Duck+-+Extinct+Animal

= Zhongjianornis yangi (Extinct Animal) = By Cheryl Young 10C

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The //Zhongjianornis yangi//, is the most likely to be closely related to the [|Canvasback Duck]. They are one of the early birds that does not have any teeth and duck-like features.

HABITAT
= = The //Zhongjianornis// existed in the duration of the Early Cretaceous Age, when continental drift caused the plates to drift further and further apart. Figure no. 2 shows an impression of what the world would have been like during that period. As for its habitat, the //Zhongjianornis// must have lived in the Asian region, where most of its fossils have been found.

The Cretaceous Age also accounted for the evolution of birds and their diversification during the late Jurassic and early Cretaceous periods. The //Zhongjianornis// fossil found in north eastern China accounts for the probable location of where the bird would have lived during its time.

The environment the //Zhongjianornis// must have lived in should be filled with diverse ferns and trees. Having evolved wings shows its means of escape from predators, such as the small [|Theropod] dinosaurs, by taking flight and shelter on higher ground, namely in trees.

During the Cretaceous period, the flora and fauna must have been thriving in the area which the //Zhongjianornis// lived in. Having only previously gained the ability to fly, they may not have adapted as to where to lay their eggs, which in that period of time must have been relatively big. It also must have lived near water, as the fossils discovered had been preserved by fine sediment which was low in oxygen in the bottom of a lake. Studies have shown that this early bird may have been semi-aquatic, signs of a partially early duck.

ADAPTATIONS
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Structural Adaptation 1
The most distinguishing feature of the //Zhongjianornis// is its toothless beak. It was the most primitive bird discovered with no teeth at all. Although there are speculations that the bird was unable to catch prey due to its teeth loss, its descendant: the Canvasback, has adapted by growing ridges on the sides of its beak, enabling grip on food.

One of the most reasonable explanations for the development of the //Zhongjianornis'// toothless beak could be the environmental pressure upon it: what it eats. All animals adapt to different foods by changing their teeth. the //Zhongjianornis//, however, probably found it advantageous to get rid of their teeth in favour of a more versatile beak, helping it catch prey. Another factor is the sharpness of the beak, enabling it to spear its prey, thus killing it, and allowing the bird to eat it without any struggle.

Structural Adaptation 2
Another adaptation of the //Zhongjianornis// is its crest. The development in the bird showed that there was a significant increase in size of the humeral deltopectoral crest, suggesting that it was a distinctive form of adaptation for flight, which is more contrasting in more advanced birds.

In its selective pressure to fly, the //Zhongjianornis// must have decided to adapt a better structural position for flight. As the bird originated from dinosaurs, who had flat chests, it created a lot of drag for the bird as it flew. To adapt to this situation, the //Zhongjianornis// developed a larger frontal crest, effectively bending its torso into a flight-like stance like advanced birds do.

Behavioural Adapation 1
With its ability to fly, the //Zhongjianornis// utilizes its ability in fleeing from predators such as Therapods, one if its predators during the Cretaceous Age, and taking to trees. Living in forests provided the bird a home-ground advantage, if any predator was in sight, all the bird had to do was fly up to a prehistoric tree: the most relatively safe place to be for a bird. Since Therapods can't climb trees and aren't big enough to knock one over, this adaptation provided safety for the bird.

The main selective pressure for this adaptation is the presence of predators, pressuring the //Zhongjianornis// to find ways to escape and survive.

Behavioural Adaptation 2
During the period which the //Zhongjianornis// lived in, they probably made their nests on the ground, as they hadn't adapted to building nests in trees. Since they lived in the forest, they had a large amount of places to hide their eggs, effectively protecting them from predators that would eat them. This trait must have been passed down to the Canvasback, as it also hides its eggs in dense vegetation, but develops another trait, as it lays its eggs in other nests of its own species.

The pressure for the location of their eggs must have been from the predators of the time. Therefore finding denser places to lay its eggs.

Physiological Adaptation
Another feature the //Zhongjianornis// poses is its possibly heavier body. Originally, the //[|Archaeopteryx]//, the earliest known bird, had needle-like teeth. However, as the its species diversified, a parallel evolutionary chain occurred, with different types of creature evolving for the same cause. In the //Zhongjianornis'// case, the need to lose weight was an important factor in its adaptation so that flight would become more efficient and it could spend longer periods of time in the air without getting tired.

The selective pressure from this need caused the //Zhongjianornis// to produce a lighter skeleton to aid its flight.

Selection Pressure
Due to the fact that the //Zhongjianornis yangi// has only been found in one specific area, its possible selective pressure could be its inability to migrate, like the Canvasback Duck. Had the //Zhongjianornis// stayed in one area, its food would've run out sooner or later, leading to the starvation of the species, initially leading to its extinction as it didn't know that it could travel to other areas in search for food. Because the Z//hongjianornis// didn't migrate, it lost its food source, unlike the Canvasback, who was able to adapt to its food shortage situation by shifting its migratory range to another area.

Another factor could be the environmental change in weather. There could have been a period in time when there was cold weather, forcing the reptiles to shut down and die. Due to its body mass and developing flight adaptations, the //Zhongjianornis// must not have been able to fly away in time and, while losing its food source to the cold, was unable to reach a warmer climate area. This has been surpassed by the Canvasback duck, who migrates to different grounds every year to stay warm.