Dinosaurs are recognized as being a group of reptiles that lived primarily on land and occupied land ecosystems for over 160 million years. These animals were introduced to the world towards the middle/end of the Triassic period about 230 million years ago. Research shows that dinosaurs evolved from a group of reptiles known as Archosaurs.
The first dinosaurs were thought to have been carnivorous, bipedal, and less than two meters long. Shortly after this, many different dinosaur species began to evolve. In addition to this, many different dinosaur species converted to a quadrupedal posture. The conversion from a bipedal to a quadrupedal posture was more common in herbivorous dinosaurs.
One of the most distinct evolutionary changes of dinosaurs …show more content…
Dinosaurs are categorized into these two groups based on the structure of their hips. Saurischia means "lizard-hipped," and scientists are able to differentiate them from other dinosaurs because these dinosaurs have asymmetrical fingers, long necks, and pelvic bones that point downard and foward at a certain angle. There are two major groups that form among the saurischians. These two groups are the Sauropoda, which are large herbivores, and the Theropoda which are carnivores. Some examples of Sauropods are the Diplodocus and the Brachiosaurus. The other group of dinosaurs are the Ornithischians. Ornithischia means "bird-hipped." All Ornithischians are herbivorous dinosaurs that have pelvic bones pointing backwards. Some examples of commonly known ornithischians include the horned dinosaurs(the ceratopsians), armored dinosaurs(the stegosaurus), and the duck billed dinosaurs(the hadrosaurids). An interesting fact about the stegosaurs specifically is that all stegosaurs evolved from an ancestor that had spikes that covered most of the entire surface of their body. Additionally, experts believe that the sharp spikes(called scute plates) on the surface of their bodies were used as a defense mechanism against the stegosaurs' main predator, the …show more content…
Herbivorous dinosaurs were identified as having short, stubby teeth that were used to chew plant material. On the other hand, carnivorous dinosaurs had sharp, knife-like teeth that were used to kill and tear apart their prey. In addition to researching the tooth structure of dinosaurs, scientists also discovered what occurs during the early limb development of dinosaurs(excluding birds). During early limb development, dinosaurs develop a cartilage cone(connective tissue) within the metaphysis(the area of growth between the epiphysis and diaphysis. Condylar structures( the area at the end of a bone, forming part of a joint) of dinosaur limbs suggest that most non-avian dinosaurs have epiphyseal plates(cartilage plate in the metaphysis). These plates indicate that the organism has stopped growing. These cartilaginous epiphyses are eliminated early in the development of smaller bodied tetrapods and living birds. A scientific analysis using cartilage correction factors obtained from living species signifies that the existence of cartilaginous epiphysis increases dinosaur height and
The first dinosaurs were thought to have been carnivorous, bipedal, and less than two meters long. Shortly after this, many different dinosaur species began to evolve. In addition to this, many different dinosaur species converted to a quadrupedal posture. The conversion from a bipedal to a quadrupedal posture was more common in herbivorous dinosaurs.
One of the most distinct evolutionary changes of dinosaurs …show more content…
Dinosaurs are categorized into these two groups based on the structure of their hips. Saurischia means "lizard-hipped," and scientists are able to differentiate them from other dinosaurs because these dinosaurs have asymmetrical fingers, long necks, and pelvic bones that point downard and foward at a certain angle. There are two major groups that form among the saurischians. These two groups are the Sauropoda, which are large herbivores, and the Theropoda which are carnivores. Some examples of Sauropods are the Diplodocus and the Brachiosaurus. The other group of dinosaurs are the Ornithischians. Ornithischia means "bird-hipped." All Ornithischians are herbivorous dinosaurs that have pelvic bones pointing backwards. Some examples of commonly known ornithischians include the horned dinosaurs(the ceratopsians), armored dinosaurs(the stegosaurus), and the duck billed dinosaurs(the hadrosaurids). An interesting fact about the stegosaurs specifically is that all stegosaurs evolved from an ancestor that had spikes that covered most of the entire surface of their body. Additionally, experts believe that the sharp spikes(called scute plates) on the surface of their bodies were used as a defense mechanism against the stegosaurs' main predator, the …show more content…
Herbivorous dinosaurs were identified as having short, stubby teeth that were used to chew plant material. On the other hand, carnivorous dinosaurs had sharp, knife-like teeth that were used to kill and tear apart their prey. In addition to researching the tooth structure of dinosaurs, scientists also discovered what occurs during the early limb development of dinosaurs(excluding birds). During early limb development, dinosaurs develop a cartilage cone(connective tissue) within the metaphysis(the area of growth between the epiphysis and diaphysis. Condylar structures( the area at the end of a bone, forming part of a joint) of dinosaur limbs suggest that most non-avian dinosaurs have epiphyseal plates(cartilage plate in the metaphysis). These plates indicate that the organism has stopped growing. These cartilaginous epiphyses are eliminated early in the development of smaller bodied tetrapods and living birds. A scientific analysis using cartilage correction factors obtained from living species signifies that the existence of cartilaginous epiphysis increases dinosaur height and