1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Rama09 [41]
3 years ago
14

N which vertebrates did feathers first evolve?

Biology
1 answer:
Lapatulllka [165]3 years ago
3 0
<span>Wings have evolved several times independently. In flying fish, the wings are formed by the enlargement of the pectoral fins. Some fish leap out of the water and glide through the air, both to save energy and to escape predators. If they were already gliding, then any mutation that would result in an increase of the gliding surface would be advantageous to the fish that has it. These advantageous may allow these fish to out-compete the others. 

Wings have also evolved in bats, pterosaurs, and birds. In these animals, the wings are formed by the forelimbs. In some lizards that have evolved gliding flight, however, the "wings" or gliding surfaces may be quite different. The lizard Draco, for example, has gliding surfaces formed by an extension of the ribs. A number of extinct reptiles have similar gliding surfaces. Frogs that glide have expanded webbing on their hands and feet. Gliding ("flying") squirrels and marsupial sugar gliders have flaps of skin that lie between the front and rear limbs. These gliding animals all have one thing in common: a gliding surface that is formed by enlarging some parts of the body. 

In pterosaurs, the wing is formed by an elongated finger and a large skin membrane attached to this finger. In bats, the wing is formed by the entire hand, with skin membranes connecting the elongated fingers. In birds, flight feathers are attached to the entire forelimb, while the fingers have fused together. In all of these animals except birds, the wing is a solid structure. In birds, however, the wing is formed by a large number of individual feathers lying close to each other and each feather is in turn formed by filaments that interlock. 

Biophysicists have determined that flight most likely evolved from the tree down. That means most active flyers evolved flight from an animal that was already gliding. Gliding was therefore probably an indispensable intermediate stage in the evolution of flight. Since gliding has evolved in so many different groups of animals, it follows that the ancestors of birds, bats, and pterosaurs were almost certainly gliders. 

Unfortunately, the fossil records of the immediate gliding ancestors of birds, bats, and pterosaurs are all missing. The first known bat and bird fossils are recognizable as flyers. The same is true of pterosaurs. Therefore the origin of these flyers remain a mystery and a subject of often acrimonious debate. There are people who claim that dinosaurs evolved insulation, which then evolved into feathers, but the evidence for that is lacking. The so-called proto-feathers found on some dinosaurs are indistinguishable from the collagen fibers found in the skin of most vertebrates. Some of the supposedly feathered dinosaurs, such as Caudipteryx and Protarchaeopteryx, are actually flightless birds. The same is probably true of Microraptor fossils, which are (as Alan Feduccia says) probably "avian non-dinosaurs." 

Even though the immediate ancestor of birds remains a mystery, there is a fossil known as Longisquama insignis, which lived during the late Triassic. It has featherlike structures on its back. It was probably a glider of some sort. So, this animal may well be the distant ancestor of Archaeopteryx, the oldest known bird. 

In sum, flying almost certainly evolved from animals that were already gliding, or from the tree down, not from the ground up. The dinosaurian origin of birds requires that dinosaurs evolved feathers from insulation and flight to have evolved from the ground up. Both of these requirements are extremely unlikely to have occurred in evolutionary history, because dinosaurs are almost certainly ectothermic (or "cold-blooded") and therefore they never evolved insulation, and because feathers are too unnecessarily complex to have evolved as insulation. Flight from the ground up is also dangerous because large animals that attempt to fly from the ground may crash and seriously injure or even kill themselves. We all know how dangerous an airplane can be if it loses power and crashes. Small and light weight animals, OTOH, that were already gliding can survive if their attempt to fly fails. Finally, if flight evolved from gliding, then why do animals glide? The answer is that gliding is energetically much cheaper than to descend a tree, walk along the ground, and then climb up another tree. Besides, it is almost certainly much safer to glide from one tree to another than to be walking on the ground for many arboreal animals. 

See link below for details of why dinosaurs are considered ectothermic according to the available scientific evidence.</span>Source(s):<span>http://discovermagazine.com/1996/dec/aco...</span>
You might be interested in
What is the term used for the elements and compounds before a chemical reaction takes place?
alexandr1967 [171]

Explanation:

Before a chemical reaction, the elements and compounds which are about to take part in the reaction are known as reactants.

And, when the chemical reaction takes place between the given elements and compounds then they change into products.

For example, we take sodium and chlorine elements and before any chemical reaction they are the reactants.

But when a chemical reaction takes place between sodium and chlorine then it results into the formation of sodium chloride which is the product.

7 0
3 years ago
In eukaryotes energy is needed to carry out most of its processes, what is the primary energy source of the cell?
Dahasolnce [82]
The answer is C. Have a good day!
4 0
2 years ago
7. List three things that can bring life to a barren island​
Yanka [14]

Answer:

Plantlife, grow a garden. Animal life, raise some livestock. And a water source, most definitley.

Explanation:

4 0
3 years ago
What usually compresses the sedimentary rock layers?
adoni [48]

Answer:

The more sediment accumulates, the more pressure is put on the lower layers

Explanation:

8 0
3 years ago
How do C4 plants fix carbons?
OverLord2011 [107]

Answer:

C4 plants—including maize, sugarcane, and sorghum—avoid photorespiration by using another enzyme called PEP during the first step of carbon fixation. ... PEP fixes carbon dioxide into a four-carbon molecule, called malate, that is transported to the deeper bundle sheath cells that contain Rubisco.

Explanation:

3 0
3 years ago
Other questions:
  • The first organisms evolved on Earth around 4 billion years ago. The fossil record indicates that the first organisms were which
    7·1 answer
  • In a certain plant species, the allele for yellow seeds (Y) is dominant to the allele for green seeds. What is the phenotype res
    5·1 answer
  • What structure do all vertebrae embryos contain
    10·1 answer
  • Which of the following statements violates the cell theory? A) Mitosis produces new cells identical to the parent cell that divi
    11·2 answers
  • A species becoming dependent on another species is _____. rapid evolution instantaneous speciation co-adaptation sympatric speci
    6·2 answers
  • Six-year-old Demetri and 4-year-old Lucien's mother gave each boy a glass of juice with their lunch, but Demetri asked her to sw
    7·1 answer
  • 2 Drag the tiles to the correct boxes to complete the pairs. Match each energy transformation to the correct image. motion energ
    11·2 answers
  • How would you describe the process of two plates moving at a convergent plate boundary?
    10·1 answer
  • What compares nucleic acids and carbohydrates
    7·1 answer
  • you discover a new microbe while working on a citizen scientist project. the microbe is taken to a lab that specializes in placi
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!