if you want to remove an article from website contact us from top.

    which mechanism for evolution was proposed by lamarck?

    James

    Guys, does anyone know the answer?

    get which mechanism for evolution was proposed by lamarck? from EN Bilgi.

    Lamarckism

    Lamarckism

    From Wikipedia, the free encyclopedia

    Jump to navigation Jump to search

    Lamarckism, also known as Lamarckian inheritance or neo-Lamarckism,[1] is the notion that an organism can pass on to its offspring physical characteristics that the parent organism acquired through use or disuse during its lifetime. It is also called the inheritance of acquired characteristics or more recently soft inheritance. The idea is named after the French zoologist Jean-Baptiste Lamarck (1744–1829), who incorporated the classical era theory of soft inheritance into his theory of evolution as a supplement to his concept of orthogenesis, a drive towards complexity.

    Introductory textbooks contrast Lamarckism with Charles Darwin's theory of evolution by natural selection. Darwin's book however supported the Lamarckian idea of use and disuse inheritance, and his own concept of pangenesis implied a Lamarckian soft inheritance.[1][2]

    Many researchers from the 1860s onwards attempted to find evidence for Lamarckian inheritance, but these have all been explained away, either by other mechanisms such as genetic contamination or as fraud. August Weismann's experiment, considered definitive in its time, is now considered to have failed to disprove Lamarckism, as it did not address use and disuse. Later, Mendelian genetics supplanted the notion of inheritance of acquired traits, eventually leading to the development of the modern synthesis, and the general abandonment of Lamarckism in biology. Despite this, interest in Lamarckism has continued.

    Studies in the fields of epigenetics, genetics, and somatic hypermutation have highlighted the possible inheritance of traits acquired by the previous generation. The characterization of these findings as Lamarckism has been disputed. The inheritance of the hologenome, consisting of the genomes of all an organism's symbiotic microbes as well as its own genome, is also somewhat Lamarckian in effect, though entirely Darwinian in its mechanisms.

    Contents

    1 Early history 1.1 Origins

    1.2 Darwin's pangenesis

    1.3 Lamarck's evolutionary framework

    1.4 Lamarck's discussion of heredity

    1.5 Weismann's experiment

    2 Textbook Lamarckism

    3 Neo-Lamarckism 3.1 Context 3.2 19th century

    3.3 Early 20th century

    3.4 Late 20th century

    3.5 Ideological neo-Lamarckism

    3.6 Critique

    4 Mechanisms resembling Lamarckism

    4.1 Transgenerational epigenetic inheritance

    4.2 Somatic hypermutation and reverse transcription to germline

    4.3 Hologenome theory of evolution

    4.4 Baldwin effect

    5 In sociocultural evolution

    6 References 7 Bibliography 8 Further reading 9 External links

    Early history[edit]

    Origins[edit]

    Jean-Baptiste Lamarck repeated the ancient folk wisdom of the inheritance of acquired characteristics.

    The inheritance of acquired characteristics was proposed in ancient times, and remained a current idea for many centuries. The historian of science Conway Zirkle wrote in 1935 that:[3]

    Lamarck was neither the first nor the most distinguished biologist to believe in the inheritance of acquired characters. He merely endorsed a belief which had been generally accepted for at least 2,200 years before his time and used it to explain how evolution could have taken place. The inheritance of acquired characters had been accepted previously by Hippocrates, Aristotle, Galen, Roger Bacon, Jerome Cardan, Levinus Lemnius, John Ray, Michael Adanson, Jo. Fried. Blumenbach and Erasmus Darwin among others.[3]

    Zirkle noted that Hippocrates described pangenesis, the theory that what is inherited derives from the whole body of the parent, whereas Aristotle thought it impossible; but that all the same, Aristotle implicitly agreed to the inheritance of acquired characteristics, giving the example of the inheritance of a scar, or of blindness, though noting that children do not always resemble their parents. Zirkle recorded that Pliny the Elder thought much the same. Zirkle pointed out that stories involving the idea of inheritance of acquired characteristics appear numerous times in ancient mythology and the Bible, and persisted through to Rudyard Kipling's .[4] The idea is mentioned in 18th century sources such as Diderots .[5] Erasmus Darwin's (c. 1795) suggested that warm-blooded animals develop from "one living filament... with the power of acquiring new parts" in response to stimuli, with each round of "improvements" being inherited by successive generations.[6]

    Darwin's pangenesis[edit]

    Charles Darwin's pangenesis theory. Every part of the body emits tiny gemmules which migrate to the gonads and contribute to the next generation via the fertilised egg. Changes to the body during an organism's life would be inherited, as in Lamarckism.

    Main article: Pangenesis

    Charles Darwin's proposed natural selection as the main mechanism for development of species, but did not rule out a variant of Lamarckism as a supplementary mechanism.[7] Darwin called this pangenesis, and explained it in the final chapter of his book (1868), after describing numerous examples to demonstrate what he considered to be the inheritance of acquired characteristics. Pangenesis, which he emphasised was a hypothesis, was based on the idea that somatic cells would, in response to environmental stimulation (use and disuse), throw off 'gemmules' or 'pangenes' which travelled around the body, though not necessarily in the bloodstream. These pangenes were microscopic particles that supposedly contained information about the characteristics of their parent cell, and Darwin believed that they eventually accumulated in the germ cells where they could pass on to the next generation the newly acquired characteristics of the parents.[8][9]

    Source : en.wikipedia.org

    Lamarckism

    Lamarckism, a theory of evolution based on the principle that physical changes in organisms during their lifetime—such as greater development of an organ or a part through increased use—could be transmitted to their offspring. The doctrine, proposed by the French naturalist Jean-Baptiste Lamarck in 1809, influenced evolutionary thought through most of the 19th century. Lamarckism was discredited by most geneticists after the 1930s, but certain of its ideas continued to be held in the Soviet Union into the mid-20th century. Biologists define an acquired characteristic as one that has developed in the course of the life of an individual in

    Lamarckism

    scientific theory

    By The Editors of Encyclopaedia Britannica • Edit History

    Jean-Baptiste Lamarck

    See all media

    Key People: Jean-Baptiste Lamarck Edward Drinker Cope

    Related Topics: epigenetics acquired character inheritance of acquired characteristics neo-Lamarckism kinetogenesis

    See all related content →

    Lamarckism, a theory of evolution based on the principle that physical changes in organisms during their lifetime—such as greater development of an organ or a part through increased use—could be transmitted to their offspring. The doctrine, proposed by the French naturalist Jean-Baptiste Lamarck in 1809, influenced evolutionary thought through most of the 19th century. Lamarckism was discredited by most geneticists after the 1930s, but certain of its ideas continued to be held in the Soviet Union into the mid-20th century.

    Acquired characteristics

    Biologists define an acquired characteristic as one that has developed in the course of the life of an individual in the somatic or body cells, usually as a direct response to some external change in the environment or through the use or disuse of a part. The inheritance of such a characteristic means its reappearance in one or more individuals in the next or in succeeding generations. An example would be found in the supposed inheritance of a change brought about by the use and disuse of a special organ. The blacksmith’s arm (or any other set of muscles) enlarges when used continually against an external resistance, such as the weight of the hammer. If the effect were inherited, the smith’s children at birth would have unusually large arms—if not at birth, then when they became adults, even though they had not used their arms excessively. There is no evidence supporting this case. A more subtle illustration is found in the supposed inheritance of an increased dexterity of the hands of a musician through practice. The skill acquired, although causing no visible increase in the size of the fingers, might be imagined to be passed along to the musician’s children, and they might then be expected to play skillfully with minimal practice. Just how the intricate interplay of cerebral sequences that has given the dexterity to the musician’s fingers could ever be transferred to the musician’s sex cells (spermatozoa or ova), and through them to any potential children, has never been brought within the range of biological possibilities.

    Lamarckism; giraffe

    Jean-Baptiste Lamarck proposed that acquired characteristics were inheritable. For example, as a giraffe stretches its neck to browse higher in trees, the continuation of the habit over an extended period results in a gradual lengthening of the limbs and neck.

    © Photos.com/Thinkstock

    Lamarck recognized several ways in which the environment brings about changes in plants and animals, and it is significant to note that his attention was directed more particularly to the adaptive character of the response, which, as Henri Bergson points out, implies the teleological, or purposeful, nature of the result. In plants the response is direct and immediate; i.e., not through the mediation of a central nervous reaction system, since this is absent in plants. In animals the adaptive changes are supposed to be more indirect. According to Lamarck, new needs (besoins) arise in animals as a result of a change in the environment. This leads to new types of behaviour involving new uses of pre-existing organs. Their use leads to an increase in size or to other methods of functioning. Conversely, the disuse of other parts leads to their decline. It is the resulting material alterations that are inherited.

    The examples that Lamarck gives to illustrate his doctrine are illuminating. In animals, as stated above, a new environment calls forth new needs, and the animal seeks to satisfy them by making some effort. Thus, new needs engender new habits, which modify the parts. The effects are inherited. For example, the giraffe, seeking to browse higher and higher on the leaves of trees on which it feeds, stretches its neck. As a result of this habit, continued for a long time in all the individuals of the species, the giraffe’s front limbs and neck have gradually grown longer. Birds that need to rest on the water—i.e., to find their food—spread out their feet when they wish to swim. The skin becomes accustomed to being stretched and forms the web between the toes. The horns of ruminants have resulted from the ruminants’ butting their heads together during combats. These examples, which appear naive in light of later discoveries, constitute some of the evidence on which Lamarck rested his theory.

    The influence of Lamarckism

    In On the Origin of Species, Charles Darwin accepted the principle of the inheritance of acquired characteristics as one of the factors contributory to evolution. This endorsement of Lamarckism has resulted in some confusion in terminology. Thus, in the Soviet Union, Lamarckism was labeled “creative Soviet Darwinism” until it lost its official endorsement in 1965. In Variation of Animals and Plants Under Domestication, Darwin elaborated his view and proposed a “provisional hypothesis” to explain the transmission. This hypothesis he called pangenesis. Each part of the body was imagined to throw off invisible particles called “gemmules,” which, passing into the blood stream, were supposed to collect in the germ cells and there combine with like units already present, modifying them in accordance with the changes that had taken place in the peripheral organs from which they came. Thus the next generation arising from the germ cells is a photograph, as it were, of the parent at the particular stage when the germ cells were formed. It is, perhaps, almost needless to point out that this vague conception of the mode of development of the germ cells is totally at variance with modern knowledge concerning the origin of eggs and spermatozoa, which in many cases are present and often developed before the adult stages are reached.

    Source : www.britannica.com

    Chapter 13 Review Questions Flashcards

    Start studying Chapter 13 Review Questions. Learn vocabulary, terms, and more with flashcards, games, and other study tools.

    Chapter 13 Review Questions

    4.9 10 Reviews

    Which of the following is the most recent example of evolution and natural selection?

    A. the genetic differences among the various populations on Earth

    B. the occurrence of many different breeds of dogs

    C. the development of pesticide-resistant insects

    D. the presence of long generation times in organisms

    Click card to see definition 👆

    The development of pesticide-resistant insects.

    Click again to see term 👆

    A process in which organisms with certain inherited characteristics are more likely to survive and reproduce than individuals with other characteristics is called ________.

    A. evolutionary adaptation

    B. descent with modification

    C. natural selection

    D. evolution

    Click card to see definition 👆

    Natural Selection

    Click again to see term 👆

    1/29 Created by tiffanynfarish

    Terms in this set (29)

    Which of the following is the most recent example of evolution and natural selection?

    A. the genetic differences among the various populations on Earth

    B. the occurrence of many different breeds of dogs

    C. the development of pesticide-resistant insects

    D. the presence of long generation times in organisms

    The development of pesticide-resistant insects.

    A process in which organisms with certain inherited characteristics are more likely to survive and reproduce than individuals with other characteristics is called ________.

    A. evolutionary adaptation

    B. descent with modification

    C. natural selection

    D. evolution Natural Selection

    Which mechanism for evolution was proposed by Lamarck?

    A. evolution by inheritance of acquired characteristics

    B. evolution by punctuated equilibrium

    C. evolution by accumulation of mutations

    D. evolution by natural selection

    Evolution by inheritance of acquired characteristics.

    Which of the following statements about early ideas of evolution is true?

    A. Darwin sailed around Earth over a five-year period and gathered information that greatly influenced his thinking about evolution.

    B. Charles Darwin came up with the idea that species evolve.

    C. Aristotle thought that species evolved.

    D. Lamarck suggested the idea of natural selection.

    Darwin sailed around Earth over a five-year period and gathered information that greatly influenced his thinking about evolution.

    While on his voyage on the HMS Beagle, Darwin was strongly influenced by this book.

    A. Encyclopedia Britannica

    B. The Origin of Species by Means of Natural Selection.

    C. The Beagle

    D. Principles of Geology by Charles Lyell

    Principles of Geology by Charles Lyell

    What do we call scientists who study fossils?

    A. comparative anatomists

    B. paleontologists

    C. comparative embryologists

    D. biogeographers Paleontologists

    Which of the following is the study of the geographic distribution of species on Earth?

    A. comparative anatomy

    B. biogeography C. paleontology

    D. comparative embryology

    Biogeography

    The study of comparative anatomy _____________.

    A. looks at early stages of development in different animal species

    B. supports the idea of fixed species

    C. is based on the genetic language of DNA and RNA

    D. provides information about the evolutionary history of species

    Provides information about the evolutionary history of species.

    A challenge to traditional (pre-1860) ideas about species came from embryology, where it was discovered that _________.

    A. all animals develop similar embryonic gills

    B. embryos of dissimilar organisms, such as sharks and humans, resemble each other

    C. the more advanced the animal, the more slowly it develops

    D. mutations have a far more dramatic effect on embryos than on adult organisms

    Embryos of dissimilar organisms, such as sharks and humans, resemble each other.

    Which of the following is a true statement?

    A. Species with nucleotide sequences that match closely share a common ancestor.

    B. Molecular biologists have suggested that bacteria are more closely related to eukaryotes than are members of the domain Archaea.

    C. Adaptation to the environment is not related to the origin of new species.

    D. The genetic language of DNA and RNA provides evidence that contradicts evolution of finches and other birds.

    Species with nucleotide sequences that match closely share a common ancestor.

    Which one of the following was an assumption of Charles Darwin's theory of natural selection?

    A. Organisms cooperate for limited resources.

    B. Earth is very young.

    C. Traits are inherited as discrete particles.

    D. Populations produce more offspring than their environment can support.

    Populations produce more offspring than their environment can support.

    Natural selection ___________.

    A. is independent of time or place

    B. is more of a creative process than an editing process

    C. and evolution cannot be directly observed

    D. relies on variation among individuals in a population

    Relies on variation among individuals in a population

    There is a group of small fish living in a lake with a sandy bottom. Most of the fish are light brown, but about 10% are mottled. These fish are normally prey for large birds that live on the shore. A construction company dumps a load of gravel in the bottom of the lake, giving it a mottled appearance. Which of these statements presents the most accurate prediction?

    Source : quizlet.com

    Do you want to see answer or more ?
    James 11 month ago
    4

    Guys, does anyone know the answer?

    Click For Answer