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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] |
Evolutionary Biology
Evolutionary biology is the subfield of biology that studies the evolutionary processes (natural selection, common descent, speciation) that produced the diversity of life on Earth. It is also defined as the study of the history of life forms on Earth. Evolution is based on the theory that all species are related and they gradually change over time. In a population, the genetic variations affect the physical characteristics i.e. phenotypes of an organism. These changes in the phenotypes will be an advantage to some organisms, which will then be passed onto their offspring. Some examples of evolution in species over many generations are the Peppered Moth and Flightless birds. In the 1930s, the discipline of evolutionary biology emerged through what Julian Huxley called the modern synthesis of understanding, from previously unrelated fields of biological research, such as genetics and ecology, systematics, and paleontology. The importance of studying Evolutionary biology is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population
Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction using a census, a process of collecting, analysing, compiling, and publishing data regarding a population. Perspectives of various disciplines Social sciences In sociology and population geography, population refers to a group of human beings with some predefined criterion in common, such as location, race, ethnicity, nationality, or religion. Demography is a social science which entails the statistical study of populations. Ecology In ecology, a population is a group of organisms of the same species who inhabit the same particular geographical area and are capable of interbreeding. The area of a sexual population is the area where inter-breeding is possible between any pair within the area and more probable than cross-breeding with in ... [...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] |
Transplant Experiment
A transplant experiment, is an experiment to test the effect of environment by moving two species from their native environments into a common environment. The name was originally applied to experiments on plants, but is now equally applied to animals such as lizards and ants, and other organisms. A reciprocal transplant experiment involves introducing organisms from each of two environments into the other; the approach can be extended to more than two environments if required. Transplant experiments are often used to test if there is a genetic component to differences in populations. Advances in molecular biology have provided researchers with the ability to study genetic variation more directly. However, transplant experiments still have the advantages of being simple and requiring little technology. On the other hand, they may require considerable time and labour, and the number of test organisms is often relatively limited. Common garden methods can be improved by combining ev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guppies
The guppy (), also known as millionfish and rainbow fish, is one of the world's most widely distributed tropical fish and one of the most popular List of freshwater aquarium fish species, freshwater aquarium fish species. It is a member of the family Poeciliidae and, like almost all American members of the family, is live-bearing aquarium fish, live-bearing. Guppies originate from northeast South America, but have been introduced to many environments and are now found all over the world. They are highly adaptable and thrive in many different environmental and ecological conditions. Male guppies, which are smaller than females, have ornamental caudal and dorsal fish fin, fins. Wild guppies generally feed on a variety of food sources, including benthic zone, benthic algae and aquatic insect larvae. Guppies are used as a model organism in the fields of ecology, evolution, and behavioural studies. Taxonomy Guppies were first described in Venezuela as ''Poecilia reticulata'' by Wilh ... [...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] |
Allopatric Speciation
Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow. Various geographic changes can arise such as the movement of continents, and the formation of mountains, islands, bodies of water, or glaciers. Human activity such as agriculture or developments can also change the distribution of species populations. These factors can substantially alter a region's geography, resulting in the separation of a species population into isolated subpopulations. The vicariant populations then undergo genetic changes as they become subjected to different selective pressures, experience genetic drift, and accumulate different mutations in the separated populations' gene pools. The barriers prevent the exchange of genetic information betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Co-adaptation
In biology, co-adaptation is the process by which two or more species, genes or phenotypic traits undergo adaptation as a pair or group. This occurs when two or more interacting characteristics undergo natural selection together in response to the same selective pressure or when selective pressures alter one characteristic and consecutively alter the interactive characteristic. These interacting characteristics are only beneficial when together, sometimes leading to increased interdependence. Co-adaptation and coevolution, although similar in process, are not the same; co-adaptation refers to the interactions between two units, whereas co-evolution refers to their evolutionary history. Co-adaptation and its examples are often seen as evidence for co-evolution. Genes and Protein Complexes At genetic level, co-adaptation is the accumulation of interacting genes in the gene pool of a population by selection. Selection pressures on one of the genes will affect its interacting prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolvability
Evolvability is defined as the capacity of a system for adaptive evolution. Evolvability is the ability of a population of organisms to not merely generate genetic diversity, but to generate ''adaptive'' genetic diversity, and thereby evolve through natural selection. In order for a biological organism to evolve by natural selection, there must be a certain minimum probability that new, heritable variants are beneficial. Random mutations, unless they occur in DNA sequences with no function, are expected to be mostly detrimental. Beneficial mutations are always rare, but if they are too rare, then adaptation cannot occur. Early failed efforts to evolve computer programs by random mutation and selection showed that evolvability is not a given, but depends on the representation of the program as a data structure, because this determines how changes in the program map to changes in its behavior. Analogously, the evolvability of organisms depends on their genotype–phenotype map. Thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Diversity
Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is distinguished from ''genetic variability'', which describes the tendency of genetic characteristics to vary. Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are more likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals. The academic field of population genetics includes several hypotheses and theories regarding genetic diversity. The neutral theory of evolution proposes that diversity is the result of the accumulation of neutral substitutions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Drift
Genetic drift, also known as allelic drift or the Wright effect, is the change in the frequency of an existing gene variant (allele) in a population due to random chance. Genetic drift may cause gene variants to disappear completely and thereby reduce genetic variation. It can also cause initially rare alleles to become much more frequent and even fixed. When few copies of an allele exist, the effect of genetic drift is more notable, and when many copies exist, the effect is less notable. In the middle of the 20th century, vigorous debates occurred over the relative importance of natural selection versus neutral processes, including genetic drift. Ronald Fisher, who explained natural selection using Mendelian genetics, held the view that genetic drift plays at most a minor role in evolution, and this remained the dominant view for several decades. In 1968, population geneticist Motoo Kimura rekindled the debate with his neutral theory of molecular evolution, which claims that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maladaptation
In evolution, a maladaptation () is a trait that is (or has become) more harmful than helpful, in contrast with an adaptation, which is more helpful than harmful. All organisms, from bacteria to humans, display maladaptive and adaptive traits. In animals (including humans), adaptive behaviors contrast with maladaptive ones. Like adaptation, maladaptation may be viewed as occurring over geological time, or within the lifetime of one individual or a group. It can also signify an adaptation that, whilst reasonable at the time, has become less and less suitable and more of a problem or hindrance in its own right, as time goes on. This is because it is possible for an adaptation to be poorly selected or become more of a dysfunction than a positive adaptation, over time. Note that the concept of maladaptation, as initially discussed in a late 19th-century context, is based on a flawed view of evolutionary theory. It was believed that an inherent tendency for an organism's adaptations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
