Presbyornis

Presbyornis

(Kafu Lai)



The Presbyornis is the ancestor of the Black Swan. It is the ancestor to all waterfowls today, its lineage can be traced back through its order (Anseriformes). This ancient creature belonged to the extinct family, Presbyornithidae, which features a type of wading goose with specially adapted bills. They were also the first family to develop to the filter feeding mechanism.


 * HABITAT **

Presbyornis lived in the Paleocene Period, they died out aroun d the early Oligocene period (a late sub-period of the Paleocene age circa 23. 03 to 28 4 m.y.a). The climate was generally warm (and arid, in the Asia region). This species was apparently a global distribution, most of the fossils are found on the North and South America (warm temperament) and also Asia (areas such as Mongolia are common). Refer to map.

These ancient birds frequent around in shallow body of water, fresh or salt. The main predators of the Presbyornis are larger carnivorous birds, crocodilians and other predatory mammals such as, preying on Presbyornis is difficult because they live in large colonies, sometimes standing at 1000 strong. The Presbyornis feed on insects and small crustaceans on dry land and other water organisms (such as seaweed or small fish e.g. Lungfish) 


 * ADAPTIONS **

The Presbyornis developed the ability to flourish in both terrestrial and aquatic environment. This may not sound important, but this ability originated from t he C-T mass extinction, almost all species in the Cretaceous Era were wiped out but few birds that were able to live in both territorial and aquatic environments as they can depend on both environments to provide resources. These birds were at a comp etitive advantage until the natural trophic webs (food chain) are restored and diversified again. Until then, these birds would have diversified as well and birds under those ‘families’ would have developed its own adaptation to its specific environment that leads to specialization evolution.Presbyornis also was adapted to specialize living in their particular niche; this gives a competitive edge over other animals since.

They had a tendency to live in colonies, rather than being nomadic. These birds learned that livings in colonies are safer in the wild than other nomadic birds, also, this provide protection from predators to single out one bird and the movement of many birds can be confusing. e.g. an attack from a river crocodile or a visit from smaller egg-stealers. This maintains Presbyornis’s survival, as natural selection naturally eliminates unsustainable development.

The Presbyornis also developed a unique filter-feeding mechanism; its main purpose is to filter out nutritious food e.g. algae and other organisms in water. This helped the animal survive because it could collect the most nutritious foods for them (small plants an organism) from the water, which means it doesn’t have to hunt, like other pre datory birds. Also provide the animal convenient and abundant food source. This is the first evolutionary tract towards the specialized mechanisms in the bills of other birds of the Anseriformes order.



Besides the other features listed above, Presbyornis developed long legs (height around a meter long) and webbed feet. This allows ease of movement in swampy, damp and saline conditions (which was wading) In result, they led a lifestyle similar to a ‘proto-flamingo’, they were also ancestors of wader-type birds who were characterized with long legs and neck e.g. swans. (refer to the photo in the title) FUNFACT: This bird’s fossil was first mistaken as a flamingo because of its long neck and legs.

The Presbyornis developed colorful feathers. According to record evidence, it had a green head, brown body, white bottom with horizontal striped across and orange beak and legs This helped them blend in with surrounding swamp/marsh colors, also, when a group of predator approaches the colony, the movement and colors of so many birds can confuse, distract and drive them away from potential preys e.g. eggs and smaller birds in the colony 


 * ENVIRONMENTAL PRESSURE **

1. Algae Filter-feeding mechanism probably evolved from feeding on algae. Proven to be a very adaptable structure as many other anseriformes developed after, as this ability subsequently diverged and radiated to other species

2. Too much salt! This filter feeding mechanism enables reduce salt intake and salinity. This mechanism helped other animals survive in salt-water regions as high levels of salinity can kill many who depend on the water to survive. This helped manage the ecosystem in their area

3. Changing Environment Front and naval bones show depression for large salt glands that imply its affinity to salt water. Because hydrologic conditions were changing (upper regions of the subtropics have developed a warm temperate) which lead to higher level of salt and alkaline in water (refer to map)

4. Natural Selection P. Isoni (a specific specie in the Presbyronis family) developed a humerus and finger bone, which is believed to have come from Headonornis (a type of bird in the Presbyornithidae family). It is most probably in the midway of evolving somewhat of a ‘thumb’ finger most flying birds have on the tip of each wing (they do not have much use). This proves the versatility of ancient birds to a changing environment. (this relates to all the other adaptations listed above).

5. Living in large groups. It protected one another from larger predators as the Presbyornis stood at a height of around 3 feet. Many animals (especially predators) gradually grew larger though the Paleocene period, which diversified (which was very different from the Cretaceous Period, giving it has low diversity of mammals), this also contributed to their extinction


 * SELECTION PRESSURE **

Climate unsuitable (the Early Oligocene features cooler and more arid conditions in geographical areas) Although it had primitive ancestry and a generalist in terms of ecology (meaning that it could do a little of everything, this was a main feature of survival), it was highly adapted to its particular environment (a manner that is not found anywhere in the modern waterfowl) because its particular environment or ecological niche was partitioned away and also due to rapidly changing environment during the transitional stage of Paleocene to Oligocene (cool, warm and dry to hot and humid to warm and arid).

b.) Future Black Swan
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