Parthenogenesis - Reproduction Without Sex

Parthenogenesis - Reproduction Without Sex Parthenogenesis is a type of asexual reproduction in which a female gamete or egg cell develops into an individual without fertilization. Animals including most kinds of wasps, bees, and ants that have no sex chromosomes reproduce by this process. Some reptiles and fish are also capable of reproducing in this manner. Many plants are also capable of reproducing by parthenogenesis. Most organisms that reproduce by parthenogenesis also reproduce sexually. This type of parthenogenesis is known as facultative parthenogenesis and organisms including water fleas, crayfish, snakes, sharks, and Komodo dragons reproduce in this manner. Other parthenogenic species, including some reptiles, amphibians, and fishes, are only capable of reproducing asexually. Key Takeaways: Parthenogenesis In parthenogenesis, reproduction occurs asexually when a female egg cell develops into a new individual without fertilization.Many different types of organisms reproduce by parthenogenesis including insects, amphibians, reptiles, fish, and plants.Most parthenogenic organisms also reproduce sexually, while others only reproduce by asexual means.Parthenogenesis is an adaptive strategy that allows organisms to reproduce when sexual reproduction is not possible due to environmental conditions.Parthenogenesis that happens by apomixis involves the replication of an egg by mitosis resulting in diploid cells that are clones of the parent.Parthenogenesis that happens by automixis involves the replication of an egg by meiosis and the transformation of the haploid egg to a diploid cell by chromosome duplication or fusion with a polar body.In arrhenotokous parthenogenesis, the unfertilized egg develops into a male.In thelytoky parthenogenesis, the unfertilized egg develops into a female.In deute rotoky parthenogenesis, a male or female may develop from the unfertilized egg. Advantages and Disadvantages of Parthenogenesis Parthenogenesis is an adaptive strategy to ensure the reproduction of organisms when conditions are not favorable for sexual reproduction. Asexual reproduction can be advantageous to organisms that must remain in a particular environment and in places where mates are scarce. Numerous offspring can be produced without costing the parent a great amount of energy or time. A disadvantage of this type of reproduction is the lack of genetic variation. There is no movement of genes from one population to another. Due to the fact that environments are unstable, populations that are genetically variable will be able to adapt to changing conditions better than those that lack genetic variation. How Does Parthenogenesis Happen? There are two main ways in which parthenogenesis occurs. One method is by apomixis, where egg cells are produced by mitosis. In apomictic parthenogenesis, the female sex cell (oocyte) replicates by mitosis producing two diploid cells. These cells have the full complement of chromosomes needed to develop into an embryo. The resulting offspring are clones of the parent cell. Among the organisms that reproduce in this manner are flowering plants and aphids. Dorling Kindersley / Getty Images The other main method of parthenogenesis is through automixis. In automictic parthenogenesis, egg cells are produced by meiosis. Normally in oogenesis (egg cell development), the resulting daughter cells are divided unequally during meiosis. This asymmetrical cytokinesis results in one large egg cell (oocyte) and smaller cells called polar bodies. The polar bodies degrade and are not fertilized. The oocyte is  haploid  and only becomes diploid after it is  fertilized by male sperm. Since  automictic parthenogenesis does not involve males, the egg cell becomes diploid by fusing with one of the polar bodies or by duplicating its chromosomes and doubling its genetic material. Since the resulting offspring are produced by meiosis, genetic recombination  occurs and these individuals are not true clones of the parent cell. Sexual Activity and Parthenogenesis In an interesting twist, some organisms that reproduce by parthenogenesis actually need sexual activity for parthenogenesis to occur. Known as pseudogamy or gynogenesis, this type of reproduction requires the presence of sperm cells to stimulate egg cell development. In the process, no genetic material is exchanged because the sperm cell does not fertilize the egg cell. The egg cell develops into an embryo by parthenogenesis. Organisms that reproduce in this manner include some salamanders, stick insects, ticks,  aphids,  mites,  cicadas, wasps, bees, and  ants. How Is Sex Determined in Parthenogenesis? In some organisms such as wasps, bees, and  ants, sex is determined by fertilization. In arrhenotokous parthenogenesis, an  unfertilized egg develops into a male and a fertilized egg develops into a female. The female is diploid and contains two sets  of chromosomes, while the male is haploid.  In thelytoky parthenogenesis,  unfertilized  eggs develop into  females.  Thelytoky parthenogenesis occurs in some ants, bees, wasps, arthropods, salamanders,  fish, and reptiles. In  deuterotoky parthenogenesis, both males and females develop from unfertilized eggs. Other Types of Asexual Reproduction In addition to parthenogenesis, there are several other types of asexual reproduction. Some of these methods include: Spores: Spores are reproductive cells that develop into new organisms without fertilization.Binary fission: In binary fission, an individual replicates and divides by mitosis creating two individuals.Budding: In budding, an individual grows out of the body of its parent.Regeneration: Regeneration occurs when the detached part of an individual forms another individual. Sources Allen, L., et al. Molecular Evidence for the First Records of Facultative Parthenogenesis in Elapid Snakes. Open Science, The Royal Society, 1 Feb. 2018, rsos.royalsocietypublishing.org/content/5/2/171901.Dudgeon, Christine L., et al. Switch from Sexual to Parthenogenetic Reproduction in a Zebra Shark. Nature News, Nature Publishing Group, 16 Jan. 2017, www.nature.com/articles/srep40537.Parthenogenesis. New World Encyclopedia, www.newworldencyclopedia.org/p/index.php?titleParthenogenesisoldid987045.

Article Analysis V Essay Example | Topics and Well Written Essays - 1000 words

Article Analysis V - Essay Example Thus it is a matter of effective communication. This is easier done in the language and culture of the consumer. In other words, the company must acquaint itself with the language and culture of consumers in order to communicate with them. In this regards, the packaging of the item being marketed also plays an important role. Standard packaging helps to create a brand identity. In the movie industry for example, dubbing is often done in local languages and this practice has improved in international studios. Differences in language and culture â€Å"have a significant impact on the way a product may be used in a market, its brand name and the advertising campaign† (Bhushan) as McDonald’s learnt for example, when they failed to appreciate the social cultural dimensions of the market in India. This makes the market hard to break into. To illustrate the problem of language in another region, the sound of Coca-Cola for example, translates into Chinese as ‘A thirsty mouthful of candle wax’. To get round this, the product is known as ‘Kee Kou Keele’ in China, which means ‘Joyful tastes and happiness’. Espoir Cosmetics is an international cosmetics company that wanted to create a new global branding initiative. Natasha Singh who is the executive vice president and global marketing officer of Espoir observes, â€Å"A global strategy will resonate in India in some cases, but I doubt if we will be able to do away with local marketing initiatives. It’s tough to overcome cultural differences.† Thus, she makes it clear that a brand identity must be created in the local region. And, this requires communicating in the language and culture of the region. In this way, the ‘packaging’ is properly targeted. But this is not without some difficulties. The problem with a standard global strategy is that there is a tendency towards ‘overstandardization’ or ‘oversimplification’, which also

Market Orientation in Business Essay Example | Topics and Well Written Essays - 2250 words

Market Orientation in Business - Essay Example Considering any business term requires a clear understanding of what is meant by its name. Thus, it is necessary to give an explanation of the term ‘market orientation’ before going to its detailed analysis. According to a definition provided by the Business Dictionary, market orientation is ‘a business approach or philosophy that focuses on identifying and meeting the stated or hidden needs or wants of customers’. As stated in the Cambridge Dictionary, by the term ‘market orientation’ one should understand ‘management of a company, product, brand, etc. so that it satisfies the needs of customers’. In the book ‘Changing Market Relationships’ written by Jean-Jacques Lambin, market orientation is defined as ‘a set of capabilities, activities and behaviors needed to implement a strong marketing orientation’ (Lambin 2008).Despite the fact that all the definitions mentioned above reflect the main idea behind mar ket orientation quite clearly, the most comprehensive definition of the term is presented by Morgan and Strong in their work named ‘Market Orientation and dimensions of strategic orientation’. In this work, the two authors define perceive the concept of market orientation as a certain mode of corporate management that is founded on encouraging a permanent gathering and sharing of statistical information regarding customers, appreciation of customer needs as a fundamental aspect of the business.

Coffee Shops Essay Example for Free

Coffee Shops Essay Whenever I am in need to study or just want to find a place to hangout, what instantly springs to my mind is a coffee shop. There are many different coffee shops around me, but only one is my absolute favorite. My favorite coffee shop is Beca House. Beca House is a locally owned business and is only about twelve minutes from my house. It is the coziest little nook, where I usually spend my mornings before class eating breakfast and drinking my favorite espresso coffee drink. After all, coffee is the best way to wake up and get the body moving. As I walk into Beca House every morning, the strong bitter aroma of ground coffee beans drift through the air, soaking into my clothes as I make my way to the counter to place my order. The smell was circulating because the coffee bar is located near the left side of the shop. The first attraction for me was the baked goods. They are tidily placed in the transparent glass cabinet, lining up and waiting for me to eat them all. There were all different types of baked goods like muffins, streusels, cheesecakes, cookies, and biscotti’s. Up above near the ceiling of the bar, there were an assortment of coffee beans packed into brown bags. The barista takes my order, large campfire frappe, double espresso. On a cooler day, I order a hot vanilla cappuccino. The delicious smell of coffee generates from the espresso machines. There is also a blackboard on the counter near the menu with a quote written with chalk that will change from day to day. The barista hands me my custom beverage order, and I stroll back to the front of the coffee shop to find a place to get comfortable. All along the walls of the shop are strategically placed vintage paintings and inspirational quotes. Dim lights shine on the spaced out vintage furniture, making for a very soothing and quiet atmosphere. No two pieces of furniture are the same, big couches, small wooden chairs, dark colored pillows, and rustic end tables. I like admiring this type of environment: soothing and calming, yet still inviting. In comparison to most restaurants, coffee shops are by no means a noisy place. The sound of chatters and laughter blends together with the background music playing around the shop, and the volume is set at a medium tone. Coffee shops provide a comfortable, yet sociable gathering spot for people of all ages. I often find peers of my own studying for big tests, writing papers, or maybe just reading a new book and relaxing. The Beca House is my favorite part to my day. I cannot start without it. Even on days that I do not have class, I find myself getting my daily cup of coffee at the crack of dawn, just before work. Stopping at Beca House has become part of my daily routine, and I do not see it being cut out any time soon. I know I go there a lot when the barista’s know my order when I walk through the door. There’s something so perfect about it being just me, my thoughts, and my morning cup of coffee.

Nature vs Nurture Essay -- Biology Science Essays

Nature vs Nurture The issues pitting nature against nurture are exceptionally significant for the gamut of discoveries that attribute an increasing proportion of traits and behaviours to one's genetic makeup. The resulting variety of physical shortcomings and limitations in each person has, for centuries, been countered by endeavours to improve or interfere where necessary, and every individual is consequently the product of a delicate middle path of balance between the two. The importance of nurturing is nearly boundless, and there is no better evidence than the oft-cited case of identical twins who, despite identical nuclear genomes and mitochondrial DNA, will duly differ in physique and behaviour if raised (i.e., nurtured) in dissimilar environments. On the other hand, the role of nurturing in the development of abilities and aptitudes as basic as walking and reading is no less estimable. Hence nature, as represented by the genome, "codes for potential", as concluded by the National Centre for Genome Resources (NCGR) in its on-line publication Genetic Odyssey. While ... Nature vs Nurture Essay -- Biology Science Essays Nature vs Nurture The issues pitting nature against nurture are exceptionally significant for the gamut of discoveries that attribute an increasing proportion of traits and behaviours to one's genetic makeup. The resulting variety of physical shortcomings and limitations in each person has, for centuries, been countered by endeavours to improve or interfere where necessary, and every individual is consequently the product of a delicate middle path of balance between the two. The importance of nurturing is nearly boundless, and there is no better evidence than the oft-cited case of identical twins who, despite identical nuclear genomes and mitochondrial DNA, will duly differ in physique and behaviour if raised (i.e., nurtured) in dissimilar environments. On the other hand, the role of nurturing in the development of abilities and aptitudes as basic as walking and reading is no less estimable. Hence nature, as represented by the genome, "codes for potential", as concluded by the National Centre for Genome Resources (NCGR) in its on-line publication Genetic Odyssey. While ...

Examine the Changes in Location and Development of Tourism Activities Essay

The changes in location and development of tourism activities over the past 50 years can be linked to advantages in air travel, economic growth and the development of technology linked to the internet dangers in the type and availability of accommodation for tourism has also been responsible for changes in the development of tourism activities. Population growth must also be considered when explaining changes in the development of tourism. Booking flights and hotels is now much easier. You can use a travel agent, but increasingly more people are going online to book their own flights and hotels and flights either directly or through agents. It is also possible to look at customer reviews so you can assess the quality of hotels, tours, etc. As communication and transport improved, more people hear about and travel to new places. At the same time that new destinations are discovered, more and more people are going on holidays on these places. Improved communication has not only made booking holidays easier, it has also meant people can now keep in contact much easier while abroad. This has removed the worry from many families. You can now update your status on Twitter or Facebook or send e-mail or texts to family letting them know where you are or what are you doing. It is now just as easy to communicate with your family half way around the world as it is from the next street. English is slowly become an international language – it is the most widely spoken second language. As the number of English speakers increase, more and more people are confident about going on holiday and knowing that they will be able to communicate. As the tourism industry develops the amount of multilingual guides is also increasing so it is possible to visit a foreign country and go on a tour in your native language. Even with the on-going global economic downturn, the world economy is growing. This economic growth is being led by the so called emerging economies e.g. China, Russia and India. With economic growth ore individuals are removed from poverty and are able to afford to go on holiday. People can afford holidays when there disposable income increases. Disposable income is the amount of money left over after all bills are paid for. Over the past 50 years the relative cost of transport has fallen and the ease of moving between countries has increased. Car ownership has increased, new train networks have been built and new airports opened. In the last decade low-cost airlines have emerged and increased tourism. Low-cost airlines offer cheaper flights that normal airlines by removing added extras like airport check-in, in-flight meals, checked baggage and seat selection. The growth of transport has meant people can go on more holidays and also go on shorter holidays (weekend breaks). We are now saturated with advertising on billboards, in magazines, on TV and increasingly online. These adverts make us aware of new destinations and persuade us to visit new places. There has also been a growth of TV programs just about holiday destinations. The emergence of credit cards has made it much easier to pay for holidays and it has made it easier for people to buy things once on holiday. Credit cards can be used to pay for hotels and flights online and can be used to pay for things on holiday or take local currency out of ATMs. Credit cars remove the worry of carrying large amounts of money and the time of exchanging currencies. In conclusion, the growth and changes in location of the tourism in the last 50 years it is caused by thing that went occurring by the pass of the year but the most important is the technology that it grows allot in the last 50 years. The tourism grow because booking flight and hotels is now much more easier, the communication improved so now the people can keep in contact being in any country in the world, the transport is better and cheaper, credit cards has made it much easier to pay for holidays.

Essay about Anzaldúa’s Genre Borderlands - 532 Words

Anzaldà ºa’s Genre Borderlands Gloria Anzaldà ºa writes of a Utopic frame of mind, the borderlands created in and lived in by the new mestiza. She describes the preexisting natures of the Anglos, Mexicanos, and Chicanos as seen around the southwest U.S. / Mexican border, indicative of the nations at large. She also probes the borders of language, sexuality, psychology and spirituality. Anzaldà ºa presents this information in various identifiable ways including the autobiography, historical/informative essay, and poetry. What is unique to Anzaldà ºa is her ability to weave a ‘perfect’ kind of compromised state of mind that melds together the preexisting cultures while simultaneously formulating a fusion of genres that stretches previously†¦show more content†¦Anzaldà ºa finds that combining the two distinct forms adds a new dimension that is necessary to fully comprehend the history of a people. Sexuality and spirituality thrives as other topics in which Anzaldua combines genres. In this instance she combines history and autobiography. Again this gives a more humane look at history. However, this use is more distinctly personal whereas the previous combination of history and poetry provided a more universal personal approach. This talks about Anzaldà ºa’s part in history. Anzaldà ºa writes, â€Å"Being lesbian and raised Catholic, I was indoctrinated as straight, I made the choice to be queer (for some it is genetically inherent)† (41). This line is found in a section dealing with homophobia that resides heavily in the cultures she identifies with. While this phobia exists in the culture at large and is recorded as such, Anzaldà ºa provides a personal account as an example. In another way, language also provides this dynamic that Anzaldà ºa aims for. Anzaldà ºa takes the separate Spanish and English languages and her own Chicana tongue and creates a book that makes uses of both. Both languages are vital in some way. While the book is primarily written in English, often titles, sentences, and poetry parts are in a Spanish that more than likely is not easily translatable to those who are not bilingual. Language seems to best sum up the importance of her borderlands in genre and life. Anzaldà ºa says,Show MoreRelatedSemiautobiographical Work- Borderlands/La Frontera: The New Mestiza by Gloria Anzaldà ºa1286 Words   |  6 Pageselements like genre, discourse, and code. Borderlands/ La Frontera: The New Mestiza is a semi-autobiographical work by Gloria Anzaldà ºa. She examines the relations of her lands, languages, and herself overall. She defines the borders she has around herself in the preface of the book: â€Å"The actual physical borderland that I’m dealing with in this book is the Texas-U.S. Southwest/Mexican border. The psychological borderlands, the sexual borderlands and the spiritual borderlands†¦the Borderlands are physicallyRead MoreThe s Borderlands / La Frontera852 Words   |  4 PagesAnzaldà ºa’s Borderlands/La frontera is a very interesting piece of writing to read because it covers a lot of issues such as identity, language, and gender. The fact that she combines several genres in her writing offers another amazement. Like a powerful concoction, her writing which embodies personal, cultural, and political realities, in a way, reflects not only the richness of her multiple cultural backgrounds but also her efforts in cultivating those cultures. In terms of language for exampleRead MoreThe, Mexican Feminist Theorist Gloria Anzladua s An Analytical Framework For Considering The Relationship Between Minority Faces,3216 Words   |  13 PagesIn Borderlands/La Frontera, Mexican Feminist theoris t Gloria Anzladua’s introduces an analytical framework for considering the relationship between minority faces, spaces, and languages as they compete, interact and inform America’s institutionalized whiteness. While her book specifically deals with the â€Å"minority faces† of Mexican immigrants, the epigraph suggests, racial minorities who interact with historically white spaces cross a â€Å"border† that is at once culturally and linguistically metaphoric