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Rock Pocket Mouse
The rock pocket mouse (''Chaetodipus intermedius'') is one of 19 species of pocket mice in the genus ''Chaetodipus''. It is sometimes grouped in the genus ''Perognathus''. Description Found mainly in rocky outcrops in the deserts of the southwestern United States and Mexico, the rock pocket mouse is medium-sized (length ~18 cm, weight ~12–18g) and nocturnal animal, nocturnal. It eats mainly plant seeds and makes small burrows in soil close to or under rocks to evade owls, its main predator. The breeding season spans a few months, starting in February or March, and the litter size is typically between three and six. As with most pocket mice, the tail is longer than the body (~10 cm). Taxonomy Historically, rock pocket mice have been subdivided into as many as ten subspecies (Benson 1933; Dice and Blossom 1937) based on geographical distribution and coat colour. Most rock pocket mouse populations have light, tawny fur consistent with the colour of the desert rocks on wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clinton Hart Merriam
Clinton Hart Merriam (December 5, 1855 – March 19, 1942) was an American zoologist, mammalogist, ornithologist, entomologist, ecologist, ethnographer, geographer, naturalist and physician. He was commonly known as the 'father of mammalogy', a branch of zoology referring to the study of mammals. Early life Clinton Hart Merriam was born in New York City in 1855 to Clinton Levi Merriam, a U.S. congressman, and Caroline Hart, a judge's daughter and a graduate of Rutgers Institute. The name Clinton, shared by both father and son, was in honor of New York governor DeWitt Clinton, whom the Merriam family had connections with. To avoid confusion, the younger Merriam went by his first initial combined with his middle name, his mother's maiden name, and thus often appears as C. Hart Merriam in both the literature of his time and thereafter. Although born in New York City, where his parents were staying the winter, the family home and place where Merriam spent his boyhood days was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammals Of Mexico
This is a list of the native wild mammal species recorded in Mexico. As of September 2014, there were 536 mammalian species or subspecies listed. Based on International Union for Conservation of Nature, IUCN data, Mexico has 23% more noncetacean mammal species than the U.S. and Canada combined in an area only 10% as large, or a species density over 12 times that of its northern neighbors. Mexico's high mammal biodiversity is in part a reflection of the wide array of biomes present over its latitudinal, climatic and altitudinal ranges, from lowland tropical rainforest to temperate desert to montane forest to alpine tundra. The general increase in terrestrial biodiversity moving towards the equator is another important factor in the comparison. Mexico includes much of the Mesoamerica#Biodiversity, Mesoamerican and Madrean pine-oak woodlands biodiversity hotspots. From a biogeographic standpoint, most of Mexico is linked to the rest of North America as part of the Nearctic realm. Howeve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammals Of The United States
About 490 species of mammals are recorded in the United States. Unincorporated territories like for example Puerto Rico, Guam or Northern Mariana Islands are not covered. Mammals introduced and extinct in the Holocene except Pleistocene/Holocene boundary are included. According to the IUCN Red List 3 of these species are critically endangered, 20 endangered, 15 vulnerable, 20 near threatened and 4 extinct. Some species are identified as indicated below: *(A) - Accidental *(E) - Extinct *(Ex) - Extirpated (extinct in the US, but exists elsewhere in the world) *(I) - Introduced The following tags are used to highlight each species' conservation status as assessed by the International Union for Conservation of Nature: (v. 2013.2, the data are current as of March 5, 2014) and the Endangered Species Act: (the data are current as of March 28, 2014) Subclass: Theria Infraclass: Metatheria Order: Didelphimorphia (common opossums) ---- Didelphimorphia is the order of common ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaetodipus
''Chaetodipus'' is a genus of pocket mouse containing 17 species endemic to the United States and Mexico. Like other members of their family such as pocket mice in the genus ''Perognathus'', they are more closely related to pocket gophers than to true mice. Characteristics Members of this genus range in size from 80 to 125 mm (head and body) and weigh 15–47 grams (Nowak, 1999). Unlike the silky pocket mice (genus ''Perognathus''), most species of the genus ''Chaetodipus'' have harsh pelage with some bordering on spiny hair. They tend to be found in arid habitats where they feed on seeds, vegetation, and insects (Nowak, 1999). Females give birth to a litter of 2–9 young after a gestation period of just under a month. The longest recorded life span is 8 years and 4 months (Nowak, 1999). Species *'' Chaetodipus arenarius'' – Little desert pocket mouse *'' Chaetodipus artus'' – Narrow-skulled pocket mouse *'' Chaetodipus baileyi'' – Bailey's pocket mouse *'' Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Arizona
The University of Arizona (Arizona, U of A, UArizona, or UA) is a public land-grant research university in Tucson, Arizona. Founded in 1885 by the 13th Arizona Territorial Legislature, it was the first university in the Arizona Territory. The university is part of the Association of American Universities and the Universities Research Association. In the former, it is the only member from the state of Arizona. The university is classified among "R1: Doctoral Universities – Very High Research Activity". The University of Arizona is one of three universities governed by the Arizona Board of Regents. , the university enrolled 49,471 students in 19 separate colleges/schools, including the University of Arizona College of Medicine in Tucson and Phoenix and the James E. Rogers College of Law, and is affiliated with two academic medical centers ( Banner – University Medical Center Tucson and Banner – University Medical Center Phoenix). In 2021, University of Arizona acquired ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peppered Moth Evolution
The evolution of the peppered moth is an evolutionary instance of directional colour change in the moth population as a consequence of air pollution during the Industrial Revolution. The frequency of dark-coloured moths increased at that time, an example of industrial melanism. Later, when pollution was reduced, the light-coloured form again predominated. Industrial melanism in the peppered moth was an early test of Charles Darwin's natural selection in action, and it remains a classic example in the teaching of evolution. In 1978, Sewall Wright described it as "the clearest case in which a conspicuous evolutionary process has actually been observed." The dark-coloured or ''melanic'' form of the peppered moth (var. ''carbonaria'') was rare, though a specimen had been collected by 1811. After field collection in 1848 from Manchester, an industrial city in England, the frequency of the variety was found to have increased drastically. By the end of the 19th century it almost com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heteromyidae
Heteromyidae is a family of rodents consisting of kangaroo rats, kangaroo mice, pocket mice and spiny pocket mice. Most heteromyids live in complex burrows within the deserts and grasslands of western North America, though species within the genus ''Heteromys'' are also found in forests and their range extends down as far as northern South America. They feed mostly on seeds and other plant parts, which they carry in their fur-lined cheek pouches to their burrows. Although they are very different in physical appearance, the closest relatives of the heteromyids are pocket gophers in the family Geomyidae. Description There are about fifty-nine members of the family Heteromyidae divided among six genera. They are all small rodents, the largest being the giant kangaroo rat (''Dipodomys ingens'') with a body length of and a tail a little longer than this. In many species the tail is tufted and is mainly used for balance. Other adaptations include partially fused vertebrae in the neck ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Convergent Evolution
Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is homoplasy. The recurrent evolution of flight is a classic example, as flying insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are ''analogous'', whereas '' homologous'' structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergence is divergent evolution, where related species evolve different traits. Convergent evolution is similar to parallel evo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with selective breeding, artificial selection, which in his view is intentional, whereas natural selection is not. Genetic diversity, Variation exists within all populations of organisms. This occurs partly because random mutations arise in the genome of an individual organism, and their offspring can inherit such mutations. Throughout the lives of the individuals, their genomes interact with their environments to cause variations in traits. The environment of a genome includes the molecular biology in the Cell (biology), cell, other cells, other individuals, populations, species, as well as the abiotic environment. Because individuals with certain variants of the trait tend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melanism
The term melanism refers to black pigment and is derived from the gr, μελανός. Melanism is the increased development of the dark-colored pigment melanin in the skin or hair. Pseudomelanism, also called abundism, is another variant of pigmentation, identifiable by dark spots or enlarged stripes, which cover a large part of the body of the animal, making it appear melanistic. The morbid deposition of black matter, often of a malignant character causing pigmented tumors, is called melanosis. Adaptation Melanism related to the process of adaptation is called adaptive. Most commonly, dark individuals become Fitness (biology), fitter to survive and reproduce in their environment as they are better camouflaged. This makes some species less conspicuous to predators, while others, such as leopards, use it as a foraging advantage during night hunting. Typically, adaptive melanism is Heritability, heritable: A Dominance (genetics), dominant allele, which is entirely or nearly ent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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