1. Skeletal system is important because it shows evolutionary trends of vertebrate phylogeny it specify information posture and locomotors adaptions of vertebrates it reveals mark and traces of other organ system2. Origin of jawsSerial TheoryComposite Theory

jaws arise completely from one of the anterior branchial archesmandibular arc is formed from elements of several adjacent arches, as well as contribute to neurocranium

3. Locomotion of mammalsTypesforExample

Graviportalsupporting great body weightElephants

CursorialrunningHumans, Horses

VolantglidingFlying Squirrels

AerialflyingBats

SaltatorialjumpingRabbits, Kangaroos

AquaticswimmingDolphin, Whales

FossorialdiggingMoles

ScansorialclimbingSquirrels

Arborealadapted for life in treesMonkeys

4. Compare bones of forelimbs and hindlimbsForelimbHumerus is a small, slender, slightly curved bone suspended in the musculature associated with the forelimbUlna is the longer of the two bones in the forearm, or antebrachium. It has a prominent proximal portion, but its shaft tapers distally.Radius is the second bone of the antebrachium. In contrast to the ulna, the radius is more slender proximally and widens distally.Manus is the distal portion the forelimb.includes three portions: the carpus (wrist), metacarpus, and phalanges in proximal to distal order.Hind LimbFemur is the bone of the proximal part of the hind limb, or thigh. Tibia is the larger and medial bone of the crus, or middle segment of the hindlimb. Its proximal surface bears lateral and medial condyles that articulate with the femur.Fibula is the slender, lateral, and shorter bone of the crus.Pesis the distal portion the hind limb.consists o tarsals, metatarsals, and phalanges.

Pectoral girdlePelvic gridle

FishesStrongerBecause it includes more replacement bones, cartilage and several dermal bones Bony Fish: It is attached to the skullCartilaginous Fish: No dermal element; it is fused called scapulocoracoid.WeaklyOther Fish: It is supported by a single bone element.Cartilaginous Fish: It is joined by a bridge of cartilage.

TetrapodsWeaklyPrimitive amphibian: Reduced dermal bonesStrongerBecause it is fused to the backbone to increase the force that can be generated by the hind legsIt is much enlarge over that of fishes.

5. JustifyReferences: Basic structural pattern of limbs.Retrieved on Feb 3, 2015 from http://www.expertsmind.com/questions/basic-structural-pattern-of-limbs- Ching, J.A. 2004. Comparative anatomy of vertebrates compendium. Philippines: National book store. pp.106-149