Critically Evaluate the Evidence for the Mode of life, Behaviour and Essay

Critically Evaluate the Evidence for the Mode of life, Behaviour and Ancestry of the Pterosaurs (flying reptiles) - Essay Example Pterosaurs form the group of the first animals to fly. The winged lizards belonged to the order pterosauria. Their wings stretched from the ankle to a lengthened forth finger. Their bones were hollow, and air filled, like those for birds. They had a keeled breastbone that developed and got attached to flight muscles. Their brain was enlarged hence, showed specialized features associated with flight. Later developments of the species saw their shoulders fused into a structure known as notarium. Its purpose was to conceal the torso during flight and provide a stable support to the shoulder blade. Wilton (2013) research shows that pterosaurs remained conservative for 70 million years after which, they started practicing adaptation with all kinds of new modes of life. Such adaptation lifestyles included change of food and food sources. Pterosaurs are believed to be the ancestors of the modern day birds. However, this is not the truth. They resemble birds in many ways, but they are not cl ose to being birds. There were two major kinds of pterosaurs, the rhamphorhynchoid and pterodactyls. The first consisted of a smaller pterosaur, and the later comprised of large bodied and rare pterosaur (Bennet, 1989). Main features of pterosaurs They belonged to the category of weak flyers. Recent studies implicate that the wings of the pterosaurs were flappers, not gliders. An elongated digit on their claws was attached to them. The flight membrane and muscle attachments connected the digit to the arm, shoulders and chest to enable the creature gain stability during flight (Bennet, 1989). The wings extended up to 40 feet and attached to the hind limbs. The essence was to connect the hands and legs. The bones were hollow (i.e. honeycomb). This made them light for easy flight (Bennet, 1989). The membranes were very complex but very thin for flight purposes. The consistent of the membrane included blood vessels, fibrous tissues and small muscles. The membrane performed cooling funct ions preventing the body from too much heat (Bennet, 1989). Pterosaurs walked on four legs. This caused constraint to the animal since it could not walk fast with its limbs connected to the wings. These features lead to the conclusion that pterosaurs evolved from tree climbing reptiles. Their claws were curled like those of tree climbing reptiles (Frey et al. 2003). The claws of the hind limbs resembled those of the birds that walked on the ground (Prentice, Ruta & Benton, 2011). Those of the forelimbs resembled those of the perching birds. The adaptability mode for the limbs was to be able to walk on the ground and perch on trees (Bennet, 1989). Scientists critically examine the head of the animals and come up with many physiological and behavioral traits of the animals. The shape of the head acts as an adaptive feature for prey catching. Some pterosaurs had beaks long, to about two feet (Witton, &Naish, 2008). Those that had teeth were very sharp aligned on the side of both jaws. The ones that did not have teeth had very long, pointed and sharp edged bills (Kellner, 2003). The animal had a head that sloped downwards. The floccolus is a lobe in the brain that had connections to the eye and neck muscles (Padian, 1997). The functions of the connection were to stabilize and sharpen view of pray within the eyes. Some pterosaurs had head crests thought to have been used to attract mates or repel rivals and attackers (Prentice, Ruta& Benton, 2008). They

Business and economics Assignment Example | Topics and Well Written Essays - 1000 words

Business and economics - Assignment Example That was the year the UK economy went into recession, pushed to the brink by the global financial contagion, together with rising levels of debt in the consumer market, as well as sharp falls in the prices of residential properties. The recession spurred government into pump-priming mode, spending on government projects to spur the economy, taking a stake in the banking system and effectively nationalizing portions of that system, reducing taxation, and putting on hold curbs on government borrowing. These acts pushed Britain to the opposite end of another brink, and that is an elevation of public debts, and the ballooning of the public deficit levels, that then spurred the government of Cameron, formed with the support of both Democrats and Conservatives, to initiate a five-year plan of austere reforms in 2010. The goal of the program was the reduction of the budget deficit to just a percent of GDP by 2015, from 10 percent of GDP at the start of 2010. By the next year, the government announced an extension of the austerity program through to 2017, owing to the perceived inadequacy of the interventions to effect change, the lower than desired rates of growth in the economy, and the effects of the crisis sparked by the debt problems in many parts of the EU (Central Intelligence Agency 2013). There was an increase in VAT in 2011 to 20 percent from 17.5 percent as part of the measures tied to this program. Meanwhile, the tax rates for companies in the UK were targeted to go down in 2014 to just 21 percent. Also, $605 billion was earmarked for a program to purchase assets by the end of 2012. In all, 2012 was characterized by public deficit levels that stuck persistently in the range of 7.7 percent of the GDP, above targets; a 0.1 percent contraction in the GDP; tepid spending by consumers; tepid investment levels among business concerns; and the continued rise in the levels of public debts (Central