| 单词 | unicellular |
| 例句 | As the colon has been wiped clean with antibiotics, the unicellular arrivals won't have to battle a lot of natives. It's a gut reaction: how other people's bacteria can cure us – extract 2013-03-31T00:05:02Z "We have illuminated the dynamics of synchronization in biological species, which can also be applied to other living creatures such as birds, animals, bacteria, and even unicellular eukaryotes," adds Ito. Two fins are better than one: Fish synchronize tail fins to save energy 2023-11-06T05:00:00Z Chlamydomonas is a simple, unicellular chlorophyte with a pear-shaped morphology and two opposing, anterior flagella that guide this protist toward light sensed by its eyespot. Fundamentals of Biology 2015-01-01T00:00:00Z Most protists are microscopic and unicellular, but some true multicellular forms exist. Concepts of Biology 2013-04-25T00:00:00Z In comb jellies and the unicellular relatives, they identified 14 groups of genes on separate chromosomes. Comb jelly ancestor may have been first animal to branch from tree of life 2023-05-17T04:00:00Z Living entities, even at the unicellular level, are highly organized and systematic. College Physics for AP Courses 2015-08-12T00:00:00Z Some cells are even capable of engulfing entire unicellular microorganisms. Biology for AP Courses 2022-06-09T00:00:00Z Conidiospores are unicellular or multicellular spores that are released directly from the tip or side of the hypha. Fundamentals of Biology 2015-01-01T00:00:00Z Whether in a simple unicellular organism or in a complex multicellular organism, each cell controls when and how its genes are expressed. Concepts of Biology 2013-04-25T00:00:00Z To maintain homeostasis, unicellular organisms grow, respond to the environment, transform energy, and reproduce. Miller & Levine Biology 2018-01-01T00:00:00Z Unlike the other domains, Domain Eukarya contains multicellular organisms, in addition to unicellular species. Environmental Biology 2018-09-06T00:00:00Z In a diploid dominant cycle, the unicellular diploid stage is present, as in humans. Biology for AP Courses 2022-06-09T00:00:00Z Dimorphic fungi can change from the unicellular to multicellular state depending on environmental conditions. Fundamentals of Biology 2015-01-01T00:00:00Z The early eukaryotes were unicellular like most protists are today, but as eukaryotes became more complex, the evolution of multicellularity allowed cells to remain small while still exhibiting specialized functions. Concepts of Biology 2013-04-25T00:00:00Z Ancestors of land plants lived in water, like green algae, and most were unicellular, though some were multicellular. Miller & Levine Biology 2018-01-01T00:00:00Z Kingdom Fungi includes multicellular and unicellular, heterotrophic fungi. Environmental Biology 2018-09-06T00:00:00Z The cell of the unicellular algae Ventricaria ventricosa is one of the largest known, reaching one to five centimeters in diameter. Biology for AP Courses 2022-06-09T00:00:00Z The red and green algae include unicellular, multicellular, and colonial forms. Fundamentals of Biology 2015-01-01T00:00:00Z Some fungi are dimorphic because they can go from being unicellular to multicellular depending on environmental conditions. Concepts of Biology 2013-04-25T00:00:00Z The smallest and most abundant microorganisms are prokaryotes—unicellular organisms that lack a nucleus. Miller & Levine Biology 2018-01-01T00:00:00Z As a group, protists are very diverse and include unicellular, multicellular, heterotrophic, and autotrophic organisms. Environmental Biology 2018-09-06T00:00:00Z Bacteria are unicellular, prokaryotic organisms that have some of the least complex life processes in place; however, prokaryotes such as bacteria do not contain membrane-bound vacuoles. Biology for AP Courses 2022-06-09T00:00:00Z Some protists are unicellular in the haploid form and multicellular in the diploid form, a strategy employed by animals. Fundamentals of Biology 2015-01-01T00:00:00Z Fungi can be unicellular as yeasts or develop a network of filaments called a mycelium, often described as mold. Concepts of Biology 2013-04-25T00:00:00Z Many unicellular protists move like amoebas, changing their shape in a process that makes use of pseudopods. Miller & Levine Biology 2018-01-01T00:00:00Z Some organisms are made of just a single cell, and are thus referred to as unicellular. Environmental Biology 2018-09-06T00:00:00Z Some unicellular organisms, such as the amoeba, ingest food by endocytosis. Biology for AP Courses 2022-06-09T00:00:00Z Like diatoms, golden algae are largely unicellular, although some species can form large colonies. Fundamentals of Biology 2015-01-01T00:00:00Z The unicellular glands are scattered single cells, such as goblet cells, found in the mucous membranes of the small and large intestine. Anatomy and Physiology 2013-06-19T00:00:00Z Then those survivors died as well; Daszak helped identify a unicellular parasite of the genus Steinhausia—which the snails caught and spread to one another in captivity—as the culprit. ‘We’ve done nothing wrong.’ EcoHealth leader fights charges that his research helped spark COVID-19 2021-11-16T05:00:00Z Indeed, many other organisms, including unicellular eukaryotes, contain the same synaptic genes, says Sally Leys, a marine biologist at the University of Alberta in Edmonton, Canada. Sponge Cells Hint at Origins of Nervous System 2021-11-09T05:00:00Z Some unicellular eukaryotic organisms undergo binary fission by mitosis. Biology for AP Courses 2022-06-09T00:00:00Z Jennings, too, as early as the turn of the 20th century, sensed and believed that the behavioral workings of animals were often elaborations on systems already in place in unicellular life. Can a Cell Remember? 2021-05-28T04:00:00Z In their experiment, Roska and his colleagues engineered a light-sensitive protein called ChrimsonR, which is found in unicellular algae, and then inserted them into modified viruses that were injected into one of his eyes. In a huge advance for gene therapy, inserting algae genes in a human partially cures blindness 2021-05-27T04:00:00Z The indifferent process of Darwinian evolution by natural selection took a laborious 3.85 billion years to craft us from our unicellular microorganism precursors into the way we are today. Review | With CRISPR, humans can create their own evolutionary future 2020-11-19T05:00:00Z Now, the field’s pioneers are moving beyond the well-established unicellular laboratory models of yeast and E. coli, towards complex bacteria — and even into plant and mammalian cells. How to build a genome 2020-02-23T05:00:00Z An example of a positive chemotaxis is exhibited by the unicellular protozoan Tetrahymena thermophila. Biology for AP Courses 2022-06-09T00:00:00Z In the unicellular world, organisms rely on their external medium when transmitting signals between cells. Cell communication in the blink of an eye 2019-07-09T04:00:00Z Others range from unicellular eukaryotes to multicellular seaweeds many metres long. A brief history of slime 2019-06-02T04:00:00Z During my doctoral work I discovered that unicellular organisms are able to replicate without exhibiting aging, and it might be that further studying how these cells maintain genetic stability is key. A New Idea about How Cancer Begins 2019-03-01T05:00:00Z A decade ago, a radical theory of cancer emerged: that this plague of multicellular organisms arises when their cells rewind the evolutionary clock and revert to acting like unicellular life. The momentous transition to multicellular life may not have been so hard after all 2018-06-28T04:00:00Z Many unicellular organisms, such as yeast, and a few multicellular organisms, such as sponges, can produce genetically identical clones of themselves through cell division. Biology for AP Courses 2022-06-09T00:00:00Z Not that we walked into his lab with the idea of eating some stinky, unicellular organism. How slime mold could shape the future of self-driving cars 2018-05-01T04:00:00Z Damasio traces core components of the human “cultural mind”, such as social behaviour and cooperation, back to the non-human biology of unicellular organisms present at the inception of life. The messy biological basis of culture 2018-01-29T05:00:00Z But Chitwood’s study showed that gene expression in the unicellular seaweed varies in ways that echo gene expression in similar structures in multicellular plants—suggesting that the dividing cell needn’t always dictate morphology. The Lost Art of Looking at Plants 2018-01-24T05:00:00Z Goode and his colleagues suggested that in cancer, mutations that cripple the networks cause those constraints to break down, giving genes suited to a unicellular lifestyle free rein to drive growth. The momentous transition to multicellular life may not have been so hard after all 2018-06-28T04:00:00Z Paramecia are unicellular protists that have contractile vacuoles to remove excess intracellular water. Biology for AP Courses 2022-06-09T00:00:00Z But Chitwood’s study showed that gene expression in the unicellular seaweed varies in ways that echo gene expression in similar structures in multicellular plants — suggesting that the dividing cell needn’t always dictate morphology. The lost art of looking at plants 2018-01-22T05:00:00Z Biologists study them to understand how unicellular organisms evolved to become the earliest multicellular animals. Bacterial 'aphrodisiac' sends single-celled organism into mating frenzy 2017-09-05T04:00:00Z Novy designed and built instruments that helped to establish that respiration is a basic metabolic activity in unicellular organisms, including the bacterium that causes TB, Mycobacterium tuberculosis. Medical Research: Pitching the big tent of modern microbiology : Nature : Nature Research 2017-05-02T04:00:00Z Whereas Volvox individuals have 500 to 60,000 cells arranged in a hollow sphere, some relatives, such as the Gonium species, have as few as four to 16 cells; others are completely unicellular. The momentous transition to multicellular life may not have been so hard after all 2018-06-28T04:00:00Z Examples of photoautotrophs include plants, algae, some unicellular eukaryotes, and cyanobacteria. Biology for AP Courses 2022-06-09T00:00:00Z All of the seaweed’s close relatives are unicellular plankton. Strange seaweed rewrites history of green plants 2016-05-08T04:00:00Z When Olson, who teaches evolutionary genomics at Kansas State University, removed the gene from a Gonium and put it in its unicellular relative, Chlamydomonas, the formerly single-celled organisms started clumping together to form colonies. This gene helps prevent cancer. Did it also give rise to all complex life? 2016-04-26T04:00:00Z Resurrection Using sophisticated methods - the bread and butter of current evolutionary research - the scientists traced the organism’s genes back through the eons to the unicellular ancestor of all animal life on the planet. University of Oregon researcher’s work attracts debate 2016-01-23T05:00:00Z For example, in a unicellular relative of Volvox, Chlamydomonas, organelles called centrioles do double duty. The momentous transition to multicellular life may not have been so hard after all 2018-06-28T04:00:00Z This is true whether it is a unicellular organism or one of many cells forming a larger organism. Biology for AP Courses 2022-06-09T00:00:00Z Even the very organisms—yeasts and tiny unicellular fungi—that produce the alcohol in wine are vulnerable to its effects: Once ethanol levels rise above about 15% in the fermenting grape juice, they die. Animals Like to Get Drunk, Too 2015-12-17T05:00:00Z And what about unicellular organisms, especially those that colonize? Readers Respond to Rise of the Tyrannosaurs 2015-08-28T04:00:00Z In unicellular protozoa, most responses are the simple movements in response to a chemical stimulus in flagella, cilia or pseudopodia, which are determined by concentrations of ions in the cytoplasm. Exclusive: Oliver Sacks, Antonio Damasio and Others Debate Christof Koch on the Nature of Consciousness 2015-06-17T04:00:00Z The gulf between unicellular and multicellular life seems almost unbridgeable. The momentous transition to multicellular life may not have been so hard after all 2018-06-28T04:00:00Z For unicellular organisms, cell division is the only method to produce new individuals. Biology for AP Courses 2022-06-09T00:00:00Z But even if it's fairly easy, what happens next is crucial: To go from simple life, consisting of unicellular organisms, to complex life requires a series of extremely unlikely events. The Weekender: 4chan, binaural audio, and Deadmau5 2015-02-14T05:00:00Z Regarding unicellular organisms: single cells and even colonial organisms such as Volvox primarily communicate by releasing chemical signals. Readers Respond to Rise of the Tyrannosaurs 2015-08-28T04:00:00Z Measured by sheer volume, Earth’s dominant life form is unicellular slime. In Search for Intelligent Life, Consider the Lottery 2014-08-18T04:00:00Z His results showed that the region seethed with mats of photosynthesizing, unicellular life forms long before the Cambrian explosion. Death Valley's First Life Came by Land, Not by Sea 2014-04-28T20:40:00Z In a haploid dominant life cycle, a unicellular haploid stage is present, as in fungi. Biology for AP Courses 2022-06-09T00:00:00Z One is small and unicellular, the other is a much larger animal. CreatureCast: Moving, Without Feet to Do So 2014-01-23T16:17:47Z To be clear: There is no conscious goal or direction or systemic intentionality built into the evolutionary trajectory of a given entity, be it unicellular or multicellular. Debate on Evolution of Multicellular Organisms Starts to Gain Focus 2013-09-30T22:45:00.843Z Some were as big as a few centimetres across — remember, built by entirely unicellular amoebae! A note on paleo-protistology in Chicago 2013-07-20T20:15:03.207Z These included unicellular algae called diatoms and dinoflagellates, and photosynthetic bacteria known as cyanobacteria. Marine ecology: Welcome to the plastisphere 2013-07-18T15:04:03Z However, sometimes large particles, such as macromolecules, parts of cells, or even unicellular microorganisms, can be engulfed by other cells in a process called phagocytosis or “cell eating.” Biology for AP Courses 2022-06-09T00:00:00Z Multicellular plants and animals are eukaryotic and so are many unicellular organisms. Archaebacteria: The Third Domain of Life Missed by Biologists for Decades 2013-01-01T00:45:00.170Z What possible reason would there by for a unicellular organism to kill itself? The Bacteria that Commit Honourable Suicide 2012-05-27T19:45:00.430Z Other instances of the coherence of the cells of unicellular organisms into indefinite and inconstant aggregations is presented by some radiolarians, individuals which cohere into what are called colonies. The Contemporary Review, Volume 36, October 1879 2012-04-18T02:00:17.060Z Familiar examples of these “unicellular” forms are Bacteria and Diatoms among the plants, and Foraminifera and Infusoria among the animals. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 8 "Cube" to "Daguerre, Louis" 2012-01-31T03:00:17.257Z In one investigation, unicellular yeast were allowed to sediment in a column of a nutrient-containing solution. Biology for AP Courses 2022-06-09T00:00:00Z And is that what you were fashioned for Our "unicellular ancestor"? Punch, or the London Charivari, Vol. 105 September 23, 1893 2012-01-27T03:00:21.910Z They dumped unicellular yeast into a tube of liquid food and waited a few minutes for the cells to settle. Test Tube Yeast Evolve Multicellularity 2012-01-16T20:15:00.203Z Thus, a unicellular plant may take on a great complexity of form while still remaining purely unicellular. The Contemporary Review, Volume 36, October 1879 2012-04-18T02:00:17.060Z In all cases, however, whether the cell-unit lives freely as a unicellular organism or forms an integral part of a multicellular individual, it exhibits in itself all the phenomena characteristic of living things. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 8 "Cube" to "Daguerre, Louis" 2012-01-31T03:00:17.257Z If we don’t destroy ourselves, either through war or the destruction of our environment, Impey believes that unicellular and other exceedingly simple organisms are our next-greatest threat. Despite Mayan predictions, scientists don?t believe the world will end soon 2012-01-09T20:44:37Z Is it merely the Life that in most things dwells, Or must we go reading the lines between, To find what you really were fashioned for, Our "unicellular ancestor"? Punch, or the London Charivari, Vol. 105 September 23, 1893 2012-01-27T03:00:21.910Z It begins when unicellular develop into multicellular organisms. Human Personality and its Survival of Bodily Death 2012-01-05T03:00:42.307Z We have seen that unicellular organisms may unite into a cylindrical or spheroidal colony, as in some Radiolaria, or into a spheroid of closely-adjusted cells, forming one layer, as in Volvox. The Contemporary Review, Volume 36, October 1879 2012-04-18T02:00:17.060Z In some of the simpler unicellular organisms, e.g. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 8 "Cube" to "Daguerre, Louis" 2012-01-31T03:00:17.257Z The nucleus remains single, so that there is no question as to the unicellular or individual nature of the entire animal. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 5 "Greek Law" to "Ground-Squirrel" 2011-12-05T03:00:51.527Z Do they tell us what you were fashioned for, Our "unicellular ancestor"? Punch, or the London Charivari, Vol. 105 September 23, 1893 2012-01-27T03:00:21.910Z A very small drop of chloroform introduced into a fluid of different density behaves exactly like a unicellular organism. Morals and the Evolution of Man 2011-11-14T03:00:18.930Z The whole of these lower creatures, therefore, may be spoken of as unicellular organisms; as though they may consist of many cells, those cells retain their individuality. The Contemporary Review, Volume 36, October 1879 2012-04-18T02:00:17.060Z Cell-differentiation.—Both among unicellular and multicellular individuals the cell assumes the most varied forms and performs the most diverse functions. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 8 "Cube" to "Daguerre, Louis" 2012-01-31T03:00:17.257Z Certain of the lowest unicellular forms might indeed have persisted, for when dormant they can stand great extremes of dry heat and of cold for a long time. Climatic Changes Their Nature and Causes 2011-10-28T02:00:24.840Z Or what you truly were fashioned for Our "unicellular ancestor"? Punch, or the London Charivari, Vol. 105 September 23, 1893 2012-01-27T03:00:21.910Z Tried by this test we may ask whether the changes produced in these unicellular organisms by the action of their environment are, or are not, inherited as variations. Embryology The Beginnings of Life 2011-09-12T02:00:28.483Z Until the vendobionts went extinct, he argues, multicellular animals "lived in the shadow of these unicellular giants". Ancient sea jelly makes tree of life wobble 2011-09-07T23:45:07.457Z The process of division, as such, appears never to be the means by which new species are called into existence among unicellular organisms. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z In certain hot springs, some of the lowest unicellular plant forms exist in water which is only a little below the boiling point. Climatic Changes Their Nature and Causes 2011-10-28T02:00:24.840Z In the green sea-weeds reproduction is effected by simple cell division in the unicellular species, and by spores resulting from the union of the contents of two cells in the others. Sea-Weeds, Shells and Fossils 2011-08-20T02:00:11.557Z Analogies have been pointed out between Chytridiaceae and unicellular algae, such as Chlorosphaeraceae, Protococcaceae, “Palmellaceae,” &c., some of which are parasitic, and suggestions may be entertained as to possible origin from such algae. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z There can be no doubt that these cysts represent a stage in the life-history of some minute unicellular plant or animal. Freshwater Sponges, Hydroids & Polyzoa 2011-06-25T02:00:17.833Z In this respect Weismann has amended his original proposition that the germ-cells were immortal, like unicellular organisms. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z Researchers who study RNA editing, which up to now was known mostly from plants and some unicellular human parasites, are intrigued by the new finding. RNA Editing to Create 'Acquired Characteristics' Appears Common 2011-05-19T23:45:07.197Z The first group, Palmelleæ, are unicellular plants, the cells of which are either free or surrounded by a gelatinous mass, and they are propagated by the division of the endochrome. Sea-Weeds, Shells and Fossils 2011-08-20T02:00:11.557Z They are characterized by their unicellular nature, their power of rapid budding, their capacity for fermenting various sugars, and their power of forming endogenous 340 spores. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z As elsewhere pointed out, reproduction is first unicellular in type and involves an expenditure of nutritive force antagonistic to the growth of the cell. Degeneracy Its Causes, Signs and Results 2011-05-02T02:00:17.657Z The twofold nature of the process of development is a cardinal point in his theory, linked to his doctrine of immortality for unicellular organisms and germ-cells and mortality for somatic cells. 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 equally certain that these unicellular plants and animals are themselves only the specialized descendants of common ancestors—unspecialized unicellular organisms which are neither strictly vegetable nor animal. The New Gresham Encyclopedia Volume 4, Part 3: Estremoz to Felspar 2011-04-14T02:00:59.373Z Encysted condition common; the green forms sometimes multiply in this state and simulate unicellular Algae. Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 4 "Finland" to "Fleury, Andre" 2011-03-20T02:00:30.697Z The basidium is a unicellular or multicellular structure from which four basidiospores arise as outgrowths; it starts as a binucleate structure, but soon, like the ascus, becomes uninucleate by the fusion of the two nuclei. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z The hair has a tendency to crack in a transverse direction, and in the cracks there come to lodge unicellular algae, to which K�hn has given the name Pleurococcus bradypi. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 10 "Echinoderma" to "Edward" 2011-01-19T03:00:19.027Z The reproductive cells, like unicellular organisms, are regarded as immortal, the somatic cells as mortal. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z For most of the first 2.5 billion years of life on Earth, most species were microscopic, rarely exceeding one millimeter in size, and unicellular. Remarkable Creatures: In a Single-Cell Predator, Clues to the Animal Kingdom?s Birth 2010-12-14T16:46:36Z Diatoms are unicellular algae that are found in the upper portions of the ocean, and are at times very plentiful. Reporters first trip in eons to the coast reveals a bounty of razor clams 2010-04-30T23:49:00Z The protoplasm then becomes cut up by a series of clefts into a number of smaller and smaller pieces which are unicellular in Pilobolus, multicellular in Sporodinia. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z In Actinians the epithelio-muscular cells of the endoderm are crowded with yellow spherical bodies, which are unicellular plants or Algae, living symbiotically in the tissues of the zooid. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 2 "Anjar" to "Apollo" He calls a unicellular organism immortal, simply because its life is preserved in the organisms arising from it by division. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z Whatever the explanation, the presence of those genes in a unicellular organism indicates that much of the machinery for making multicellular animals was in place long before the origin of animals. Remarkable Creatures: In a Single-Cell Predator, Clues to the Animal Kingdom?s Birth 2010-12-14T16:46:36Z The phylogenetic significance of the alternation of generations consists in its representing a transition stage from the unicellular to the simpler multicellular and from the latter to the more complex multicellular plants. A Mechanico-Physiological Theory of Organic Evolution Germ.—A minute unicellular organism, either animal or vegetable; a micro-organism; a microbe. American Red Cross Text-Book on Home Hygiene and Care of the Sick Even the egg-cell has a specific character, and is totally different from any unicellular organism at the Protistan level. Naturalism And Religion The immortality of the unicellular forms depends upon their divisibility, upon a property which, according to the philosophical use of the word, is incompatible with immortality. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z Scientists are eager to understand how transitions from a unicellular to multicellular lifestyle were accomplished. Remarkable Creatures: In a Single-Cell Predator, Clues to the Animal Kingdom?s Birth 2010-12-14T16:46:36Z Later the cell generations of an ontogeny are united by parts into plant individuals; the ontogenetic period consists of a cycle of multicellular and unicellular, or only of multicellular plant generations. A Mechanico-Physiological Theory of Organic Evolution —Bacteria are composed of single cells and are consequently called unicellular organisms. American Red Cross Text-Book on Home Hygiene and Care of the Sick It is in the investigation of the “Protists,” the study of the vital phenomena of the microscopically minute unicellular organisms, that attempts of this kind have been most frequently made. Naturalism And Religion The unicellular organism is not immortal in itself, but only in as much as it may give rise to other organisms. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z But the unicellular ancestor of animals and those first animals are long extinct. Remarkable Creatures: In a Single-Cell Predator, Clues to the Animal Kingdom?s Birth 2010-12-14T16:46:36Z In the lowest forms of cell differentiation the cells of successive generations are all independent; the ontogenetic period consists of a cycle of generations of unicellular plants. A Mechanico-Physiological Theory of Organic Evolution Yes, and as such may be classed the drops of life known as unicellular organisms. The Kempton-Wace Letters But in reality it proves to be rather a process of selection on the part of the epithelial cells of the intestine, analogous to the selection and rejection exercised elsewhere by unicellular organisms. Naturalism And Religion Adam is immortal quite as much as unicellular organisms, for he survives in his successors. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z Even in unicellular animals, negative adaptation can be observed, but in them is only temporary, like the "sensory adaptation" described in the chapter on sensation. Psychology A Study Of Mental Life Each sporangium is at maturity filled with numerous unicellular spores. The North American Slime-Moulds A Descriptive List of All Species of Myxomycetes Hitherto Reported from the Continent of North America, with Notes on Some Extra-Limital Species Bacteria may be defined as very minute, unicellular organisms of a plantlike character. Special Report on Diseases of Cattle This study of germination leads also to a very definite conclusion with regard to the genus Uromyces—that it is much more closely related to Puccinia and its immediate allies than to other unicellular Uredines. Fungi: Their Nature and Uses From this point of view, the immortality of unicellular organisms and of the germplasm breaks down, and, above all, the artificial distinction between somatic cells and reproductive cells. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z In these unicellular organisms reproduction is known as asexual, because there are no special germ-cells, nor is there anything corresponding to fertilisation. The Truth About Woman Except as just described, the slime-moulds present abundant, minute, unicellular spores, enclosed in sporangia more or less perfectly defined, and attended by peculiar thread-like structures, free or variously attached and conjoined, the so-called capillitium. The North American Slime-Moulds A Descriptive List of All Species of Myxomycetes Hitherto Reported from the Continent of North America, with Notes on Some Extra-Limital Species At first there are unicellular organisms, in which one cell penetrates the other in the act of conjugation. The Sexual Question A Scientific, psychological, hygienic and sociological study It may be added here, that in this order the spore is simple and unicellular. Fungi: Their Nature and Uses A unicellular animal takes organic particles bodily into its protoplasm, and forming around them temporary cavities known as food vacuoles, treats them chemically. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z Even among many unicellular organisms the process becomes more elaborate with distinct specialisation of reproductive elements. The Truth About Woman Bishop has found a few new unicellular types, but nothing dangerous. Competition In the simplest unicellular organisms which are known fission constitutes the only means of reproduction. The Sexual Question A Scientific, psychological, hygienic and sociological study What really happens is that whenever alternative courses of action are called for, the individuality splits up and continues on two or more divergent planes, very much like the parthenogenesis of a unicellular animal ... The Doorway Weismann believes himself to have established a fundamental distinction between unicellular and multicellular organisms. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z Potato rot and downy mildew on grape vines belong to this family.Myxomycetes—Slime moulds.Saccharomycetes—Yeast fungi.Schizomycetes—are minute, unicellular Protophytes which reproduce mainly by transverse fission. The Mushroom, Edible and Otherwise Its Habitat and its Time of Growth She looked still at the unicellular shadow that lay within the field of light, under her microscope. The Rainbow These phenomena, as we have seen, commence among unicellular organisms. The Sexual Question A Scientific, psychological, hygienic and sociological study This is excellently illustrated by many of the lower, particularly the unicellular, animals, in which reproduction is not yet sexual, but by the simple method of division. Introduction to the Science of Sociology He makes an exception of the sexual cells, which, like unicellular organisms, are able to multiply indefinitely, and so are immortal. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z Infusoria and other unicellular animals multiply by division. The Beauties of Nature and the Wonders of the World We Live In Vegetative body unicellular; spheroidal, cylindrical or spirally twisted; isolated or connected in filamentous or other growth series. Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 2 "Baconthorpe" to "Bankruptcy" For example, a unicellular animal applies itself against one of its fellows. The Sexual Question A Scientific, psychological, hygienic and sociological study The neurone, however, is a little unicellular animal, like the amoeba or the paramecium. Introduction to the Science of Sociology Doubling division alone exists, or could exist, among unicellular organisms. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z First simple monera are formed by spontaneous generation, and from these arise unicellular protists.... Life and Matter A Criticism of Professor Haeckel's 'Riddle of the Universe' The reproduction of unicellular organisms consists in just this—the living being divides into two halves, of which each is a complete individual. Creative Evolution Death or destruction of the cell is therefore death of the entire organism when this is unicellular. The Sexual Question A Scientific, psychological, hygienic and sociological study In all the unicellular organisms the phenomena of reproduction appear to be more or less identical with those of growth. Darwin, and After Darwin (Vol. 1 and 3, of 3) An Exposition of the Darwinian Theory and a Discussion of Post-Darwinian Questions All research shows that unicellular fungi, algæ, infusoria, and so forth, in dividing, transmit specific characters so strongly and in detail so minute that their descendants, a million generations off, resemble them in every respect. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z Bacteria may be defined as very minute unicellular organisms of plantlike character. Special Report on Diseases of the Horse Even the external motions of a unicellular organism—of an amoeba, at any rate—are sometimes explained mechanically. Creative Evolution Dermal glands: hypodermal unicellular glands which secrete wax, setae, spines, etc. Explanation of Terms Used in Entomology Thus far, then, the phenomena of multiplication are identical in all the lowest or unicellular organisms, and in the constituent cells of all the higher or multicellular. Darwin, and After Darwin (Vol. 1 and 3, of 3) An Exposition of the Darwinian Theory and a Discussion of Post-Darwinian Questions No one has doubted the fact, and Weismann himself recognises that division, among unicellular organisms, is always doubling. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z The same thing has been shown by Schütt in regard to the lowly unicellular plants, the Peridineae, which abound alike on the surface of the ocean and in its depths. Evolution in Modern Thought Evolution has taught us that life, however it started, has been one long continuous process which has increased in complexity from the unicellular animals to man. Human Traits and their Social Significance Leucocytes: pale, unicellular bodies, numerous in the insect blood. Explanation of Terms Used in Entomology For the distinction is clearly one which must necessarily arise, if the doctrine of continuity between unicellular and multicellular organisms be true. Darwin, and After Darwin (Vol. 1 and 3, of 3) An Exposition of the Darwinian Theory and a Discussion of Post-Darwinian Questions Many unicellular organisms pass through a regular series of developmental stages; the stages themselves being inherited, and following each other as infallibly as in the case of embryonic stages of higher animals. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z Since such a creature as the rabbit is formed through the co-operation of a vast multitude of cells, it is called multicellular; the amoeba, on the other hand, is unicellular. Text Book of Biology, Part 1: Vertebrata The multicellular organism was a colony of unicellular organisms, and its life was a sum of the lives of its constituent elements. Form and Function A Contribution to the History of Animal Morphology To understand the vital economy of the open sea, we must recognise the incalculable abundance of minute unicellular plants, for they form the fundamental food-supply. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told Lastly, with respect to karyokinesis, although it is true that the microscope has in comparatively recent years displayed this apparently important distinction between unicellular and multicellular organisms, two considerations have here to be supplied. Darwin, and After Darwin (Vol. 1 and 3, of 3) An Exposition of the Darwinian Theory and a Discussion of Post-Darwinian Questions The epidermis is sparingly covered with unicellular hairs, some of which are curiously branched, being irregularly star-shaped. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses We actually do find colonies of unicellular animals much like amœba, so that the muscle-cells and all other cells of the body may be compared to amœba and other one-celled animals. Voice Production in Singing and Speaking Based on Scientific Principles (Fourth Edition, Revised and Enlarged) The unicellular organism can by its very nature transform itself into a multicellular organism only by the method of cell-division. Form and Function A Contribution to the History of Animal Morphology The fauna of the shore is remarkably representative—from unicellular Protozoa to birds like the oyster-catcher and mammals like the seals. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told Like that of all other organisms, unicellular or multicellular, his development starts from the nucleus of a single cell. Darwin, and After Darwin (Vol. 1 and 3, of 3) An Exposition of the Darwinian Theory and a Discussion of Post-Darwinian Questions They are characterized by being actively motile, and are either strictly unicellular, or the cells are united by a gelatinous envelope into a colony of definite form. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses But while in such unicellular creatures all functions are properties of the individual cell, among higher forms systems take the place of the protoplasm of the single cell. Voice Production in Singing and Speaking Based on Scientific Principles (Fourth Edition, Revised and Enlarged) The spores, with few exceptions, are unicellular when shed, and may develop at once or after a resting period. Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" No. 1166.—This appearance is due to the presence of a minute unicellular plant of a red color, which grows and multiplies with great rapidity on the surface of bread, starch-paste, and similar substances. Current Superstitions Collected from the Oral Tradition of English Speaking Folk But do we not know enough to see that it did not originate in this sudden spectacular way?—that it began very slowly, in unicellular germs? The Last Harvest They are for the most part plants of simple structure, many being unicellular, and very few of them plants of large size. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses Why did not unicellular life always remain unicellular? The Breath of Life The low unicellular organisms are potentially immortal, the higher multicellular forms with well-differentiated organs contain the germs of death within themselves. The Birth-Time of the World and Other Scientific Essays If two similar unicellular organisms are placed under different conditions they become unlike, since their unstable protoplasm is directly affected by the surrounding conditions. 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 Every living creature from a man to a mushroom, or even to the smallest animalcule or unicellular plant is always partly fluid, but never entirely so. Young Folks' Library, Volume XI (of 20) Wonders of Earth, Sea and Sky The members of this order are minute unicellular plants, growing either in water or on the damp surfaces of stones, tree trunks, etc. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses Nor does old age supervene in the unicellular organisms. Disease and Its Causes The phenomenon of old age is not evident in the case of the unicellular organism reproducing by fission. The Birth-Time of the World and Other Scientific Essays Among some of the lowest forms of unicellular organisms it is not known, but in most others some form of such union is universal. 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 But a further complication of great importance affects the reproduction and the rejuvenescence of these unicellular organisms; this is the process of conjugation. Scientific American Supplement, No. 810, July 11, 1891 The desmids include the most beautiful examples of unicellular plants to be met with, the cells having extremely elegant outlines. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses A simple conception of health and disease can be arrived at by the study of these conditions in a unicellular animal directly under a microscope, the animal being placed on a glass slide. Disease and Its Causes According to Mr. Darwin's theory all the species of higher animals have developed from unicellular ancestors. 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 This has long been believed, but has now been clearly demonstrated by the experiments of cutting into fragments the cell bodies of unicellular animals. 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 This remnant, in the spore-forming unicellular plants represented by the cell wall, is then naturally dead. Scientific American Supplement, No. 810, July 11, 1891 Those consisting of but one cell are termed unicellular; those comprising more than one cell are called pluricellular. Psychology and Achievement Being the First of a Series of Twelve Volumes on the Applications of Psychology to the Problems of Personal and Business Efficiency Living things may be unicellular or composed of a multitude of cells which are interdependent. Disease and Its Causes The amœba is an illustration of a great kingdom of similar, practically unicellular forms, which have played no unimportant part in the geological history of the globe. 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 In the simplest case, that of the unicellular animals, the cell divides, giving rise to two animals, each of which divides again, producing four, and these again, giving eight, etc. 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 From this it follows that these unicellular beings are immortal. Scientific American Supplement, No. 810, July 11, 1891 The unicellular organism is the unit of life on this earth. Psychology and Achievement Being the First of a Series of Twelve Volumes on the Applications of Psychology to the Problems of Personal and Business Efficiency The peculiar thing with the lower unicellular organisms is that the changes which so arise do not tend to become permanent, the organism reverts to its usual character, the disease to its sporadic type. Disease and Its Causes They are usually unicellular, and their protoplasm is surrounded by a thin, structureless membrane. 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 Among the unicellular plants are the bacteria, while the unicellular animals are known as the protozoa. Q. E. D., or New Light on the Doctrine of Creation All unicellular beings, such as the protozoa and the simpler alg�, fungi, etc., reproduce themselves by means of simple fission. Scientific American Supplement, No. 810, July 11, 1891 Yet tiny and ultimate as it is, every unicellular organism is possessed of an independent and "free living" existence. Psychology and Achievement Being the First of a Series of Twelve Volumes on the Applications of Psychology to the Problems of Personal and Business Efficiency The protozoa, like the bacteria, are unicellular organisms and contain a nucleus as do all cells. Disease and Its Causes We must emphasize that these little animals correspond in all essential respects to the cells of our bodies; they are unicellular animals. 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 But we hesitate to say how many of these powers or characteristics of free and independent personality can be assigned to the unicellular organisms, such as the amoeba or the corpuscles of our blood. Q. E. D., or New Light on the Doctrine of Creation The mother organism may split into two similar halves, as the amoeba does, or, as is more common in the lowest unicellular plants, it may divide into a great number of small spores. Scientific American Supplement, No. 810, July 11, 1891 The pluricellular organism is nothing more nor less than a later development, a confederated association of unicellular organisms. Psychology and Achievement Being the First of a Series of Twelve Volumes on the Applications of Psychology to the Problems of Personal and Business Efficiency They have power of active independent motion and somewhat resemble certain of the free living unicellular organisms. Disease and Its Causes And these unicellular animals have the rudiments of all our functions. 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 How can we deny that this "persistence" of these unicellular forms constitutes a very strong argument in favor of the "fixity" of these forms? Q. E. D., or New Light on the Doctrine of Creation The immortality of unicellular beings is not at any time absolute, but only potential. Scientific American Supplement, No. 810, July 11, 1891 It includes the phenomena of conjugation and fertilization among both unicellular and multicellular organisms. Youth: Its Education, Regimen, and Hygiene All the unicellular algæ are included under this head. Scientific American Supplement, No. 384, May 12, 1883 It may therefore be useful to consider one or two intermediate forms and the parallel embryonic stages of higher animals, and to see how the higher many-celled animal originates from the unicellular stage. 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 While agreeing with Cienkowski as to the parasitic nature of the yellow cells of Radiolarians, he holds strongly that those of anemones and jelly-fishes are unicellular glands. Scientific American Supplement, No. 324, March 18, 1882 In the beginning, there existed no other animal organisms than these aggregations of similar unicellular beings, all of which reproduced themselves. Scientific American Supplement, No. 810, July 11, 1891 Can we conceive of an indestructible thing - be it unicellular or multicellular, alive or robotic, composed of independent individuals or acting in perfect, centrally-dictated unison? Moral Deliberations in Modern Cinema The amalgamation of individuals into nationalities and empires is as much in the cosmic plan as the development of highly organized beings out of unicellular organisms. The National Being Some Thoughts on an Irish Polity One of man's earliest ancestors was almost certainly a unicellular animal. 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 Every step is an advance, and many a step must have been taken to produce flowering plants from the simplest unicellular algae. Species and Varieties, Their Origin by Mutation The transit, we are told, from the unicellular to the multicellular organism cannot be explained by individualism, but implies a diminution of the competitive, an increase of the social and subordinative tendency. The Faith of the Millions (2nd series) The process of division is repeated, until the organism, from being unicellular, becomes multicellular. Darwiniana : Essays — Volume 02 The life of the amoeba or any other unicellular organism is low compared with the life in more complex organisms, like the ant or bee. The National Being Some Thoughts on an Irish Polity To explain this Weismann went back to the unicellular protozoa. 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 The oldest Amoebae lived isolated lives, and even the amoeboid cells that were formed by the segmentation of these unicellular organisms must have continued to live independently for a long time. The Evolution of Man — Volume 2 These simplest forms multiply or reproduce by fission, but such asexual reproduction is almost entirely confined to the unicellular forms of life. Sociology and Modern Social Problems The only exception is found in the protozoa, the very lowest and simplest forms of animal life; these remain unicellular throughout life. The Evolution of Man — Volume 1 In this bladder, as well as in several others, there were some unicellular Algae, and one multicellular Alga, which no doubt had lived as intruders. Insectivorous Plants Some impulse or tendency was latent or potential in the first unicellular life that rested not till it eventuated in each of these higher forms. Time and Change Following out this curious theory, Dohrn came to contest the general belief that the Coelenterata and Worms are "lower animals"; he even declared that the unicellular Protozoa were degenerate Coelenterata. The Evolution of Man — Volume 2 From one or more simple primitive unicellular forms have arisen the great multitude of multicellular forms that now exist. Sociology and Modern Social Problems There are independent unicellular organisms of the simplest character which develop no further, but reproduce themselves as such, without any further growth. The Evolution of Man — Volume 1 I could detect no sessile glands; nor would these have been of any use, as the upper surface of the leaves is thickly clothed with pointed, unicellular hairs directed upwards. Insectivorous Plants It is typical of the course of the creative energy from the first unicellular life up to man, each succeeding stage flowing out of, and necessitated by, the preceding stage. Time and Change In the unicellular Protozoa, which do not form germinal layers, there is, of course, neither nervous system nor skin. The Evolution of Man — Volume 2 It has finally been shown, however, to be caused by a microscopic organism belonging to the group of unicellular animals, and somewhat closely related to the well-known amoeba. The Story of Germ Life To give a few examples, we can infer from the fact that the human ovum is a simple cell that the first ancestor of our species was a tiny unicellular being, something like the amoeba. The Evolution of Man — Volume 1 As no instance is known of unicellular structures having any power of movement,* Byblis, no doubt, catches insects solely by the aid of its viscid secretion. Insectivorous Plants But we must go back even earlier than that, back to unicellular life and to original protoplasm, and finally back to fiery nebulous matter. Time and Change The Gastraea itself has originated from the simple multicellular vesicle, the Blastaea, and this in turn must have been evolved from the lowest circle of unicellular animals, to which we give the name of Protozoa. The Evolution of Man — Volume 2 Of voluntary capacities and powers the newborn infant possesses little more than the simplest unicellular animalcule, that is, about all it can do is to scent and swallow food. Nature Cure That these unicellular ancestral forms did once exist follows directly from the phenomena which we perceive every day in the fertilised ovum. The Evolution of Man — Volume 1 Inheritance must be looked at as merely a form of growth, like the self- division of a lowly-organised unicellular organism. The Variation of Animals and Plants under Domestication — Volume 2 The same thing has been shown by Schutt in regard to the lowly unicellular plants, the Peridineae, which abound alike on the surface of the ocean and in its depths. Darwin and Modern Science We have already considered the most important primitive type of these, the unicellular Amoeba, which is extremely instructive when compared with the human ovum. The Evolution of Man — Volume 2 They point out that a man is made up of a great multitude of cells, each equivalent to a unicellular organism. God the Invisible King MONERA: the most primitive of the unicellular organisms. The Evolution of Man — Volume 1 The unicellular stem-form of the race is reproduced daily in the unicellular embryonic stage of the individual. The Evolution of Man — Volume 2 Large unicellular organisms like the Amoebae were found creeping about inside the body of the sponge, and were thought to be parasites. The Evolution of Man — Volume 2 The earliest unicellular organisms can only have been evolved from the simplest organisms we know, the Monera. The Evolution of Man — Volume 2 The egg, in the modern physiological sense of the word, did not make its appearance until the descendants of the unicellular Protozoon had developed into multicellular animals, and these had undergone sexual differentiation. The Evolution of Man — Volume 2 I say this is very important, because our whole science of embryology now resolves itself into the problem: "How does the multicellular organism arise from the unicellular?" The Evolution of Man — Volume 1 During this period the whole of the invertebrate ancestors of the human race were evolved from the unicellular organisms. The Evolution of Man — Volume 2 Many millions of years had to pass before the most advanced vertebrate, man, was evolved, step by step, from his ancient unicellular ancestors. The Evolution of Man — Volume 2 The egg lived for thousands of years as an independent unicellular organism, the Amoeba. The Evolution of Man — Volume 2 This inference from the unicellular embryonic form to the unicellular ancestor is so simple, but so important, that we cannot sufficiently emphasise it. The Evolution of Man — Volume 1 This unicellular body moves about continually, creeping in every direction on the glass on which we are examining it. The Evolution of Man — Volume 1 We must, therefore, turn next to the question whether there are to-day any unicellular organisms, from the features of which we may draw some approximate conclusion as to the unicellular ancestors of the multicellular organisms. The Evolution of Man — Volume 1 Later, though the ova remain unicellular, they differ in size and shape, enclose various kinds of yelk-particles, have different envelopes, and so on. The Evolution of Man — Volume 1 It is clear that this morula reproduces for us to-day the simple structure of the multicellular animal that succeeded the unicellular amoeboid form in the early Laurentian period. The Evolution of Man — Volume 2 There are assuredly still unicellular organisms which are, in their whole nature, really nothing more than permanent ova. The Evolution of Man — Volume 1 The same direct cleavage of the nuclei is also witnessed in the reproduction of many other protists, while other unicellular organisms show the indirect division of the cell. The Evolution of Man — Volume 1 |
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