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Senecio Gregorii
''Senecio gregorii'', commonly known as annual yellowtop or fleshy groundsel, is a native Australian wildflower species, found in arid and semi-arid regions of the Australia and across the globe. It often grows prolifically after autumn/winter rains, showcasing stunning yellow flowers and fleshy foliage. The scientific name of this species was first published by Ferdinand von Mueller. Description ''Senecio gregorii'' is an erect annual herb that ranges from 15 to 40 centimetres in height. Its stem is simple or branched, with leaves that are broad, linear and up to 9 centimetres long. The leaves can have a succulent appearance, although this varies among the species. It produces clusters of bright yellow flowers that appear from May through to October. Seeds are distributed by wind after the flower sets seed. ''S. gregorii'' reproduces sexually. ''Senecio gregorii'' is distributed predominantly across arid to semi-arid inland Australia. It can tolerate unstable environments and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferdinand Von Mueller
Baron Sir Ferdinand Jacob Heinrich von Mueller, (german: Müller; 30 June 1825 – 10 October 1896) was a German-Australian physician, geographer, and most notably, a botanist. He was appointed government botanist for the then colony of Victoria (Australia) by Governor Charles La Trobe in 1853, and later director of the Royal Botanic Gardens, Melbourne. He also founded the National Herbarium of Victoria. He named many Australian plants. Early life Mueller was born at Rostock, in the Grand Duchy of Mecklenburg-Schwerin. After the early death of his parents, Frederick and Louisa, his grandparents gave him a good education in Tönning, Schleswig. Apprenticed to a chemist at the age of 15, he passed his pharmaceutical examinations and studied botany under Professor Ernst Ferdinand Nolte (1791–1875) at Kiel University. In 1847, he received his degree of Doctor of Philosophy from Kiel for a thesis on the plants of the southern regions of Schleswig. Mueller's sister Bertha had be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Othonna
''Othonna'' is a genus of approximately 90 species of succulent or subsucculent perennial herbs or shrubs, with its center of diversity in the Greater Cape Floristic Region (GCFR) of South Africa but some species' ranges include southern Namibia, Angola, and Zimbabwe. The genus was established by Linnaeus in 1753 containing 14 species, however, of those original species, only four are still retained in ''Othonna'', while the others have been transferred to different genera including ''Cineraria'', ''Euryops'', ''Hertia (plant), Hertia'', ''Ligularia'', ''Senecio'', and ''Tephroseris''. The genus Othonnna is known to be monophyletic. In 2012, a new genus ''Crassothonna'' B. Nord. was erected with 13 species transferred from ''Othonna''. A complete modern taxonomic treatment of the genus is being undertaken by the Kirstenbosch National Botanical Garden, Compton Herbarium and the South African National Biodiversity Institute. The first part, a revision of the ''Othonnna bulbosa'' group ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybridisation (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] |
Polyploidy
Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei ( eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contains one or more chromosomes and comes from each of two parents, resulting in pairs of homologous chromosomes between sets. However, some organisms are polyploid. Polyploidy is especially common in plants. Most eukaryotes have diploid somatic cells, but produce haploid gametes (eggs and sperm) by meiosis. A monoploid has only one set of chromosomes, and the term is usually only applied to cells or organisms that are normally diploid. Males of bees and other Hymenoptera, for example, are monoploid. Unlike animals, plants and multicellular algae have life cycles with two alternating multicellular generations. The gametophyte generation is haploid, and produces gametes by mitosis, the sporophyte generation is diploid and produces spores by mei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local Adaptation
Local adaptation is a mechanism in evolutionary biology whereby a population of organisms evolves to be more well-suited to its local environment than other members of the same species that live elsewhere. Local adaptation requires that different populations of the same species experience different natural selection. For example, if a species lives across a wide range of temperatures, populations from warm areas may have better heat tolerance than populations of the same species that live in the cold part of its geographic range. Definition More formally, a population is said to be locally adapted if organisms in that population have evolved different phenotypes than other populations of the same species, and local phenotypes have higher fitness in their home environment compared to individuals that originate from other locations in the species range. This is sometimes called 'home site advantage'. A stricter definition of local adaptation requires 'reciprocal home site advantage' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptive Radiation
In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, alters biotic interactions or opens new environmental niches. Starting with a single ancestor, this process results in the speciation and phenotypic adaptation of an array of species exhibiting different morphological and physiological traits. The prototypical example of adaptive radiation is finch speciation on the Galapagos ("Darwin's finches"), but examples are known from around the world. Characteristics Four features can be used to identify an adaptive radiation: #A common ancestry of component species: specifically a ''recent'' ancestry. Note that this is not the same as a monophyly in which ''all'' descendants of a common ancestor are included. #A phenotype-environment correlation: a ''significant'' association between environments and the morp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrrolizidine Alkaloids
Pyrrolizidine alkaloids (PAs), sometimes referred to as necine bases, are a group of naturally occurring alkaloids based on the structure of pyrrolizidine. Pyrrolizidine alkaloids are produced by plants as a defense mechanism against insect herbivores. More than 660 PAs and PA N-oxides have been identified in over 6,000 plants, and about half of them exhibit hepatotoxicity. They are found frequently in plants in the Boraginaceae, Asteraceae, Orchidaceae and Fabaceae families; less frequently in the Convolvulaceae and Poaceae, and in at least one species in the Lamiaceae. It has been estimated that 3% of the world’s flowering plants contain pyrrolizidine alkaloids. Honey can contain pyrrolizidine alkaloids, as can grains, milk, offal and eggs. To date (2011), there is no international regulation of PAs in food, unlike those for herbs and medicines. Unsaturated pyrrolizidine alkaloids are hepatotoxic, that is, damaging to the liver. PAs also cause hepatic veno-occlusive disea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halictidae
Halictidae is the second-largest family of bees (clade Anthophila) with nearly 4,500 species. Halictid species are an extremely diverse group that can vary greatly in appearance. These bees occur all over the world and are found on every continent except Antarctica. Usually dark-colored (frequently brown or black) and often metallic, halictids are found in various sizes, colors and patterns. Several species are all or partly green and a few are red, purple, or blue. A number of them have yellow markings, especially the males, which commonly have yellow faces, a pattern widespread among the various families of bees. The family is one of many with short tongues and is best distinguished by the arcuate (strongly curved) basal vein found on the wing. Females in this family tend to be larger than the males. They are commonly referred to as "sweat bees" (especially the smaller species), as they are often attracted to perspiration. Ecology Most halictids nest in the ground, often in ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch. During the Early Miocene, the Arabian Peninsula collided with Eurasia, severing the connection between the Mediterranean and Indian Ocean, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. During the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Claypan
Claypan is a dense, compact, slowly permeable layer in the subsoil. It has a much higher clay content than the overlying material, from which it is separated by a sharply defined boundary. The dense structure restricts root growth and water infiltration. Therefore, a perched water table might form on top of the claypan. In the Canadian classification system, claypan is defined as a clay-enriched illuvial B (Bt) horizon. Location Claypan is present in a wide area of the central United States (about 4 million ha) across multiple states such as Kansas, Oklahoma, and Illinois. It can also be found in Australia throughout the south-west Queensland. Formation Claypan is formed in different parent materials depending on geological locations, such as floodplains. The formation of the claypan relates to a lack of vegetation coverage, soil particle size distribution, and high rainfall. The lack of vegetation coverage makes soil become more susceptible to raindrop attacks. When the raindro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Near Threatened (NT)
A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify for the threatened status. The IUCN notes the importance of re-evaluating near-threatened taxon at appropriate intervals. The rationale used for near-threatened taxa usually includes the criteria of vulnerable which are plausible or nearly met, such as reduction in numbers or range. Near-threatened species evaluated from 2001 onwards may also be ones which are dependent on conservation efforts to prevent their becoming threatened, whereas before this conservation-dependent species were given a separate category ("Conservation Dependent"). Additionally, the 402 conservation-dependent taxa may also be considered near-threatened. IUCN Categories and Criteria version 2.3 Before 2001, the IUCN used the version 2.3 Categories and Criteria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Least-concern Species
A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. They do not qualify as threatened, near threatened, or (before 2001) conservation dependent. Species cannot be assigned the "Least Concern" category unless they have had their population status evaluated. That is, adequate information is needed to make a direct, or indirect, assessment of its risk of extinction based on its distribution or population status. Evaluation Since 2001 the category has had the abbreviation "LC", following the IUCN 2001 Categories & Criteria (version 3.1). Before 2001 "least concern" was a subcategory of the "Lower Risk" category and assigned the code "LR/lc" or lc. Around 20% of least concern taxa (3261 of 15636) in the IUCN database still use the code "LR/lc", which indicates they have not been re-evaluate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
