Tuesday, May 16, 2006

GENERAL ADAPTATIONS BIRDS HAVE EVOLVED FOR FLIGHT.

Evolution of bird from small Theropod Dinosaurs as it was suggested by paleothropologist can be the start of flight evolution. It was suggested that this flight evolution has evolve from ground living species, so with the evolution of feathers bird tend to have a chance to live on skies. Some paleothropologist suggest that flight evolve as result of benefits that are found in the sky. For example, small insect that are found on air, flying birds species feed on them.

Flight is the mode of locomotion used by most of the world birds species. It is important for birds; for feeding, breeding and avoiding predators. They adapt to fly because they have modified limbs as wings. And because flying need energy bird had evolved several other adaptations to improve flying. They have skeletal hollow that serve to reduce weight and it also lost some bones. The earliest birds where having bones that, the modern flying birds do not have. Bones such as bony tails, toothed jaw which has been replaced by lightweight beak

Bones which are lost are those ones that are necessary or that does not pose any impact on the surviving of birds. Birds have developed the body which weigh less than their ancestor, which enable them to fly. It have vanes on the feathers known as barbules that close them together, allowing feathers to stretch and giving bird strength to fly.

Anatomically bird had undergone modification, early birds where having large muscles on hind limbs. Because of modification, it was reduced as the pelvic gridle which provides support for the bird to weigh less and enable them to fly. This anatomical change in most of the birds helps them to evolve for flight, this because they weigh less than their ancestor theropod dinosaurs which was ground living species.

The limbs that develop from bird as the wing helps the bird to fly; they play an important role for flight as they are the ones that hit the wind. This forelimb is composed of three limbs that function to balance the bird on the air. Feathers also enable the bird to hang up on the air.

Adaptations of bird for flight can be suggested as the way in which bird have to survive. They evolve a wing, which was used as limbs to catch preys; they then become modified and become wings to fly. They fly to avoid predators, and also the way to access pray, insect on the air. Most of the diets chosen by birds are on air because insect can fly or tall trees have flowers that bird feed on. Which is difficult for ground animal to feed on that diet? so it encourage the bird to develops wing for flying .

Scientist also suggested that for bird to be able for flight they need to be endothermic, so that they could be able to maintain energy level that they use for flapping wings. but it was indicated that the warm-blooded animals are mammals, so bird are not mammals but because they originate from dinosaurs which is regarded as warm-blooded animal and also they have feathers that hold temperature. They are able to maintain their temperature

In general most of the species adapt different behaviour because of the environment they are living in. predators influence some species to adapt different behaviour, and also diet that different species choose to feed on can also introduce different behaviour on certain species. Birds avoid under ground predators by developing mode of locomotion which enable them to fly higher so that the predators cannot access them. They also choose diet which is abundant in the higher level which is only accessible by species that can fly only, diet such as nectars and flying insects.

References:

1. Hasting L.Your guide to animal/wild life, Birds. [Internet] cited 2006-May-09 Available from: http://animals.about.com/od/birdsastudyguide/a/introtobirds.htm


2. Adaptations for Flight.[Internet]cited 2006-May-09, Available from: http://www.stanford.edu/group/stanfordbirds/text/essays/Adaptations.html


3. Bird flight.2006-May-10[Internet]cited 2006-May-09.Available from: http://en.wikipedia.org/wiki/Bird_flight

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