Ancient Greece Ancient Greece was the birthplace of Western philosophical ethics. The ideas of Socrates c.
The concept was later extended to include any biological system from the cell to the entire biosphereall the areas of Earth inhabited by living things. Unity All living organisms, regardless of their uniqueness, have certain biological, chemical, and physical characteristics in common. All, for example, are composed of basic units known as cells and of the same chemical substances, which, when analyzed, exhibit noteworthy similarities, even in such disparate organisms as bacteria and humans.
Furthermore, since the action of any organism is determined by the manner in which its cells interact and since all cells interact in much the same way, the basic functioning of all organisms is also similar.
Animal cells and plant cells contain membrane-bound National academy of sciences human cloning essay, including a distinct nucleus. In contrast, bacterial cells do not contain organelles. There is not only unity of basic living substance and functioning but also unity of origin of all living things.
If, however, life originated on Earth more than once in the past, the fact that all organisms have a sameness of basic structure, compositionand function would seem to indicate that only one original type succeeded.
A common origin of life would explain why in humans or bacteria—and in all forms of life in between—the same chemical substance, deoxyribonucleic acid DNAin the form of genes accounts for the ability of all living matter to replicate itself exactly and to transmit genetic information from parent to offspring.
Furthermore, the mechanisms for that transmittal follow a pattern that is the same in all organisms.
Whenever a change in a gene a mutation occurs, there is a change of some kind in the organism that contains the gene. It is this universal phenomenon that gives rise to the differences variations in populations of organisms from which nature selects for survival those that are best able to cope with changing conditions in the environment.
Evolution itself is a biological phenomenon common to all living things, even though it has led to their differences. Evidence to support the theory of evolution has come primarily from the fossil recordfrom comparative studies of structure and function, from studies of embryological development, and from studies of DNA and RNA ribonucleic acid.
Three types of natural selection, showing the effects of each on the distribution of phenotypes within a population. The downward arrows point to those phenotypes against which selection acts. Stabilizing selection left column acts against phenotypes at both extremes of the distribution, favouring the multiplication of intermediate phenotypes.
Directional selection centre column acts against only one extreme of phenotypes, causing a shift in distribution toward the other extreme. Diversifying selection right column acts against intermediate phenotypes, creating a split in distribution toward each extreme.
Diversity Despite the basic biological, chemical, and physical similarities found in all living things, a diversity of life exists not only among and between species but also within every natural population. The phenomenon of diversity has had a long history of study because so many of the variations that exist in nature are visible to the eye.
The fact that organisms changed during prehistoric times and that new variations are constantly evolving can be verified by paleontological records as well as by breeding experiments in the laboratory.
Long after Darwin assumed that variations existed, biologists discovered that they are caused by a change in the genetic material DNA. That change can be a slight alteration in the sequence of the constituents of DNA nucleotidesa larger change such as a structural alteration of a chromosomeor a complete change in the number of chromosomes.
In any case, a change in the genetic material in the reproductive cells manifests itself as some kind of structural or chemical change in the offspring. The consequence of such a mutation depends upon the interaction of the mutant offspring with its environment.
It has been suggested that sexual reproduction became the dominant type of reproduction among organisms because of its inherent advantage of variability, which is the mechanism that enables a species to adjust to changing conditions.
New variations are potentially present in genetic differences, but how preponderant a variation becomes in a gene pool depends upon the number of offspring the mutants or variants produce differential reproduction.
Thus, when a species is introduced into a new habitatit either adapts to the change by natural selection or by some other evolutionary mechanism or eventually dies off. Because each new habitat means new adaptationshabitat changes have been responsible for the millions of different kinds of species and for the heterogeneity within each species.
The total number of extant animal and plant species is estimated at between roughly 5 million and 10 million; about 1. The use of classification as a means of producing some kind of order out of the staggering number of different types of organisms appeared as early as the book of Genesis —with references to cattle, beasts, fowl, creeping things, trees, and so on.
The first scientific attempt at classification, however, is attributed to the Greek philosopher Aristotlewho tried to establish a system that would indicate the relationship of all things to each other.
Other schemes that have been used for grouping species include large anatomical similarities, such as wings or fins, which indicate a natural relationship, and also similarities in reproductive structures.
Taxonomy has been based on two major assumptions: Behaviour and interrelationships The study of the relationships of living things to each other and to their environment is known as ecology. Because these interrelationships are so important to the welfare of Earth and because they can be seriously disrupted by human activities, ecology has become an important branch of biology.
Continuity Whether an organism is a human or a bacterium, its ability to reproduce is one of the most important characteristics of life. Because life comes only from preexisting life, it is only through reproduction that successive generations can carry on the properties of a species.
The study of structure Living things are defined in terms of the activities or functions that are missing in nonliving things.Aug 08, · Wednesday was a sweaty-poignant reminder that summer isn't even close to being done with us yet. I realize many of us are already back into back-to .
John M. Haas, Ph.D., S.T.L., K.M., President John M. Haas is the President of The National Catholic Bioethics Center.
The Center was established in to apply the teachings of the Catholic Church to ethical issues arising from developments in medicine, the life sciences and civil law.
The history of Western ethics Ancient civilizations to the end of the 19th century The ancient Middle East and Asia. The first ethical precepts must have been passed down by word of mouth from parents and elders, but as societies learned to use the written word, they began to set down their ethical beliefs.
These records constitute the first historical evidence of the origins of ethics. Reproductive cloning is most controversial because it involves making a genetically identical copy of a whole organism (National Academy of Sciences ).
It is an asexual method of reproduction but one that usually requires the use of a surrogate mother to allow for development of the cloned embryo. Human enhancement is "any attempt to temporarily or permanently overcome the current limitations of the human body through natural or artificial means.
It is the use of technological means to select or alter human characteristics and capacities, whether or not the alteration results in characteristics and capacities that lie beyond the existing human range.".
Psychology is the science of behavior and mind, including conscious and unconscious phenomena, as well as feeling and ashio-midori.com is an academic discipline of immense scope and diverse interests that, when taken together, seek an understanding of the emergent properties of brains, and all the variety of epiphenomena they manifest.
As a social science it aims to understand individuals and groups.