Zeitschrift für Säugetierkunde : im Auftrage der Deutschen
... ontologists feel that such variables as generation length should also enter into ...
... ontologists feel that such variables as generation length should also enter into ...
Biological Aging: Active and Passive Mechanisms Compared
... evolve improvements to the designs of all of its many mechanisms, a likely very much longer process. In the active concept a much simpler change to the clock could increase as well as decrease life span much more rapidly. The ability to adapt more rapidly would be a competitive advantage. De Grey co ...
... evolve improvements to the designs of all of its many mechanisms, a likely very much longer process. In the active concept a much simpler change to the clock could increase as well as decrease life span much more rapidly. The ability to adapt more rapidly would be a competitive advantage. De Grey co ...
Alfred Russel Wallace`s Concepts of Variation
... cupied the same area, the struggle between individuals must be translated into a struggle between the species in which the least fit would become extinct. But if similar species are in competition, so must there also be a struggle among any varieties which form within a single species. The rest of W ...
... cupied the same area, the struggle between individuals must be translated into a struggle between the species in which the least fit would become extinct. But if similar species are in competition, so must there also be a struggle among any varieties which form within a single species. The rest of W ...
Fission and fusion of Darwin`s finches populations
... increasing genetic variation because it simultaneously affects numerous genetic loci. The total effect on continuously varying traits can be up to two or three orders of magnitude greater than mutation (Grant & Grant 1994). Introgression can be particularly effective in small isolated populations, s ...
... increasing genetic variation because it simultaneously affects numerous genetic loci. The total effect on continuously varying traits can be up to two or three orders of magnitude greater than mutation (Grant & Grant 1994). Introgression can be particularly effective in small isolated populations, s ...
Fission and fusion of Darwin`s finches populations
... increasing genetic variation because it simultaneously affects numerous genetic loci. The total effect on continuously varying traits can be up to two or three orders of magnitude greater than mutation (Grant & Grant 1994). Introgression can be particularly effective in small isolated populations, s ...
... increasing genetic variation because it simultaneously affects numerous genetic loci. The total effect on continuously varying traits can be up to two or three orders of magnitude greater than mutation (Grant & Grant 1994). Introgression can be particularly effective in small isolated populations, s ...
Evolution by Natural Selection, continued
... become part of their genetic instructions. Therefore, more and more changes in a gene’s nucleotide sequence should build up over time. • If evolution has taken place, then species descended from a recent common ancestor should have fewer amino acid differences between their proteins than do species ...
... become part of their genetic instructions. Therefore, more and more changes in a gene’s nucleotide sequence should build up over time. • If evolution has taken place, then species descended from a recent common ancestor should have fewer amino acid differences between their proteins than do species ...
SJG Essays parsed by Category - A Website About Stephen Jay
... limbs may not reflect the fact that five is better than four or six (and thus favored by natural selection), but may instead happen to reflect that an earlier ancestor just happened to have that particular number. It could have been otherwise; in his widely used metaphor of the tape of life (referri ...
... limbs may not reflect the fact that five is better than four or six (and thus favored by natural selection), but may instead happen to reflect that an earlier ancestor just happened to have that particular number. It could have been otherwise; in his widely used metaphor of the tape of life (referri ...
Conceptual Barriers to Progress Within Evolutionary Biology
... a result, it is difficult or impossible for evolutionary biologists to describe changes in selection caused by niche-construction as evolutionarily causal. Instead, standard evolutionary theory is forced by its own explanatory reference device to “explain away” all observed instances of niche constr ...
... a result, it is difficult or impossible for evolutionary biologists to describe changes in selection caused by niche-construction as evolutionarily causal. Instead, standard evolutionary theory is forced by its own explanatory reference device to “explain away” all observed instances of niche constr ...
Evolutionary Development and HOX Genes
... Homeotic and Homeobox Genes • Control how an organism’s body develops as it grows from a zygote into a complete organism. • They determine the body plan including the polarity (front and back part) and positioning of organs. • Homeotic genes define a region or position in the embryo and code for tr ...
... Homeotic and Homeobox Genes • Control how an organism’s body develops as it grows from a zygote into a complete organism. • They determine the body plan including the polarity (front and back part) and positioning of organs. • Homeotic genes define a region or position in the embryo and code for tr ...
MCAS 2010 February Biology Released ITems
... The vision of the Department of Elementary and Secondary Education is to work in partnership with policy makers, communities, parents, school districts, and students to build a system that will prepare all students to succeed as productive and contributing members of our democratic society and the g ...
... The vision of the Department of Elementary and Secondary Education is to work in partnership with policy makers, communities, parents, school districts, and students to build a system that will prepare all students to succeed as productive and contributing members of our democratic society and the g ...
evolutio - The Skeptic Tank
... variation in the population to begin with, or a way to generate it. Genetic variation is "grist for the evolutionary mill". For example, if there were no dark moths, the population could not have evolved from mostly light to mostly dark. In order for continuing evolution there must be mechanisms to ...
... variation in the population to begin with, or a way to generate it. Genetic variation is "grist for the evolutionary mill". For example, if there were no dark moths, the population could not have evolved from mostly light to mostly dark. In order for continuing evolution there must be mechanisms to ...
The morphogenesis of evolutionary developmental biology
... Evolutionary developmental biology has its origins in the evolutionary morphology of the late nineteenth century. In 1859, Darwin had written, «It is generally acknowledged that all organic beings have been formed on two great laws—Unity of Type and Conditions of Existence.» While natural selection ...
... Evolutionary developmental biology has its origins in the evolutionary morphology of the late nineteenth century. In 1859, Darwin had written, «It is generally acknowledged that all organic beings have been formed on two great laws—Unity of Type and Conditions of Existence.» While natural selection ...
Deciphering the genetic basis of animal domestication
... and sparse, and the focus was on specific markers [16,17], but in the current environment of dense, genome-wide markers for many species, genome scans of differentiation have become a viable strategy to identify selected genes or genomic regions using the tails of the genome-wide FST distribution to ...
... and sparse, and the focus was on specific markers [16,17], but in the current environment of dense, genome-wide markers for many species, genome scans of differentiation have become a viable strategy to identify selected genes or genomic regions using the tails of the genome-wide FST distribution to ...
F - DHSTAKS
... (severe acute respiratory syndrome) can be transmitted when an infected person coughs or sneezes. This virus is transmitted in a manner most similar to the transmission of— ...
... (severe acute respiratory syndrome) can be transmitted when an infected person coughs or sneezes. This virus is transmitted in a manner most similar to the transmission of— ...
The morphogenesis of evolutionary developmental biology
... Evolutionary developmental biology has its origins in the evolutionary morphology of the late nineteenth century. In 1859, Darwin had written, «It is generally acknowledged that all organic beings have been formed on two great laws—Unity of Type and Conditions of Existence.» While natural selection ...
... Evolutionary developmental biology has its origins in the evolutionary morphology of the late nineteenth century. In 1859, Darwin had written, «It is generally acknowledged that all organic beings have been formed on two great laws—Unity of Type and Conditions of Existence.» While natural selection ...
Isolation by environment
... divergent populations; Nosil et al. 2005; McBride & Singer 2010). If hybrid offspring have intermediate phenotypes, then they may not occupy an available ecological niche in their natal environment or may have limited mating opportunities, both of which will reduce effective rates of long-term gene ...
... divergent populations; Nosil et al. 2005; McBride & Singer 2010). If hybrid offspring have intermediate phenotypes, then they may not occupy an available ecological niche in their natal environment or may have limited mating opportunities, both of which will reduce effective rates of long-term gene ...
Year 9 Term 2: Body Systems and Responses
... 5LW1e. discuss, using examples, how the values and needs of contemporary society can influence the focus of scientific research, eg the occurrence of diseases affecting animals and plants, an epidemic or pandemic disease in humans or lifestyle related non-infectious diseases in humans Students are t ...
... 5LW1e. discuss, using examples, how the values and needs of contemporary society can influence the focus of scientific research, eg the occurrence of diseases affecting animals and plants, an epidemic or pandemic disease in humans or lifestyle related non-infectious diseases in humans Students are t ...
Theorists: Charles Darwin, Sigmund Freud, and BF Skinner
... 1958, p. 43). Darwin went on to say that “Biology defines what can be learned, when it can be learned, how likely behaviors are to occur, and what is reinforcing” (Scarr, 1993, p. 1335). Darwin maintained the most favorable parts of the human species’ personality and intellectual traits would “surv ...
... 1958, p. 43). Darwin went on to say that “Biology defines what can be learned, when it can be learned, how likely behaviors are to occur, and what is reinforcing” (Scarr, 1993, p. 1335). Darwin maintained the most favorable parts of the human species’ personality and intellectual traits would “surv ...
The Evolution of Bacterial DNA Base Composition
... Starting from the mid‐1950s, biologists have been intrigued by the enormous variation in bacterial DNA base composition (the relative abundance of G/C versus A/T nucleotides [Zamenhof et al., '52]), currently estimated to extend from 13% to 75% GC (Figure 1). It was important to account for this var ...
... Starting from the mid‐1950s, biologists have been intrigued by the enormous variation in bacterial DNA base composition (the relative abundance of G/C versus A/T nucleotides [Zamenhof et al., '52]), currently estimated to extend from 13% to 75% GC (Figure 1). It was important to account for this var ...
2007 Biology papers - Australian Science Innovations
... related to the pig than to humans. What is the best way to test this theory? A. Compare the vestigial structures of humans, horses and pigs. B. Compare the genetic information contained in the red blood cells of humans, horses and pigs. C. Compare the genetic information contained in liver cells of ...
... related to the pig than to humans. What is the best way to test this theory? A. Compare the vestigial structures of humans, horses and pigs. B. Compare the genetic information contained in the red blood cells of humans, horses and pigs. C. Compare the genetic information contained in liver cells of ...
What does Drosophila genetics tell us about speciation?
... USA are mated to females from Bogotá, Colombia [16]. The two populations are separated by O2000 km. If these forms were to come together today, three outcomes are possible: (i) one of the species could go extinct; (ii) genes causing hybrid sterility could be selected against, and would be gradually ...
... USA are mated to females from Bogotá, Colombia [16]. The two populations are separated by O2000 km. If these forms were to come together today, three outcomes are possible: (i) one of the species could go extinct; (ii) genes causing hybrid sterility could be selected against, and would be gradually ...
The Importance of Developmental Repatterning in the Evolution of
... One of the striking features of the oryctocephalid trilobites that occur in the Early Cambrian Balang Formation in eastern Ghuizhou Province, southwest China, is the occurrence of convergent evolution in two clades of trilobites: in species of Arthricocephalus (McNamara et al. 2003) and in the Duyun ...
... One of the striking features of the oryctocephalid trilobites that occur in the Early Cambrian Balang Formation in eastern Ghuizhou Province, southwest China, is the occurrence of convergent evolution in two clades of trilobites: in species of Arthricocephalus (McNamara et al. 2003) and in the Duyun ...
Chapter 10 - Semantic Scholar
... (see “trait hierarchy” in Box 10.1). For example, Fry (1996) has defined a tradeoff as any case in which traits that increase fitness on one host are detrimental on others (i.e., phenotypic focus) or any case for which there is no (homozygous) genotype with maximal fitness in both environments (i.e. ...
... (see “trait hierarchy” in Box 10.1). For example, Fry (1996) has defined a tradeoff as any case in which traits that increase fitness on one host are detrimental on others (i.e., phenotypic focus) or any case for which there is no (homozygous) genotype with maximal fitness in both environments (i.e. ...
Introduction to evolution
Evolution is the process of change in all forms of life over generations, and evolutionary biology is the study of how evolution occurs. Biological populations evolve through genetic changes that correspond to changes in the organisms' observable traits. Genetic changes include mutations, which are caused by damage or replication errors in an organism's DNA. As the genetic variation of a population drifts randomly over generations, natural selection gradually leads traits to become more or less common based on the relative reproductive success of organisms with those traits.The age of the Earth is about 4.54 billion years old. The earliest undisputed evidence of life on Earth dates at least from 3.5 billion years ago, during the Eoarchean Era after a geological crust started to solidify following the earlier molten Hadean Eon. There are microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia. Other early physical evidence of a biogenic substance is graphite in 3.7 billion-year-old metasedimentary rocks discovered in western Greenland. More than 99 percent of all species, amounting to over five billion species, that ever lived on Earth are estimated to be extinct. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described.Evolution does not attempt to explain the origin of life (covered instead by abiogenesis), but it does explain how the extremely simple early lifeforms evolved into the complex ecosystem that we see today. Based on the similarities between all present-day organisms, all life on Earth originated through common descent from a last universal ancestor from which all known species have diverged through the process of evolution. All individuals have hereditary material in the form of genes that are received from their parents, then passed on to any offspring. Among offspring there are variations of genes due to the introduction of new genes via random changes called mutations or via reshuffling of existing genes during sexual reproduction. The offspring differs from the parent in minor random ways. If those differences are helpful, the offspring is more likely to survive and reproduce. This means that more offspring in the next generation will have that helpful difference and individuals will not have equal chances of reproductive success. In this way, traits that result in organisms being better adapted to their living conditions become more common in descendant populations. These differences accumulate resulting in changes within the population. This process is responsible for the many diverse life forms in the world.The forces of evolution are most evident when populations become isolated, either through geographic distance or by other mechanisms that prevent genetic exchange. Over time, isolated populations can branch off into new species.The majority of genetic mutations neither assist, change the appearance of, nor bring harm to individuals. Through the process of genetic drift, these mutated genes are neutrally sorted among populations and survive across generations by chance alone. In contrast to genetic drift, natural selection is not a random process because it acts on traits that are necessary for survival and reproduction. Natural selection and random genetic drift are constant and dynamic parts of life and over time this has shaped the branching structure in the tree of life.The modern understanding of evolution began with the 1859 publication of Charles Darwin's On the Origin of Species. In addition, Gregor Mendel's work with plants helped to explain the hereditary patterns of genetics. Fossil discoveries in paleontology, advances in population genetics and a global network of scientific research have provided further details into the mechanisms of evolution. Scientists now have a good understanding of the origin of new species (speciation) and have observed the speciation process in the laboratory and in the wild. Evolution is the principal scientific theory that biologists use to understand life and is used in many disciplines, including medicine, psychology, conservation biology, anthropology, forensics, agriculture and other social-cultural applications.