The Evolution Of Whales

In biology, evolution is the change in characteristics of a species over several generations and it relies on the process through which organisms better adapted to their environment tend to survive and produce more offspring compared to the organisms that aren’t adapted to survive in their charging surroundings. Whales are large organisms that dwell in the sea and have been around for approximately 48 million years, the first proof of a whale existing in fossil records date back to 50 million years. In this essay we will be looking at anatomy, embryology, and fossils and analysing DNA.

Fossils are the remains of past life preserved in rock, soil or amber. Generally, the remains were once the hard parts of an organism, such as bones and shell

This shows that they lived in estuaries and between the two water sources. These creatures had sharp teeth used to feed on fish when later on it would evolve to get rid of them.

The later evolutions of the Ambulocetus and the Pakicetus evolved so that their nostrils moved back, eventually evolving into the common whale’s blowhole. They also started to develop early signs of a tailfin, which show evidence that the later evolution of animals with tailfins evolved from these animals. These creatures lived in nearshore marine habitats.

The next evolution, the Dorudon, showed the evolution of the whale’s spine. Instead of moving from side to side the spine now moved up and down, allowing the creature to swim more effortlessly and efficiently. This creature now more closely resembled the whale but still had teeth for consuming fish that would later evolve and disappear.

Finally the organisms evolved into what we now call a whale. The evolution from the Dorudon to the whale has shown that the whale has developed bigger fins has gotten rid of its teeth, now eating plankton instead of small

Whereas embryology is the study of embryos and their development. 48 million years ago there existed an animal called the Indohyus. (Thewissen, 2007)This animal was the first relative of the whale, the indohyus was a small deer like creature that consumed terrestrial plants instead of fish, and it thrived under water and moved around like a hippo would, along the banks of waterways. Which doesn’t sound like a whale but the indohyus has more similarities to whales than other species. The similarity between whales and indohyus were that the indohyus had heavy bones much like the whale that allowed them to sink and stay on the bottom of the water floor instead of floating to the surface. This heavy bone trait was carried on through generations eventually leading to the whale, now having the heaviest bones on earth. Compared to the elephant and hippopotamus which would be the second biggest animals on earth. These creatures, unlike the whale, are land dwelling creatures that are also herbivores just like the whale. The embryo of a whale sees the development of the embryo into a fetus. This process forms the basic shape of the whale and how it’s going to look like. The early stages of fetal development shows how the whale has evolved from its land based ancestors. Most cetaceans in their fetal stage share many similar traits such as skin, hair, the birth position, spinal cord,