Group size measures
Many animals, including humans, tend to live in groups, flocks, packs, shoals, or colonies of conspecific individuals. The size of these groups, as expressed by the number of people/etc in a group such as 8 groups of 9 people in each one, is an important aspect of their social environment. Group size tend to be variable within the same species, thus we need statistical measures to quantify group size and statistical tests to compare these measures between two or more samples. Group size measures are notoriously hard to handle statistically since groups sizes follow an aggregated distribution: most groups are small, few are large, a few are large. Statistical measures of group size fall into two categories. Group size is the number of individuals within a group; as Jarman pointed out, average individuals live in groups larger than average. Therefore, when we wish to characterize a typical individual’s social environment, we should apply non-parametric estimations of group size. Reiczigel et al. proposed the following measures: Crowding is the size of a group that a particular individual lives in.
It describes the social environment of one particular individual. This was called Individual Group Size in Jovani & Mavor's paper.. Imagine a sample with 3 groups, where group sizes are 1, 2, 6 individuals then mean group size equals / 3 = 3. Speaking, given there are G groups with sizes n1, n2... nG, mean crowding can be calculated as: mean crowding= ∑ i = 1 G n i 2 / ∑ i = 1 G n i Due to the aggregated distribution of group members among groups, the application of parametric statistics would be misleading. Another problem arises. Crowding data consist of non-independent values, or ties, which show multiple and simultaneous changes due to a single biological event. Reiczigel et al. discuss the statistical problems associated with group size measures and offer a free statistical toolset. Debout G 2003. Le corbeau freux nicheur en Normandie: recensement 1999 & 2000. Cormoran, 13, 115–121. Jarman PJ 1974; the social organisation of antelope in relation to their ecology. Behaviour, 48, 215–268. Jovani R, Mavor R 2011.
Group size versus individual group size frequency distributions: a nontrivial distinction. Animal Behaviour, 82, 1027–1036. Lengyel S, Tar J, Rozsa L 2012. Flock size measures of migrating Lesser White-fronted Geese Anser erythropus Acta Zoologica Academiae Scientiarum Hungaricae, 58, 297–303. Reiczigel J, Lang Z, Rózsa L, Tóthmérész B 2008. Measures of sociality: two different views of group size. Animal Behaviour, 75, 715–721. Reiczigel J, Mejía Salazar MF, Bollinger TK, Rozsa L 2015. Comparing radio-tracking and visual detection methods to quantify group size measures. European Journal of Ecology, 1, 1–4. Size of groups and communities Flocker 1.1 – a statistical toolset to analyze group size measures
The lesser frigatebird is a seabird of the frigatebird family Fregatidae. At around 75 cm in length, it is the smallest species of frigatebird, it occurs over tropical and subtropical waters across the Indian and Pacific Oceans as well as off the Atlantic coast of Brazil. The lesser frigatebird is a built seabird with brownish-black plumage, long narrow wings and a forked tail; the male has a striking red gular sac. The female is larger than the male and has a white breast and belly. Frigatebirds feed on fish taken in flight from the ocean's surface, sometimes indulge in kleptoparasitism, harassing other birds to force them to regurgitate their food; the lesser frigatebird was first described as Atagen ariel by the English zoologist George Gray in 1845 from a specimen collected on Raine Island, Australia. The lesser frigatebird is one of five related species belonging to the genus Fregata; the other four are: the great frigatebird, the Christmas frigatebird, the magnificent frigatebird and the Ascension frigatebird.
The genus is the only member of the Fregatidae family. Three subspecies are recognised: F. a. ariel occurs in the central and eastern Indian Ocean, the seas off South East Asian and from northern Australia to the west and central Pacific Ocean. F. a. iredalei named by the Australian ornithologist Gregory Mathews in 1914. It occurs in the western breeds on the Aldabra atoll. F. a. trinitatis was named by the Brazilian zoologist Alípio de Miranda-Ribeiro in 1919. It occurs in the South Atlantic off the coast of breeds on the Trindade Archipelago, it has disappeared as a breeding bird from the main island, but small numbers remain on a small offshore islet. Some ornithologists have questioned the validity of these subspecies as they appeared to differ only in their size. Few museum specimens of the isolated Atlantic F. a. trinitatis exists, making comparisons difficult, but a comprehensive study published in 2017 found that it differed in both color of plumage and skeletal details, leading to the recommendation of treating it as a separate species.
The lesser frigatebird is the smallest species of frigatebird and measures 66–81 cm in length with a wingspan of 155–193 cm and long forked tails. Male birds weight 625–875 g. Female birds are heavier and weight 760–955 grams. Like all frigatebirds the male has a large red sac on the front of the throat, inflated during courtship. Courtship display involves a variety of calls, bill rattling and spreading of the wings; the male is all black save for a white patch on the flank which extends on to the underwing as a spur. Males have a pale bar on the upper wing. Females have a black head and neck with a white collar and breast as well as a spur extending on to the underwing; the female has a narrow red ring around the eye. Juveniles and immature birds are more difficult to differentiate but the presence of the spurs of white in the armpits is a helpful distinguishing sign. Frigate birds are built for flying, they have a light skeleton and long narrow wings and are masters of the air. Their name derives from the fact that they harass other sea birds such as boobies and tropicbirds as they return to their nests from feeding, forcing them to disgorge their catch, swooped upon and caught by the frigate birds before it reaches the water below.
This practice seems to be more common among female frigate birds, but only accounts for a small proportion of the diet, which consists of squid and flying fish scooped up from the surface of the sea. The lesser frigatebird is said to be the most widespread frigatebird in Australian seas, it is common in tropical seas, breeding on remote islands, including Christmas Island in the Indian Ocean in recent years. These birds are most to be seen from the mainland prior to the onset of a tropical cyclone, once this abates they disappear again. Breeding seems to occur between December in the Australian region, they nest in trees and both sexes contribute to nest building and incubation and feeding of the young. One egg is laid -- 7 weeks to hatch. Fledglings are not left alone for another seven weeks or so for fear that they may be attacked and eaten by other birds including other frigate birds, they remain in the nest for another 6 months or so until fledged but they are cared for and fed by their parents for quite a long time after that.
The total world population is estimated to be several hundred thousand birds. At least 6,000 pairs breed on the Aldabra Islands in the Indian Ocean and another 15,000 pairs breed on islands off the north coast of Australia; the largest colonies are on the Phoenix Islands and Line Islands in the central Pacific Ocean. Nests placed on the ground are vulnerable to predation by introduced species such as feral cats; the elimination of cats from Howland and Jarvis Islands has led to the reestablishment and growth of colonies. Baker Island had no nesting lesser frigatebirds in 1965 but after the elimination of the feral cats on the island in around 1970 the birds returned and in 2002 16,200 individuals were recorded; because of the large overall population and extended range the species is classified by the International Union for Conservation of Nature as being of Least Concern. In the South Atlantic, lesser frigatebirds once bred on Fernando de
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. While these definitions may seem adequate, when looked at more they represent problematic species concepts. For example, the boundaries between related species become unclear with hybridisation, in a species complex of hundreds of similar microspecies, in a ring species. Among organisms that reproduce only asexually, the concept of a reproductive species breaks down, each clone is a microspecies. All species are given a two-part name, a "binomial"; the first part of a binomial is the genus.
The second part is called the specific epithet. For example, Boa constrictor is one of four species of the genus Boa. None of these is satisfactory definitions, but scientists and conservationists need a species definition which allows them to work, regardless of the theoretical difficulties. If species were fixed and distinct from one another, there would be no problem, but evolutionary processes cause species to change continually, to grade into one another. Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped. Charles Darwin's 1859 book The Origin of Species explained how species could arise by natural selection; that understanding was extended in the 20th century through genetics and population ecology. Genetic variability arises from mutations and recombination, while organisms themselves are mobile, leading to geographical isolation and genetic drift with varying selection pressures.
Genes can sometimes be exchanged between species by horizontal gene transfer. Viruses are a special case, driven by a balance of mutation and selection, can be treated as quasispecies. Biologists and taxonomists have made many attempts to define species, beginning from morphology and moving towards genetics. Early taxonomists such as Linnaeus had no option but to describe what they saw: this was formalised as the typological or morphological species concept. Ernst Mayr emphasised reproductive isolation, but this, like other species concepts, is hard or impossible to test. Biologists have tried to refine Mayr's definition with the recognition and cohesion concepts, among others. Many of the concepts are quite similar or overlap, so they are not easy to count: the biologist R. L. Mayden recorded about 24 concepts, the philosopher of science John Wilkins counted 26. Wilkins further grouped the species concepts into seven basic kinds of concepts: agamospecies for asexual organisms biospecies for reproductively isolated sexual organisms ecospecies based on ecological niches evolutionary species based on lineage genetic species based on gene pool morphospecies based on form or phenotype and taxonomic species, a species as determined by a taxonomist.
A typological species is a group of organisms in which individuals conform to certain fixed properties, so that pre-literate people recognise the same taxon as do modern taxonomists. The clusters of variations or phenotypes within specimens would differentiate the species; this method was used as a "classical" method of determining species, such as with Linnaeus early in evolutionary theory. However, different phenotypes are not different species. Species named in this manner are called morphospecies. In the 1970s, Robert R. Sokal, Theodore J. Crovello and Peter Sneath proposed a variation on this, a phenetic species, defined as a set of organisms with a similar phenotype to each other, but a different phenotype from other sets of organisms, it differs from the morphological species concept in including a numerical measure of distance or similarity to cluster entities based on multivariate comparisons of a reasonably large number of phenotypic traits. A mate-recognition species is a group of sexually reproducing organisms that recognize one another as potential mates.
Expanding on this to allow for post-mating isolation, a cohesion species is the most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic cohesion mechanisms. A further development of the recognition concept is provided by the biosemiotic concept of species. In microbiology, genes can move even between distantly related bacteria extending to the whole bacterial domain; as a rule of thumb, microbiologists have assumed that kinds of Bacteria or Archaea with 16S ribosomal RNA gene sequences more similar than 97% to each other need to be checked by DNA-DNA hybridisation to decide if they belong to the same species or not. This concept was narrowed in 2006 to a similarity of 98.7%. DNA-DNA hybri
Johann Jakob von Tschudi
Johann Jakob von Tschudi was a Swiss naturalist and diplomat. Tschudi was born in Glarus, studied natural sciences and medicine at the universities of Neuchâtel and Paris. In 1838 he travelled to Peru, where he remained for five years exploring and collecting plants in the Andes, he went to Vienna in 1843. In 1845 he described 18 new species of South American reptiles. Between 1857 and 1859 he visited other countries in South America. In 1860 he was appointed Swiss ambassador to Brazil, remaining so until 1868, again spent time exploring the country and collecting plants for the museums of Neuchâtel and Freiburg. In 1868 he became minister to Vienna, he wrote a textbook on Peru called Peruvian antiquities in which he recorded various aspects of Peruvian life and history. In his book he explained the various skull angles of Peruvians in the context of the Angle of Camper. Tschudi claimed that Camper's facial angles were an "important angle in anthropology", whose "greater or less opening indicates the intellectual superiority of a race, and, up to a certain point, of individuals".
He went on to explain that he had obtained for his personal collection the mummified foetus of a woman at seven months found in the cave of "Huichay", included two engravings of it, to prove that the shape of the cranium of the Huancas was not due to pressures placed upon the cranium after birth for cultural reasons. Tschudi is commemorated in the scientific name of a species of venomous South American coral snake, Micrurus tschudii. Classification der Batrachier, mit Berucksichtigung der fossilen Thiere dieser A btheilung der Reptilien Untersuchungen über die Fauna Perus "Reptilium conspectus quae in Republica Peruana reperiuntur et pleraque observata vel collecta sunt in itinere". Archiv für Naturgeschichte 11: 150-170. Peruanische Reiseskizzen während der Jahre 1838-42 Die Ketchua-Sprache Reise durch die Andes von Südamerika Die brasilianische Provinz Minas-Geraes Reisen durch Südamerika Organismus der Khets̆ua-Sprache He edited, in association with Mariano Eduardo de Rivera, Antigüedades Peruanas.
Wilson, J. G.. "Tschudi, Johann Jakob von". Appletons' Cyclopædia of American Biography. New York: D. Appleton. "Johann Jakob von Tschudi," in Tom Taylor and Michael Taylor, Aves: A Survey of the Literature of Neotropical Ornithology, Baton Rouge: Louisiana State University Libraries, 2011. Works by Johann Jakob von Tschudi at Project Gutenberg Works by or about Johann Jakob von Tschudi at Internet Archive
In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. Other well-known ranks are life, kingdom, class, family and species, with order fitting in between class and family. An higher rank, may be added directly above order, while suborder would be a lower rank. A taxonomic unit, a taxon, in that rank. In that case the plural is orders. Example: All owls belong to the order StrigiformesWhat does and does not belong to each order is determined by a taxonomist, as is whether a particular order should be recognized at all. There is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in recognizing an order; some taxa are accepted universally, while others are recognised only rarely. For some groups of organisms, consistent suffixes are used to denote; the Latin suffix -formes meaning "having the form of" is used for the scientific name of orders of birds and fishes, but not for those of mammals and invertebrates.
The suffix -ales is for the name of orders of plants and algae. For some clades covered by the International Code of Zoological Nomenclature, a number of additional classifications are sometimes used, although not all of these are recognised. In their 1997 classification of mammals, McKenna and Bell used two extra levels between superorder and order: "grandorder" and "mirorder". Michael Novacek inserted them at the same position. Michael Benton inserted them between magnorder instead; this position was adopted by others. In botany, the ranks of subclass and suborder are secondary ranks pre-defined as above and below the rank of order. Any number of further ranks can be used as long as they are defined; the superorder rank is used, with the ending -anae, initiated by Armen Takhtajan's publications from 1966 onwards. The order as a distinct rank of biological classification having its own distinctive name was first introduced by the German botanist Augustus Quirinus Rivinus in his classification of plants that appeared in a series of treatises in the 1690s.
Carl Linnaeus was the first to apply it to the division of all three kingdoms of nature in his Systema Naturae. For plants, Linnaeus' orders in the Systema Naturae and the Species Plantarum were artificial, introduced to subdivide the artificial classes into more comprehensible smaller groups; when the word ordo was first used for natural units of plants, in 19th century works such as the Prodromus of de Candolle and the Genera Plantarum of Bentham & Hooker, it indicated taxa that are now given the rank of family. In French botanical publications, from Michel Adanson's Familles naturelles des plantes and until the end of the 19th century, the word famille was used as a French equivalent for this Latin ordo; this equivalence was explicitly stated in the Alphonse De Candolle's Lois de la nomenclature botanique, the precursor of the used International Code of Nomenclature for algae and plants. In the first international Rules of botanical nomenclature from the International Botanical Congress of 1905, the word family was assigned to the rank indicated by the French "famille", while order was reserved for a higher rank, for what in the 19th century had been named a cohors.
Some of the plant families still retain the names of Linnaean "natural orders" or the names of pre-Linnaean natural groups recognised by Linnaeus as orders in his natural classification. Such names are known as descriptive family names. In zoology, the Linnaean orders were used more consistently; that is, the orders in the zoology part of the Systema Naturae refer to natural groups. Some of his ordinal names are still in use. In virology, the International Committee on Taxonomy of Viruses's virus classification includes fifteen taxa: realm, kingdom, phylum, class, order, family, genus and species, to be applied for viruses and satellite nucleic acids. There are each ending in the suffix - virales. Biological classification Cladistics Phylogenetics Rank Rank Systematics Taxonomy Virus classification McNeill, J.. R.. R.. L.. S.. F.. F.. H.. J.. International Code of Nomenclature for algae and plants adopted by the Eighteenth International Botanical Congress Melbourne, July 2011. Regnum Vegetabile 154. A. R.
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The masked booby is a large seabird of the booby family, Sulidae. First described by French naturalist René-Primevère Lesson in 1831, the masked booby is one of six species of booby in the genus Sula; this species breeds except in the eastern Atlantic. It is called the masked gannet or the blue-faced booby; the masked booby nests in small colonies, laying two chalky white eggs on sandy beaches in shallow depressions. The first chick kills the second one. French naturalist René-Primevère Lesson described the masked booby in 1829 in Louis Isidore Duperrey's work Voyage autour du Monde, Exécuté par Ordre du Roi, Sur la Corvette de Sa Majesté, La Coquille, pendant les années 1822, 1823, 1824 et 1825, after encountering it in Ascension Island in the South Atlantic; the species name is from the Ancient Greek word dactyl "finger" and Latin ater "black". "Black fingers" refers to the splayed wingtips in flight. Swedish zoologist Carl Jakob Sundevall described it as Dysporus cyanops in 1837, from a subadult collected in the Atlantic Ocean on 6 September 1827.
The species name was derived from the Ancient Greek words cyanos "blue", ops "face". John Gould described Sula personata in 1846 from Australia, the species name being the Latin adjective personata "masked". Gould adopted the name Sula cyanops in his 1865 Handbook to the Birds of Australia. Sundevall's binomial name was followed as Lesson's 1829 record did not sufficiently describe the species, however in 1911 Australian amateur ornithologist Gregory Mathews pointed out that although Lesson's 1829 account did not describe the bird, his 1831 account did and thus predated Sundevall by six years, hence Sula dactylactra had priority; the American Ornithological Union followed in their 17th supplement to their checklist in 1920."Masked booby" has been designated the official name by the International Ornithologists' Union. It has been called masked gannet, blue-faced booby, white booby, whistling booby. Australian ornithologist Doug Dorward promoted the name "white booby" as he felt the blue coloration of its face was less prominent than that of the red-footed booby.
The masked booby is one of six species of booby in the genus Sula. A genetic study using both nuclear and mitochondrial DNA showed the Masked and Nazca boobies to be each other's closest relatives, their lineage diverging from a line that gave rise to the blue-footed and Peruvian boobies; the masked and Nazca boobies were divergent enough to indicate the latter regarded as a subspecies of the former, should be classified as a separate species. Molecular evidence suggests they most diverged between 0.8 and 1.1 million years ago. Complex water currents in the eastern Pacific may have established an environmental barrier leading to speciation. Reviewing the genus, Rothschild recognised five subspecies. There is a clinal change in size across its range, where birds in the Atlantic are the smallest, with the size increasing westwards though the Pacific to the Indian Ocean, where the largest individuals are found. Four subspecies are recognized by the IOC. S. d. personata Gould, 1846: Austropacific masked boobyBreeds in the central and western Pacific and around Australia, as well as off Mexico and on Clipperton Island.
Birds of the latter two locations have been separated as subspecies californica, the north west Australian population has been named as subspecies bedouti, but neither is considered distinct. S. D. dactylatra Lesson, 1831: Atlantic masked boobyBreeds in the Caribbean and some Atlantic islands including Ascension Island. It has started breeding off Tobago being known in this area only from a single sight record from an oil rig off Trinidad. S. D. melanops Hartlaub, 1859: Western Indian Ocean masked boobyBreeds in the western Indian Ocean. Hartlaub described this taxon in 1859 from Maydh Island off the coast of Somalia near Maydh, he noted its black mask and blue-grey feet to be distinct from Sundevall's cyanops with a blue face, Lesson's dactylatra with yellow feet. The subspecies name is derived from the Ancient Greek words melas "black", ops "face". S. d. tasmani van Tets, Fullagar & Davidson, 1988: Tasman booby or Lord Howe masked boobyThe form breeding on Lord Howe and the Kermadec Islands. New Zealand naturalist Walter Oliver had noted that this bird had dark brown rather than pale irises since 1930, but it was not until 1990 that it was formally investigated by O'Brien and Davies and found to have longer wings than other populations as well.
They classified it as a new subspecies—S. D. fullagari—in 1990. Meanwhile, large prehistoric specimens known from the former and Norfolk Island were classified as a separate species—S. Tasmani—in 1988, thought to have become extinct from Polynesian and European seafarers and settlers; however and colleagues cast doubt on the distinctness of the fossil taxon in 2001, a 2010 review by Tammy Steeves and colleagues of the fossil material and DNA found the two overlapped and hence the extinct and living entities were found to be the same taxon, now known as S. d. tasmani as it has priority over S. d. fullagari. Fieldwork in the Kermadec Islands indicates the bills of adults are bright yellow, that adult males had brighter yellow feet than females; the largest species of booby, the masked booby ranges from 75 to 85 cm long, with a 160–170 cm wingspan and 1.2–2.2 kg weight. It has a typical sulid body shape, with a long pointed bill
Binomial nomenclature called binominal nomenclature or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomen, binominal name or a scientific name; the first part of the name – the generic name – identifies the genus to which the species belongs, while the second part – the specific name or specific epithet – identifies the species within the genus. For example, humans belong within this genus to the species Homo sapiens. Tyrannosaurus rex is the most known binomial; the formal introduction of this system of naming species is credited to Carl Linnaeus beginning with his work Species Plantarum in 1753. But Gaspard Bauhin, in as early as 1623, had introduced in his book Pinax theatri botanici many names of genera that were adopted by Linnaeus; the application of binomial nomenclature is now governed by various internationally agreed codes of rules, of which the two most important are the International Code of Zoological Nomenclature for animals and the International Code of Nomenclature for algae and plants.
Although the general principles underlying binomial nomenclature are common to these two codes, there are some differences, both in the terminology they use and in their precise rules. In modern usage, the first letter of the first part of the name, the genus, is always capitalized in writing, while that of the second part is not when derived from a proper noun such as the name of a person or place. Both parts are italicized when a binomial name occurs in normal text, thus the binomial name of the annual phlox is now written as Phlox drummondii. In scientific works, the authority for a binomial name is given, at least when it is first mentioned, the date of publication may be specified. In zoology "Patella vulgata Linnaeus, 1758"; the name "Linnaeus" tells the reader who it was that first published a description and name for this species of limpet. "Passer domesticus". The original name given by Linnaeus was Fringilla domestica; the ICZN does not require that the name of the person who changed the genus be given, nor the date on which the change was made, although nomenclatorial catalogs include such information.
In botany "Amaranthus retroflexus L." – "L." is the standard abbreviation used in botany for "Linnaeus". "Hyacinthoides italica Rothm. – Linnaeus first named this bluebell species Scilla italica. The name is composed of two word-forming elements: "bi", a Latin prefix for two, "-nomial", relating to a term or terms; the word "binomium" was used in Medieval Latin to mean a two-term expression in mathematics. Prior to the adoption of the modern binomial system of naming species, a scientific name consisted of a generic name combined with a specific name, from one to several words long. Together they formed a system of polynomial nomenclature; these names had two separate functions. First, to designate or label the species, second, to be a diagnosis or description. In a simple genus, containing only two species, it was easy to tell them apart with a one-word genus and a one-word specific name; such "polynomial names" may sometimes look like binomials, but are different. For example, Gerard's herbal describes various kinds of spiderwort: "The first is called Phalangium ramosum, Branched Spiderwort.
The other... is aptly termed Phalangium Ephemerum Virginianum, Soon-Fading Spiderwort of Virginia". The Latin phrases are short descriptions, rather than identifying labels; the Bauhins, in particular Caspar Bauhin, took some important steps towards the binomial system, by pruning the Latin descriptions, in many cases to two words. The adoption by biologists of a system of binomial nomenclature is due to Swedish botanist and physician Carl von Linné, more known by his Latinized name Carl Linnaeus, it was in his 1753 Species Plantarum that he first began using a one-word "trivial name" together with a generic name in a system of binomial nomenclature. This trivial name is what is now known as specific name; the Bauhins' genus names were retained in many of these, but the descriptive part was reduced to a single word. Linnaeus's trivial names introduced an important new idea, namely that the function of a name could be to give a species a unique label; this meant. Thus Gerard's Phalangium ephemerum virginianum became Tradescantia virgi