Links assignment - Biology Essay Example
What is a gene?
According to the national institute for health and ‘TheBody.com” a gene is a unit of heredity. The gene represents the smallest collection of DNA that can be demonstrated to transmit characteristics (traits) to an organism’s offspring.
Both sites are well established bodies involved in the science of physiology and health fields dealing with biological systems.
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Gene—A functional unit of heredity that is a segment of DNA located in a specific site on a chromosome. A gene directs the formation of an enzyme or other protein.
< http://stemcells.nih.gov/info/glossary.asp > May 2 2005. June 10, 2004.
1. A unit of DNA that carries information for the biosynthesis of a specific product in the cell. 2. Ultimate unit by which inheritable characteristics are transmitted to succeeding generations in all living organisms. Genes are contained by, and arranged along the length of, the chromosome. The gene is composed of deoxyribonucleic acid (DNA). Each chromosome of each species has a definite number and arrangement of genes, which govern both the structure and metabolic functions of the cells and thus of the entire organism. They provide information for the synthesis of enzymes and other proteins and specify when these substances are to be made. Alteration of either gene number or arrangement can result in mutation (a change in the inheritable traits).
< http://www.thebody.com/hivatis/glossary/g.html > May 2 2005. June 1999.
2. What is Biological Fitness?
Biological fitness of any individual is determined by how successful it is in reproducing according to the USDA and OSSU.
OSSU is more concerned with mechanical(inorganic) evolution, but uses concepts derived from the biological sciences such as biological fitness to evaluate and determine mechanical fitness in the evolution of machine design.
The USDA is a government organization involved in dietary and biological science.
Formal Definition of Biological Fitness:
The fitness of a genotype s is proportional to the average number of offspring of an individual possessing the genotypes.
< http://www.ossu.co.uk/manstrategy/index.shtml >
Biological fitness was defined as total number of survivors, mean biomass (dry weight) accumulated per cage over the total treatment period, egg production, time to adult emergence, and time to start of egg laying.
< http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=122747 >
What is biological evolution?
According to both Wikipedia and Answers.com biological evolution is synonymous with evolution applied to a biological system, that is the gradual change of an organism over time. This process is sometimes referred to as descent with modification or “survival of the fittest”.
Generally, evolution is any process of change over time. In the context of life science, evolution is a change in the traits of living organisms over generations, including the emergence of new species. Since the development of modern genetics in the 1940s, evolution has been defined more specifically as a change in the frequency of alleles in a population from one generation to the next.
< http://en.wikipedia.org/wiki/Evolution > May 3 2005. May 3, 2005.
evolution, concept that embodies the belief that existing animals and plants developed by a process of gradual, continuous change from previously existing forms. This theory, also known as descent with modification, constitutes organic evolution
4. What is Natural and Artificial Selection and how are they the same and how are they different?
According to the links provided by Answers.com, a general reference site, Natural and artificial selection refers to the alteration of a populations traits by manipulating the fitness of certain individuals in that population.
In the case of natural selection it is any trait that enhances an individual’s survival and/or biological fitness by increasing its offspring. Artificial selection in contrast uses the same mechanism but the selection process is performed by Man selecting traits deemed beneficial or desirable to Man. An example of the results of artificial selection are the numerous dog breeds.
A process fundamental to evolution as described by Charles Darwin. By natural selection, any characteristic of an individual that allows it to survive to produce more offspring will eventually appear in every individual of the species, simply because those members will have more offspring.
· The expression survival of the fittest was used to describe this process in the nineteenth century but is not favored by modern scientists.
The breeding of plants and animals to produce desirable traits. Organisms with the desired traits, such as size or taste, are artificially mated or cross-pollinated with organisms with similar desired traits. (Compare natural selection.)
Web Journal stuff
How Does the male bowerbird attract a mate?
The male bowerbird builds a bower. The bower is built of straw, sticks, and twigs. The bower may one of many forms: Maypole , hut, wall, avenue, or mat.
If the bower attracts a female inside the male begins a courtship dance which if successful leads to copulation.
< http://www.pbs.org/wgbh/nova/bowerbirds/trail.html >
How does the male prairie chicken attract a mate?
In all the prairie chicken species courtship consists of calls ( booming ), dancing, rhythmic stamping or drumming of feet, and feather displays performed on a raised area called a lek.
How does the human male attract a mate?
There is no set criteria for humans. The male typically will attempt to impress a female by his athletic prowess, his financial status, or talent in another area. Most men don’t worry about their appearance to the degree women do.
What does the female assess in all three cases?(more than one answer)
The female attempts to determine if her choice is healthy, and able to provide food or shelter for her and her offspring. She may also have preferences for strength, speed, and some appearance preferences.
In the case of a Human female, the male must also meet whatever social requirements she has developed from the media or from the female community as well as any personal requirements for intelligence, charm, and personality.
A new study finds that a young, inexperienced, female bowerbird judges a male by the manner in which he decorates his bachelor pad. Once she’s aged and mated a few times, this affinity for a swanky domicile fades, and she then relies on courtship routine—a vigorous song and dance—to select the most worthy suitor.
This research suggests that feminine taste, throughout the animal kingdom, may be more complicated than anyone thought.
“Natural selection favors males that are responsive to females and know how to communicate well,” said Patricelli. Males that are sensitive to females’ signals are more likely to mate with several females, she added
What constitutes an alpha male, the best male with which to mate and produce the best possible offspring, depends on far more factors than any other animal on earth. The criteria for her to desire sexually a man can include strength or health or fighting ability, like the lion or the wolf. However, they can also include intelligence, money, power, prestige, position, status, attitudes, political or religious convictions, any number and combination of factors.
How does a human female attract a mate? What does the male assess?
The human female attracts primarily by appearance. The use of cosmetics, costumes and other tools to alter the appearance toward one that seems to be healthy
The human male has a drive to impregnate as many females as possible, to create as many offspring with his genes as possible. (Ehrlichman & Eichenstein, 1992) Thus, he applies criteria typical for a male animal. He looks for women who are impregnable: those who are old enough to be past puberty, but young enough to care for children for at least several years. He looks for healthy (i.e., clear, smooth skin, “bright” eyes, good conformation of body and limbs, etc.) women, so they can carry the fetus to term, deliver it, and care for it after birth. Beyond that, he doesn’t really care. She doesn’t have to be intelligent, talented, socially aware, or in any other way have a brain. In fact, the dumber she is the easier it would be for him to meet her criteria for desirability since they are less likely to be extensive.
How do your genes affect your choice of mate and your fitness? Do your mate choices have an impact on the fitness of your children.
To the extent that genes affect appearance and intelligence, yes genes have an impact on the eventual fitness of the children of any union. However, in Human society good genes don’t guarantee fitness; many other social and cultural factors influence mate selection, and may occasionally over-ride genetic pre-disposition positively or negatively.
Are the choices you make regarding mates the same as gene manipulation? Are you altering the genes of your children (500 words)
The choice men and women make to select their mates affect the potential genetic makeup of their children. Humans reproduce sexually; each parent contributes half of the resulting genetic code inherited by the child. Each sex utilizes different parameters to determine whether a potential mate is suitable. Taken as a whole these preferences cause what is known as sex-selection.
Sex-selection means that each sex is selecting for certain traits that are desired in the offspring, or that benefit the offspring in some way. Men primarily focus on appearance; this is one explanation for the narrow variation present in body form of women (Harms). While women will typically make additional criteria into account that may over-ride appearance alone (Taflinge) resulting in a broader physical variation among men in cultural groups than seen in women( Harms ).
In many ways, sex-selection is identical to artificial selection. Artificial selection is the selection (breeding) for certain traits in the hope that they are passed to children. In the same way, each sex is selecting for traits in the other. As the traits selected for become reinforced, they become more general and prevalent. These traits are those that are the cultural stereotypes for beauty both masculine and feminine. Sex selection is a form of artificial selection and is the most common force behind human evolution for large parts of our history (Harms).
Since this program of selection involves determining which genes will provide the combination of a child’s make-up, it is definitely a form of genetic manipulation or evolution. Biological evolution is the gradual change of an offspring over time (Answers.com). By favoring some genetic combinations we preserve some traits but inevitably will lose some traits not dependent on a selected for trait. This means that humans are gradually changing, evolving now.
The selected for traits will be inherited by the children. Children possessing traits that are being selected for, will more likely have children of their own. This is how the selected traits will become more general in a population. Overtime, new traits may be selected for in response to climatic, cultural, or economic reasons. Each change affects the potential mix in the gene pool and impacts the fitness of the offspring in the same manner selection for other traits did. Each choice affects the potential genome of the child. While this is true sex selection is not the same as genetic manipulation such as genetic engineering, it is virtually the same as artificial selection, which has resulted in the many breeds of dog and various types of apple.