IConservationist believes that awareness is the key to successful conservation. To conserve what is in our nature, it is important to understand its life forms. Birds are one of the magnificent creations that Mother Earth has created. Today’s aviation is predominantly inspired by birds. These natural aviators are evolved with many features that help them in flight. The flying process of a bird itself is an amazing phenomenon in nature. How could these animals stay in the air? How do they maintain their balance and posture? How do they handle the air pressure? More than everything, how did these creatures have the ability to incorporate with the fundamentals of aerodynamics? As an answer to all these questions, today iConservationist will be discussing about flight adaptations that birds possess relative to the main organ systems in the bird body.
1. Digestive System
Birds do not possess teeth. Teeth are heavy and it affects the flight by making it difficult to the bird to keep its head in the proper position. The process of flight requires a great deal of control and balance. Also, the positioning of its head plays a major role in making the flight aerodynamically efficient. The function of teeth is replaced by an organ called gizzard. It is also aid in flight by lowering the center of gravity and creating an efficient posture during flight.
Birds have a high rate of metabolism as an adaptation to flight. They have a relatively large yet short rectum, because of the small amounts of undigested food waste to dispose which helps the bird to lose excessive weight which again disturbs the flight. Their intestines are slender and comparatively short in length. It helps to fasten the rate of metabolism. The omission of gall bladder shows an adaptation which again developed to lose excessive weight. Having short intestines also creates the problems of the efficiency of digestion. To overcome this problem, the birds have developed a sac-like structure which is named ‘crop’. Its primary function is to store and moisten the food in order to fasten the digestion. Also, the above-mentioned gizzard, aid in effective metabolism and digestion aiding birds to enhance the efficiency of their flight.
2. Circulatory System
Birds are homeothermic vertebrates which means with the temperature variabilities in nature, birds can sustain their body temperature. They are usually warm blooded and it helps in high altitudes when flying. Birds have a comparatively big heart due to their high demand of energy for functions like flapping. Their circulatory system has developed in an efficient way to facilitate the high rate of metabolism and high energy consumption.
The heart has lost the sinus venosus due to the lack of need that chamber to step up the venous return pressure. Even if the hepatic portal system is present, the renal portal system is reduced. Hence, birds’ circulatory system is well equipped to handle the rigours of flight.
3. Excretory System
Excretory system functions to remove nitrogen containing waste which produce from protein breakdown, out of the animal bodies. The first product of this process is Ammonia which is a toxic substance that needs a massive amount of water to dispose out of bodies. Hence, when life ascend land, animals adapted according to these needs.
Those animals who are aquatic do not have any issues with disposing ammonia yet the land animals were adapted to other form other substances such as urea. The main requirement for flight is maintaining a lighter body weight. Hence birds cannot produce urea due to the amount of water that needs to be in the body. Instead of urea, birds convert ammonia in to a semisolid compound called uric acid. Even if it is high in energy consumption, for flight this factor has contributed immensely.
Uric acid is not toxic and does not dissolve in water hence it acts as a way of waster preservation as well. Furthermore, they do not possess the urinary bladder and all these adaptations have helped birds to have more control over their flight making it easier.
4. Reproductive System
The gonads (testes, ovaries and oviducts) are tiny throughout the year except for the breeding seasons. They enlarge in breeding seasons. Because of these tiny gonads the excess weight birds have to carry has reduced. Also, most female birds have only a single ovary rather than having a pair. This is in exception of most hawks and some pigeons and gulls. Both testes and ovaries enlarge in reproductive seasons and regresses dramatically after the season to in cooperate with flying.
5. Respiratory System
As an adaptation o flight birds have developed a proportionately larger and a much more efficient respiratory system even than the humans! This is because flight is a more demanding activity than walking or running.
One fifth of an average bird’s body volume has been devoted to its respiratory system. Even if the bird lungs are less flexible and relatively small, they have an interconnected system of air sacks in both anterior and posterior portions of body. They are connected with the air spaces in bones it is evolved with a smarter respiration process. This way the air moves in one direction through the lungs; hence it is described as a one-way flow system.
Flight movements and respiratory movements of birds are independent. Due the efficient bird’s breathing apparatus, the ratio of breaths to heartbeats is low. Even if it was believed that the rhythm of bird’s respiration is related to the beats of its wings, it has proved otherwise. The respiration mechanism of birds has evolved with a great consideration of its flying process.
6. Nervous System
In relative to their body size, birds possess large brains compared to lizards and rodents and proved to be smart. The portion of brain which is responsible for flight is the most developed part. Due to their large brain, birds sometimes show intelligence and complex behavior.
Birds have a poor sense of smell but possess a sharp sight. This is predominant in predatory birds such as eagles and hawks. When it comes to intelligence, birds such as ravens are known for their skills in assessing situations. In fact, they are known as the smartest animals due to this behavior. The brains of birds possess ample processing centers for coordinating the information they receive via eyes. A bird’s nerves can rapidly transmit commands of the brain to its wings due to short nerves it is present with. Birds are equipped with visual acuity and quick decision-making processes.
7. Skeletal System
The skeletal systems of birds unveil 3 major adaptations; Fusion, elimination and the pneumatization (Hollowing) of the bones. Some of the vertebrae and some bones in the pelvic gridle of birds are fused in to one structure. Some of the finger and leg bones show the same adaptation. Apart from that many tail, finger and leg bones are missing altogether to reduce excess weight. Not all the bones of birds are light weight; especially leg bones are considered to be strong to maintain the balance of bird body.
The skeleton is light weighed where it is possible by creating hollow bones. Also, it stays strong by adding weight to those bones which are essential to maintain the posture. The degree of skeletal pneumatization depends on the bird type and its lifestyle. Also, skull of a bird is relatively very small and it is present with a beak instead of teeth – losing excess weight. Birds are present with a strong sternum – a solid breast bone which helps the wing muscles to anchor. Also, birds possess a fused collarbone which again helps with keeping the posture while flying.
https://web.stanford.edu/group/stanfordbirds/text/essays/Adaptations.html
(Source: Matthieu O, Krauer R, Hoppeler H, Gehr P, Lindstedt SL, Alexander RMcN, Taylor CR, Weibel ER. 1981. Design of the mammalian respiratory system. VII. Scaling mitochondrial volume in skeletal muscle to body mass. Respir. Physiol. 44, 113–128. (10.1016/0034-5687(81)90079-7) [PubMed] [CrossRef] [Google Scholar] , Bird Physiology and Migration, By Herb Wilson in Migration, Physiology, September 15, 2011 [Originally published on August 21, 2011] )
All these adaptations aid birds to become great aviators. According to the species variation, there are changes in these adaptations. Above mentioned facts are ones you can commonly notice in flying birds. I hope this article will help you realise how wondrous this Mother Earth can be and why it is essential to safeguard her sustainability for our future generations. Do not forget to identify these details next time you observe a bird closely. As we always encourage you, stay close to the environment and stay connected. You will be so surprised at how much you can learn from the nature! With that short reminder, iConservationist will be wrapping up for today. Keep exploring the nature!
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