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Differential Fitness
Differential fitness is the third of Darwin's four postulates for natural selection. It states that survival and reproduction rates vary between individuals. Fitness differentials are widespread and detectable throughout nature. This fitness differential is visible in several ways, and it can be detected throughout nature. It can be based on behavioral differences that can act with or against environmental changes; one notable example was a 2014 study of snowshoe hares, where researchers found that white snowshoe hares did not change their behavior due to increased snow melt.Zimova M., Mills L.S., Lukacs P.M., and Mitchell M.S. (2014). Snowshoe hares display limited phenotypic plasticity to mismatch in seasonal camouflage. ''Proc of the Royal Society'' 281, (1782).https://doi.org/10.1098/rspb.2014.0029 Subsequent research found that brown hares survived and bred more than the white snowshoe hares.Nowak, Zimova M., Mills L.S., and Joshua J. (2016). High fitness costs of climate cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Darwin
Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended from a common ancestor is now generally accepted and considered a fundamental concept in science. In a joint publication with Alfred Russel Wallace, he introduced his scientific theory that this branching pattern of evolution resulted from a process he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. Darwin has been described as one of the most influential figures in human history and was honoured by burial in Westminster Abbey. Darwin's early interest in nature led him to neglect his medical education at the University of Edinburgh; instead, he helped to investigate marine invertebrates. His studies at the University of Cambridge's Christ's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproduction Rate
In epidemiology, the basic reproduction number, or basic reproductive number (sometimes called basic reproduction ratio or basic reproductive rate), denoted R_0 (pronounced ''R nought'' or ''R zero''), of an infection is the Expected value, expected number of cases directly generated by one case in a population where all individuals are Susceptible individual, susceptible to infection. The definition assumes that no other individuals are infected or Immunization, immunized (naturally or through vaccination). Some definitions, such as that of the Department of Health (Australia), Australian Department of Health, add the absence of "any deliberate intervention in disease transmission". The basic reproduction number is not necessarily the same as the effective reproduction number R (usually written R_t [''t'' for time], sometimes R_e), which is the number of cases generated in the current state of a population, which does not have to be the uninfected state. R_0 is a dimensionless n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fitness (biology)
Fitness (often denoted w or ω in population genetics models) is the quantitative representation of individual reproductive success. It is also equal to the average contribution to the gene pool of the next generation, made by the same individuals of the specified genotype or phenotype. Fitness can be defined either with respect to a genotype or to a phenotype in a given environment or time. The fitness of a genotype is manifested through its phenotype, which is also affected by the developmental environment. The fitness of a given phenotype can also be different in different selective environments. With asexual reproduction, it is sufficient to assign fitnesses to genotypes. With sexual reproduction, recombination scrambles alleles into different genotypes every generation; in this case, fitness values can be assigned to alleles by averaging over possible genetic backgrounds. Natural selection tends to make alleles with higher fitness more common over time, resulting in Darw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snowshoe Hares
The snowshoe hare (''Lepus americanus''), also called the varying hare or snowshoe rabbit, is a species of hare found in North America. It has the name "snowshoe" because of the large size of its hind feet. The animal's feet prevent it from sinking into the snow when it hops and walks. Its feet also have fur on the soles to protect it from freezing temperatures. For camouflage, its fur turns white during the winter and rusty brown during the summer. Its flanks are white year-round. The snowshoe hare is also distinguishable by the black tufts of fur on the edge of its ears. Its ears are shorter than those of most other hares. In summer, it feeds on plants such as grass, ferns, and leaves; in winter, it eats twigs, the bark from trees, and plants and, similar to the Arctic hare, has been known to occasionally eat dead animals. It can sometimes be seen feeding in small groups. This animal is mainly active at night and does not hibernate. The snowshoe hare may have up to four lit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linum Pubescens
''Linum pubescens'', the hairy pink flax, is an herbaceous flowering plant in the genus ''Linum'' native to the east Mediterranean region. The plant is annual and blooms in the spring. References Linum, pubescens Flora of Lebanon Flora of Palestine (region) Flora of Israel Taxa named by Joseph Banks Taxa named by Daniel Solander {{Malpighiales-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Elephant Seal
The southern elephant seal (''Mirounga leonina'') is one of two species of elephant seals. It is the largest member of the clade Pinnipedia and the order Carnivora, as well as the largest extant marine mammal that is not a cetacean. It gets its name from its massive size and the large proboscis of the adult male, which is used to produce very loud roars, especially during the breeding season. A bull southern elephant seal is about 40% heavier than a male northern elephant seal (''Mirounga angustirostris''), twice as heavy as a male walrus (''Odobenus rosmarus''), and 6–7 times heavier than the largest living mostly-terrestrial carnivoran, the polar bear (''Ursus maritimus'') and the Kodiak bear (''Ursus arctos middendorffi''),. Taxonomy The southern elephant seal was one of the many species originally described by Swedish zoologist Carl Linnaeus in the landmark 1758 10th edition of his ''Systema Naturae'', where it was given the binomial name of ''Phoca leonina''. John Edwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Woodrat
A pack rat or packrat, also called a woodrat or trade rat, are any species in the North and Central American rodent genus ''Neotoma''. Pack rats have a rat-like appearance, with long tails, large ears, and large, black eyes. Pack rats are noticeably larger than deer mice, harvest mice, and grasshopper mice, and are usually somewhat larger than cotton rats. Species ''Neotoma'' includes three subgenera: * Subgenus ''Neotoma'' ** '' Neotoma albigula'' - white-throated woodrat *** '' Neotoma albigula varia'' - Turner Island woodrat ** '' Neotoma angustapalata'' - Tamaulipan woodrat ** '' Neotoma bryanti'' - Bryant's woodrat *** '' Neotoma bryanti anthonyi'' - Anthony's woodrat † *** '' Neotoma bryanti bunkeri'' - Bunker's woodrat † *** '' Neotoma bryanti martinensis'' - San Martín Island woodrat † ** '' Neotoma chrysomelas'' - Nicaraguan woodrat ** '' Neotoma devia'' - Arizona woodrat ** '' Neotoma findleyi'' - Findley's woodrat † ** '' Neotoma floridana'' - eastern wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neotoma Fuscipes
The dusky-footed woodrat (''Neotoma fuscipes'') is a species of nocturnal rodent in the family Cricetidae. They are commonly called "packrats" or "trade rats" and build large, domed dens that can reach several feet in height. Coyotes and other predators will attempt to prey on these rodents by laying waste to the dens, but the sheer volume of material is usually dissuasive. Occasionally, dusky-footed woodrats will build satellite dens in trees. Although these animals are solitary, except in the mating season (when they are most vulnerable to predation), dens are frequently found in clusters of up to several dozen, forming rough "communities". The mating system in this species appears to be variable, with promiscuity most generally at high population densities and monogamy at lower densities. They are similar in appearance to the common rat species ''Rattus rattus'' and ''Rattus norvegicus'', but with larger ears and eyes, softer coats, and furred tails. The California mous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neotoma Macrotis
The big-eared woodrat (''Neotoma macrotis'') is a nocturnal rodent of the woodrat genus ''Neotoma'', in the family Cricetidae. Closely related to, and formerly included in the species ''Neotoma fuscipes'', it is endemic to western North America and occurs west and south of the Salinas Valley from the California Coast Ranges south of Monterey Bay to northern Baja California, as well as in the Sierra Nevada, extending north to the South Fork American River.Matocq, Marjorie D. 2002. Morphological and Molecular Analysis of a Contact Zone in the Neotoma Fuscipes Species Complex. Journal of Mammalogy, Volume 83, Issue 3, August 2002, Pages 866–883. /ref> The big-eared woodrat is light to dark brown in color, often with a lighter underside. It has characteristically large mobile ears, large eyes, and a long, fur covered tail. It is a primarily arboreal herbivore and functions as an important keystone species in oak and other forest ecosystems. Taxonomy Although often misconstrued ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eastern Cottontail
The eastern cottontail (''Sylvilagus floridanus'') is a New World cottontail rabbit, a member of the family Leporidae. It is the most common rabbit species in North America. Distribution The eastern cottontail can be found in meadows and shrubby areas in the eastern and south-central United States, southern Canada, eastern Mexico, Central America and northernmost South America. It is also found on the Caribbean island of Margarita. It is abundant in Midwest North America. Its range expanded north as forests were cleared by settlers.Godin, Alfred J. (1977). ''Wild mammals of New England''. Baltimore, MD: The Johns Hopkins University Press Originally, it was not found in New England, but it has been introduced and now competes for habitat there with the native New England cottontail. It has also been introduced into parts of Oregon, Washington, and British Columbia. In the 1950s and 1960s, the eastern cottontail was introduced to France and northern Italy, where it displayed a rapi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burmese Pythons
The Burmese python (''Python bivittatus'') is one of the largest species of snakes. It is native to a large area of Southeast Asia and is listed as Vulnerable on the IUCN Red List. Until 2009, it was considered a subspecies of the Indian python, but is now recognized as a distinct species. It is an invasive species in Florida as a result of the pet trade. Description The Burmese python is a dark-colored non-venomous snake with many brown blotches bordered by black down the back. In the wild, Burmese pythons typically grow to , while specimens of more than are unconfirmed. This species is sexually dimorphic in size; females average only slightly longer, but are considerably heavier and bulkier than the males. For example, length-weight comparisons in captive Burmese pythons for individual females have shown: at length, a specimen weighed , a specimen of just over weighed , a specimen of weighed , and a specimen of weighed . In comparison, length-weight comparisons for males ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allobates Femoralis
''Allobates femoralis'' (common name brilliant-thighed poison frog, brilliant-thighed poison-arrow frog) is a species of frog in the family Aromobatidae. It is found in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, and Suriname. Its natural habitat is tropical lowland forests. Description ''Allobates femoralis'' is a small frog, the males growing to in length and the females being marginally larger. The coloration on the back is dark brown or black and the limbs are colored dark brown. The throat is black and the belly is white, marked with black. A pale brown dorso-lateral stripe runs from the snout to the base of the legs and an intermittent white ventro-lateral line runs from the snout to the arm and onwards to the leg. There is an orange-yellow patch behind the arm and a half-moon shaped orange patch on the outside of the thigh. ''A. femoralis'' resembles '' Lithodytes lineatus'' in general appearance, but ''L. lineatus'' has a dorso-lateral line encircling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
