Transitions Of Reptiles To Mammals Essay

The evolutionary path of a whale is a fascinating process of a terrestrial mammal that evolves into a marine mammal. This evolutionary path started with one of the earliest ancestors called “Pakicetus”. A Pakicetus was discovered to be a land animal with four legs that had teeth as carnivores. It skull structure was long, but this organism didn’t look like any marine animal. The scientist then discovered that on the skull’s ear region it was surrounded by a bony wall. This feature on an organism only was distinct from one type of species, scientist discovered that this animal “Pakicetus” was an ancestor of a whale. By comparing the early whales Pakicetus to the next generation of ancestors Ambulocetus, the Ambulocetus whale looks more like

So what killed the dinosaurs? Without having any background education in science it is hard for the general public to comprehend such matters and they rely on the knowledge of the scientists in this field. Although there has been much research on the subject nobody has come up with a conclusive answer. And we are left to read the countless articles, all having their own opinions as to the mass extinction. One such theory is that a shift in the solar system could have caused the mass destruction. According to an article published in Nature magazine,

What makes a primate a primate? A primate is defined by its many incredible features. A primate is a mammal that has certain characteristics such as: flexible fingers and toes, opposable thumbs, flatter face than other mammals, eyes that face forward and spaced close together, large and complex cerebrum, and social animals. What makes a primate a primate is its characteristics. Some of the physical features primates are identified by is their teeth, snouts, eyes, ears, arms, legs, fingers, and toes. Human evolution is a big part of humans being primates, and having similar features and characteristics make humans to be considered to be a primate, but both humans and non-humans have differences.

There are four main groups of reptiles, known as Crocodilians, Squamates, Tuataras, and Turtles. Crocodilians consists of large reptiles which includes alligators, crocodiles, gharials, and caimans. Squamates are lizards, snakes, and worm-lizards. A worm-lizard is a subterranean burrowing reptile that resembles an earthworm, a legless lizard. Tuataras are a group of reptiles that are lizard-like in appearance but are different from squamates because their skull isn’t jointed. Turtles are the most ancient reptiles alive today. They have changed very little since they first showed up 220 million years ago. The first turtle appeared 220 million years ago.(Laura Klappenbach)

Biological evolution is not simply a matter of change over time. Lots of things change over time. Trees lose their leaves, mountain ranges rise and erode, but they aren 't examples of biological evolution because they don 't involve descent through genetic inheritance.

Recent evidence suggests that whales may not have always inhabited the oceans. Bones of an ancient ancestor of modern day whales, the Basilosaurus, were discovered in Pakistan that suggest whales evolved from a wolf-like creature. This genus of an early whale lived 34-40 million years ago in the late Eocene. These fossils show many different features in common with both modern day whales and modern day land mammals. Since the discovery of these bones, many other evidences show that whales are a likely descendant of the Basilosaurus through many different ways, such as embryologic comparison and DNA testing. Whales aren’t the only suspected descendants

Mammals are a subcategory of vertebrates, and mammals are more closely related to each other than to other types of vertebrates. They are so closely related, in fact, that the pictures at Station 9, of embryos of different mammals, are nearly indistinguishable. They all seem to have developing vertebrae, heads, and limbs, that are identical. Some of these will be lost as the embryo develops. The human embryo will lose its tail, while the dolphin embryo will lose a large part of its limbs. Primates are a category of mammals, and apes are a type of primates. All apes come from a common ancestor, and that includes humans. Even humans speciated multiple times before the modern human, or homo sapiens, evolved, as evidenced by the skulls at Station 5. They were all skulls of different species of prehistoric human. The skull most similar to the modern skull belonged to the most recent species of human. There were times when two types of humans lived together. The species that was best adapted to fit the environment at the time survived, while the

For many animals, the ability to move is essential for survival. Animals move for a variety of reasons such as: to find food, a mate, a habitat to live in, or to escape predators. It is important for animals to develop new abilities and traits to accomplish these necessities of living. Natural selection has shaped the locomotion methods and mechanisms used by moving organisms for millions of years. Generally, non-human primates are studied to garner an understanding of evolution caused by natural selection because of the many distinctive adaptations that have occurred within their taxonomic order. To understand the origin of locomotion that exist amongst primates, the two categories of primates must be analyzed to recognize morphological trait differences. Then, three major determinants can be evaluated to describe the variety of locomotor patterns primates display: the ecological niches in which the primate originates, the current inhabited niches, and the major key aspects of survival such as

Primates first evolved from the trees of tropical forests, later to the ground. Through the times of promisians to human, many characteristics has been represented due to the adaptations to new environments and resulted in evolutionary changes. The Earth has encountered several geological and climatic changes over time. For the primates existed at that time had to adjust itself especially in body configurations and locomotion in order to better survive. It is important to be aware of this information since we are the part of occurring changes as well. Throughout the evolution owing to

Hey! No large domestic animals, so there's your excuse for a failure in the Americas. But there was a domestic mammal throughout the two continents:

This could also be a main topic question. This question can furthermore investigate my first question on

Dinosaur extinction: An analysis of events and theories that possibly led to the dinosaurs' demise.

The entirety of Earth’s ecosystem was affected by the K-Pg extinction, caused by volcanoes, oceanic shifts, and ultimately, an asteroid. Lucky for humans, mammals capitalized on the opportunity

The biggest mystery surrounding the dinosaur is how did they die? For over 130 million years dinosaurs ruled the earth. Then 65 million years ago, at the end of the Cretaceous period, they died out.

They say as mammals continued to evolve, they drove the dinosaurs into extinction (“What Killed the Dinosaurs”). “Not only did mammals likely compete with dinosaurs for resources, many species survived the end-Cretaceous extinction and subsequently came to dominate Earth.” (“What Killed the Dinosaurs?”). This is primarily because the early mammals were a lot smaller than the mammals that exist today. “Some of the world's earliest mammals were the multituberculates, a group of small rodent like animals that first emerged on Earth about 165 million years ago.” (Welsh, Jennifer). Scientists predict that any mass extinction event that caused animals to go extinct affected larger animals than it did the smaller animals, such as mammals ("Dinosaurs Became Extinct 'due to Laying Eggs'"). Mammals remained small for almost 100 million years, while they out competed small and baby dinosaurs for food, shelter and resources until they were extinct. Once the dinosaurs were out of the way mammals were able to evolve and grow large in size like the mammals that exist today today (LiveScience). Fossil evidence sheds some light on this theory as well. Fossils of mammals believed to date back to about eighty five million years ago show that mammals began to change rapidly and grow. “This matches up with other mammal groups, including recently discovered species from the Late Cretaceous (between 100 million and 65 million years ago) showing highly specialized