Diversity Of Phylum Chordata Essay Example | Topics and Well Written Essays - 2500 words

Diversity Of Phylum Chordata - Essay Example In fish they are modified to form gills and they may disappear as the animal grows especially in some of the vertebrates. The pharyngeal gill slit is present at some point in life of the animals. Nerve cord: It is hollow and dorsoventrally placed to the notochord and ends in the brain. Other features are muscular tail (post anal tail) and endostyle (a groove like structure in the ventral wall of the pharynx. However the general features exhibited by animals in this phylum are: The animals have a bilaterally symmetrical body Their bodies are segmented and therefore have segmented muscles Their coelom is well developed They have well developed circulatory system with a ventrally placed heart and are therefore more active than their counterpart invertebrates. Their skeleton is either bony or cartilaginous Their digestive system is complete meaning that their gut runs through the body from mouth to the anus. The phylum chordate falls under the Kingdom Animalia and is further divided into the subphyla Urochordata, Cephalochordata and Vertebrata. However, animals in these subphyla may show different characteristics but the reason for them being grouped in the same phylum is because they exhibit similar characters referred to as unifying links such as urochordates’ larvae have both notochord and nerve cord which vanishes in adulthood. Cephalochordates have a notochord and nerve cord which persist to adulthood but do not have cranium. In vertebrates, the notochord is replaced with vertebral column at adulthood stage and the nerve cord becomes the spinal cord. Subphylum Urochordata Urochordates also known as Tunicates and exemplified by Ascidia have the following characteristics: At adult stage, their body is covered with a suck like structure (Tunica) and has two siphons one through which water enters the body (incurrent siphon) and the other through which water leaves the body (excurrent siphon). They are filter feeders and sessile. Although adults are sessile, their larvae are free swimming and exhibit almost all chordate characteristics. Subphylum Cephalochordata Exemplified by amphioxus and lancelets, cephalochordates have eel like bodies, they are marine, their bodies are segmented. Members of the phylum are soft bodied and therefore, cephalochordates are not fossilized. A notochord extends through their elongated body and mouth is armed with cirri which aids in obtaining food. They have numerous gill slits and are also dioecious. They are filter feeders (extract food from water taken in though the mouth by help of cilia on their wheel organ. Subphylum vertebrata Vertebrates are the most advanced chordates and apart from having an internal skeleton, they exhibit the following characteristics: Their bodies are segmented They have a bilateral symmetrical body Their endoskeleton is either a bony or cartilaginous Pharyngeal gill slits are lost in adults but are present during embryonic stage Their heart is ventrally placed They posses pos t anal tail They have a closed circulatory system Vertebrata Classes Classes captured are: Agnatha, Chondrichthyes, Osteichthyes,Amphibia ,Reptila ,aves and Mammalia Class Agnatha Agnathans arise from a group of vertebrates known as Cylclostomes (fishes or group of vertebrates without jaws) which excludes Gnathostomes (group of vertebrat

Compliance Standards in Education Essay Example | Topics and Well Written Essays - 2500 words

Compliance Standards in Education - Essay Example Students will be able to immediately discuss, write about, and implement material from the classroom in everyday life. Based upon a learner-centred workshop model of classroom participation, the Lesson Plan: Weather is intended to provide students with core curriculum on climate change, environmental science management, and economic and social policies. An advanced lexicon within the English language, the universality of 'Weather Speak' as part of the mediated landscape in the late-capitalist moment, makes the topic both pertinent and timely. Pervasive and highly accessible, classroom activities on weather offer ready assimilation of key concepts, while learning vocabulary and linguistic usages. Mitigation of GHG emissions toward reductions that might decrease carbon dioxide to 1990 levels stand to have long-term effects on environmental health and social foms. From atmospheric research to new models of finance, climate change as a cultural exchange is reinforcing knowledge of our surroundings in new ways never thought possible. Indeed, something as simple as Weather, is now a site for inquiries into environmental science, poetry, and urban planning. Technologies employed within the classroom are responsive to prescriptive methodologies for teaching in the 21st century. Within present pedagogical discussion on training students in the global village, requisite inputs for a well rounded curriculum are constituted not only of the traditional verbal and mathematical proficiency models, but competency building in creative dialogues based on interpretation, critique, the semantic application of visual communications. Deep engagement in visual media has brought us to a state of sophistication in image iconography and accompanying performance. The cultivation of linguistic literacy from visual and media literacy promotes rapid assimilation of concepts familiar from both a consumption and production point of view. Innovative opportunities for skill development, and introduction to secondary sources of research that are now entirely mediated, as in the utility of satellite GIS mapping in weather monitoring, would not be possible without reliance upon media communications strategies, and the attendant lexicons of Science or other disciplinary specific terms. Visual learning models also introduce an element of application within discursive contexts dedicated to intuitive intelligence, for the furtherance of student knowledge and critical inquiry. The implementation of media methods in this course is standardized throughout, and the students become