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Arion Circumscriptus
''Arion circumscriptus'', common name brown-banded arion, is a species of air-breathing land slug, a terrestrial pulmonate gastropod mollusk in the family Arionidae. It is commonest in woodland, occurring across most of Europe, except for more southern regions, and is also widespread in North America. It has been argued that ''A. circumscriptus'' is best considered a colour morph of ''Arion fasciatus''. Taxonomy The subgenus ''Carinarion'' Hesse, 1926 contains three species—'' Arion fasciatus'', ''Arion silvaticus'' and ''Arion circumscriptus''—distinguished on the basis of small differences in pigmentation and in proportions of their genital anatomy. Further study of these morphospecies (typological species) revealed that their body colour may be influenced by diet, and that the putative genital differences do not consistently agree with identifications based on pigmentation and allozymes. In much of their range these slugs predominantly self-fertilise, leading to distinct g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Johnston (naturalist)
George Johnston (1797 – 1855) was a Scottish physician and naturalist. Johnston was one of the founders of the Berwickshire Naturalists' Club and became its first president. His books include ''The Flora of Berwick-upon-Tweed'', ''History of British Zoophytes'', and ''History of British Sponges and Lithophytes''. Life He was born at Simprin, Berwickshire, on 20 July 1797. When he was still young, his family moved to Ilderton in Northumberland. Johnston was educated first at Kelso, then at Berwick grammar school, and finally at the University of Edinburgh. He was apprenticed to John Abercrombie, and in 1817, qualifying as a member of the Royal College of Surgeons of Edinburgh, he went to London. Contains obituary of Johnston and a list of publications. In 1818 Johnston began practice at Berwick-on-Tweed, where he remained. On 23 November 1819 he married Catharine Charles. Catharine illustrated many of his publications. Also in 1819 he graduated M.D. of Edinburgh, and in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensu Stricto
''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular concept, but it also appears in expressions that indicate the convention or context of the usage. Common qualifiers ''Sensu'' is the ablative case of the noun ''sensus'', here meaning "sense". It is often accompanied by an adjective (in the same case). Three such phrases are: *''sensu stricto'' – "in the strict sense", abbreviation ''s.s.'' or ''s.str.''; *''sensu lato'' – "in the broad sense", abbreviation ''s.l.''; *''sensu amplo'' – "in a relaxed, generous (or 'ample') sense", a similar meaning to ''sensu lato''. Søren Kierkegaard uses the phrase ''sensu eminenti'' to mean "in the pre-eminent r most important or significantsense". When appropriate, comparative and superlative adjectives may also be used to convey the meaning o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aelurostrongylus Abstrusus
''Aelurostrongylus abstrusus'' is a species of nematode from the family Angiostrongylidae.PDF Hosts Intermediate hosts include: * land snail '' Achatina fulica'' * land snail '' Thelidomus aspera'' Final hosts include: * cats (family Felidae)References Further reading *[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michigan Department Of Natural Resources And Environment
The Michigan Department of Natural Resources (DNR) is the agency of the state of Michigan charged with maintaining natural resources such as state parks, state forests, and recreation areas. It is governed by a director appointed by the Governor and accepted by the Natural Resources Commission. Currently the Director is Daniel Eichinger. The DNR has about 1,400 permanent employees, and over 1,600 seasonal employees. History In 1887, the Michigan legislature created the salaried position of state game warden. The position, which was initially created to oversee market hunting and the supply of essential foodstuffs to local lumber camps, was the direct ancestor of the state's conservation infrastructure. In 1921, the Michigan Legislature created the Department of Conservation and a Conservation Commission to manage the state's natural resources. The first director of the department was John Baird. The Michigan Department of Natural Resources was created in 1965 as a part of the con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parelaphostrongylus Tenuis
''Parelaphostrongylus tenuis'' (also known as meningeal worm or brainworm) is a neurotropic nematode parasite common to white-tailed deer, ''Odocoileus virginianus'', which causes damage to the central nervous system. Moose (''Alces alces''), elk (''Cervus canadensis''), caribou (''Rangifer tarandus''), mule deer The mule deer (''Odocoileus hemionus'') is a deer indigenous to western North America; it is named for its ears, which are large like those of the mule. Two subspecies of mule deer are grouped into the black-tailed deer. Unlike the related whi ... (''Odocoileus hemionus''), and others are also susceptible to the parasite, but are aberrant hosts and are infected in neurological instead of meningeal tissue. The frequency of infection in these species increases dramatically when their ranges overlap high densities of white-tailed deer. The lifecycle begins in infected meningeal tissues in the central nervous system (CNS) where adult brainworms lay eggs. The egg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Introduced Species
An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there by human activity, directly or indirectly, and either deliberately or accidentally. Non-native species can have various effects on the local ecosystem. Introduced species that become established and spread beyond the place of introduction are considered naturalized. The process of human-caused introduction is distinguished from biological colonization, in which species spread to new areas through "natural" (non-human) means such as storms and rafting. The Latin expression neobiota captures the characteristic that these species are ''new'' biota to their environment in terms of established biological network (e.g. food web) relationships. Neobiota can further be divided into neozoa (also: neozoons, sing. neozoon, i.e. animals) and neophyt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vulnerable Species
A vulnerable species is a species which has been Conservation status, categorized by the International Union for Conservation of Nature as being threatened species, threatened with extinction unless the circumstances that are threatened species, threatening its survival and reproduction improve. Vulnerability is mainly caused by habitat loss or destruction of the species' home. Vulnerable habitat or species are monitored and can become increasingly threatened. Some species listed as "vulnerable" may be common in captivity (animal), captivity, an example being the military macaw. There are currently 5196 animals and 6789 plants classified as Vulnerable, compared with 1998 levels of 2815 and 3222, respectively. Practices such as cryoconservation of animal genetic resources have been enforced in efforts to conserve vulnerable breeds of livestock specifically. Criteria The International Union for Conservation of Nature uses several criteria to enter species in this category. A tax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outcrossing
Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity. Outcrossing can be a useful technique in Animal husbandry, animal breeding. The outcrossing breeder intends to remove the traits by using "new blood." With dominant traits, one can still see the expression of the traits and can remove those traits whether one outcrosses, line breeds or inbreeds. With recessive traits, outcrossing allows for the recessive traits to migrate across a population. Many traits are Mendelian and therefore exhibit a more complicated intermediate phenotype. The outcrossing breeder then may have individuals that have many deleterious genes that may be expressed by subsequent inbreeding. There is now a gamut of deleterious genes within each individual in many dog breeds. Increasing the variation of genes or alleles within the gene pool may pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterozygotes
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal sex-determination system. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous. The DNA sequence of a gene often varies from one individual to another. These gene variants are called alleles. While some gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autogamy
Autogamy, or self-fertilization, refers to the fusion of two gametes that come from one individual. Autogamy is predominantly observed in the form of self-pollination, a reproductive mechanism employed by many flowering plants. However, species of protists have also been observed using autogamy as a means of reproduction. Flowering plants engage in autogamy regularly, while the protists that engage in autogamy only do so in stressful environments. Occurrence Protists ''Paramecium aurelia'' ''Paramecium aurelia'' is the most commonly studied protozoan for autogamy. Similar to other unicellular organisms, ''Paramecium aurelia'' typically reproduce asexually via binary fission or sexually via cross-fertilization. However, studies have shown that when put under nutritional stress, ''Paramecium aurelia'' will undergo meiosis and subsequent fusion of gametic-like nuclei. This process, defined as hemixis, a chromosomal rearrangement process, takes place in a number of steps. First, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxonomy
Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. Among other things, a taxonomy can be used to organize and index knowledge (stored as documents, articles, videos, etc.), such as in the form of a library classification system, or a search engine taxonomy, so that users can more easily find the information they are searching for. Many taxonomies are hierarchies (and thus, have an intrinsic tree structure), but not all are. Originally, taxonomy referred only to the categorisation of organisms or a particular categorisation of organisms. In a wider, more general sense, it may refer to a categorisation of things or concepts, as well as to the principles underlying such a categorisation. Taxonomy organizes taxonomic units known as "taxa" (singular "taxon")." Taxonomy is different from me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keel (slug)
Slug, or land slug, is a common name for any apparently shell-less terrestrial molluscs, terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a small internal shell, particularly Opisthobranchia, sea slugs and semislugs (this is in contrast to the common name ''snail'', which applies to gastropods that have a coiled shell large enough that they can fully retract their soft parts into it). Various Taxonomy (biology), taxonomic families of land slugs form part of several quite different evolutionary lineages, which also include snails. Thus, the various families of slugs are not closely related, despite a superficial similarity in the overall body form. The shell-less condition has arisen many times independently as an example of convergent evolution, and thus the category "slug" is Polyphyly, polyphyletic. Taxonomy Of the six orders of Pulmonata, two – the Onch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
