What are vestigial structures? How are they used as evidence that evolution has taken place? Give several examples of vestigial structures and explain the current and previous function of these structures.
The word vestigial comes from the concept of vestigiality which applies to genetically determined structures or attributes that have apparently lost most or all of their ancestral function in a given species. Vestigial structures are mostly referred to an organ that was useful in animal’s evolutionary past. Vestigial structures are considered evidence for evolution because they show residuals of a structure that once had a use in the organism’s ancestry. Vestigial structures became first unnecessary due to changes in environment and receded over times in populations to the point that they become non-functional. These structures have not impact in the organisms in any way; therefore there is no need for evolution to get rid of them.
One example of vestigial structures could be the plantaris muscle, which is a long and thing muscle in the human foot and calf that has no longer significant purpose. This muscle was once used to provide proprioceptive feedback information to the central nervous system regarding the position of the foot, but it has no important function and in fact, it is regularly removed by doctors harvesting muscle tissues to use in reconstructive heart surgery. The removal of this has no loss of function in walking or balance.
Another example could be the human appendix which has no function nowadays but it is believed that in earlier organisms it helped to break down food like plants.
Finally, one last example could be the limbs and pelvises of snakes, suggesting that their ancestors must’ve had legs at some point but through the course of evolution it’s just become another vestigial function and has no function in modern snakes. However, this doesn’t impair them in any way so the pelvic bones are kept being passed onto the next generations.
Miller, B. (2005, 02 09). Top 10 useless limbs (and other vestigial organs). Retrieved from http://www.livescience.com/11317-top-10-useless-limbs-vestigial-organs.html
Scoville, H. (2013). Vestigial structures in humans. Retrieved from http://evolution.about.com/od/evidence/tp/Vestigial-Structures-In-Humans.htm
Abedon, S. (n.d.). Vestigial structure. Retrieved from http://www.biologyaspoetry.com/terms/vestigial_structure.html
Vestigial structures are one of the biggest proofs that the evolution theory is accurate.Vestigial literally means when referring to an organ degenerate, rudimentary, or atrophied, having become functionless in the course of evolution(New Oxford Dictionary). So vestigial structures are parts of our body that remain there but are no longer in use and remain as proof of how we evolved and stopped using them.
Some salamanders that live in caves still have eyes even though the species is blind, so this would be a vestigial structure. http://bioweb.cs.earlham.edu/9-12/evolution/HTML/live.html
The appendix is another vestigial structure, it is derived from a larger caceum which is an organ that has bacteria that helps herbivorous creatures digest their food. http://www.talkorigins.org/faqs/vestiges/appendix.html
Body hair is also a vestigial structure and while parts of it are useful like eyebrows to keep sweet away from our eyes, most of it is useless since we do not depend on our body hair to keep us warm http://science.howstuffworks.com/life/human-biology/vestigial-organ1.htm
Vestigial structures are bookmarks that show that over time we have indeed evolved. As defined by the oxford dictionary the word vestigial means: (of or pertaining to an organ or part of the body) degenerate, rudimentary, or atrophied, having become functionless in the course of evolution. The word’s first known usage was in 1880-1885, when it was derived from the Latin word vestigium which means a trace or a footstep. Furthermore a vestigial structure is a no longer needed body part that serves as a bookmark or a footprint to show our ancestry. Wisdom teeth which are humans third set of molars, and are the last to protrude the gum line are a vestigial structure. The most common postulation is that human mandible used to be larger and therefore required more teeth. As the human skull became smaller the molars remained. In the life of this common assenters the wisdom teeth where required to chew and mash up plants. Currently in our bodies most wisdom teeth need to be surgically removed for fear of infection and being impacted, which is the lack of space in the jaw. Johnson, Dr. George B. "Evidence for Evolution". Jun 8,2006 The plica luminaris is a small piece of tissue on the inside of your eye that is pink. This is a vestigial structure is thought to be the remains of a nictitating membrane a sort of third eye lid that moves around the eye to moisten it or protect it from dangers. Although many animals still have fully functional nictitating membranes humans only have a plica luminaris that serves no purpose. Vestigial Structures in Humans//" Evolution - Natural Selection, //History of Life on Earth, Darwinism,. The dandelion has stamens and pistils which in most plants, is used to sexually reproduce with other plants. In the case of the dandelion instead of using these organs the dandelion uses asexual reproduction, therefore basically creating a clone of itself. In the past the dandelion probably reproduced asexually and over time it has been able to become self-sufficient. Consequently the stamens and pistils in dandelions are vestigial structure because they no longer serve a useful purpose for the dandelion. "Vestigial Structures." Published: 1/30/2011 http://www.livescience.com/11317-top-10-useless-limbs-vestigial-organs.html Sources . http://darwinsdarlings.blogspot.com/2013/02/vestigial-structures-by-alia-bhimji.html http://en.wikipedia.org/wiki/Human_vestigiality#cite_note-18 http://www.livescience.com/11317-top-10-useless-limbs-vestigial-organs.html http://gartlerwritingstudio.blogspot.com/2013/05/vestigial-organs.html
Vestigial Structures are parts of an organism that have seemingly lost all or most of their function for that species. Knowledge of the existence of said functionless parts has been taking part since ancient times, since their existence was much before Darwinism evolution, but this time provided a widely accepted explanation. Even Aristotle discussed the peculiar existence of vestigial eyes of moles in his book “History of Animals”. The term Vestigial structures came from … Charles Darwin explained how vestigial structures are vestiges of bygone eras, so these useless parts are a type of fossil from what our ancestors used to look like and what body parts they would need to survive, so these rudimentary parts are a way for us to know what life used to be like a long time ago and how far we and other species have com. We could say that there are three types of vestigial features, which are: the ones that have survived with this status through many years of research, like the coccyx (tail bone) or wisdom teeth (tonsils); then there are transient embryonic organs, which slowly fade away due to lack of purpose, like the embryonic tail; and at last there are structures misidentified as vestigial, such as endocrine glands. The most well known vestigial structures in humans are tonsils, the appendix, and wisdom teeth. Even though we do not hold the same need for these as for homologous organs, they do have their somewhat “functions” or did. Scientists believe earlier forms of human beings had tonsils in order to eat certain foods at their disposition. Drs. Maeda and Mogi wrote that the tonsil functions both in antibody production and cell-mediated immunity. [Maeda] Other contributors to this supplement said that the tonsil is important as a lymphoid organ in the upper respiratory tract. The appendix holds on to “gut bacteria”, which is very useful, yet it regularly it can become infected and kill you if it ruptures. As for evidence that we have some genes in common with animals, one vestigial function would be goose bumps, There's a very small muscle at the base of every single hair follicle that will contract and pull the hair up, and for a bird or a dog, that might help it gain size and posture in order to scare off predators and hold onto more air so it can stay warm, yet we have them as well.
What fossil evidence exists for bacteria? How do scientists know bacteria existed 3.5 BYA?
There is one group that has left a fossil record that goes back to the precambrian era that was about 3.5 billion years ago. The name of this bacteria is cyanobacteria or blue-green algae. This type of bacteria is bigger than the other bacterias and form stromatolites, which are large structures that form as a mat of cyanobacteria in an aquatic environment. Stromatolites trap sediment by secreting calcium carbonate. Minerals and grains of sediment can be found on those layers. Shark bay on Australia is one of the places where this stromatolites can be found. The oldest stromatolites recorded go back to the Archean era. Cyanobacteria has also been really important because they generated a big amount of oxygen that we breathe today during the Archean and Proterozoic eras. Before this the components of our atmosphere was very different, and wouldn't allowed life like the one we have in present day. To conclude We can say that the fossil evidence of bacteria that dates all the way back to 3.5 bya can be identified largely because of cyanobacteria. Since the cyanobacteria make layers called stromatolites, we can see the ages of the sediment in it and date it all the way back to the Archean and Proterozoic eras. This fossil evidence provides a good background for future theories that can later be supported or found untrue.
What fossil evidence exists for bacteria? How do scientists know bacteria existed 3.5 BYA?
There is one group that has left a fossil record that goes back to the precambrian era that was about 3.5 billion years ago. The name of this bacteria is cyanobacteria or blue-green algae. This type of bacteria is bigger than the other bacterias and form stromatolites, which are large structures that form as a mat of cyanobacteria in an aquatic environment. Stromatolites trap sediment by secreting calcium carbonate. Minerals and grains of sediment can be found on those layers. Shark bay on Australia is one of the places where this stromatolites can be found. The oldest stromatolites recorded go back to the Archean era. Cyanobacteria has also been really important because they generated a big amount of oxygen that we breathe today during the Archean and Proterozoic eras. Before this the components of our atmosphere was very different, and wouldn't allowed life like the one we have in present day. To conclude We can say that the fossil evidence of bacteria that dates all the way back to 3.5 bya can be identified largely because of cyanobacteria. Since the cyanobacteria make layers called stromatolites, we can see the ages of the sediment in it and date it all the way back to the Archean and Proterozoic eras. This fossil evidence provides a good background for future theories that can later be supported or found untrue.
Vestigial structures are anatomical features that seem to no longer have a purpose. These structures usually are organs that performed an important function in an organism before its evolution happened. Due to Natural Selection these structures became less and less necessary. Due to this most vestigial structures disappear over generations, and others just get passed down generations but have no real function. These structures provide evidence of evolution since it shows how some organisms before had organs for functions they don’t do anymore. There are many examples of vestigial structures in humans. For example fish species that live in completely dark caves have vestigial, non-functioning eyes. Their sighted ancestors ended up living in a cave, so the sense of vision was lost due to its futility in the dark caves. An example of a vestigial structure in humans would be the appendix. This organ has little apparent function; this organ can actually be disadvantageous due to the possibility of nasty infections.
Adrian v. What fossil evidence exists for bacteria? How do scientists know bacteria existed 3.5 BYA? There is group that has left a fossil record that goes back to the Precambrian Era that was about 3.5 billion years ago. The name of this bacteria is Cyanobacteria or Blue-Green Algae. This type of bacteria is bigger than the other bacterias and form stromatolites, which are large structures that form as a mat of cyanobacteria in an aquatic environment. Stromatolites trap sediment by secreting calcium carbonate (1) . Minerals and grains of sediment can be found on those layers. Shark bay on Australia is one of the places where this stromatolites can be found(1) . The oldest stromatolites recorded go back to the Archean Era. Cyanobacteria has also been really important because they generated a big amount of oxygen that we breathe today during the Archean and Proterozoic eras. Before this the components of our atmosphere was very different, and wouldn't allowed life like the one we have in present day. Fossil evidence of bacteria that dates all the way back to 3.5 bya can be identified largely because of cyanobacteria. Since the cyanobacteria make layers called stromatolites, we can see the ages of the sediment in it and date it all the way back to the Archean and Proterozoic eras. This fossil evidence provides a good background for future theories that can later be supported or found untrue. Sources : Cano, Raul. Bacteria: Fossil record. 1 http://www.ucmp.berkeley.edu/bacteria/bacteriafr.html T.N. & E.L. Taylor. 1993. The Biology and Evolution of Fossil Plants. Prentice Hall, New Jersey 2 http://www.ucmp.berkeley.edu/bacteria/cyanofr.html
The evolution of flight in each organism depended on what their ancestor did and the adaptations they had. In order to determine the evolution of flight there has to be a comparison of their adaptations with their ancestor (1) . To understand flight evolution we have to understand how wings evolved (1). We have 4 facts about wings. The first and more important one is that wings come from arms used to capture small preys. The second one says that the reason that wings evolved is because bipedal animals were leaping into the air (1). Wings were and still are used as sexual display parts of the body (1). Finally, wings evolved from gliding ancestors who began to flap their gliding structures in order to produce thrust (1). There are 4 groups that can fly and those are insects, reptiles, mammals and before, dinosaurs (2). Flight only evolved once, but it may of been lost and then regained in some generations (3).
Bibliography
1- The Evolution of Flight, John R. Hutchinson: created 12/15/95, completed 1/11/96 http://www.ucmp.berkeley.edu/vertebrates/flight/evolve.html
2- The Evolution of Flight, University of Portsmouth. http://www.port.ac.uk/special/pterosaurs/evolutionofflight/
3- Evolution of Flight, The Trek BBS. http://www.trekbbs.com/showthread.php?t=127463
The word vestigial comes from the concept of vestigiality which applies to genetically determined structures or attributes that have apparently lost most or all of their ancestral function in a given species. Vestigial structures are mostly referred to an organ that was useful in animal’s evolutionary past.
ReplyDeleteVestigial structures are considered evidence for evolution because they show residuals of a structure that once had a use in the organism’s ancestry. Vestigial structures became first unnecessary due to changes in environment and receded over times in populations to the point that they become non-functional. These structures have not impact in the organisms in any way; therefore there is no need for evolution to get rid of them.
One example of vestigial structures could be the plantaris muscle, which is a long and thing muscle in the human foot and calf that has no longer significant purpose. This muscle was once used to provide proprioceptive feedback information to the central nervous system regarding the position of the foot, but it has no important function and in fact, it is regularly removed by doctors harvesting muscle tissues to use in reconstructive heart surgery. The removal of this has no loss of function in walking or balance.
Another example could be the human appendix which has no function nowadays but it is believed that in earlier organisms it helped to break down food like plants.
Finally, one last example could be the limbs and pelvises of snakes, suggesting that their ancestors must’ve had legs at some point but through the course of evolution it’s just become another vestigial function and has no function in modern snakes. However, this doesn’t impair them in any way so the pelvic bones are kept being passed onto the next generations.
Miller, B. (2005, 02 09). Top 10 useless limbs (and other vestigial organs). Retrieved from http://www.livescience.com/11317-top-10-useless-limbs-vestigial-organs.html
Scoville, H. (2013). Vestigial structures in humans. Retrieved from http://evolution.about.com/od/evidence/tp/Vestigial-Structures-In-Humans.htm
Abedon, S. (n.d.). Vestigial structure. Retrieved from http://www.biologyaspoetry.com/terms/vestigial_structure.html
Vestigial structures are one of the biggest proofs that the evolution theory is accurate.Vestigial literally means when referring to an organ degenerate, rudimentary, or atrophied, having become functionless in the course of evolution(New Oxford Dictionary). So vestigial structures are parts of our body that remain there but are no longer in use and remain as proof of how we evolved and stopped using them.
ReplyDeleteSome salamanders that live in caves still have eyes even though the species is blind, so this would be a vestigial structure. http://bioweb.cs.earlham.edu/9-12/evolution/HTML/live.html
The appendix is another vestigial structure, it is derived from a larger caceum which is an organ that has bacteria that helps herbivorous creatures digest their food. http://www.talkorigins.org/faqs/vestiges/appendix.html
Body hair is also a vestigial structure and while parts of it are useful like eyebrows to keep sweet away from our eyes, most of it is useless since we do not depend on our body hair to keep us warm http://science.howstuffworks.com/life/human-biology/vestigial-organ1.htm
Vestigial structures are bookmarks that show that over time we have indeed evolved. As defined by the oxford dictionary the word vestigial means: (of or pertaining to an organ or part of the body) degenerate, rudimentary, or atrophied, having become functionless in the course of evolution. The word’s first known usage was in 1880-1885, when it was derived from the Latin word vestigium which means a trace or a footstep. Furthermore a vestigial structure is a no longer needed body part that serves as a bookmark or a footprint to show our ancestry.
ReplyDeleteWisdom teeth which are humans third set of molars, and are the last to protrude the gum line are a vestigial structure. The most common postulation is that human mandible used to be larger and therefore required more teeth. As the human skull became smaller the molars remained. In the life of this common assenters the wisdom teeth where required to chew and mash up plants. Currently in our bodies most wisdom teeth need to be surgically removed for fear of infection and being impacted, which is the lack of space in the jaw. Johnson, Dr. George B. "Evidence for Evolution". Jun 8,2006
The plica luminaris is a small piece of tissue on the inside of your eye that is pink. This is a vestigial structure is thought to be the remains of a nictitating membrane a sort of third eye lid that moves around the eye to moisten it or protect it from dangers. Although many animals still have fully functional nictitating membranes humans only have a plica luminaris that serves no purpose. Vestigial Structures in Humans//" Evolution - Natural Selection, //History of Life on Earth, Darwinism,.
The dandelion has stamens and pistils which in most plants, is used to sexually reproduce with other plants. In the case of the dandelion instead of using these organs the dandelion uses asexual reproduction, therefore basically creating a clone of itself. In the past the dandelion probably reproduced asexually and over time it has been able to become self-sufficient. Consequently the stamens and pistils in dandelions are vestigial structure because they no longer serve a useful purpose for the dandelion.
"Vestigial Structures." Published: 1/30/2011
http://www.livescience.com/11317-top-10-useless-limbs-vestigial-organs.html
Sources
.
http://darwinsdarlings.blogspot.com/2013/02/vestigial-structures-by-alia-bhimji.html
http://en.wikipedia.org/wiki/Human_vestigiality#cite_note-18
http://www.livescience.com/11317-top-10-useless-limbs-vestigial-organs.html
http://gartlerwritingstudio.blogspot.com/2013/05/vestigial-organs.html
Vestigial Structures are parts of an organism that have seemingly lost all or most of their function for that species. Knowledge of the existence of said functionless parts has been taking part since ancient times, since their existence was much before Darwinism evolution, but this time provided a widely accepted explanation. Even Aristotle discussed the peculiar existence of vestigial eyes of moles in his book “History of Animals”.
ReplyDeleteThe term Vestigial structures came from … Charles Darwin explained how vestigial structures are vestiges of bygone eras, so these useless parts are a type of fossil from what our ancestors used to look like and what body parts they would need to survive, so these rudimentary parts are a way for us to know what life used to be like a long time ago and how far we and other species have com.
We could say that there are three types of vestigial features, which are: the ones that have survived with this status through many years of research, like the coccyx (tail bone) or wisdom teeth (tonsils); then there are transient embryonic organs, which slowly fade away due to lack of purpose, like the embryonic tail; and at last there are structures misidentified as vestigial, such as endocrine glands.
The most well known vestigial structures in humans are tonsils, the appendix, and wisdom teeth. Even though we do not hold the same need for these as for homologous organs, they do have their somewhat “functions” or did. Scientists believe earlier forms of human beings had tonsils in order to eat certain foods at their disposition. Drs. Maeda and Mogi wrote that the tonsil functions both in antibody production and cell-mediated immunity. [Maeda] Other contributors to this supplement said that the tonsil is important as a lymphoid organ in the upper respiratory tract. The appendix holds on to “gut bacteria”, which is very useful, yet it regularly it can become infected and kill you if it ruptures.
As for evidence that we have some genes in common with animals, one vestigial function would be goose bumps, There's a very small muscle at the base of every single hair follicle that will contract and pull the hair up, and for a bird or a dog, that might help it gain size and posture in order to scare off predators and hold onto more air so it can stay warm, yet we have them as well.
Sources
• http://nerdfighteria.info/video/51/OAfw3akpRe8
• http://rationalwiki.org/wiki/Vestigial_structure
• http://www.creationinthecrossfire.com/Articles/VestigialOrgans.html
Please summarize in your own words. Much of this information seems as if it were taken verbatim, word for word, from your sources.
ReplyDeleteAdrian v.
ReplyDeleteWhat fossil evidence exists for bacteria? How do scientists know bacteria existed 3.5 BYA?
There is one group that has left a fossil record that goes back to the precambrian era that was about 3.5 billion years ago. The name of this bacteria is cyanobacteria or blue-green algae. This type of bacteria is bigger than the other bacterias and form stromatolites, which are large structures that form as a mat of cyanobacteria in an aquatic environment.
Stromatolites trap sediment by secreting calcium carbonate. Minerals and grains of sediment can be found on those layers. Shark bay on Australia is one of the places where this stromatolites can be found. The oldest stromatolites recorded go back to the Archean era. Cyanobacteria has also been really important because they generated a big amount of oxygen that we breathe today during the Archean and Proterozoic eras. Before this the components of our atmosphere was very different, and wouldn't allowed life like the one we have in present day.
To conclude We can say that the fossil evidence of bacteria that dates all the way back to 3.5 bya can be identified largely because of cyanobacteria. Since the cyanobacteria make layers called stromatolites, we can see the ages of the sediment in it and date it all the way back to the Archean and Proterozoic eras. This fossil evidence provides a good background for future theories that can later be supported or found untrue.
Sources :
Cano, Raul. Bacteria: Fossil record.
http://www.ucmp.berkeley.edu/bacteria/bacteriafr.html
T.N. & E.L. Taylor. 1993. The Biology and Evolution of Fossil Plants. Prentice Hall, New Jersey. http://www.ucmp.berkeley.edu/bacteria/cyanofr.html
Adrian v.
ReplyDeleteWhat fossil evidence exists for bacteria? How do scientists know bacteria existed 3.5 BYA?
There is one group that has left a fossil record that goes back to the precambrian era that was about 3.5 billion years ago. The name of this bacteria is cyanobacteria or blue-green algae. This type of bacteria is bigger than the other bacterias and form stromatolites, which are large structures that form as a mat of cyanobacteria in an aquatic environment.
Stromatolites trap sediment by secreting calcium carbonate. Minerals and grains of sediment can be found on those layers. Shark bay on Australia is one of the places where this stromatolites can be found. The oldest stromatolites recorded go back to the Archean era. Cyanobacteria has also been really important because they generated a big amount of oxygen that we breathe today during the Archean and Proterozoic eras. Before this the components of our atmosphere was very different, and wouldn't allowed life like the one we have in present day.
To conclude We can say that the fossil evidence of bacteria that dates all the way back to 3.5 bya can be identified largely because of cyanobacteria. Since the cyanobacteria make layers called stromatolites, we can see the ages of the sediment in it and date it all the way back to the Archean and Proterozoic eras. This fossil evidence provides a good background for future theories that can later be supported or found untrue.
Sources :
Cano, Raul. Bacteria: Fossil record.
http://www.ucmp.berkeley.edu/bacteria/bacteriafr.html
T.N. & E.L. Taylor. 1993. The Biology and Evolution of Fossil Plants. Prentice Hall, New Jersey. http://www.ucmp.berkeley.edu/bacteria/cyanofr.html
Vestigial structures are anatomical features that seem to no longer have a purpose. These structures usually are organs that performed an important function in an organism before its evolution happened. Due to Natural Selection these structures became less and less necessary. Due to this most vestigial structures disappear over generations, and others just get passed down generations but have no real function. These structures provide evidence of evolution since it shows how some organisms before had organs for functions they don’t do anymore.
ReplyDeleteThere are many examples of vestigial structures in humans. For example fish species that live in completely dark caves have vestigial, non-functioning eyes. Their sighted ancestors ended up living in a cave, so the sense of vision was lost due to its futility in the dark caves. An example of a vestigial structure in humans would be the appendix. This organ has little apparent function; this organ can actually be disadvantageous due to the possibility of nasty infections.
Sources:
http://evolution.about.com/od/evidence/g/Vestigial-Structures.htm
http://atheism.about.com/od/evolutionexplained/a/VestigialOrgansAppendix.htm
http://evolution.berkeley.edu/evosite/evo101/IIIE5Adaptation.shtml
Adrian v.
ReplyDeleteWhat fossil evidence exists for bacteria? How do scientists know bacteria existed 3.5 BYA?
There is group that has left a fossil record that goes back to the Precambrian Era that was about 3.5 billion years ago. The name of this bacteria is Cyanobacteria or Blue-Green Algae. This type of bacteria is bigger than the other bacterias and form stromatolites, which are large structures that form as a mat of cyanobacteria in an aquatic environment.
Stromatolites trap sediment by secreting calcium carbonate (1) . Minerals and grains of sediment can be found on those layers. Shark bay on Australia is one of the places where this stromatolites can be found(1) . The oldest stromatolites recorded go back to the Archean Era. Cyanobacteria has also been really important because they generated a big amount of oxygen that we breathe today during the Archean and Proterozoic eras. Before this the components of our atmosphere was very different, and wouldn't allowed life like the one we have in present day.
Fossil evidence of bacteria that dates all the way back to 3.5 bya can be identified largely because of cyanobacteria. Since the cyanobacteria make layers called stromatolites, we can see the ages of the sediment in it and date it all the way back to the Archean and Proterozoic eras. This fossil evidence provides a good background for future theories that can later be supported or found untrue.
Sources :
Cano, Raul. Bacteria: Fossil record.
1 http://www.ucmp.berkeley.edu/bacteria/bacteriafr.html
T.N. & E.L. Taylor. 1993. The Biology and Evolution of Fossil Plants. Prentice Hall, New Jersey
2 http://www.ucmp.berkeley.edu/bacteria/cyanofr.html
Adrian Villalobos
ReplyDeleteEvolution of Flight!
The evolution of flight in each organism depended on what their ancestor did and the adaptations they had. In order to determine the evolution of flight there has to be a comparison of their adaptations with their ancestor (1) . To understand flight evolution we have to understand how wings evolved (1). We have 4 facts about wings.
The first and more important one is that wings come from arms used to capture small preys. The second one says that the reason that wings evolved is because bipedal animals were leaping into the air (1). Wings were and still are used as sexual display parts of the body (1). Finally, wings evolved from gliding ancestors who began to flap their gliding structures in order to produce thrust (1).
There are 4 groups that can fly and those are insects, reptiles, mammals and before, dinosaurs (2). Flight only evolved once, but it may of been lost and then regained in some generations (3).
Bibliography
1- The Evolution of Flight, John R. Hutchinson: created 12/15/95, completed 1/11/96
http://www.ucmp.berkeley.edu/vertebrates/flight/evolve.html
2- The Evolution of Flight, University of Portsmouth.
http://www.port.ac.uk/special/pterosaurs/evolutionofflight/
3- Evolution of Flight, The Trek BBS. http://www.trekbbs.com/showthread.php?t=127463