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Drift Load
Drift load, a type of genetic load, is the decline in Fitness (biology), fitness in a population due to the Fixation (population genetics), fixation of deleterious mutations by genetic drift. Drift load generally decreases as a function of effective population size, and is a mechanism of inbreeding depression. If all individuals in a population become homozygous for one allele, that allele is Fixed allele, fixed, and any other alleles at that Locus (genetics), locus are lost from that population by the random evolutionary process of genetic drift. As fixation of deleterious alleles occurs at more loci and variability is lost, drift load increases. With increasing drift load, populations become less fit with each generation, a mutational meltdown, which can lead to an extinction vortex. Strategies to address drift load in endangered species is a goal of conservation genetics. Calculating drift load For realistic values of N_e, the effective population size, and \lambda_D, the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Load
Genetic load is the difference between the fitness of an average genotype in a population and the fitness of some reference genotype, which may be either the best present in a population, or may be the theoretically optimal genotype. The average individual taken from a population with a low genetic load will generally, when grown in the same conditions, have more surviving offspring than the average individual from a population with a high genetic load. Genetic load can also be seen as reduced fitness at the population level compared to what the population would have if all individuals had the reference high-fitness genotype. High genetic load may put a population in danger of extinction. Fundamentals Consider n genotypes \mathbf _1, \dots, \mathbf _n, which have the fitnesses w_1, \dots, w_n and frequencies p_1, \dots, p_n, respectively. Ignoring frequency-dependent selection, the genetic load L may be calculated as: :L = where w_\max is either some theoretical optimum, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Flow
In population genetics, gene flow (also known as migration and allele flow) is the transfer of genetic variation, 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 Genetic drift, drift. Populations can diverge due to Natural selection, 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. Gene flow has b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctic Fox
The Arctic fox (''Vulpes lagopus''), also known as the white fox, polar fox, or snow fox, is a small species of fox native to the Arctic regions of the Northern Hemisphere and common throughout the Tundra#Arctic tundra, Arctic tundra biome. It is well adaptation, adapted to living in cold environments, and is best known for its thick, warm fur that is also used as camouflage. It has a large and very fluffy tail. In the wild, most individuals do not live past their first year but some exceptional ones survive up to 11 years. Its body length ranges from , with a generally rounded body shape to minimize the escape of body heat. The Arctic fox preys on many small creatures such as lemmings, voles, ringed seal pups, fish, waterfowl, and seabirds. It also eats carrion, berries, seaweed, and insects and other small invertebrates. Arctic foxes form Monogamy in animals, monogamous pairs during the breeding season and they stay together to raise their young in complex underground dens. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MHC Class I
MHC class I molecules are one of two primary classes of major histocompatibility complex (MHC) molecules (the other being MHC class II) and are found on the cell surface of all nucleated cells in the bodies of vertebrates. They also occur on platelets, but not on red blood cells. Their function is to display peptide fragments of proteins from within the cell to cytotoxic T cells; this will trigger an immediate response from the immune system against a particular non-self antigen displayed with the help of an MHC class I protein. Because MHC class I molecules present peptides derived from cytosolic proteins, the pathway of MHC class I presentation is often called ''cytosolic'' or ''endogenous pathway''. In humans, the HLAs corresponding to MHC class I are HLA-A, HLA-B, and HLA-C. Function Class I MHC molecules bind peptides generated mainly from the degradation of cytosolic proteins by the proteasome. The MHC I: peptide complex is then inserted via the endoplasmic re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Everglades
The Everglades is a natural region of flooded grasslands in the southern portion of the U.S. state of Florida, comprising the southern half of a large drainage basin within the Neotropical realm. The system begins near Orlando with the Kissimmee River, which discharges into the vast but shallow Lake Okeechobee. Water leaving the lake in the wet season forms a slow-moving river wide and over long, flowing southward across a limestone shelf to Florida Bay at the southern end of the state. The Everglades experiences a wide range of weather patterns, from frequent flooding in the wet season to drought in the dry season. Throughout the 20th century, the Everglades suffered significant loss of habitat and environmental degradation. Human habitation in the southern portion of the Florida peninsula dates to 15,000 years ago. Before European colonization, the region was dominated by the native Calusa and Tequesta tribes. With Spanish colonization, both tribes declined g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Felis Concolor Stanleyana
''Felis'' is a genus of small and medium-sized cat species native to most of Africa and south of 60° latitude in Europe and Asia to Indochina. The genus includes the domestic cat. The smallest of the seven ''Felis'' species is the black-footed cat with a head and body length from . The largest is the jungle cat with a head and body length from . Genetic studies indicate that the Felinae genera ''Felis'', '' Otocolobus'' and ''Prionailurus'' diverged from a Eurasian progenitor of the Felidae about 6.2 million years ago, and that ''Felis'' species split off 3.04 to 0.99 million years ago. Etymology The generic name ''Felis'' is derived from Classical Latin meaning 'cat, ferret'. Taxonomy Carl Linnaeus considered ''Felis'' to comprise all cat species known until 1758. Later taxonomists split the cat family into different genera. In 1917, the British zoologist Reginald Innes Pocock revised the genus ''Felis'' as comprising only the ones listed in the following table. Estimated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Florida Panther
The Florida panther is a North American cougar (''P. c. couguar'') population in South Florida. It lives in pinelands, tropical hardwood hammocks and mixed freshwater swamp forests. Its range includes the Big Cypress National Preserve, Everglades National Park, Florida Panther National Wildlife Refuge, Picayune Strand State Forest, as well as rural communities in the counties of Collier County, Florida, Collier, Hendry County, Florida, Hendry, Hardee County, Florida, Hardee, DeSoto County, Florida, Desoto, Lee County, Florida, Lee, Miami-Dade County, Florida, Miami-Dade, and Monroe County, Florida, Monroe County. It is the only confirmed cougar population in the Eastern United States, and currently occupies 5% of its historic range. As of 2024, about 200 individuals are left in the wild. Description Florida panthers are spotted at birth, and typically have blue eyes. As the panther grows, the spots fade and the coat becomes completely tan, while the eyes typically take on a yell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Florida Panther (Felis Concolor Coryi) At Jacksonville Zoo (3)
The Florida panther is a North American cougar (''P. c. couguar'') population in South Florida. It lives in pinelands, tropical hardwood hammocks and mixed freshwater swamp forests. Its range includes the Big Cypress National Preserve, Everglades National Park, Florida Panther National Wildlife Refuge, Picayune Strand State Forest, as well as rural communities in the counties of Collier, Hendry, Hardee, Desoto, Lee, Miami-Dade, and Monroe County. It is the only confirmed cougar population in the Eastern United States, and currently occupies 5% of its historic range. As of 2024, about 200 individuals are left in the wild. Description Florida panthers are spotted at birth, and typically have blue eyes. As the panther grows, the spots fade and the coat becomes completely tan, while the eyes typically take on a yellow hue. The panther's underbelly is a creamy white, and it has black tips on the tail and ears. Florida panthers lack the ability to roar, and instead make distinc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Sciences
Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, History of life, origin, evolution, and distribution of life. Central to biology are five fundamental themes: the cell (biology), cell as the basic unit of life, genes and heredity as the basis of inheritance, evolution as the driver of biological diversity, energy transformation for sustaining life processes, and the maintenance of internal stability (homeostasis). Biology examines life across multiple biological organisation, levels of organization, from molecules and cells to organisms, populations, and ecosystems. Subdisciplines include molecular biology, physiology, ecology, evolutionary biology, developmental biology, and systematics, among others. Each of these fields applies a range of methods to investigate biological phenomena, including scientific method, observation, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
