Interpretation of the biological species concept from interspecific
... In fact, at some region hybridization occurs when genetically distinct populations meet and mate, resulting in at least some offspring of mixed ancestry. The region is called a hybrid zone. The populations on either side of the hybrid zone may be different enough to have been classified as separate ...
... In fact, at some region hybridization occurs when genetically distinct populations meet and mate, resulting in at least some offspring of mixed ancestry. The region is called a hybrid zone. The populations on either side of the hybrid zone may be different enough to have been classified as separate ...
1 The house mouse and its relatives: systematics and taxonomy
... the systematics of the house mouse. All taxa were then considered as subspecies of the house mouse (Mus musculus). In other words, there was only one species within the subgenus Mus. It was a relatively large-scale study, but the taxonomic criteria were obviously based solely on external morphology ...
... the systematics of the house mouse. All taxa were then considered as subspecies of the house mouse (Mus musculus). In other words, there was only one species within the subgenus Mus. It was a relatively large-scale study, but the taxonomic criteria were obviously based solely on external morphology ...
Seed and pollen dispersal
... That can lead to selection for self-fertilization to assure reproduction. Fitness could be very low for a plant that can only outcross when it is isolated or its density is low. ...
... That can lead to selection for self-fertilization to assure reproduction. Fitness could be very low for a plant that can only outcross when it is isolated or its density is low. ...
Ch17 Lecture-Speciation
... groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups.” Ernst Mayr Reproductive isolation: two groups of organisms can no longer exchange genes. ...
... groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups.” Ernst Mayr Reproductive isolation: two groups of organisms can no longer exchange genes. ...
species
... biological diversity Speciation is the emergence of new species Every time speciation occurs, the diversity of life increases The many millions of species on Earth have all arisen from an ancestral life form that lived around 3.6 billion years ago ...
... biological diversity Speciation is the emergence of new species Every time speciation occurs, the diversity of life increases The many millions of species on Earth have all arisen from an ancestral life form that lived around 3.6 billion years ago ...
Species, Variability, and Integration
... of a sexually reproducing species can exemplify (Okasha 2002, p. 196). Furthermore, we can have distinct species sharing a considerable array of genes. Thereby, the assumption that essences are genetic is empirically problematic because it fails to single out individual species. The argument present ...
... of a sexually reproducing species can exemplify (Okasha 2002, p. 196). Furthermore, we can have distinct species sharing a considerable array of genes. Thereby, the assumption that essences are genetic is empirically problematic because it fails to single out individual species. The argument present ...
![122 [Study Guide] 24-1 Species and Speciation](http://s1.studyres.com/store/data/003755348_1-2b34702407fa0adfdab7672da07af706-300x300.png)
122 [Study Guide] 24-1 Species and Speciation
... Speciation—the process by which one species splits into two or more species—is at the focal point of evolutionary theory because the appearance of new species is the source of biological diversity. ...
... Speciation—the process by which one species splits into two or more species—is at the focal point of evolutionary theory because the appearance of new species is the source of biological diversity. ...
Ancient Athens
... strays that rode the ocean currents and winds from other islands and continents. Organisms can also be carried to islands by other organisms, such as sea birds that travel long distances with seeds clinging to their feathers. The species on the Galapagos Islands today, most of which occur nowhere el ...
... strays that rode the ocean currents and winds from other islands and continents. Organisms can also be carried to islands by other organisms, such as sea birds that travel long distances with seeds clinging to their feathers. The species on the Galapagos Islands today, most of which occur nowhere el ...
Dr. Robeva`s PPT
... Blood Glucose Fluctuation Characteristics Quantified from Self-Monitoring Data In both human and economic terms, diabetes is one of the nations most costly diseases. Diabetes is the leading cause of kidney failure, blindness in adults, and amputations. It is a major risk factor for heart disease, s ...
... Blood Glucose Fluctuation Characteristics Quantified from Self-Monitoring Data In both human and economic terms, diabetes is one of the nations most costly diseases. Diabetes is the leading cause of kidney failure, blindness in adults, and amputations. It is a major risk factor for heart disease, s ...
Chapter 17 ppt
... Reinforcement of prezygotic isolating mechanisms is often detected by comparing sympatric and allopatric populations of potentially hybridizing species. Sympatric populations are expected to evolve more effective prezygotic reproductive barriers than do allopatric populations. Experiments with Phlox ...
... Reinforcement of prezygotic isolating mechanisms is often detected by comparing sympatric and allopatric populations of potentially hybridizing species. Sympatric populations are expected to evolve more effective prezygotic reproductive barriers than do allopatric populations. Experiments with Phlox ...
sympatric speciation
... • Sympatric speciation can also result from the appearance of new ecological niches • For example, the North American maggot fly can live on native hawthorn trees as well as more recently introduced apple trees ...
... • Sympatric speciation can also result from the appearance of new ecological niches • For example, the North American maggot fly can live on native hawthorn trees as well as more recently introduced apple trees ...
Notes on population genetics and evolution: “Cheat sheet” for
... lost from the population. Perhaps the easiest way to see how the Wright-Fisher binomial sampling model works is through a biologically motivated example. Imagine that before dying each individual in the population produces a very large number of gametes. However, the population size is tightly contr ...
... lost from the population. Perhaps the easiest way to see how the Wright-Fisher binomial sampling model works is through a biologically motivated example. Imagine that before dying each individual in the population produces a very large number of gametes. However, the population size is tightly contr ...
B6C-12 - De Anza College
... Under normal light, females of each species mated only with males of their own species. But under orange light, females of each species mated indiscriminately with males of both species. The resulting hybrids were viable and fertile. ...
... Under normal light, females of each species mated only with males of their own species. But under orange light, females of each species mated indiscriminately with males of both species. The resulting hybrids were viable and fertile. ...
Species distribution
Species distribution is the manner in which a biological taxon is spatially arranged. Species distribution is not to be confused with dispersal, which is the movement of individuals away from their area of origin or from centers of high population density. A similar concept is the species range. A species range is often represented with a species range map. Biogeographers try to understand the factors determining a species' distribution. The pattern of distribution is not permanent for each species. Distribution patterns can change seasonally, in response to the availability of resources, and also depending on the scale at which they are viewed. Dispersion usually takes place at the time of reproduction. Populations within a species are translocated through many methods, including dispersal by people, wind, water and animals. Humans are one of the largest distributors due to the current trends in globalization and the expanse of the transportation industry. For example, large tankers often fill their ballasts with water at one port and empty them in another, causing a wider distribution of aquatic species.Biogeography is the study of the distribution of biodiversity over space and time. It is very useful in understanding species distribution through factors such as speciation, extinction, continental drift, glaciation, variation of sea levels, river capture and available resources. This branch of study not only gives a description of the species distribution, but also a geographical explanation for the distribution of particular species. The traditional biogeographic regions were first modeled by Alfred Wallace in The Geographical Distribution of Animals (1876). These were based on the work of Sclater's terrestrial biogeographic regions. Wallace's system was based on both birds and vertebrates, including non-flying mammals, which better reflect the natural divisions of the Earth due to their limited dispersal abilities.