| 单词 | sexual reproduction |
| 例句 | Fossils, for example, and whether their existence disproved the Book of Genesis; Brother Mendel’s experiments on the sexual reproduction of the sweet pea; the fallacy of laudable pus. The Evolution of Calpurnia Tate 2009-05-12T00:00:00Z The song envisions the evolutionary moment when a one-celled organism grew tired of dividing alone and decided to share DNA with another cell: the beginning of sexual reproduction and, eventually, love. Jorge Drexler’s Music Connects Genres, Generations and Continents 2022-04-19T04:00:00Z Enter: “Tangerine Reef,” an audiovisual album featuring images of the sexual reproduction of coral reefs created to coincide with the celebration of 2018 as the “International Year of the Reef.” Animal Collective wants to do their own thing and that means saving coral reefs 2018-08-16T04:00:00Z We have to appeal to a multiplicity of binaries, however, because sexual reproduction has evolved many times and in many different ways across the living world. To Understand Sex, We Need to Ask the Right Questions 2023-10-24T04:00:00Z Studying parthenogenesis, she says, helps biologists to understand the benefits and trade-offs associated with sexual reproduction. ‘Virgin Birth’ Engineered into Female Animals for First Time 2023-08-01T04:00:00Z Not only do they lack the genetic diversity of organisms created in sexual reproduction but they only inherit half of their mother’s genetic diversity. Crocodile’s ‘Virgin Birth’ Is a First for Science’s History Books 2023-06-09T04:00:00Z Most species of diatoms reproduce asexually, although some instances of sexual reproduction and sporulation also exist. Fundamentals of Biology 2015-01-01T00:00:00Z Cells produced by meiosis in a diploid-dominant organism such as an animal will only participate in sexual reproduction. Concepts of Biology 2013-04-25T00:00:00Z The process has to be repeated for each new batch of seed to avoid the reshuffling of genes and loss of favorable traits that happens during ordinary sexual reproduction. ‘Game changer.’ Scientists are genetically engineering crops to clone themselves 2023-05-17T04:00:00Z A new preprint reveals the Californian death cap reproduces by fertilizing itself rather than waiting for a mate—an unusual sort of sexual reproduction in mushrooms that’s rarely been observed outside the lab. Death cap mushroom’s unusual sex life may be key to its rapid spread 2023-02-02T05:00:00Z They rely mainly on sexual reproduction, but can use asexual reproduction if necessary. Crocodile’s ‘Virgin Birth’ Is a First for Science’s History Books 2023-06-09T04:00:00Z During sexual reproduction, thousands of asci fill a fruiting body called the ascocarp. Fundamentals of Biology 2015-01-01T00:00:00Z Diplontic refers to a life cycle in which the diploid stage is the dominant stage, and the haploid chromosome number is only seen for a brief time in the life cycle during sexual reproduction. Concepts of Biology 2013-04-25T00:00:00Z During sexual reproduction, gametes—eggs and sperm—are created through meiosis, a process that results in haploid cells, with half the number of chromosomes. ‘Game changer.’ Scientists are genetically engineering crops to clone themselves 2023-05-17T04:00:00Z Some birds and bats also benefit flowering vegetation, acting as the liaison for sexual reproduction, a strange but widespread evolutionary practice. Climate change means more flies and fewer moths and bees, study says 2023-01-07T05:00:00Z If environmental conditions are poor, asexual reproduction involves less effort than sexual reproduction, because the female doesn’t need to waste time and energy finding a mate. Crocodile’s ‘Virgin Birth’ Is a First for Science’s History Books 2023-06-09T04:00:00Z Trematodes have complex lifecycles that involve a primary host in which sexual reproduction occurs, and one or more secondary hosts in which asexual reproduction occurs. Fundamentals of Biology 2015-01-01T00:00:00Z During sexual reproduction, the genetic material of two individuals is combined to produce genetically diverse offspring that differ from their parents. Concepts of Biology 2013-04-25T00:00:00Z For an apomictic hybrid variety to appeal to farmers, 100% of the seeds must be clonal because they won’t want the less vigorous seeds that are produced through normal sexual reproduction. ‘Game changer.’ Scientists are genetically engineering crops to clone themselves 2023-05-17T04:00:00Z So, too, are biology classes that involve sexual reproduction — even nonhuman reproduction. Montana’s new sex ed law ensnares English and history lessons, too 2022-12-02T05:00:00Z The improvement of the microscope in the 17th century and beyond made possible the identification of two components in sexual reproduction, but the functions of sperm and egg were still unclear. Abortion and authoritarianism: Why women's freedom threatens male supremacy 2022-10-23T04:00:00Z In fungi, sexual reproduction often occurs in response to adverse environmental conditions. Fundamentals of Biology 2015-01-01T00:00:00Z Trematodes have complex life cycles that involve a primary host in which sexual reproduction occurs and one or more secondary hosts in which asexual reproduction occurs. Concepts of Biology 2013-04-25T00:00:00Z For example, budding yeasts often release mating factors that enable them to participate in a process that is similar to sexual reproduction. Biology for AP Courses 2022-06-09T00:00:00Z “There’s so little information about the sexual reproduction of sea plants and algae,” van Tussenbroek says. In a First, Tiny Crustaceans Are Found to “Pollinate” Seaweed like Bees of the Sea 2022-07-28T04:00:00Z The haploid cells produced by meiosis develop into the gametes for sexual reproduction. Miller & Levine Biology 2018-01-01T00:00:00Z Both fertilization and embryo development take place inside an anatomical structure that provides a stable system of sexual reproduction largely sheltered from environmental fluctuations. Fundamentals of Biology 2015-01-01T00:00:00Z A likely explanation is that the variation that sexual reproduction creates among offspring is very important to the survival and reproduction of those offspring. Concepts of Biology 2013-04-25T00:00:00Z Because both asexual and sexual reproduction is rapid, yeast has become an important organism for the experimental investigation of mutagenesis and evolution among eukaryotes. Biology for AP Courses 2022-06-09T00:00:00Z Genetic diversity in a population comes from two main sources: mutation and sexual reproduction. Environmental Biology 2018-09-06T00:00:00Z Meiosis is an early step in sexual reproduction. Miller & Levine Biology 2018-01-01T00:00:00Z Some plants reproduce sexually, and others asexually, in contrast to animal species, which rely almost exclusively on sexual reproduction. Fundamentals of Biology 2015-01-01T00:00:00Z Sexual reproduction, specifically meiosis and fertilization, introduces variation into offspring that may account for the evolutionary success of sexual reproduction. Concepts of Biology 2013-04-25T00:00:00Z Although all life shares various genetic similarities, only certain organisms combine genetic information by sexual reproduction and produce viable and fertile offspring that, in turn, can successfully reproduce. Biology for AP Courses 2022-06-09T00:00:00Z Variation within populations occurs by the natural mixing of genes through sexual reproduction or from naturally occurring mutations. An Introduction to Geology 2017-01-01T00:00:00Z In sexual reproduction, cells from two different parents come together to produce the first cell of the new organism. Miller & Levine Biology 2018-01-01T00:00:00Z Birds produce offspring by laying eggs which are fertilised by sexual reproduction. Fundamentals of Biology 2015-01-01T00:00:00Z All of these advantages to asexual reproduction, which are also disadvantages to sexual reproduction, should mean that the number of species with asexual reproduction should be more common. Concepts of Biology 2013-04-25T00:00:00Z For the changed trait to be passed on by sexual reproduction, a gamete, such as a sperm or egg cell, must possess the changed trait. Biology for AP Courses 2022-06-09T00:00:00Z Endocrine disruptors mimic hormones and can cause long-term effects in developing sexual reproduction systems in developing animals. An Introduction to Geology 2017-01-01T00:00:00Z There are two types of reproduction, asexual and sexual reproduction. Miller & Levine Biology 2018-01-01T00:00:00Z Some fungal organisms multiply only asexually, whereas others undergo both asexual reproduction and sexual reproduction with alternation of generations. Fundamentals of Biology 2015-01-01T00:00:00Z During sexual reproduction, specialized haploid cells from two individuals join to form a diploid zygote. Concepts of Biology 2013-04-25T00:00:00Z What is a likely evolutionary advantage of sexual reproduction over asexual reproduction? Biology for AP Courses 2022-06-09T00:00:00Z In 2003, a study found that two species of irradiated worms near Chernobyl had altered their sexual behavior, in many cases becoming more prone to sexual reproduction than asexual reproduction. Animals near Fukushima are doing surprisingly well despite radiation from nuclear accident 2021-10-19T04:00:00Z Offspring produced by sexual reproduction inherit some of their genetic information from each parent. Miller & Levine Biology 2018-01-01T00:00:00Z Spores are generally produced through sexual reproduction, rather than asexual reproduction. Fundamentals of Biology 2015-01-01T00:00:00Z So, in addition to fertilization, sexual reproduction includes a nuclear division, known as meiosis, that reduces the number of chromosome sets. Concepts of Biology 2013-04-25T00:00:00Z Two alternative explanations for the evolution of sexual reproduction are popular. Biology for AP Courses 2022-06-09T00:00:00Z Forced sterilization is defined as the involuntary medical “process or act that renders as individual incapable of sexual reproduction” and a grave human rights violation still occurring in many pockets around the world. New documentary highlights the forced sterilization of women in California prison 2020-06-15T04:00:00Z Genetic variation is produced in three main ways: mutation, genetic recombination during sexual reproduction, and lateral gene transfer. Miller & Levine Biology 2018-01-01T00:00:00Z However, sexual reproduction is often associated with resistant cysts that are a protective, resting stage. Fundamentals of Biology 2015-01-01T00:00:00Z Natural sexual reproduction involves the union, during fertilization, of a sperm and an egg. Concepts of Biology 2013-04-25T00:00:00Z Genetic diversity in a population comes from two main mechanisms: mutation and sexual reproduction. Biology for AP Courses 2022-06-09T00:00:00Z It’s also only visible when it sprouts gory, red, funguslike flowers up from the ground for sexual reproduction. Caught in the act: Opossums pollinate bizarre parasitic plant 2020-02-12T05:00:00Z The special aspect of sexual reproduction is the random association of individual chromosomes of homologous pairs during meiosis and the combination of different alleles coming from two parents. Miller & Levine Biology 2018-01-01T00:00:00Z Plant sexual reproduction usually depends on pollinating agents, while asexual reproduction is independent of these agents. Fundamentals of Biology 2015-01-01T00:00:00Z Sexual reproduction, involving meiosis and fertilization, is common among protists, and many protist species can switch from asexual to sexual reproduction when necessary. Concepts of Biology 2013-04-25T00:00:00Z We also previously explored how meiosis followed by sexual reproduction produces offspring that are genetically different from their parents. Biology for AP Courses 2022-06-09T00:00:00Z That way they can benefit from the host's sexual reproduction, which enables intact copies to replace mutated ones. A love of insects and their microbial partners helped this biologist reveal secrets of symbiosis 2019-11-14T05:00:00Z Because meiosis and fertilization do not change the proportions of allele occurrences, sexual reproduction alone does not lead to evolution. Miller & Levine Biology 2018-01-01T00:00:00Z Traditionally, these plants survive well under stable environmental conditions when compared with plants produced from sexual reproduction because they carry genes identical to those of their parents. Fundamentals of Biology 2015-01-01T00:00:00Z However, sexual reproduction is also often associated with cysts that are a protective, resting stage. Concepts of Biology 2013-04-25T00:00:00Z Although sexual reproduction allows for greater genetic variation in offspring, organisms that reproduce sexually must maintain males and females in the population, which can limit the ability to colonize new habitats. Biology for AP Courses 2022-06-09T00:00:00Z And it took just 100 generations for the species to evolve "barriers to sexual reproduction". The stick insect that lost its sex drive 2019-08-20T04:00:00Z In sexual reproduction, reproductive cells from two parents are fused to form a new individual. Miller & Levine Biology 2018-01-01T00:00:00Z The process of sexual reproduction in Paramecium underscores the importance of the micronucleus to these protists. Fundamentals of Biology 2015-01-01T00:00:00Z Some fungal organisms multiply only asexually, whereas others undergo both asexual reproduction and sexual reproduction. Concepts of Biology 2013-04-25T00:00:00Z Parthenogenesis is a type of sexual reproduction that produces diverse offspring. Biology for AP Courses 2022-06-09T00:00:00Z Also, sexual reproduction introduces new genetic variation within a species. Life With No Males? These Termites Show That It’s Possible 2018-09-28T04:00:00Z During sexual reproduction, male and female reproductive cells join in a process called fertilization to produce a new cell. Miller & Levine Biology 2018-01-01T00:00:00Z The true characteristic shared by all of these diverse species is that their gonads for sexual reproduction are derived from epidermal tissue, whereas in all other cnidarians they are derived from gastrodermal tissue. Fundamentals of Biology 2015-01-01T00:00:00Z Most animals undergo sexual reproduction, while many also have mechanisms of asexual reproduction. Concepts of Biology 2013-04-25T00:00:00Z In sexual reproduction, gametes with either an X or Y chromosome are formed in males, whereas gametes in females contain a single X chromosome. Biology for AP Courses 2022-06-09T00:00:00Z Two unique versions in one organism – biologists call them alleles – implies that neither a simple mutation nor sexual reproduction could easily explain their presence. Get Big Quick? Just Graft Some Friends 2018-09-15T04:00:00Z Mutation and gene shuffling during sexual reproduction produce the heritable variation on which natural selection works. Miller & Levine Biology 2018-01-01T00:00:00Z The haploid gametophyte alternates with the diploid sporophyte during the sexual reproduction process of angiosperms. Fundamentals of Biology 2015-01-01T00:00:00Z During sexual reproduction, the male and female gametes of a species combine in a process called fertilization. Concepts of Biology 2013-04-25T00:00:00Z In sexual reproduction, two cells of a species combine to form another cell. Biology for AP Courses 2022-06-09T00:00:00Z Haploid yeast reproduce asexually, but they can also mate through sexual reproduction to form diploid yeast, which contain two copies of each chromosome. Yeast chromosome numbers minimized using genome editing 2018-07-31T04:00:00Z A mature male germ cell, this microscopic vessel is crucial for sexual reproduction. Human Sperm Has a Surprising Tail Shape We've Never Noticed Before 2018-02-22T05:00:00Z Nature tends to prefer sexual reproduction because the mix of genes creates healthier animals. Virgin Birth, Double Uteri, and Other Wondrous Female Abilities 2017-08-12T04:00:00Z Trematodes have complex life cycles involving a secondary mollusk host and a primary host in which sexual reproduction takes place. Concepts of Biology 2013-04-25T00:00:00Z Haploid cells that are necessary for sexual reproduction are produced by a type of cell division called meiosis. Biology for AP Courses 2022-06-09T00:00:00Z The groups showed that the n = 1 and n = 2 strains can undergo sexual reproduction, albeit with reduced efficiency compared with wild-type yeast, and produce spores that are slightly less viable. Yeast chromosome numbers minimized using genome editing 2018-07-31T04:00:00Z The model explains several diverse aspects of sexual reproduction, says Lane, but testing it will be challenging. Why humans develop sex cells as embryos — but corals don't 2016-12-19T05:00:00Z Gene drives are highly controversial: if they work, they could give humans the power to wipe out—with minimal effort—any species that engages in sexual reproduction. A mystery no more 2016-09-15T04:00:00Z Some animals produce offspring through asexual reproduction while other animals produce offspring through sexual reproduction. Concepts of Biology 2013-04-25T00:00:00Z Not all sexually reproducing eukaryotes reproduce solely by sexual reproduction. Biology for AP Courses 2022-06-09T00:00:00Z That’s because, with CRISPR, a change made on one chromosome would copy itself in every successive generation, so that nearly all descendants would inherit the change, dispensing with the random selection involved in sexual reproduction. Could Genetically Modified Mosquitoes Save Hawaii’s Endangered Birds? 2016-09-09T04:00:00Z Although domestication led sexual reproduction to decay, traits useful for life in a brewery became more common. Domesticated tipple 2016-09-08T04:00:00Z The next big moment, Schopf said, was the appearance of sexual reproduction roughly a billion years ago. The 4 biggest milestones in the history of life on Earth 2016-09-01T04:00:00Z This is a disadvantage of sexual reproduction compared to asexual reproduction. Concepts of Biology 2013-04-25T00:00:00Z The fact that nearly every multicellular organism on Earth employs sexual reproduction is strong evidence for the benefits of producing offspring with unique gene combinations, though there are other possible benefits as well. Biology for AP Courses 2022-06-09T00:00:00Z Honeysuckle is not solely dependent upon sexual reproduction, though; the aggressive vine reproduces vegetatively as well, easily rooting where its stems contact the ground. Why the Sweet Scent of Japanese Honeysuckle Signals Trouble 2016-06-24T04:00:00Z Six lines of each mating type were forced to undergo sexual reproduction every 90 generations, by mixing the sexes together and adding the antibiotics. Plucking rubies from the rubbish 2016-02-24T05:00:00Z The organism is easy to work with in the laboratory and unlikely to spread a gene drive into wild populations because of its infrequent sexual reproduction. Safety upgrade found for gene-editing technique 2015-11-15T05:00:00Z During sexual reproduction, a sperm and an egg combine to form a fetus. The Verge Review of Animals: the all-female whiptail lizard 2015-07-19T04:00:00Z One of the ways that sexual reproduction enhances the diversity of offspring from the same parents is through a process called crossing over. Biology for AP Courses 2022-06-09T00:00:00Z The trilogy is a metaphor for sexual reproduction. 5 Fan Theories About 'Back to the Future' So Absurd They Might Be True 2015-07-02T04:00:00Z But sexual reproduction offers no guarantees that offspring will exhibit the desired traits of the parents. Preemptive Genetics Girds Farmers for Climate Extremes and Disease 2015-06-10T04:00:00Z This roster of surprise arrivals included sharks, snakes, Komodo dragons and turkeys - all species that normally use sexual reproduction. 'Virgin-born' sawfish are a first in the wild - BBC News 2015-06-01T04:00:00Z "The core technology can be used in any insect really, as long as it employs sexual reproduction," says Mr Parry. Is the world ready for GM animals? 2015-02-24T05:00:00Z In eukaryotes, sexual reproduction involves the recombination of heritable information from both parents via meiosis followed by fertilization. Biology for AP Courses 2022-06-09T00:00:00Z He noted that while American zoos preferred to use contraception to prevent overpopulation or inbreeding, European zoos often let animals breed and express their natural behavior, including sexual reproduction. Lion-Killing at Danish Zoo Provokes Fresh Outrage 2014-03-26T21:04:32Z This month, a team of researchers in Oregon and Germany released a series of remarkable photographs of a 100-million-year-old flower frozen in the act of sexual reproduction in a piece of amber. How amber locks history in its golden tomb 2014-01-20T20:49:32Z All seed-producing plants make pollen, with each grain enclosing the developing male cell used in sexual reproduction. Earlier origin for flowering plants 2013-10-01T19:40:40Z Loss of sexual reproduction is considered an evolutionary dead end for metazoans, but bdelloid rotifers challenge this view as they appear to have persisted asexually for millions of years. Genomic evidence for ameiotic evolution in the bdelloid rotifer Adineta vaga 2013-08-21T17:50:58.107Z The role of the meiotic segregation of chromosomes in sexual reproduction was not understood by the scientific community during Mendel’s lifetime. Biology for AP Courses 2022-06-09T00:00:00Z Many plants we're familiar with, such as flowering plants, undergo sexual reproduction by making seeds, where each seed contains an embryo that will grow into a mature plant under the right conditions. Sci-Fi Science: Attack of the Cabbage Clones 2013-03-14T14:15:00.353Z After five weeks in the dark, the fungi produced special structures called cleistothecia and ascospores, which only occur after sexual reproduction. The Joy of Fungal Sex: Penicillin Mold Can Reproduce Sexually, Which Could Lead to Better Antibiotics 2013-02-08T12:15:00.507Z SNPs act as markers for blocks of DNA that get swapped around during the process of sexual reproduction. Prehistoric migration: An Antipodean Raj 2013-01-17T16:04:38Z Biologists think that sexual reproduction evolved as a way to mix the gene pool and reduce the impact of harmful mutations. Slideshow: Virgin Birth Not So Miraculous in Animal Kingdom 2012-12-27T14:51:40Z When variations occur within a species, they can only be passed to the next generation along two main pathways: asexual reproduction or sexual reproduction. Biology for AP Courses 2022-06-09T00:00:00Z These two different types of reproduction are sexual reproduction and asexual reproduction. Sci-Fi Science: Attack of the Cabbage Clones 2013-03-14T14:15:00.353Z But this trait also removes sexual reproduction from the equation. Banana Genome Could Help Bunches 2012-07-23T21:45:00.283Z This sexual reproduction strategy is actually quite remarkable, considering that the mosses and the microarthropods that apparently help pollinate them emerged as some of the first co-occurring forms of life on land. Moss Sperm Smells Sweet Enough for Sex 2012-07-18T17:45:00.430Z This method of sexual reproduction produces eggs with an extra shell layer that lets them survive the stressful period. Slideshow: Virgin Birth Not So Miraculous in Animal Kingdom 2012-12-27T14:51:40Z However, the process of sexual reproduction, which also introduces genetic variance, is not random. Biology for AP Courses 2022-06-09T00:00:00Z Although asexual reproduction usually produces plants with relatively less diversity compared with those created via sexual reproduction, asexual reproduction can be quite useful. Sci-Fi Science: Attack of the Cabbage Clones 2013-03-14T14:15:00.353Z But bear this in mind, parents, there are other ways for your child to contribute to your overall genetic success than humdrum sexual reproduction. Is Your Child Gay? 2012-07-06T14:15:00.207Z In a process akin to sexual reproduction, the loops swap bits of code to create offspring. Computer Program 'Evolves' Music From Noise 2012-06-18T22:38:42Z Sexual Reproduction in Relation to New Characters.—Some biologists attribute great importance to sexual reproduction as a basis of variation and the origin of new characters. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z Because sexual reproduction is not random, the overall process of evolution is not random, either. Biology for AP Courses 2022-06-09T00:00:00Z In a region where abortion is restricted almost everywhere, the issue of sexual reproduction rights, Ms. Lasagabaster said, is a lightning rod. The Female Factor: Latin America Opens Up to Equality 2012-05-01T15:25:07Z In sexless reproduction one parent is enough; in sexual reproduction equivalent masses of germ-plasm from each parent combine to form the new individual. Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 3 "Helmont, Jean" to "Hernosand" 2012-04-14T02:00:23.707Z Flowers, the means of sexual reproduction, present an opportunity to diversify. City Room: Spring Time: Dance of the Bumblebees 2012-04-12T18:06:10Z As a matter of fact the two ideas are not mutually exclusive; sexual reproduction may accomplish both of these ends. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z So, in addition to fertilization, sexual reproduction includes a nuclear division that reduces the number of chromosome sets. Biology for AP Courses 2022-06-09T00:00:00Z What other reason can there be why the circuitous process of sexual reproduction has been preferred? Herbert Spencer 2012-02-29T03:00:20.773Z These experiments and results, however, appear to relate exclusively to sexual reproduction and almost entirely to the crossing of artificial varieties of animals and plants. Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 3 "Helmont, Jean" to "Hernosand" 2012-04-14T02:00:23.707Z Parthenogenesis is prevalent in the Branchiopoda and Ostracoda, often in more or less definite seasonal alternation with sexual reproduction. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z The Fertilized Ovum Termed a Zygote.—After a number of generations of such asexual reproduction, sexual reproduction occurs. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z And yet, scientists recognize some real disadvantages to sexual reproduction. Biology for AP Courses 2022-06-09T00:00:00Z We believe the answer to be that sexual reproduction is an adaptive process securing the benefits of amphimixis, for in amphimixis and in the changes preparatory to it, there is an important source of variation. Herbert Spencer 2012-02-29T03:00:20.773Z Zeugung, and may comprehend the whole history of the first origin and continued reproduction of living bodies, whether plants or animals; but it is frequently restricted to the sexual reproduction of animals. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 5 "Gassendi, Pierre" to "Geocentric" 2011-09-02T02:00:20.450Z In sexless reproduction one parent is enough; in sexual reproduction equal masses of germplasm from each parent combine to form the new individual. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z It is clear that sexual reproduction may be one important means by which a given new character which has arisen in one or a few individuals may become incorporated in the species at large. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z The mechanisms of variation—crossover, random assortment of homologous chromosomes, and random fertilization—are present in all versions of sexual reproduction. Biology for AP Courses 2022-06-09T00:00:00Z Conversely the recurrence of sexual reproduction occurs when the conditions are no longer so favourable to growth. Herbert Spencer 2012-02-29T03:00:20.773Z Mycelium well developed; sexual reproduction by zygospores; asexual reproduction by sporangia and conidia. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Although it is rare for more than two buds to be produced simultaneously, budding is apparently a more usual form of reproduction than sexual reproduction. Freshwater Sponges, Hydroids & Polyzoa 2011-06-25T02:00:17.833Z For in all higher animals, at least, offspring may possess some of the characteristics originally present in either of two lines of ancestry, and this commingling of such possessions is possible only through sexual reproduction. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z The variation introduced into the reproductive cells by meiosis appears to be one of the advantages of sexual reproduction that has made it so successful. Biology for AP Courses 2022-06-09T00:00:00Z Now, while Spencer was probably right in saying that fertilisation promotes change, we cannot think that he succeeded in finding what he was seeking, namely a primary physiological reason why sexual reproduction should occur. Herbert Spencer 2012-02-29T03:00:20.773Z A. Phycomycetes.—Most of the recent work of importance in this group deals with the cytology of sexual reproduction and of spore-formation, and the effect of external conditions on the production of reproductive organs. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z One school considers the intricate complications of genetics, like the ways different versions of a gene interact in sexual reproduction. How Evolution Explains Altruism 2011-04-09T05:00:06Z The sexual reproduction of the colonies of the Volvocaceae is one of the most important phenomena presented by the Protozoa. Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 4 "Finland" to "Fleury, Andre" 2011-03-20T02:00:30.697Z What is a disadvantage of sexual reproduction over asexual forms of reproduction? Biology for AP Courses 2022-06-09T00:00:00Z Thus in sexual reproduction two hereditary tendencies are in a sense intermingled. Herbert Spencer 2012-02-29T03:00:20.773Z The sexual reproduction shows all transitions between forms which are normally sexual, like the Peronosporaceae, to forms in which no antheridium is developed and the oospheres develop parthenogenetically. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z It must include all the developmental processes which take place as a result of sexual reproduction. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" 2011-02-06T03:00:53.093Z This special type of sexual reproduction only occurs in some mosses and some other seedless plants such as ferns. Single plant 'conquered America' 2011-01-13T09:47:53Z There are several possible explanations, one of which is that the variation that sexual reproduction creates among offspring is very important to the survival and reproduction of the population. Biology for AP Courses 2022-06-09T00:00:00Z Anabolism and katabolism are the two sides of protoplasmic life, and the major rhythms of the respective preponderance of these give the antitheses of growth and multiplication, asexual and sexual reproduction. Herbert Spencer 2012-02-29T03:00:20.773Z Before then, sexual reproduction in fish consisted of spawning, wherein females deposit eggs in the , the males fertilize them, and the embryos then develop out in the open. Dawn of the Deed: the Origin of Sex [Video] 2011-01-04T16:18:07.643Z It has been present in the great lyric poets of all time, a mystery like that of sexual reproduction, which awakens only at the age of ripeness. Paul Verlaine 2010-12-28T03:00:19.670Z The rate of sexual reproduction remained the same where the food quality was consistently high or low, but it increased significantly in the mixed region over generations, the researchers found. Observatory: When Procreation Is a Matter of Real Estate 2010-10-13T17:06:00Z However, sexual reproduction produces offspring whose genotypes differ from both parents, thus creating a moving target for pathogen evolution, which slows down pathogen advances. Genetic Diversity Protects Against Viruses 2010-09-30T17:45:00Z But there remains, he says, the more difficult question—Why does sexual reproduction recur? Herbert Spencer 2012-02-29T03:00:20.773Z Behaviour of the sexes The hormone of laddishness Oestrogen, not testosterone, is what makes a male act like a male IN ALL species that practise sexual reproduction, males and females show gender-specific behaviours. Behaviour of the sexes: The hormone of laddishness 2010-04-29T11:22:00Z Another difficulty might be supposed to arise between animals which produce themselves other than by sexual reproduction. Was Man Created? In this species, besides the regular sexual development, by means of sporangia, there is a so-called sexual reproduction by means of zygospores, which takes place in this wise. Fungi: Their Nature and Uses This is required to favor sexual reproduction in their hosts, and also what will cause the greatest problems for low diversity hosts, such as endangered species, he said. Genetic Diversity Protects Against Viruses 2010-09-30T17:45:00Z In this mingling, I see the cause of the hereditary individual characteristics; and in the production of these characters, the task of sexual reproduction. Herbert Spencer 2012-02-29T03:00:20.773Z So far as we have studied the question we see in the animal and vegetable kingdoms sexual reproduction, or conjugation, as a sine qua non for the indefinite continuation of life. The Sexual Question A Scientific, psychological, hygienic and sociological study If this fact were fully established, it would, by the aid of our hypothesis, connect gemmation and sexual reproduction in the closest manner. The Variation of Animals and Plants Under Domestication, Volume II (of 2) They are characterized by the absence of ordinary sexual reproduction and by the absence of an ordinary nucleus. Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 2 "Baconthorpe" to "Bankruptcy" Those of the next order propagate both by solitary and sexual reproduction, as those buds and bulbs which produce flowers as well as other buds or bulbs; and the aphis, and probably many other insects. The Temple of Nature; or, the Origin of Society A Poem, with Philosophical Notes We have entered on this digression partly for clearness sake, and partly to explain why Spencer had, as we think, very limited success in his answer to the question: Why does sexual reproduction occur? Herbert Spencer 2012-02-29T03:00:20.773Z Fission and sexual reproduction arise from the simple fact that the growth of each individual is necessarily limited in space as well as time. The Sexual Question A Scientific, psychological, hygienic and sociological study Splitting into two or many parts was the old-fashioned way of multiplying, but one of the great steps in evolution was the discovery of a better method, namely, sexual reproduction. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told It is a much-disputed point whether sexual reproduction occurs in any of them, and it is highly probable that in the great majority, at any rate, the reproduction is purely non-sexual. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses So in the sexual reproduction of animals, certain parts separated from the living organs, and floating in the blood, are arrested by the sexual glands of the female, and others by those of the male. The Temple of Nature; or, the Origin of Society A Poem, with Philosophical Notes The reproductive organs borne by the thallus or plant are called antheridia and archegonia, and serve for sexual reproduction. Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" Back in 75, we had had a two-week session on sexual reproduction, like all the other subjects. A Place so Foreign Now, this sexual reproduction occurs very widely in the organic world. The Story of the Living Machine A Review of the Conclusions of Modern Biology in Regard to the Mechanism Which Controls the Phenomena of Living Activity Thus, according to Weismann's earlier view, the origin of variation was to be sought in sexual reproduction through the mingling of slightly different germ-plasms. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 There came a time in the evolution of the groups possessing sexual reproduction, when increasing specialization necessitated the division into reproductive and non-reproductive cells. Taboo and Genetics A Study of the Biological, Sociological and Psychological Foundation of the Family Nature has put upon women the greater part of the burden of sexual reproduction; they have consequently become the supreme authorities on all matters in which the sexual emotions come into question. Studies in the Psychology of Sex, Volume 3 Analysis of the Sexual Impulse; Love and Pain; The Sexual Impulse in Women Thus I have endeavored to sum up the processes of asexual and of sexual reproduction. Scientific American Supplement, No. 531, March 6, 1886 The sexual reproduction of the many-celled animals is always essentially alike. The Story of the Living Machine A Review of the Conclusions of Modern Biology in Regard to the Mechanism Which Controls the Phenomena of Living Activity Especially, that form of sexual reproduction in which an embryo undergoes a series of marked changes of external form, as the chrysalis stage, pupa stage, etc., in insects. The Gutenberg Webster's Unabridged Dictionary Section M, N, and O If this nucleus is a male the characters are those of the male line; if a female those of the female line, and in sexual reproduction where the two are fused, half and half. Taboo and Genetics A Study of the Biological, Sociological and Psychological Foundation of the Family Segregation seems to be a very difficult process in the vegetative way, but it must be very easy in sexual reproduction, indeed so easy as to show itself in nearly every single instance. Species and Varieties, Their Origin by Mutation We base these hypotheses on the fact that we do to-day find the simplest form of sexual reproduction in some of the living gastraeads and other lower animals, especially the sponges. The Evolution of Man — Volume 2 The variations which occur in organisms are so great that they would sometimes run into abnormal structures were it not for the fact that sexual reproduction constantly tends to reduce them. The Story of the Living Machine A Review of the Conclusions of Modern Biology in Regard to the Mechanism Which Controls the Phenomena of Living Activity In these intermediate stages sexual reproduction is usually impossible, but they ultimately pass into final and sexually developed forms, from the union of which organisms are produced which pass through the same cycle of changes. The Gutenberg Webster's Unabridged Dictionary Section M, N, and O The origin of sexual reproduction in animals must have been something as follows: The first method of reproduction was by a simple division of the unicellular organism to form two new individuals. Taboo and Genetics A Study of the Biological, Sociological and Psychological Foundation of the Family Biologists tell us that the meaning or purpose of sexual reproduction is to bring about greater organic variation. Sociology and Modern Social Problems On the other hand, sexual reproduction is the general rule with all the higher organisms, both animal and plant; very rarely do we find asexual reproduction among them. The Evolution of Man — Volume 1 But this must be the meaning of sexual reproduction. Darwiniana; Essays and Reviews Pertaining to Darwinism For if, as I am now convinced, this is possible, it is a most important fact, which will sooner or later change the views held by physiologists with respect to sexual reproduction. The Variation of Animals and Plants under Domestication — Volume 1 Mr. Galton supposes, in sexual reproduction, where two parents contribute germs to the embryo the chance of deficiency of any of the necessary germs is greatly diminished. More Letters of Charles Darwin — Volume 1 The individuality of the species is represented by the whole of the form produced between two sexual reproductions; and these forms, which are apparently individual animals, have been called ZOOIDE. The Origin of Species by means of Natural Selection, 6th Edition We must, however, try to get a very clear idea of this process and the meaning of sexual reproduction. The Evolution of Man — Volume 1 These also have sexual reproduction; but in it two old individuals are always destroyed to make a single new one! Darwiniana; Essays and Reviews Pertaining to Darwinism These were concerned with plants of different families and led to results which are of fundamental importance for a true explanation of sexual reproduction. Darwin and Modern Science This suggests the conclusion that quantitative internal changes in the cells, and with them disturbances in the degree of concentration, are induced, through which the chemical reactions are led in the direction of sexual reproduction. Darwin and Modern Science The answer to this question must, moreover, possess the greatest significance for the correct understanding of sexual reproduction in general. Darwin and Modern Science It is certain that so difficult a problem as that of the significance of sexual reproduction requires much more investigation. Darwin and Modern Science And again his work "Cross and Self Fertilisation" may be condensed to a point of view of great importance in reference to the meaning and origin of sexual reproduction. Darwin and Modern Science If we wish to form a mental image of the process of evolution we have to reckon with the possibility that parthenogenetic propagation may have preceded sexual reproduction. Darwin and Modern Science This holds good for the quantitative variations which induce sexual reproduction in algae. Darwin and Modern Science We have seen that his object was to elucidate important general questions, particularly the question of the significance of sexual reproduction. Darwin and Modern Science The distribution of quantities is especially important in the sexual reproduction of algae, for which a vigorous production of the materials formed during carbon-assimilation appears to be essential. Darwin and Modern Science The most important stage in the life of a flowering plant is the transition from purely vegetative growth to sexual reproduction—that is, the production of flowers. Darwin and Modern Science To quote a single example; I may put the question, what internal changes produce a transition from vegetative growth to sexual reproduction? Darwin and Modern Science |
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