|
Neolamprologus Walteri
''Neolamprologus'' is a genus of cichlids endemic to eastern Africa with all but one species, '' Neolamprologus devosi'' from the Malagarasi River, occurring in Lake Tanganyika. It is the largest genus of cichlids in Lake Tanganyika and also the largest genus in the tribe Lamprologini, which includes '' Altolamprologus'', ''Chalinochromis'', '' Julidochromis'', ''Lamprologus'', '' Lepidiolamprologus'', ''Telmatochromis'' and '' Variabilichromis''. The latter is a monotypic genus doubtfully distinct from ''Neolamprologus''. It is already known for some time that according to mtDNA sequence analysis, this genus is very probably polyphyletic. It is likely that it will be revised eventually; if ''Variabilichromis'' is split off, at least some of the more ancient lineages currently placed in ''Neolamprologus'' are probably worthy of separation also. However, the morphological similarity and numerous undescribed species do not make analyses easier, and as with many cichlids, recen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neolamprologus Brichardi
''Neolamprologus brichardi'' is a species of cichlid endemic to the alkaline waters of Lake Tanganyika in East Africa. It is a popular aquarium fish kept in the fishkeeping hobby, where it is known under a variety of common names including Princess cichlid, Princess of Burundi, Lyretail cichlid, Fairy cichlid and Brichard's lamprologus.Axelrod HR, Vorderwinkler W (1995) ''Encyclopedia of tropical fishes''. 30th edition. Tropical Fish Hobbyist Publications, USA. In addition, the species is also the subject of numerous studies on fish behaviour. It is closely related to '' N. pulcher'' from the southern half of Lake Tanganyika (''N. brichardi'' is more widespread) and some have recommended merging the two into a single species.Duftner; Sefc; Koblmüller; Taborsky; and Sturmbauer (2007). Parallel evolution of facial stripe patterns in the Neolamprologus brichardi/pulcher species complex endemic to Lake Tanganyika. Molecular Phylogenetics and Evolution 45: 706–715. Behaviour ''N. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monotypic
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispecific" or "monospecific" is sometimes preferred. In botanical nomenclature, a monotypic genus is a genus in the special case where a genus and a single species are simultaneously described. In contrast, an oligotypic taxon contains more than one but only a very few subordinate taxa. Examples Just as the term ''monotypic'' is used to describe a taxon including only one subdivision, the contained taxon can also be referred to as monotypic within the higher-level taxon, e.g. a genus monotypic within a family. Some examples of monotypic groups are: Plants * In the order Amborellales, there is only one family, Amborellaceae and there is only one genus, '' Amborella'', and in this genus there is only one species, namely ''Amborella trichopoda. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neolamprologus Multifasciatus 3
''Neolamprologus'' is a genus of cichlids endemic to eastern Africa with all but one species, ''Neolamprologus devosi'' from the Malagarasi River, occurring in Lake Tanganyika. It is the largest genus of cichlids in Lake Tanganyika and also the largest genus in the tribe Lamprologini, which includes ''Altolamprologus'', ''Chalinochromis'', ''Julidochromis'', ''Lamprologus'', ''Lepidiolamprologus'', ''Telmatochromis'' and '' Variabilichromis''. The latter is a monotypic genus doubtfully distinct from ''Neolamprologus''. It is already known for some time that according to mtDNA sequence analysis, this genus is very probably polyphyletic. It is likely that it will be revised eventually; if ''Variabilichromis'' is split off, at least some of the more ancient lineages currently placed in ''Neolamprologus'' are probably worthy of separation also. However, the morphological similarity and numerous undescribed species do not make analyses easier, and as with many cichlids, recent specia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neolamprologus Cylindricus
''Neolamprologus cylindricus'' is a species of cichlid endemic to Lake Tanganyika where it is only known to occur in the southeastern part of the lake. It prefers to live in recesses in the substrate and eats small benthic invertebrates. It lays its eggs in caves. It keeps close to the rocky bottom of the lake, mainly in depths less than . This species can reach a length of TL. This species can also be found in the aquarium trade. References *Konings, A., 1998. Tanganyika cichlids in their natural habitat. Cichlid Press. 272 p. Fish described in 1986 Taxa named by Wolfgang Staeck Taxa named by Lothar Seegers Fish of Tanzania Fish of Zambia cylindricus {{Lamprologini-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isolating Mechanisms
The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offspring are sterile. These barriers maintain the integrity of a species by reducing gene flow between related species.Strickberger, M. 1978. ''Genética''. Omega, Barcelona, España, p.: 874-879. .Futuyma, D. 1998. ''Evolutionary biology'' (3ª edición). Sinauer, Sunderland. The mechanisms of reproductive isolation have been classified in a number of ways. Zoologist Ernst Mayr classified the mechanisms of reproductive isolation in two broad categories: pre-zygotic for those that act before fertilization (or before mating in the case of animals) and post-zygotic for those that act after it.Mayr, E. 1963. ''Animal species and evolution''. Harvard University Press, Cambridge. The mechanisms are genetically controlled and can appear in species whose ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Flow
In population genetics, gene flow (also known as gene migration or geneflow and allele flow) is the transfer of genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalent allele frequencies and therefore can be considered a single effective population. It has been shown that it takes only "one migrant per generation" to prevent populations from diverging due to drift. Populations can diverge due to selection even when they are exchanging alleles, if the selection pressure is strong enough. Gene flow is an important mechanism for transferring genetic diversity among populations. Migrants change the distribution of genetic diversity among populations, by modifying allele frequencies (the proportion of members carrying a particular variant of a gene). High rates of gene flow can reduce the genetic differentiation between the two groups, increasing homogeneity. For this reason, gene flow has been thought to con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogeny
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. All life on Earth is part of a single phylogenetic tree, indicating common ancestry. In a ''rooted'' phylogenetic tree, each node with descendants represents the inferred most recent common ancestor of those descendants, and the edge lengths in some trees may be interpreted as time estimates. Each node is called a taxonomic unit. Internal nodes are generally called hypothetical taxonomic units, as they cannot be directly observed. Trees are useful in fields of biology such as bioinformatics, systematics, and phylogenetics. ''Unrooted'' trees illustrate only the relatedness of the leaf nodes and do not require the ancestral root to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NDNA
Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the DNA contained within each cell nucleus of a eukaryotic organism. It encodes for the majority of the genome in eukaryotes, with mitochondrial DNA and plastid DNA coding for the rest. It adheres to Mendelian inheritance, with information coming from two parents, one male and one female—rather than matrilineally (through the mother) as in mitochondrial DNA. Structure Nuclear DNA is a nucleic acid, a polymeric biomolecule or biopolymer, found in the nucleus of eukaryotic cells. Its structure is a double helix, with two strands wound around each other, a structure first described by Francis Crick and James D. Watson (1953) using data collected by Rosalind Franklin. Each strand is a long polymer chain of repeating nucleotides. Each nucleotide is composed of a five-carbon sugar, a phosphate group, and an organic base. Nucleotides are distinguished by their bases: purines, large bases that include adenine and guanine; and pyr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid (biology)
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in blending inheritance), but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are. Species are reproductively isolated by strong barriers to hybridisation, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization and others after it. Similar barriers exist in plants, with differences in flowering tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speciation
Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within lineages. Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book ''On the Origin of Species''. He also identified sexual selection as a likely mechanism, but found it problematic. There are four geographic modes of speciation in nature, based on the extent to which speciating populations are isolated from one another: allopatric speciation, allopatric, peripatric speciation, peripatric, parapatric speciation, parapatric, and sympatric speciation, sympatric. Speciation may also be induced artificially, through animal husbandry, agriculture, or laboratory experiments of speciation, laboratory experiments. Whether genetic drift is a minor or major contributor to speciation is the subject of much ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Undescribed Species
In taxonomy, an undescribed taxon is a taxon (for example, a species) that has been discovered, but not yet formally described and named. The various Nomenclature Codes specify the requirements for a new taxon to be validly described and named. Until such a description has been published, the taxon has no formal or official name, although a temporary, informal name is often used. A published scientific name may not fulfil the requirements of the Codes for various reasons. For example, if the taxon was not adequately described, its name is called a '' nomen nudum''. It is possible for a taxon to be "undescribed" for an extensive period of time, even if unofficial descriptions are published. An undescribed species may be referred to with the genus name, followed by "sp"., but this abbreviation is also used to label specimens or images that are too incomplete to be identified at the species level. In some cases, there is more than one undescribed species in a genus. In this case, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morphology (biology)
Morphology is a branch of biology dealing with the study of the form and structure of organisms and their specific structural features. This includes aspects of the outward appearance (shape, structure, colour, pattern, size), i.e. external morphology (or eidonomy), as well as the form and structure of the internal parts like bones and organs, i.e. internal morphology (or anatomy). This is in contrast to physiology, which deals primarily with function. Morphology is a branch of life science dealing with the study of gross structure of an organism or taxon and its component parts. History The etymology of the word "morphology" is from the Ancient Greek (), meaning "form", and (), meaning "word, study, research". While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Friedrich Burdach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Speciation")
