The origin and significance of diversity Essay Example for Free

The origin and signifi sternce of diversity EssayIntroductionAnts make waterca are arguably the most successful organisms shortly on earth. They evolved from a wasp same common ancestor approximately 150 million years ago(2006 Chuck Lydeard)1. Due to their long ecologic dominancy amongst insect and short life span they choose undergone a high rate of adaptational radiation. leash to a reasonably round amount of species and inter- species diversity. There are at least 12000 incompatible species of family progress toicidae (2008 Edward O. Wilson)2 which down colonised almost every(prenominal) landmass on the planet(Alice S. Jones 2006)3This unique dominancy and prevalence means that Ants p envyly account for an incompar subject 15 to 20%(2000 Ted R. Schultz)4,3 of the worlds terrestrial animal biomass. Formca exhibit eusociality, they have complex rigid social affairs and interactions. They form colonies varying form a few hundred to tiptop colonies with billions of individuals. Ants prevalence is often over looked due to their size and nature. The time when we most notice their vast verse is when it starts affecting us except to put it in perspective thither are around 1.7billion pismires for every person in Scotland(2006 Edward O. Wilson) 5,6.History of OriginThe Origin of the Ant stems back even further than we originally thought. A new D.N.A. study which included researchers from Harvard University states that they evolved around 140 to 168 million years ago in the Jurassic or Cretaceous period1. This is signific emmet when we analyze how Ants became so successful and diverse. They evolved from the same common ancestor family as wasps called Vespoidea (1999 Denis J. Brothers)7 the similarity is light in the family velvet emmet (Mutillidae,) See anatomy 1 which is actually a wasp but exhibits ant like qualities. They originally evolved in a rain forest type climate breathing predominantly amongst large herbivores. Indeed this is where we see the greatest number of Formca and variation in species at present3,4. For a long time Ants were scarce making up lone(prenominal) around 1 percent of the insect population(2000 David Grimaldi and Donat Agosti)8. withal around 100 million years ago with the appearance of flower plants the r-selection species experienced a high rate of evolutionary radiation.As a result of this period of adaptive radiation, ants ecological dominancy increased 20-40% of insects found in fossil deposits from the middle of the Tertiary period are ants8. anthesisplants were the key to the ants increased population they created a much wider range of niches and thus reduced competition amongst insects, which make it to an increase in insects that ants could utilise as a food source(2006 Moreau CS.)9 Over time ants exhibited complex symbiotic relationships. I noted a good example of this in the Edinburgh Botanic Gardens(). The Acacia sphaerocephala See figure 2 is offer inbred to Central and South America it exhibits a symbiotic relationship with an ant species Pseudo myrmex sphaerocephala.Its thorns are kettle of fish and perfect for the ants to live in protecting them from predators which could disrupt their colonies if on the ground. In turn this mutualistic relationship benefits the tree as the ants guard it from other leaf eating insects. The eusociality social structure exhibited by Formca is significant to its success. Instinctive genes inherited from its common ancestor Vespoidea give rise to its social dependence structure. This is excessively still seen in most wasps which evolved from the same ancestral family.Diversity at heart Formca-QueensFormca demonstrate a specific, highly organised, affective social settlement structure. Diversity within species of Ant is based on the needs of the colony. The colony is even looked at as an organism in itself (a Super Organism) for the purpose of more or less field work. Individuals have specific instruction pa thways which lead to specific roles such as, Soldiers, Workers, Drones, Queens, Foragers and food stores (repletes). The festering into these divergent classes is determined mostly by environmental factors such as nutrition and hormones. Yet in a few studies genetic variation has been found among castes. These genetic transmutes are small a change in one gene which can, for instance, decide whether a colony has one or multiple queens. However in most cases all ants start with the same genes with the exception of males. Ants generally have 4 development stages, egg, larva, pupa and adult(2002 Myrm)10.The larvae (see figure 3) are only capable of some minor movement, such as bending their head toward a food source. It is in the larval stage where differing the direct of care and nourishment leads to different development pathways. When resources are low most larvae will develop into sterile female workers. Only if the developed colony has an abundant food supply will worker ants map selected larvae using pheromones. These then receive dampen nourishment than others whichtriggers select genes to activate(1978 Edward O. Wilson.)11 These larvae develop into, normally winged, sexually mature female ants (See figure 4)which leave to chance upon a male (Drone) and start a new colony. In some colonies for whatever reason there is no queen in this case a female worker (all ants apart from drones are female) becomes stiff and lays fertile eggs. The Queens main role is to allow gene flow in the gene pool. She join with one or more males from other colonies before starting her own. This is the only sexual interaction between ants from different colonies. This important role exhibits the significance of variation within a species.Diversity within Formca-DronesWorkers generally cannot mate yet beca drill of the haplodiploid sex-determination system in most species they have the ability to lay sterile eggs that become fully fertile haploid males. This system means t hat offspring created from the combination of a sperm and an egg develop as a female (Worker or Queen) and an unfertilized egg develops as a male. This results in males having half the number of chromosomes compared to females (males are haploid).This system means that a drone (See figure 5) has no father and cannot have sons however he has a grandfather and is able to have grandsons. The scallywag Jumper Ant Myrmecia pilosulas (See figure 6) genome is enclosed on a single pair of chromosomes as males are haploid they only have 1 chromosome, the lowest amount identified for any animal. ( 1986 Michael W. J. Crosland Ross H. Crozier)12 interestingly Myrmecia pilosula have a venomous poison and cause more deaths in Tasmania than spiders, snakes, wasps, and sharks combined.(2008 Killer Ants T.V.)13 The only purpose of drones is to mate with a queen so she can start a new colony when this is complete he dies.Diversity within Formca-WorkersWorkers carry out every other role in ant socie ty. Depending on their age and a number of environmental conditions, including the state of the colony, workers can be spends, nurses, farmers, repletes and more, depending on the species. Ants are the only taxonomic group to evolve into specific eusocialit roles with age. This creates a very clear and significant diversity within species. Soldiers are often older workers which develop powerful mandibles. In phone line to workers soldiers are a lot larger in the species Pheidologeton diversus the dry mass of asoldier can be calciferol times that of a worker. The difference is most prevalent in the army ant genus Dorylus(See figure 7.) Due to seasonal food shortages they leave their temporary ant hill and march in columns of up to 50 million individuals.Columns are ordered with workers being flanked and protected by the larger soldier ants(1991Bert Hlldobler)14. The soldiers create a defensive moving wall allowing the workers to safely and swiftly move through with(predicate) the corridor (at around 20 meters an hour.) A clear example of the diversity within a species is found in the genus Myrmecocystus. It is literally a living food store, workers feed another worker until its abdomen swells and it gets too large to get out of the chamber it is in. They are termed repletes (See figure 8) and are used by the colony to abide in times of reduced resources such as food, water and nutrients(1993 Randy C. Morgan)15.Diversity between different species of genus FormicaFormicas ecological dominance has driven diversity between species to reduce competition. To allow successful resource segmentation and acquisition of new resources there are vast differences in the physical abilities of different species. A resent example of this is the study of the species Odontomachus bauri (Trap Jaw Ant) by Andrew Suarez (an ecologist and entomologist at the University of Illinois) in late 2006. Through the use of high speed cameras (about 10,000 times faster than those used to film movies) the speed of the ant jaws closing was able to be measured. It is, by a clear margin, the fastest self perpetuated moment in the animal demesne with speeds exceeding 144 miles per hour. Even more interesting is the power involved in this movement the jaws quicken at 100,000 times the force of gravity. This results in the movement being completed very quickly, the movement could be repeated approximately 2300 times in the time it takes you to blink exerting a force up to 500 times the ants body mass(2006 Andrew Suarez)16.This diversity gives the ant a competitive advantage over other species. They use this ability to kill pray, attack predators and to flee from predators. As when the jaws close against the predator or ground the ant gets propelled away. An example of very specific diversity is that of leaf cutter ants Myrmicinae. They farm specific fungi as food sources in their colonies. Gathering specific leaves to feed the fungi and carrying antimicrobialbacteria to stop transmittance or competition for their specific fungi. However a more unique and resent discovery in Formica diversity is Polyrhachis sokolova (See figure 9) discovered in Australia in 2006 in mangrove swamps it is the only ant found to swim and nest under water. They survive in air pockets and by swimming to the issue to breath (2006 Dr Simon Robson)17. Not much more is known about them and research is ongoing. They clearly demonstrate the level of diversity and its significance in avoiding and reducing competition between ant species.ConclusionTo conclude Formica are exceedingly diverse both within and between species. They exhibit very specific roles within their colonies so much so that the entre colony can be viewed as a single organism. They have been present on earth for a comparably long time. During this time they have diversified amongst species creating many another(prenominal) complex and delicate symbiotic relationships with other organisms. However the impendi ng threat of climate change bring together with deforestation and loss of habitat could threaten ant species. With a body I work with- the IPCC (international table on climate change) predicting that Climate change alone is expected to force a further 15%- 37% of species to the brink of extinction within the next 50 years.(2006 IPCC.)18 There may be a serious impact on the biodiversity of ants due to their many obligate host habitats and specific dependency on other organisms.References1 http//news.bio-medicine.org/biology-news-3/Ancient-ants-arose-140-168-million-years-ago-7286-1/2 http//www.nytimes.com/2008/07/15/science/15wils.html3 http//ngm.nationalgeographic.com/2007/08/ants/did-you-know-learn4 http//www.pnas.org/content/97/26/140285 http//everything2.com/index.pl?node_id=17930206 http//www.gro-scotland.gov.uk/press/2007-news/scotlands-mid-year-population-estimates.html7 phylogeny and evolution of wasps, ants and bees 233- 249.8 http//www.pnas.org/content/97/25/136789 http// www.ncbi.nlm.nih.gov/pubmed/1660119010 http//www.antnest.co.uk/cycle.html11 Caste and ecology in the social