loss, also called economic threshold.
cornicle. Two tubular structures located on the posterior part of an aphid's abdomen.
Gene flow: The exchange of genetic traits between ~s by movement of individuals, gametes, or spores. It involves the spread of new variants among different ~s through dispersal.
Those organisms are removed from the ~ so that healthier animals can survive. But the virus life cycle, that of a parasite, only hurts the organisms. Some even destroy cells in order to reproduce. And don't think you are the only one to get sick. Viruses attack plants and even bacteria.
Solution hybridization is designed to measure the levels of a specific mRNA species in a complex ~ of RNA. An excess of radioactive probe is allowed to hybridize to the RNA, then single-strand specific nuclease is used to destroy the remaining unhybridized probe and RNA.
The natural processes involved are
genetic variation among members of a ~
inheritance of those variations by offspring
natural selection, the survival and enhanced reproduction of organisms with favorable variations.
Warts are caused by the human papillomavirus. About half the ~ of children have them at some time. Warts appear about 1-8 months after infection and can last for years if not treated.
Single base differences of DNA sequences between individuals of a ~. For PCR screening and detection of SNP, please visit Primo SNP. See also PCR Glossary.
PubMed Google ...
polymorphic; polymorphous (relating to the occurrence of more than one kind of individual (independent of sexual differences) in an interbreeding ~)
isomorphic; isomorphous (having similar appearance but genetically different)
extracellular (located or occurring outside a cell or cells) ...
He studied theories of economics and ~ by Thomas Malthus. He bred fancy pigeons and collected natural artifacts on his farm. And yes, he took an amazing voyage to study exotic creatures around the world.
the legal prohibition of movement of animals from a ~ with disease ...
Note 58. The measurements of the pelvis given above are fairly accurate, but different figures are given by various authors no doubt due mainly to differences in the physique and stature of the ~ from whom the measurements have been taken. [back] ...
spontaneous Mutations that occur in the absence of treatment with a chemical or biological mutagen. Usually refers to mutations in natural ~s.
Genetic variations occurring in more than 1% of a ~ would be considered useful polymorphisms for genetic linkage analysis. Compare mutation.
Predisposition Intrinsic likelyhood of developing a particular disorder.
See also: What is the meaning of Organ, Human, Trans, Biology, DNA?