Transitions Of Reptiles To Mammals Essay

2568 words - 10 pages

Transitions of Reptiles to Mammals

     A long long time ago, in a galaxy not too far away, was a little blue
planet called Earth, and on this world not a single mammal lived. However a lot
of time has past since then and we now have lots of furry creatures that are
collectively called mammals. How did they get their? Where did they come from?
These are the kinds of questions that led me to my subject of choice. I will
endeavor to provide examples, using specific transitional fossils, to show that
mammals have evolved from a group of reptiles and were simply not placed here by
unknown forces.

     Before I begin, I would like to define some terms so that nobody gets
left in the dust. The term transitional fossil can be used in conjunction with
the term general lineage, together they help explain the how one species became

"General lineage":

This is a sequence of similar genera or families, linking an older to a very
different younger group. Each step in the sequence consists of some fossils that
represent certain genus or family, and the whole sequence often covers a span of
tens of millions of years. A lineage like this shows obvious intermediates for
every major structural change, and the fossils occur roughly (but often not
exactly) in the expected order. However, usually there are still gaps between
each of the groups. Sometimes the individual specimens are not thought to be
directly ancestral to the next-youngest fossils (e.g. they may be "cousins"" or
"uncles" rather than "parents"). However they are assumed to be closely related
to the actual ancestor, since the have similar intermediate characteristics.

Where Does It All Begin ?

     Mammals were derived during the Triassic Period ((from 245 to 208
million years ago) It began with relatively warm and wet conditions, but as it
progressed conditions became increasingly hot and dry.) from members of the
reptilian order Therapsida. The therapsids, members of the subclass Synapsida
(sometimes called the mammal-like reptiles),generally were unimpressive in
relation to other reptiles of their time. Synapsids were present in the
Carboniferous Period (about 280 to 345 million years ago) and are one of the
earliest known reptilian groups. Although therapsids were primarily predators by
nature, some adaptations included a herbivorous species as well, they were
generally small active carnivores. Primitive therapsids are present as fossils
in certain Middle Permian deposits; later forms are known from every continent
except Australia but are most common in the Late Permian and Early Triassic of
South Africa.

     The several features that separate modern reptiles from modern mammals
doubtlessly evolved at different rates. Many attributes of mammals are
correlated with their highly active lifestyle; for example, efficient double

Find Another Essay On Transitions Of Reptiles To Mammals

Religion vs. Science Essay

1007 words - 4 pages . Birds, which, according to both creation myths in Genesis, "were created on the same day as fish,"(Genesis) do not enter the fossil record until the Jurassic Period "190-136 million years ago"(Encarta). Representing an ultimate variation on the dinosaur theme, birds trace their descent from reptiles. This is quite different from those ancestral to the mammals. Contrary to the claims of some creationists, evolutionists do not claim that reptiles

A brief History of Life on Earth.

521 words - 2 pages continents slowly moved northward. At the end of the Devonian there was another 75% mass extinction of all marine life due to climatic circumstances. The Carboniferous (354-290 mya) brought large amounts of glacial formation on Gondwana. Terrestrial animals diversified and some of the first reptiles appeared during Carboniferous period. During the Permian period (290-245 mya), all of the continents came together to form the super-continent Pangaea

What is the evidence for the thory of evolution?

530 words - 2 pages the fact that dinosaurs that lived 150 millions of years ago that suggest that they are related to crocodiles. Also certain fossils have been found that are similar to both reptiles and mammals. This suggests that they were the animals that created the first mammals.Although all of this evidence is not absolute proof, it is still very strong evidence that the theory of evolution is true.

The Green Anole (Anolis Carolinis): Physique, mating, and needs. Small reptile care.

605 words - 2 pages Reptiles manage to endure as one of the most fascinating types of creatures on earth. One of the most commonly found reptiles in southern United States is the Green Anole, or Anolis Carolinis. The life of one of these unique creatures comprises of numerous intriguing physical properties, interesting mating behavior, and invigorating physical needs.Overall, the physical characteristics of a Green Anole interest many. Out of over 300 species of

Human Origins

2113 words - 8 pages different taxon because birds and dinosaurs share a feature of the pelvis not found in any other group, including reptiles.” Earlier, on (pg 95), they are discussing transitional forms of fossils and use in parentheses the clarification “dinosaurs to birds and reptiles to mammals”. These two statements imply very different definitions for the term “reptile”. First of all, “reptiles” as commonly defined is not a monophyletic clade. In order to

Temperate Deciduous Forest and Missouri

1401 words - 6 pages , hydrangeas, and lilacs (Alphonse; O'Connell). The fauna in both Missouri and the temperate deciduous forest relies heavily on the flora. The animal wildlife in the temperate deciduous forest biome and Missouri share many common traits when it comes to insects, birds, reptiles, amphibians, and mammals. Some of the insects that make Missouri their home are ants, eastern tiger swallowtail butterflies, cicadas, wasps, and praying mantises

Compare responses of named Australian ectothermic and endothermic organisms to changes in the ambient temperature and explain how these responses assist in temperature regulation

528 words - 2 pages - ECTOTHERMS are organisms that have a limited ability to control their body temperature. Their cellular activities generate little heat. Their body temperatures rise and fall with ambient temperature changes. Most organisms are ectotherms. Examples are plants, all invertebrates, fish, amphibians and reptiles- ENDOTHERMS are organisms whose metabolism generates enough heat to maintain an internal temperature independent of the ambient

The Story of How the Universe and the World Came to Be

1122 words - 5 pages absorption of Vitamin D as mammals do. These animals must rely on various forms of natural and unnatural UV light to supply the vitamins necessary for bone formation and calcium metabolism. Hedley notes in her article that reptiles kept as pets will often lack the appropriate amount of Vitamin D. The reptile’s keeper may not be providing the adequate amount of heat using artificial UV-B rays and a reptile will then bask in a separate heat source

Warm Blooded Versus Cold Blooded Dinosaurs

1533 words - 6 pages blood both to the lungs and to the remainder of the body.  All modern reptiles have paired systemic aortas arising from the ventricle and distributing blood to the body.”  Dr. Dale Russell continues on to explain, the four-chambered heart of warm blooded mammals and birds.  Mammals and birds have “completely separated ventricles and a single systemic aorta, ensuring that only completely oxygenated blood is distributed to the body. These

Adaptions in Ectothermic and Endothermic Animals to Extreme Climates

1425 words - 6 pages Adaptions in Ectothermic and Endothermic Animals to Extreme Climates First of all we need to understand what ectothermic and endothermic animals are. Animals differ in their abilities to regulate body temperature (thermoregulation). We sometimes use the terms "cold-blooded" or "warm-blooded." Most reptiles feel cold to the touch, while mammals and birds often feel warm. Somewhat more precise descriptions can be made by using the terms

Evolutionism versus Creationism

691 words - 3 pages the creation of earth; but one side is more logical when evaluating the facts. God created man is what the Creationists believe. But what is proven true through fact is that there were five or six types of 'man' created. Why would God create 5 or 6 of the similar species, but only write about one of them? When comparing the facts of the similar bone structures of mammal like reptiles and mammals, the interpreting is left up to the reader

Similar Essays

Transitions Of Reptiles To Mammals Essay

2603 words - 10 pages characteristics that separate reptiles and mammals evolved at differentrates and in a response to a variety of interrelated conditions, at any point in the period oftransition from reptiles to mammals there were forms that combined variouscharacteristics of both groups. such a pattern of evolution is termed 'mosaic' and is acommon phenomenon in those transitions marking the origin of major new adaptive types.To simplify definitions and to allow the

A Journey Through Evolution The Locomotion And Behavioral Changes Of Fishes, Reptiles, Amphibians, Birds And Mammals. A Good Starting Place For Short Biology Papers.

2071 words - 8 pages This is a huge area of discussion, therefore, you must be very selective of your topic, and write succinctly and to the point. For example, you may want to choose the theme of "reproductive strategies" of fishes, amphibians, reptiles, birds, and mammals, or you may choose "locomotion", "environmental adaptations", etc etc etc - the list is endless. I am interested in reading your specific interest in evolutionary biology.Throughout the millions

Warm Blooded Or Cold Bloded Essay

668 words - 3 pages Dinosaurs, like other reptiles, were thought until fairly recently to be cold-blooded. There is still a good case for this viewpoint. But lately some scientists have swung to the idea that dinosaurs were warm-blooded. There is a good case for this too. Scientists have conflicting opinions on this subject. Some paleontologists think that all dinosaurs were "warm-blooded" in the same sense that modern birds and mammals are: that is, they had rapid

Extinction Essay

1174 words - 5 pages because they all died! All animals die, but extinction happens because lesser new are born than die.The dinosaurs were a very great success and the superiors of their time with no competition from other vertebrates. The mammals, which did exist during the entire dinosaurian period, were small nocturnal animals, which played only little or no role to the dinosaurs.At the beginning of the Triassic various other groups of reptiles, which had survived