- Discover essay samples

From water to land

4.9 of 5.0 (18 reviews)

614 words

From water to land Page 1
From water to land Page 2
From water to land Page 3
The above thumbnails are of reduced quality. To view the work in full quality, click download.

From water to land

From Water to Land (Revision)


The early tetrapods were the first vertebrates to actually walk the solid earth. They began their conquest of land in the Paleozoic era around 360 million years ago. The question many paleontologists have been asking for a long period of time is whether the anatomy for locomotion on land was developed in water for swimming purposes, or if it was adapted after the creatures became terrestrial. Recent findings of fossils indicate that the transformations of the aquatic creatures happened underwater in order to help them survive in the changing world. When looking for answers, they had to examine forearm, hip, wrist, finger, and other bones, as well as the lungs or gills of the early tetrapod fossils. This information is critical in understanding the history and the process of growth and change. It aids in learning about human evolution.


Tetrapods are creatures with four limbs, hips, shoulders, fingers, and toes, which developed sometime after lobe-finned fish, and before the first fully terrestrial vertebrates. The earliest tetrapod known is Acanthostega. It is also considered the most primitive tetrapod. It is very close to its fish ancestry, but still anatomically far from its terrestrial relatives. These creatures still lived in water, but they had a lot of the terrestrial tetrapod anatomical characteristics.


Before tetrapods existed, all vertebrates were confined to living in aquatic habitats. The only animals that lived on land were arthropods. Through natural adaptations, the fish developed into amphibians. This colossal stage of change made necessary the evolution of new ways of breathing, locomotion, and reproduction. Paleontologists needed to understand how this transition took place. If the changes in anatomy of the fish developed on land, then they served the same purposes they serve today, such as walking. But what advantages would those same body parts give to the aquatic creatures still living in water? This is one of the questions the scientists are asking themselves. There have been a few hypotheses on this matter. The most recent one states that the transformations of the aquatic creatures happened underwater in order to help them survive. This time period is very difficult to study because there is a very small amount of fossils preserved. After all, this occurred approximately 350 million years ago; and since the first tetrapods lived in water, their remains were damaged as time went on.


. In 1940 Alfred Romer of Harvard offered a powerful scenario about the process of evolution of the fish into amphibians. He argued that the freshwater pools that the early tetrapods lived in were suffering seasonal droughts. He compared these early creatures to lungfish. Because of the draughts tetrapods evolved lungs and were able to breathe air when necessary. This happened over a long period of time. The lungs came to the rescue when the oxygen became scarce in water or when the ponds dried out. Romer also suggested that instead of digging burrows with their teeth, such as lungfish do in similar situations, tetrapods used their fins to struggle over the harsh land to the nearest pond. By the process of natural selection, fish with weak fins died along the way, but fish with strong ones lived to reproduce and pass on their genotype to their offspring. Gradually fins turned into limbs, which are much better for overland travel. At the same time, many other parts of the body, such as eyes, ears, and skin, changed to better cope with this new environment (Gardiner, 1998, p.659).

Romer's theory was very controversial because there were a lot ...

You are currently seeing 50% of this paper.

You're seeing 614 words of 1227.

Keywords: from water to land evolution, transition from water to land animals, plants from water to land evolution, plane from water to land, from water to earth, from water landscape, how much does it cost to get water to land, how to get water to your land

Similar essays

Coral fish

As a by standee over viewing the preparation and or the act of courtship in the coral reef fishes, one may think they have taken leave of their senses. The bicolor damselfish tends to quiver while performing a headstand. Blue pullers engage in a series of high-speed jumps. Lyretailfish swim in jerky zigzag patters. Frillfish goby undulates...

5 reviews
Dvd vs

. vcr INTRODUCTIONThis report will strive to clearly discern the differences between the average home Video Cassette Recorder (VCR) and the recently developed Digital Video Disc (DVD) system. These two home entertainment components have very clear differences. It is important for consumers to carefully consider each of these concerns before deci...

22 reviews
Marijuana for migranes

1) Russo, Ethan M.D. (1998). Cannabis for migraine treatment. Pain, 76, 3 ' 8. This particular journal entry is actually a historic review on the benefits of utilizing cannabis for the medicinal use of relieving migraines. In an attempt to find a journal that might actually have a case study or something on the affects of marijuana on a...

39 reviews
Do science and technology provide a solid base for technocra

To answer this question one must first understand that every politico-economic ideology, like every religious belief, proclaims that it has the one true doctrine and that all others are entirely different or at opposite ends. In most instances individuals join in voluntary association to act upon those opinions, ideas or beliefs which they hol...

23 reviews
Chemical bonding

Chemical bonds are what make up the world. In bonds, elements are held together and form compounds that may have new physical and chemical properties. There are two main kinds of bonds, they ionic and covalent. In bonding the goal of the atoms involved is to reach a level of stability with less energy. In order to reach the epitome of stabil...

148 reviews
Atsisiųsti šį darbą