Asexual Reproduction

In: Science

Submitted By maiiih
Words 2152
Pages 9
Asexual reproduction
Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only; it is reproduction which almost always does not involve meiosis, ploidy reduction, or fertilization. The offspring will be exact genetic copies of the parent, except in the specific case of automixis. A more stringent definition is agamogenesis which is reproduction without the fusion ofgametes. Asexual reproduction is the primary form of reproduction for single-celled organisms such as the archaea, bacteria, and protists. Many plants and fungi reproduce asexually as well.
While all prokaryotes reproduce asexually (without the formation and fusion of gametes), mechanisms for lateral gene transfer such asconjugation, transformation and transduction are sometimes likened to sexual reproduction.[1] A complete lack of sexual reproduction is relatively rare among multicellular organisms, particularly animals. It is not entirely understood why the ability to reproduce sexually is so common among them. Current hypotheses [2] suggest that asexual reproduction may have short term benefits when rapid population growth is important or in stable environments, while sexual reproduction offers a net advantage by allowing more rapid generation of genetic diversity, allowing adaptation to changing environments. Developmental constraints[3] may underlie why few animals have relinquished sexual reproduction completely in their life-cycles. Another constraint on switching from sexual to asexual reproduction would be the concomitant loss of meiosis and the protective recombinational repair of DNA damage afforded as one function of meiosis.[4][5] (Also see Meiosis section: Origin and function of meiosis)
[hide] * 1 Types of asexual reproduction * 1.1 Fission * 1.2 Budding * 1.3 Vegetative…...

Similar Documents

Factors That Influence the Reproduction of Sea Cucumbers

...a few sea cucumbers live deep in the ocean, some among hydrothermal vents (Smirnov et al. 2000). Regardless of the environment in which they are found, sea cucumbers have become highly adapted to life in that environment, especially in their reproductive cycles. Sea cucumbers can reproduce through sexual reproduction as well as asexual reproduction. Each mode of reproduction has several environmental factors that have been proposed to control its timing. This paper will first introduce the two types of reproduction found in sea cucumbers. I will then discuss some of the factors that have been shown to regulate sexual reproduction, specifically the processes of gametogenesis and spawning, and the factors assumed to control asexual reproduction. Finally, I will make a few suggestions as to directions that should be taken during future studies on external cues for reproduction in holothuroids. TYPES OF REPRODUCTION IN HOLOTHUROIDS Sexual Reproduction For most sea cucumbers, the primary means of reproduction is sexual reproduction. Male and female sexes are usually separate, but there have been a few reports of hermaphroditism in some species (Smiley et al. 1991). Sexual reproduction consists of two main phases: gametogenesis and spawning. Gametogenesis is the formation of sperm and ova, and this process takes place in the sea cucumber’s single gonad (Pearse et al. 1987). The term spawning refers to the act of releasing mature gametes into the water. Smiley et al. (1991) report two......

Words: 3737 - Pages: 15

Assisted Reproduction

...Assisted Reproduction Richard Grogoza Grand Canyon University Ethics for Health Care Professionals HLT 312V Professor Paula Janine Duistermars March 31, 2013 Assisted Reproduction Assisted reproduction is an area that requires much thought. Who should be able to receive this assistance to who pays for it in the case of those receiving public funds. The ethical question as to whether a mother should be made to agree to “selective reduction,” or in common terms abort a fetus or fetuses in the case of multiple eggs that become fertilized needs to be addressed and answered. There are several ethical dilemmas that arise when dealing with donating eggs or sperm, as well as with surrogate pregnancies. Those in the low income bracket are susceptible to being exploited by the idea they can make money by donating their eggs. A woman willing to donate her eggs needs to be informed of the dangers associated with this process, such as; it is time consuming and requires a commitment to follow through with the process. Once the process is started the donor must give themselves daily injections of one of various medications that temporarily shut down their ovaries. These medications come with side effects that the donor may not be informed of. Ovarian hyper stimulation syndrome is another danger in which in some cases can lead to kidney failure and even death. The egg harvesting procedure is invasive surgical procedure in which there is a risk of injury to the bladder,......

Words: 1458 - Pages: 6

Patriarchy and Women's Reproduction

...Patriarchy and Women’s Reproduction The systems of male domination and female subordination have been a part of the history but these systems still continue to exist even today. The purpose of this paper is to explore how patriarchy controls women’s reproduction resulting in oppression and subordination of women. The paper argues that patriarchy controls women’s lives and their freedom by controlling their reproduction. The paper discusses the following aspects of this social issue: 1) why and how this social problem occurs, 2) the social process by which it is normalized or legitimized in our society, 3) analysis of new reproductive technologies from feminist perspective, and 4) some suggested solutions that would help to resolve this issue. Patriarchy has been defined as the system of male domination or the power relationships by which men dominate women or it is simply, the rule of men (Omvedt, ). It controls women and treats them as inferior to men. Shulamith Firestone argues that reproduction plays a central role in women’s subordination and it is the basis of women’s subordination by men (Walby, 1990). The conventional patriarchal notion of a family is composed of a husband as the bread-winner and the wife as the homemaker and this notion still runs in this contemporary society (Walby, 1990). In other words, women are associated with childbirths and child-rearing whereas men are the ones who financially support the family, meaning they are the ones who have......

Words: 1787 - Pages: 8

Animal Reproduction Case Study

...Animal Reproduction Reproduction is a process by which offspring is produced to continue onto the next generation. There are two types of reproduction. Asexual reproduction involves one parent and its genes, which the offspring inherits. It doesn’t need fertilization or meiosis to occur. Fission, budding, and fragmentation are the three types of asexual reproduction. Fission is when the parent separates into at least two or more individuals of the same size. The development of different independent organisms are results from current individuals is budding. The dismantling of the body into various pieces, some or all of which evolve into entirely new organisms through the redevelopment of absent body parts is fragmentation. Sexual Reproduction involves two parents of different sexes that combine their genetic information to produce an offspring. Some animals are hermaphrodites while others use parthenogenesis. Parthenogenesis is asexual reproduction that doesn’t require fertilization from males. Hermaphrodites have both male and female reproductive systems. Some hermaphrodites can inseminate themselves, while others may still need the help of the opposite sex. Animals reproduce using internal or external fertilization. Internal fertilization, used by terrestrial animals as well as whales and dolphins, occurs insides the body. The internally fertilized eggs are protected and fed while they develop inside the body. External fertilization, used by fish and amphibians, occurs......

Words: 345 - Pages: 2

Judd's Reproduction

...JUDD’s Reproductions Variance Assignment 10/20/2010 To: Judd’s Reproductions’ CEO From: William Baker, Michael Derrig, Nicole Lapointe Terry Pikul, Brendan Sayers and Ryan Suerth Judd’s Reproduction prepares and sets standards for material and labor on each of its three products produced: chairs, tables and cabinets. (Refer to Schedule A). However, Judd’s does not have a formal process to compare actual results to the estimated standards and report the variances by product. Currently, Judd’s is not taking full advantage of the expected standards in terms of assessing price and quantity efficiency variances arising from the actual costs to highlight performance problems. After reviewing the company’s budgeted projections and comparing them to the actual cost of their products for January, a flexible budget (Schedule D) and variance analysis (Schedule B) was completed. Through this analysis, it has been determined that there are significant variances related to material price and quantity and labor rate and efficiency. Schedule D | | Budgeted | | Actual | | Variance | Direct Materials | | 129,300 | | 137,718 | | $ (8,418) | Direct Labor Carpenters | | 37,680 | | 32,432 | | $ 5,248 | Direct Labor Helpers | | 32,970 | | 40,637 | | $ (7,667) | Total Variance | | | | | | $(10,837) | Schedule B | | Amount | Material Price Variance | | (6,558) | Labor Rate Variance | | (4,791) | Material Quantity Variance | | (1,860) | ......

Words: 1347 - Pages: 6

Ethical Implications of Assisted Reproduction

...Ethical Implications of Assisted Reproduction The ethical implications of assisted reproduction are obvious. There is no doubt the process of assisted reproduction has caused more harm than good as massive killing of unwanted fertilized embryos are carried out during the process. Also some of the babies born through this process have some serious physical and genetic deformities that make some of their parents regret having them. Even a doctor once asserted that he did not get into assisted reproduction to help in creating severely damaged babies (Pence 88). This concern expressed by a physician shows how ethically horrendous assisted reproduction could be. Assisted reproduction has been a hotly debated issue in recent times mainly because of its ethical implications. Despite the ethical implications, assisted reproduction also has some moral, social, and religious concerns coupled with some psychological and biological or genetic implications both to the conceived embryos and their mothers. It is not an overstatement to adduce that there are disastrous health implications and consequences associated with assisted reproduction, which more often than not are overlooked by physicians and those desperate for children. There are three main types of assisted reproduction namely – artificial insemination, In Vitro Fertilization (IVF), and surrogacy. The ethical concern of these procedures is that they are unnatural method of conception, creating life in the laboratory, and......

Words: 2128 - Pages: 9

Human Reproduction

...ANIMAL REPRODUCTION & DEVELOPMENT Dr Ilma • The two earthworms in this picture are mating • Each worm produces both sperm and eggs, which will fertilize – And in a few weeks, new worms will hatch Asexual And Sexual Reproduction • Both occur in the animal kingdom • Asexual reproduction is the creation of new individuals – Whose genes all come from one parent • Sexual reproduction is the creation of offspring – By the fusion of male and female gametes to form a zygote Mechanisms of Asexual Reproduction • Many invertebrates reproduce asexually by fission – The separation of a parent into two or more individuals of approximately the same size Mechanisms of Asexual Reproduction • Budding – In which two new individuals arise from outgrowths of existing ones • A two-step process – Fragmentation • The breaking of the body into several pieces, some or all of which develop into complete adults – Regeneration • Follows fragmentation • the regrowth of lost body parts • Some animals reproduce by parthenogenesis – A process in which an egg develops without being fertilized • Among vertebrates, several genera of fishes, amphibians, and lizards, including whiptail lizards – Reproduce exclusively by a complex form of parthenogenesis Ovary size (a) Both lizards in this photograph are C. uniparens females. The one on top is playing the role of a male. Every two or three weeks during the breeding season, individuals switch sex......

Words: 2979 - Pages: 12


...what are their relative sizes? 11. What are the stages of mitosis? What is happening to the chromosomes cytoskeleton and membranes at each stage of mitosis and interphase? For this material you may want to make and study a table in addition to writing a paragraph and drawing, labeling and explaining mitosis and interphase. 12. Compare cytokinesis in plant versus animal eukaryotic cells. 13. What is the human life cycle? I recommend drawing, labeling and explaining a diagram, and writing a paragraph. 14. What is asexual reproduction, including examples? For this answer I especially recommend writing a paragraph. 15. What is sexual reproduction, including categories and examples? For this answer I recommend writing a paragraph. I also recommend making a table comparing asexual (question 1) with sexual (question 2) reproduction. 16. What are the advantages and disadvantages of sexual versus asexual reproduction? For this answer I especially recommend writing a paragraph and making a comparison table. 17. What are homologous chromosomes? I recommend drawing, labeling and explaining a diagram, and writing a short paragraph. 18. What is the purpose of meiosis? One or two good sentences are a good answer to this question. 19. What are the phases and events of meiosis? For this answer I recommend you write a paragraph and draw a cell going through meiosis with all the terms in the list below included as labels. I highly......

Words: 2183 - Pages: 9

Biology Chapter 8 the Cellular Reproduction and Inheritance

...Chapter 8 The Cellular Basis of Reproduction and Inheritance Multiple-Choice Questions 1) The creation of offspring carrying genetic information from a single parent is called A) asexual reproduction. B) sexual reproduction. C) a life cycle. D) regeneration. E) spontaneous generation. Answer: A 2) Which of the following statements regarding sexual and asexual reproduction is true? A) Cell division only occurs after sexual reproduction. B) Only offspring from asexual reproduction inherit traits from two parents. C) Sexual reproduction typically includes the development of unfertilized eggs. D) Sexual reproduction is more likely to increase genetic variation than is asexual reproduction. E) Only asexual reproduction results from the union of a sperm and an egg. Answer: D 3) Strictly speaking, the phrase "like begets like" refers to A) all forms of reproduction. B) sexual reproduction only. C) asexual reproduction only. D) production of gametes from a premeiotic cell. E) sexual reproduction between different species. Answer: C 4) Asexual reproduction requires ________ individual (s). A) 0 B) 1 C) 2 D) 3 E) 4 Answer B 5) With the exception of identical twins, siblings who have the same two biological parents are likely to look similar, but not identical, to each other because we have A) identical chromosomes, but different genes. B) identical genes but different chromosomes. C) the same combination of......

Words: 3000 - Pages: 12

Issues on Social Reproduction

...Social reproduction is broadly defined as nonprofit or profited procedures and tasks that maintain attributes of a specific social custom throughout one’s time. Primary, these tasks are usually in forms of domestic labor, child bearing, nurturing, educating one’s child and fostering individuals with disadvantages. In Barbara Cameron's Social Reproduction and Canadian Federalism, Cameron described social reproduction as two separate outlooks; “The concept includes but goes beyond physical recreation, in the sense of both biological reproduction and the daily maintenance of the current and future generation of workers” (Cameron, 45). The first outlook is the “biological reproduction”, the process of conception to childbirth, encompassing reproductive behavior, the “nonprofit procedure” and the second outlook, the “daily maintenance”—the day-by-day tasks of one’s “daily reproduction” and “profit” of life. In this assignment, I will evidently demonstrate my examples of “daily reproduction” and “profited tasks” through my eyes, as a young female adult that has not undergone “biological reproduction” or conceived. Upon recording my day-to-day activities, I have conjured up “broad range of activities, in an array of locations, which combine to ensure the daily and generational reproduction of the popluaton”(Bezanson, 24). In such, they are unpaid and my individual way of living and social contributions to the westernized population. This definition is governed and portrayed in......

Words: 711 - Pages: 3

Cell Reproduction

...Cell Reproduction Introduction Cellular reproduction is the process by which cells duplicate their contents and then divide to yield two cells with similar, if not duplicate contents. Life as we know it depends on the ability of cells to store, retrieve and translate the genetic instructions required to make and maintain a living organism. In this assignment, I will discuss two different types of cell reproduction, mitosis and meiosis and, include the different stages required in order for the reproduction to take place. Mitosis Mitosis is a process by which a cell divides to form two daughter cells and produces an almost carbon copy of the parent cell. The daughter cells will consist of the same number and type of chromosomes as the parent cell and will be identical to each other. Although cell division is the defining characteristic of mitosis, a number of events must take place during mitosis prior to the splitting of the cell. There are four phases that constitute the period in which cells make preparation for cell division. The four phases are prophase, metaphase, anaphase and telophase. Prophase, the first stage of mitosis during which the chromosomes become shorter, thicker and consist of two chromatids. At this time, the chromosomes are still enclosed in the cell nucleus within the nuclear envelope. The chromosomes also contain a centromere, which is necessary in later phases for attachment to microtubules for migration. Late in prophase,......

Words: 1146 - Pages: 5

Cell Reproduction

...WHAT IS CELL REPRODUCTION AND WHY IT HAPPENS According to our text book, Essentials of Biology, we begin life as a single cell but over the period of several months, we become a collection of trillions of cells. This process continues as we grow up and as we reach a fully mature adult age, old cells are replaced with new ones. Many cells divide at least once during their short life span and some divide many times before they die. This is known as cell division (parent cells and daughter cells) which are given the names of binary fission, meiosis and mitosis. New red blood cells, skin cells and digestive track cells are also generated. Reproduction is also how organisms are able to reproduce through meiosis which involves the replication of DNA and the splitting of molecules. Mitosis involves the cell division which produces two of the same identical cells from one single cell and happens as a result of a process that cells go through to form to nuclei with each of the nuclei containing the same number of chromosomes. Many eukaryotic organisms use this process for reproduction. Cells go though many cycles but all of the cycles happen in a specific event, some of which I partially mentioned above. The first in the Interphase cycle which is time it takes for a cell to perform its normal functions, depending on where it is in the human body. The next stage is the M state which includes both the division of the nucleus and the division of the cytoplasm—this is......

Words: 619 - Pages: 3

Basic Processes of Reproduction

...Basic Processes of Reproduction Bacteria: Bacteria reproduce asexually, under positive environment settings this process is carried out through the method binary fission, where the most bacterial reproduction occurs in prokaryotic cells. The second method is through mitosis in eukaryotic cells except gametes (Pruitt & Underwood, 2006). Binary fission is asexual by nature and involves the splitting of the parent cells into two equal parts which once the split can be capable of independent existence (MediLexicon, 2004-2011). Grasshopper: Grasshoppers sexually reproduce when the male grasshopper introduces his spermatozoa through his aedeagus (reproductive organ) into the females ovipositor. The sperm sack contains a large packet of proteins known as spermatophylax that helps keep the eggs properly nourished (New World Encyclopedia, 2008). Once fertilized the female lays the eggs with her ovipositor and stomach one to two inches underground to keep them protected during the winter months until they hatch in warmer weather (New World Encyclopedia). Fish: Fish reproduce is, based on the location, time of year, and the presence of a proper mate (Pruitt & Underwood, 2006). Depending on the type of fish they gather in huge schools, and females expel eggs and the males follow behind discharging Milt (sperm) into the water. Some of the eggs float some sink to the bottom, and others are, laid in nests. Once the eggs are laid, they are commonly...

Words: 412 - Pages: 2

Reproduction Ussues Are Essential Survival

...Reflection on Reproduction Issues are Essential Survival Issues for The Asian-American Communities What a sad state we live in when women, living in the United States are still denied basic health care simply because either they are unable to understand what is expected of them or the physician and/or medical office are unable to explain it. Connie C. Chan writes of the frightening ordeal that these non-English speaking women are forced to face. Imagine walking into a medical office where you are unable to fill out the forms, are given 3 minutes with the physician and come out unable to explain what it is that has brought you there. This scenario isn’t fiction, it happens every day. The Statue of Liberty states to “Give me your tired, your poor, Your huddled masses, yearning to breathe free”, but what it doesn’t say on the bottom line is you can have these benefits as long as you can speak English. We are supposed to be a land of equal opportunity, but that just isn’t true. Chan writes when speaking on the issue of Asian-American immigrant woman and their lack of available healthcare for abortions that “they do not speak English; they do not demand equal access to health care; their needs are easily overlooked.” But why are they overlooked? I would argue that they do not demand their rights because they do not know they have them. It is a sad state indeed when women, such as Chan must personally advocate for women’s health issues without even the support of......

Words: 677 - Pages: 3

Cell Reproduction

...Cell Reproduction The term cell reproduction refers to the process of a cell splitting to form two similar cells; this is known as cell division. Eukaryotic cells reproduce by mitosis or meiosis; and prokaryotic cells use binary fission as a means of cell reproduction. (Simon,Reece,Dickey.(2010)) Mitosis is defined as a process of asexual reproduction in which the parent cell divides in two producing a replica, with an equal number of chromosomes in a haploid cell. The product of mitosis is two diploid daughter cells. The process of mitosis creates everything accept sex cells; and occurs in all organisms. The steps of mitosis are Interphase, Prophase, Metaphase, Anaphase, Telophase and Cytokinesis. In the prophase step of mitosis the chromosomes duplicate into two sister chromatids. In metaphase the chromosomes align in the center of the cell, the spindle microtubes attach to the two sister chromatids are pulled toward the opposite poles of the cell. In anaphase the two sister chromatids separate and are considered full daughter chromosome; the mirotubes push toward opposite poles cause the cell to elongate. In telophase the chromosomes are at the far point of the opposite poles of the cell; the nucleus separates into two separate but identical daughter nuclei. In the final stage cytokinesis the cytoplasm divides forming two separate but genetically identical daughter cells. (Simon,Reece,Dickey.(2010)) Meiosis is a process of sexual reproduction which creates sex......

Words: 780 - Pages: 4

Körperpflege (213652) | wowwhatafail11 | Randall Berger