Role of Natural Selection:
Evolution can be very slow but it allows living creatures to develop an anatomy that is structured for them to thrive. Dolphins have ancestral connections to terrestrial mammals (something most people don't know). It is believed that the ancestors of dolphins entered the water about 50 million years ago!
There are several facts that tell that the dolphins is related to terrestrial origins such as the fact that they need to go up to the surface of the water to get some air which is the most dominant factor. Many researchers have carefully researched studied the bones of the fins of dolphins and what they have found is that they strongly resemble the limbs of many animals that live on land. Dolphins have spines that move vertically and this is a characteristic that is mainly found in animals that are able to run on land, when you look at the movements of fish their spines move horizontally.
The size and shape of the dolphins skull has definitely changed over time. The skull has become larger which indicates that the development of the fat pad in the lower jaw emerged. The skull extends to the middle ear and it helps the dolphins be able to hear as well as to use the process of echolocation. It is believed that the use of echolocation was developed in the form that dolphins rely on it today in the early Miocene period. The earlier dolphins were smaller and it is believed that they consumed small fish as well as various organism in the water.
An older theory is that the evolution was of whales and that they came from hoofed land animals that were very similar to wolves and even toed ungulates. These animals had teeth that were similar to those of whales. However, that theory was drown away because of new evidence and it also offers information that they would be closer related to hippopotamus and their ancestors. People who argue this point out that the ancestors of hippopotamus hasn't been in the fossil record until more than 1 million years after the first known ancestor of the whale, Pakicetus.
The most recent information about the Pakicetus, shows that whales are not ancestors of mesonhyds but instead they are artiodactyls and it is believed that when they split from the mseonychids is when the process of living in the water started to occur. Unliked many other mmmals, they did not change to being herbivores, instead they continued to be carnivores in the water as they would have been on land.
What was once outwardly seen of the whale hind parts are now smaller and they are also internalized. However, sometimes the development of mini legs called atavism is believed to be the result of a genetic code that will call for longer extremities to form. Another change in dolphins was the nasal openings moved from the end of the snout to the top of the skull area, referred to as the nasal drift.
The nostrils later evolved into blowholes so that they can get to the surface of the water, take in air, and then be submerged again with ease. The movement of the ears closer to the eyes is also part of the evolution process. Interesting changes over time that help dolphins survive in their environment in the water only and not on land as before due to ancestral links.
The good news about the evolution process is that some of the evidence that has been found fives a better idea of what really occurred. It has also helped to add some support to various theories that still have to be tested and proven. Some of the fossil remains found in Pakistan in the 1970's identify some of the different changes that took place for the anatomy of the dolphin.
Current process of evolution could be slowly changing the limbs of dolphins and some embryos have been spotted with hind limb buds that will develop close to the base of the fluke which is the tail. The modern body of the dolphin does show two small pelvic bones that are rod shaped yet the limbs aren't really shown on the outside.
A great deal of research is still necessary but it is possible that what is being witnessed is the slow movement of evolution for the body of dolphins that is taking place. Only time will tell if that is what occurs and if these hind limb buds start to be visually present on future generations and offspring's.
There are several facts that tell that the dolphins is related to terrestrial origins such as the fact that they need to go up to the surface of the water to get some air which is the most dominant factor. Many researchers have carefully researched studied the bones of the fins of dolphins and what they have found is that they strongly resemble the limbs of many animals that live on land. Dolphins have spines that move vertically and this is a characteristic that is mainly found in animals that are able to run on land, when you look at the movements of fish their spines move horizontally.
The size and shape of the dolphins skull has definitely changed over time. The skull has become larger which indicates that the development of the fat pad in the lower jaw emerged. The skull extends to the middle ear and it helps the dolphins be able to hear as well as to use the process of echolocation. It is believed that the use of echolocation was developed in the form that dolphins rely on it today in the early Miocene period. The earlier dolphins were smaller and it is believed that they consumed small fish as well as various organism in the water.
An older theory is that the evolution was of whales and that they came from hoofed land animals that were very similar to wolves and even toed ungulates. These animals had teeth that were similar to those of whales. However, that theory was drown away because of new evidence and it also offers information that they would be closer related to hippopotamus and their ancestors. People who argue this point out that the ancestors of hippopotamus hasn't been in the fossil record until more than 1 million years after the first known ancestor of the whale, Pakicetus.
The most recent information about the Pakicetus, shows that whales are not ancestors of mesonhyds but instead they are artiodactyls and it is believed that when they split from the mseonychids is when the process of living in the water started to occur. Unliked many other mmmals, they did not change to being herbivores, instead they continued to be carnivores in the water as they would have been on land.
What was once outwardly seen of the whale hind parts are now smaller and they are also internalized. However, sometimes the development of mini legs called atavism is believed to be the result of a genetic code that will call for longer extremities to form. Another change in dolphins was the nasal openings moved from the end of the snout to the top of the skull area, referred to as the nasal drift.
The nostrils later evolved into blowholes so that they can get to the surface of the water, take in air, and then be submerged again with ease. The movement of the ears closer to the eyes is also part of the evolution process. Interesting changes over time that help dolphins survive in their environment in the water only and not on land as before due to ancestral links.
The good news about the evolution process is that some of the evidence that has been found fives a better idea of what really occurred. It has also helped to add some support to various theories that still have to be tested and proven. Some of the fossil remains found in Pakistan in the 1970's identify some of the different changes that took place for the anatomy of the dolphin.
Current process of evolution could be slowly changing the limbs of dolphins and some embryos have been spotted with hind limb buds that will develop close to the base of the fluke which is the tail. The modern body of the dolphin does show two small pelvic bones that are rod shaped yet the limbs aren't really shown on the outside.
A great deal of research is still necessary but it is possible that what is being witnessed is the slow movement of evolution for the body of dolphins that is taking place. Only time will tell if that is what occurs and if these hind limb buds start to be visually present on future generations and offspring's.
Timeline:
The timelines shown are the evolution of the dolphins. The timelines show how the dolphins have evolved from 65 million years ago to the very first humans which was about 5 million years ago. Since dolphins have been around their population has been increasing, an exact number can not be determined but there are 38 species of dolphins of the oceanic dolphin family and an extra 4 species that are river dolphins. All of these different species add up to 41 dolphin species in total.
4 Part Summary:
A bottleneck event occurred in the Tursiops population in the Belegear Ocean around 6 million years ago due to the climate changes on Arda. Many large marine fish started adapting to the warm temperatures when the Arda started warming up. The warm temperatures and new fish caused the bottlenose dolphins to start adapting. Some dolphins grew in size and others shrinked in size. Whatever the size of the Bottlenose Dolphin was they were able to eat small fish, krill, etc. The color of the Bottlenose Dolphins allows them to hide from their predators and at the same time it allows them to catch their prey. Their bonding and interactions with each other also makes it easier for them to catch their prey and the way they travel together allows them to protect each other from predators. The environment that the Bottlenose Dolphins live in are not at their best because of us humans. Humans are putting their environment because we are polluting their environment by throwing the majority of our waste into the oceans. Some plants that can be found in the Bottlenose Dolphins envrionment are Kelp, Red Algae, and Sea Grasses. Kelp is large brown seaweed that typically has a long, tough stalk with a broad frond divided into strips. Red Algae is a large group of algae that includes many seaweeds that are mainly red in color. And Sea Grasses are flowering marine plants that live submerged in the marine environment. Bottlenose Dolphins have many adaptations that have helped them survive through all these years such; as their skin color, blubber (hypodermis), pectoral flippers, muscles of the back and tail stock, dorsal fin, its teeth, glands, blowhole, the fact that only half of its brain is asleep and the other half is awake when they are sleeping, its high-pitched clicks, and the dolphins use of echolocation. The way that it has survived is by its establishment and their maintenance of biting, chasing, jaw clapping, and smacking of tails on the water. The dolphins daily activities such as feeding, socializing, traveling, and resting have played a major role to their survival. The use of the dolphins tail flukes to flip a fish out of water have played a major role to the survival of the dolphins survival. And last but not least the dolphins evolution. The fact that dolphins have to go up to the surface to get some air shows that they are related to terrestrial animals. The size and shape of the skull has changed over time becoming larger indicating that the development of the fat pad in the lower jaw emerged. The nasal openings moved from the ends of the snout to the top of the skull area and it is usually referred to as the nasal drift. The nostrils evolved into blowholes so that they can get to the surface of the water to take in air. This is what has helped the Bottlenose Dolphins survive today.