Research how flight evolved. How many times has it evolved and in what kind of organisms? What kind of evidence is there?
OR
Research how eyes evolved. What kind of evidence is there that explains the process of complex eyes being created through natural selection?
The evolution of flight has been a very controversial subject and it is a topic that is of huge interest to many biologists. Flight first evolved around 410 millions years go. Since it occurred so long ago, it is impossible to have observed behavioral changes and changes in the morphology of the species. However, there are fossil records that show the change in the morphological structure that show that flight has evolved. Scientist believe wings were exaptations, which means they were used by the ancestor for one functions and then became useful for other purposes among the descendants. [2]. Flight has evolved approximately evolved around four times. [3] The first animals to evolve flight were insects. The innovation allowed the insects to evolve into over six million different species, so flight has caused variation. Flight also evolved in gliding reptiles. There was a small group of small reptiles that were similar to lizards who evolved the ability to glide. However they did not become active flyers. In fact, most of them died in a mass extinction that was 248 millions years ago. Pterosaurs were the first vertebrate that evolved active flapping flight. The origin of their flight, however, is a mystery. [1]There are many hypothesis proposed as to why wings evolved. These include:
ReplyDeleteo Wings evolved from arms that were used to capture small prey.
o Wings evolved because animals that were bipedal would leap into the air.
o The wings could be used as a sexual display structures.
o Wings evolved from ancestors that would glide.
1.John R. Hutchinson: created 12/15/95, completed 1/11/96
Dave Smith: Code cleanup, minor reorganization, addition of footer includes, application of UCMP style sheet, addition of some new images and removal of some — 9/29/05
2. http://www.trekbbs.com/showthread.php?t=127463
3. N/A
University of Portsmouth
http://www.port.ac.uk/special/pterosaurs/evolutionofflight/
In 1861, some workers in limestone quarry in Germany discovered the impression of a single 145 million- year- old feather. Then the scientist Hermann von Meyer declared “No draughtsman could produce anything so real” [by Carl Zimmer, 2013]. While working with more fossils the paleontologists found out that this feather came from an Archaeopteryx, meaning, “ancient wing”. The Archaeopteryx is a primitive bird of the Jurassic Period. Having lizard-like characteristics such as teeth and a long bony tail. It may represent a transitional form between dinosaurs and birds [Wester’s New World, 2013].
ReplyDeleteScientists have discovered that Archaeopteryx is closely related to living birds. The Archaeopteryx shares bird-like characteristics.
For example:
1. They have an anatomy suited for flying
2. Have traits such as long arms
3. Animal with feathers
The difference is that birds have a larger brain in proportion to their body than reptiles this term is called “Hyperinflated”. In the case of the Archaeopteryx’s brain is more like in the “in between”. In other words, the Archaeopteryx had a mind ready to fly but never got there by itself.
Birds have evolved about eight times to be the creatures they are now. The researchers found, in fact, that several species of feathered dinosaurs, such as a troodontid called Zanabazar and an oviraptor called Conchoraptor, have brains that are bigger, relative to their body size, than Archaeopteryx. [by Carl Zimmer, 2013]. This presents that there were many other theropods that evolved into birds later after the Archaeopteryx appeared.
There is a big possibility that the Archaeopteryx is a common ancestor of birds but also many other creatures had to evolve in order for birds to be what they are now.
References:
Zimmer, Carl. "Phenomena: The Loom." Archaeopteryx’s Evolutionary Humiliation Continues. National Geographic, 31 July 2013. Web.
http://phenomena.nationalgeographic.com/2013/07/31/archeopteryxs-evolutionary-humuliation-continues/
Hone, David. "Lost Worlds." Why did dinosaurs evolve feathers? The guardian, 5 Jun 2013.
http://www.theguardian.com/science/lost-worlds/2013/jun/05/dinosaurs-fossils
Webster's , New World College. "Archaeopteryx definition." Your dictionary , 2 October 2013.
http://www.yourdictionary.com/archaeopteryx
Evolution of fight began with the question WHY? and HOW? the flight evolved? The evolution of flight didn't occur because of their need to the future, but the opportunity to respond and by selective process in the force of their environment (The evolution of flight, Dave Smith, Jan 11th, 1996). There are several ideas of why evolution of flight was necessary.
ReplyDelete1. To help escape from predators.
2. To catch flying or speedy animals.
3. To help move from place to place.
These ideas cannot be tested directly (The origin of flight, Dave Smith, Jan 11th 1996), but there are fossil records of animals evolved to fly, fossil record shows that powered flight is attained, flying lineages tend to evolve quickly and radiate into diverse niches (Three solutions to flight, Dave Smith, Jan 11th, 1996), and also homologous structure of animals shows the similarity of their wings in different species, which supports ideas above (Bio II class, Mrs. Rudolph).
But HOW the flight evolved? Samuel Wendell Williston proposed a theory "flight evolved in running bipeds through a series of short jumps" in 1879. Wings are used to thrust and stability as the length of jump extended. Also the idea of Archaeopteryx would expend less energy by running and jumping than by running alone was proposed by John Ostrom by 1970s (wikipedia). Therefore, wings evolved for their benefits of using energy to capture.
Wings evolved from gliding ancestors who began to flap their gliding structures in order to produce thrust (The evolution of flight, Dave Smith, Jan 11th, 1996). This theory can be supported by eagles learn how to fly by jumping off from the cliff when their learning it from their mother, and there were dinosaurs that could fly by jumping off from the cliff
Sources:
The Evolution of Flight: http://www.ucmp.berkeley.edu/vertebrates/flight/evolve.html
The Origin of Flight: http://www.ucmp.berkeley.edu/vertebrates/flight/origins.html
Three Solutions to Flight: http://www.ucmp.berkeley.edu/vertebrates/flight/converge.html
Wikipedia.org (Origin of avian flight) : http://en.wikipedia.org/wiki/Origin_of_avian_flight
Research how flight evolved. How many different times has it evolved and in what kind of organisms? What is the evidence?How did eyes evolve?
ReplyDeleteThe functions of the eye in humans and animals have evolved greatly over the years. According to research by the University of Utah; “96% of animal species have eyes. The first animal eyes did little but detect light—they helped to establish day/night cycles and coordinate behavior—but more-complex eyes soon evolved.” (1) In the past children and animals would open their eyes approximately eight days after being born, nowadays human babies are born and immediately open there eyes. This is advancement in the evolution of the eye.
The Genetic Science Learning Center of the University of Utah mentions that the eye has three basic functions, which are to detect light, to sense the direction that light is coming from, and to connect to motor structures in order to respond to the movement of light. A photoreceptor works by connecting to ciliated cells, and these cause movement in order for an animal to respond to light. As time passed photoreceptors became more abundant and this causes the eye to have better perception of images, just like a camera lens can improve the quality of pictures.
Eyes have changed their shapes as well over time. Research indicates that eyes have become more circular. The pupil of the eye has also increased its potential by allowing just the necessary light in, by doing so this produces images that are clearer and more precise. Research done by the Genetic Science Learning Center has also shown that “muscles evolved to fine-tune focusing and to point the eye in different directions.” (1).
“550 million years have passed since the formation of the oldest fossil eyes, enough time for complex eyes to have evolved more than 1,500 times.” (2) Some scientists that study the eye and its evolution criticize Darwin’s theory of evolution, because it is hard to understand how the eye has evolved and perfected itself through mutation or natural selection. Some researchers find it hard to believe that the parts of the eye that work together to be able to see were separate in the past. “Scientists have come up with scenarios through which the first eye-like structure, a light-sensitive pigmented spot on the skin, could have gone through changes and complexities to form the human eye, with its many parts and astounding abilities.” (3) An eye therefor cannot lack any of its parts because they are all fundamental in their individual and grouped functions. “According to one scientist's calculations, only 364,000 years would have been needed for a camera-like eye to evolve from a light-sensitive patch.” (3) I would have never even imagined how an eye was created or how it has changed over the years.
It is interesting to learn about these things in order to understand that every living species has evolved ever since it was first created. Some scientists question whether a “god” created life or not. They say it is hard to believe that someone so perfect created something so imperfect that has needed to change and improve as time passes. I do not question religion or science; what I do believe is that thousands of years ago my ancestors might have seen a less perfect world. I never stop to think whether my pupil is detecting light or shadows, nor do animals when they are hunting or being preyed on. Life evolves and so do all living things on this planet. The fact that the eye might have started off as a patch on an organism and has now almost perfected itself is mind-blowing.
1) http://learn.genetics.utah.edu/content/variation/eye/
2) Colorow Dr, Salt Lake City, Utah (http://learn.genetics.utah.edu/content/variation/eye/)
3) http://www.pbs.org/wgbh/evolution/library/01/1/l_011_01.html
Flight evolved so long ago, that it is difficult to figure out how it happened. However, we do know from the animals today that 3 different groups developed flight – the ptesosaurus, the birds and the bats. Whend ifferent groups evolve in the same way, this is called convergent evolution.
ReplyDeleteEvidence for the evolution is found in fossils. This tells what happened – we can see the cahnges as they happened over a long period of time. However, it does not tell us why it happened. For this, we have to look at the animals themselves at that period of time and try to understand what they were doing. We can look at the the first of that group, and see the adaptations of that group, even up to ending with the ones today.
If we want to look at why, then we must look at the possible functions of the adaptations, according to their environment and needs. We can use the evlution of wings as than example.
The required ítem for flight are wings, so we can look at the evolution of wings, and find out –
- what were the wing precursors, and what were they used for
- how did they evolve and what was their use and need as they evolved
- does the fossil record support this theory
- sorce : http://www.ucmp.berkeley.edu/vertebrates/flight/evolve.html
In 1861 some workers in limestone quarry discovered the impression of a single 145 million- year- old feather. Then the scientist Hermann von Meyer declared “No draughtsman could produce anything so real” [by Carl Zimmer, 2013]. While working with more fossils, the paleontologists found out that this feather came from an Archaeopteryx meaning “ancient wing”.
ReplyDeleteThe Archaeopteryx is a primitive bird of the Jurassic Period. This primitive bird has lizard-like characteristics such as teeth and a long bony tail. It may represent a transitional form between dinosaurs and birds [Wester’s New World, 2013].
The Archaeopteryx has been researched and investigated as a bird ancestor. There is evidence that supports this theory.
For example:
1. It is a feathered dinosaur.
2. Its anatomy is suited for flying.
3. It has long wings.
4. It has a particular brain.*
*Archaeopteryx’s particular brain
Scientists have discovered that birds’ brains are larger in proportion to their body than the reptiles’. This term is called “Hyperinflated”. In the Archaeopteryx’s case the brain is more like in “the in between”. In comparison to other dinosaurs this one resembles more to the bird’s brain than from its own species. Meaning, that its mind is ready to fly, but it needs to evolve a lot more in order for it to happen. [by Carl Zimmer, 2013].
There is not a specific answer of how flight evolved from dinosaurs and birds but yes there are many characteristics that prove this theory true by the similarities and traits that can be observed and compared with.
"There is a really grey, wobbly line between the two. Just one or two changes across a huge body of data can make the difference between an animal being on one side of this bird-dinosaur divide or the other.” [Jonathan Amos, 2013]
Flight has evolved at least four times in insects, birds, pterosaurs and bats. [Sam Wong, 2013] Flying and gliding animals have evolved several times separately in similar or in different locations. They had to adapt to a different climate and to predators in order to survive.
References:
Zimmer, Carl. "Phenomena: The Loom." Archaeopteryx’s Evolutionary Humiliation Continues. National Geographic, 31 July 2013. Web.
http://phenomena.nationalgeographic.com/2013/07/31/archeopteryxs-evolutionary-humuliation-continues/
Hone, David. "Lost Worlds." Why did dinosaurs evolve feathers? The guardian, 5 Jun 2013.
http://www.theguardian.com/science/lost-worlds/2013/jun/05/dinosaurs-fossils
Webster's , New World College. "Archaeopteryx definition." Your dictionary , 2 October 2013.
http://www.yourdictionary.com/archaeopteryx
Sam Wong. "Flying and gliding animals." Wikipedia. 24 Sep, 2013. Web.
http://en.wikipedia.org/wiki/User:Samw
Amos, Jonathan. "BBC NEWS." Archaeopteryx restored in fossils. News science and environment, 29 May, 2013. Web.
http://www.bbc.co.uk/news/science-environment-22695914
One of the first traces of flight millions of years ago was when German miners discovered an impression or fossil in the shape of a feather in 1860 , at a later date it was studied at the Munich University (Barthel K.W, 1994, Cambridge University ) this sparked the interest if there was a possibility of finding the first species of bird, the species was called Archaeopteryx , it was the size of a common magpie, living around 150 million years ago. the first full skeleton was found in the same place than the feather imprint in 1861, this skeleton showed the link and evolution between reptiles and birds since the Archaeopteryx beak had a full set of teeth and a long bony tail, like one found in reptiles(unknown, 2013, BBC Nature-Prehistoric life. Many believe that the evolution of a bird has happened over 8 times, there is quite a lot of evidences supporting this because there is dinosaurs with the same homologous structures like a bird, for example the : troodontidae, this dinosaur has a similar bone structure that of a bird. (owler, D.W.; Freedman, E.A.; Scannella, J.B.; Kambic, R.E. 2001) there are many reasons why a species would need to adapt, for a bird flying can make hunting easier, it can make the species be able to travel longer distances and stay away from predators. one of the main theory's is that wings evolved from gliding ancestors, they would flap and glide, many say that there is evidence behind this because certain birds start flying by falling off the tree or cliff and then gliding and flying (John R. Hutchinson: created 12/15/95, completed 1/11/96)
ReplyDeletesource:
http://www.bbc.co.uk/nature/life/Archaeopteryx
http://www.ucmp.berkeley.edu/vertebrates/flight/evolve.html
http://www.ucmp.berkeley.edu/diapsids/birds/archaeopteryx.html
http://en.wikipedia.org/wiki/Specimens_of_Archaeopteryx