1.What were the first mineralized structures in vertebrates? What sort of functi
ID: 134979 • Letter: 1
Question
1.What were the first mineralized structures in vertebrates? What sort of functional changes did the mineralization of those structures allow? 2.Describe three new evolutionary adaptations that occurred with the origin of gnathostomes. 3.Explain what the term “amphibian” says about their habitat, and about the evolution of this group of organisms. 4.Compare the developmental differences between protostomes and deuterostomes, including pattern of cleavage, coelom development, and cell determination. Why can it be said that deuterostomes develop ‘butt-first’? 1.What were the first mineralized structures in vertebrates? What sort of functional changes did the mineralization of those structures allow? 2.Describe three new evolutionary adaptations that occurred with the origin of gnathostomes. 3.Explain what the term “amphibian” says about their habitat, and about the evolution of this group of organisms. 4.Compare the developmental differences between protostomes and deuterostomes, including pattern of cleavage, coelom development, and cell determination. Why can it be said that deuterostomes develop ‘butt-first’? 1.What were the first mineralized structures in vertebrates? What sort of functional changes did the mineralization of those structures allow? 2.Describe three new evolutionary adaptations that occurred with the origin of gnathostomes. 3.Explain what the term “amphibian” says about their habitat, and about the evolution of this group of organisms. 4.Compare the developmental differences between protostomes and deuterostomes, including pattern of cleavage, coelom development, and cell determination. Why can it be said that deuterostomes develop ‘butt-first’?Explanation / Answer
Answer 1 ::
The earliest known mineralized structures in vertebrates were conodont dental elements.
the armor seen in later jawless vertebrates was derived from dental mineralization.
Only in more derived vertebrates did the endoskeleton begin to mineralize,starting with the skull.
a.Conodonts
-Cone Teeth
-First to have mineralized skeletal elements
b.Pteraspis
-Armored
-Jawless
-Have defensive bony plates in their skin
Answer 2::
The gnathostomes have true jaws, hinged structures that enable vertebrates to grasp food firmly.
According to one hypothesis, gnathostome jaws evolved by modification of the skeletal rods that had previously supported the anterior pharyngeal gill slits.
The remaining gill slits were no longer required for suspension feeding and remained as the major sites of respiratory gas exchange.
Few focused charecters,
a. Jawed
b. Lateral line system to sense vibrations
c. Enlarged forebrain = Enhanced smell and vision
Answer 3 ::
Amphibians were the first group of vertebrates to develop limbs and to be able to leave the water to conquer the land. Even if they are seen as simple and primitive animals by most people, amphibians show a wide diversity of survival strategies which have allowed them to occupy most terrestrial and fresh-water habitats.
Evolution of lungs
They are homologous to the gas bladder that allows fish to control its buoyancy. Lungs appeared as an additional way to get oxygen from the air.
Development of the choanaes, or internal nostrils.
While fish present a pair of external nostrils at each side of its snout through which water passes on while swimming, the ancestors of the tetrapods only had one external nostril at each side connected to the internal nostrils, the choanae, which communicated with the mouth. This allowed them to get air through their noses using lung ventilation and this way to smell outside of water.
Apparition of the quiridium-like limb.
The quiridium is the tetrapod’s most basic characteristic. This limb is known for having the differentiated parts:
-Atylopodium (one bone, the humerus or the femur)
-Zeugopodium (two bones, the radius or tibia and ulna or fibula)
-Autopodium (fingers, hands, toes and feet).
While the stylopodium and zeugopodium derived from the sarcopterygian’s fins, the autopodium is a newly-evolved structure exclusive from tetrapods.
Answer 4::
Protostome development
There is spiral radical and indeterminate cleavage.
The blastopore becomes the mouth and the coelom forms from the mesoderm
Deuterostome development
Radial and indeterminate cleavage takes place.
The blastopore is the new an*s and the coelom forms from budding off the wall of the archenteron.
Protostomes:
Protostomes are called schizocoelomates
since the coelom is developed by splitting of the solid mass of the embryonic mesoderm.
Deuterostomes:
Deuterostomes are called enterocoelous
since the longitudinal pouches of the archenteron forms the coelom.
During embryological development there is a period where part of the tissue “folds” back into itself creating a blastopore. The blastopore, in insects (and other members of the “other” group called protostomes, or first-mouth), forms the mouth.
In deuterostomes,blastopore develops into the an*s. that come out butt -first
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.