Monotreme Reproductive Biology and Behavior
Monotremes are mammals that are oviparous, or egg-laying. There are only 3 extant species of monotremes: the playtpus and two species of echidna. Their reproductive systems are highly specialized to facilitate both the production of eggs and milk. The male tract is quite simple. The female tract has qualities similar to those of birds, though female echidnas also possess pouches. The monotreme egg is also very specialized and somewhat similar to a reptile egg. Platypuses and echidnas have very different behaviors when it comes to mating, but their genetics are quite similar. Monotremes possess a few large chromosomes and several unpaired microchromosomes. The descendants of the first radiation of mammals, monotremes have characteristics of both placentals and marsupials, while still retaining characteristics of reptiles and birds in a combination all their own.
Introduction
At first glance platypuses seem to be an amalgamation of mammals, birds, and everything in between. In fact, their reproduction biology also has much in common with a variety of animals—reptiles, birds, placentals and marsupial mammals. Platypuses belong to a group of animals called monotremes. These egg-laying mammals have been a mystery to researchers since their discovery by Westerners over 200 years ago. The first specimens of platypuses brought back to England were thought to be hoaxes similar to mermaids (Moyal, 2001). Found only in and around Australia, there are only three living species of monotremes: the platypus (Ornithorhynchus anatinus) and two species of echidnas (Tachyglossus aculeatus, and Zaglossus bruijni).
The word “monotreme” is Greek for “one-hole,” referring to the cloaca that is the exit for the urinary, reproductive, and excretory systems (Dawson, 1983). The creatures are oviparous--the females lay eggs that develop outside of her body. This paper will explain the background of the animals, the anatomy of the tract and egg, breeding behavior, and genetics behind this unique reproductive system. It will pay special attention to the similarities of the monotreme reproductive system to those of animals we are more familiar with.
Background
Monotremes are crepuscular animals only found in Australia and New Guinea.
"Bradypus pygmaeus pygmy three-toed sloth” (b). Encyclopedia of Life. N.p., n.d. Web. The Web. The Web.
According to Catholics for Peace and Justice, “the just war tradition begins with a strong presumption against the use of force and then establishes the conditions when this presumption may be overridden for the sake of preserving the kind of peace which protects human dignity and human rights.” The Just War Theory states that there are seven conditions that must be met in order for a declared war to be a true and just war. The first of these values is Just Cause. This means that force can only be utilized to correct an aggression or evil. If the war is being declared out of spite or to seek revenge, the war cannot be defined as being just. Also, there must be a formal declaration of war and warning with spoken terms of what the aims are and what this war will plan to fulfill. The next criterion is Comparative Justice which means the injustice suffered by one party can NOT significantly outweigh the suffering from the other party. For example, if the initial attack o...
Today we will be taking about the Duck Billed Platypus, we will be seeing that makes them different. The first thing we will start out with is their appearance. The Platypus has brown waterproof fur and a flat tail like a beaver they also have a bill and webbed feet like a duck. They next thing I will talk about a Platypus diet. A Platypus mainly eat insects and larvae, shellfish, and worms but because Platypus have no teeth they use gravel they scoop up to break up there food. Platypus are also Carnivore meaning they only eat meat or flesh. Next we will talk about the Platypus defenses. When swimming the Platypus have folds of skin covering their eyes and ears to prevent water from entering, and the nostrils close with a watertight
Many, including the Catholic Church, judge the justifications of a war based on several factors given in the “just war theory,” which is used to evaluate the war based on its causes and means. The first required factor is a just cause, meaning that a nation’s decision to begin a war must be due to “substantial aggression” brought about by the opposition which cannot be resolved through non-violent solutions without excessive cost whereas armed conflict is not hopeless or excessively costly (“Just War Theory”1). In most cases, wars are started for a reason; however, many of these reasons are for the benefit of the governments who start the wars. The just war theory is widely accepted as a way to determine the moral standing of the reasons. This part of the theory is to ensure that the objective of a war is a reasonable and moral one. It prevents the needless bloodshed and loss of human lives over petty disputes while still protecting the rights and lives of the innocent by acknowledging the necessity of war in dire situations.
Christmas is one of the most celebrated festivals in the western world. The nativity celebration of Jesus. In every country, or every region, local customs influence the ceremonies, and Christmas is celebrated differently everywhere because of those customs. But what most western people have no idea of is that Christmas is not the only nativity festival of a founder of a religion. It is not even the oldest nativity festival! That would be the traditional Buddhist festival of the birth of Buddha.
Fox, R. 2001. Invertebrate Anatomy OnLine: Artemia Franciscana. Lander University. http://webs.lander.edu/rsfox/invertebrates/artemia.html, retrieved February 13, 2011.
1These two populations are different species because they have different capabilities of performing in nature. For example there is behavioral isolation. My evidence for that is that in the data, it states that the average time spent in courtship display for the St. Kitts rodent is 12.6 seconds. While the courtship display for the Nevis Rodent is 21.3. You can see that there is a major difference in the way that they behave. Also there is another type of isolation which is gametic isolation. There is gametic isolation because the average gestation time for St. Kitts rodent is 29.3 days. The average gestation for the Nevis rodent is 42.7 days. Therefore a sperm from St. Kitts rodent wouldn’t survive in the reproductive tract of the Nevis rodent. It wouldn’t survive because it wouldn’t develop properly and is not accustomed to its environment. There is also another type of isolation happening with the rodents of St. Kitts. This type of isolation is called temporal isolation. There is temporal isolation because the article states, “the reproductive seasons are being delayed by up to one year.” This is talking about that the rodents are having a hard time finding mates therefore, their reproductive season is being delayed. Also in the article it states, “In the 240 attempts to bring a Nevis animal into the St. Kitts population, you are unable to observe a single successful reproductive event.” The rodents are mechanically isolated, because if you can’t have a reproductive event, there reproductive organs might not be matching with one another. Their appearance might look identical but they are genetically different.
Ah Christmas, it is said to be the most wonderful time of the year. In the United States Christmas is a time of giving and receiving, spending time with your family, and in most Christian families, celebrating the birth of Jesus Christ. Christmas is hands-down the most highly commercialized holiday celebrated by Americans. In fact, according to CBS news, the average American will spend $700 on gifts this holiday season, totaling for a whopping $465 billion spent nation-wide. From mall Santas as far as the eye can see, to hearing Christmas music in every retail store you enter. Christmas is a time of high spirits and high spending in the U.S.
Many people in American society assume that the main purpose of Christmas is the supposed coming of Santa Claus. Their assumption however is far from the truth. The origins of Christmas, which literally means "Christ mass," actually lie in Christianity-not in the fat man with a stomach that jiggles like a bowl full of jelly. Centuries ago, Christians developed a tradition of celebrating Jesus Christ's birthday. Although Christians were unsure of the exact date of Christ's birth, they officially declared December 25th as the day they would celebrate it. The holiday began simply as a day in which families would spend quality time together, reflecting on Jesus' life, giving thanks to God for sending his "one and only son."
Evolutionary developmental biology (evo-devo) was instituted in the early 1980s as a distinctive field of study to characterise the new synthesis of evolution hypothesis (Müller, 2007). Evo-devo is regarded as a new rule in evolutionary biology and a complement to neo-Darwinian theories. It has formed from the combination of molecular developmental biology and evolutionary molecular genetics; their integration has helped greatly to understand both of these fields. Evo-devo as a discipline has been exploring the role of the process of individual development and the changes in evolutionary phenotype, meaning the developmental procedure by which single-celled zygotes grow to be multicellular organisms. Alterations in the developmental program frequently cause differences in adult morphology. When these alterations are helpful, they grow to be fixed in a population and can result in the evolution of new phyla. Evo-devo seeks to figure out how new groups happen by understanding how the method of development has evolved in different lineages. In other word, evo-devo explains the interaction between phenotype and genotype (Hall, 2007). Explanation of morphological novelty of evolutionary origins is one of the middle challenges in current evolutionary biology, and is intertwined with energetic discussion regarding how to connect developmental biology to standard perspectives from the theory of evolution (Laubichler, 2010). A large amount of theoretical and experiential effort is being devoted to novelties that have challenged biologists for more than one hundred years, for instance, the basis of fins in fish, the fin-to-limb change and the evolution of feathers. The biology of development promises to formulate a main contribution to these...
Colossians 2:12 states, “Having been buried with him in baptism, in which you were also raised with him through your faith in the working of God, who raised him from the dead (Cabal).” This scripture really gives us a clear visual on what baptism represents. Romans 6:2-7 states “Or do you not know that all of us who have been baptized into his death (Cleave Pg. 235)? These scriptures make the it clear to me that the baptism is very much a symbolic action that we are making a public statement of faith. In the Theology book the author makes a very good point where states that Eph. 2:1 tells that we a identifying with Christ’s Death,burial, and resurrection. This verse states, “And you hath he quickened, who were dead in trespass and sins (Cleave Pg. 235). It is a very clear picture of our new birth in Jesus Christ. The next question I and others have is, “Is baptism necessary for salvation?”Let me take a good look at this question because of so much debate over it.
Sikes, Roberts. and William L. Gannon. "Guidelines of the American Society of Mammalogists for the Use of Wild Mammals in Research." Journal of Mammalogy 92.1 (Feb. 2011): 235-253. Academic Search Premier. EBSCO. Web. 5 Oct. 2011.
Given the outrageous effort some people go to to ensure Christmas is celebrated extravagantly, the true meaning of why we actually celebrate it has been completely lost. Sadly, Christmas has becoming the victim of a completely commercialised world where society can't say no. Everyone always wants too much and never seem to stop to think about how Christmas is meant to be a time of joy and happiness. Christmas should be about giving, not receiving and certainly not about how many presents you get. Businesses should try and distance themselves from commercialisation and materialism and stop advertising for their Christmas stocks as early as August. Maybe then we would not be completely wrapped up in false pretentious views on Christmas and celebrate it for the true meaning- to celebrate the birth of Jesus Christ.
Christmas was declared a Federal Holiday in America on June 26, 1870 under the government headed by President Ulysses S.
But now, directly comparing them to other mammals, the platypus is one of only two monotremes, which are mammals who lay eggs. The other one is the echidna. Unlike “normal” mammals like lions or pretty much anyone that can come up to your mind right now, these two (platypus and echidna) lay eggs. Another difference is that the adult platypi do not have teeth but they have heavily keratinized pads instead, while most mammals have teeth. In all mammals, the tiny bones that conduct sound in the ear are incorporated to the skull, rather than in the jaw as in the cynodonts. However, the external opening of the ear is still in the base of the jaw. The platypus has extra bones in the shoulder, one of them is called the interclavicle, which is a bone not found in any other mammal. Also, its legs are in the side of its body, like a reptile, and not underneath like other