Study of Bird Genetics to Reveal Some Odd Ducks

The largest study ever of bird genetics has discovered some surprising facts about the avian evolutionary tree, including many that are bound to ruffle some feathers. For example, Falcons are not closely related to eagles and hawks, despite many similarities, while colorful hummingbirds that flit around in the day, evolved from a drab-looking nocturnal bird called a nightjar. In addition, songbirds and parrots are closer cousins than once thought.

Sushma Reddy of Chicago's Field Museum of Natural History, whose study appears in the journal Science, said one of the lessons we have learned is appearances seem to be very deceiving. Moreover, she said things that are quite different-looking sometimes end up being related. Reddy and colleagues studied the genetic sequences of 169 bird species in an effort to sort out family relationships in the bird family tree.

The findings challenge many assumptions about bird family relationships and suggest many biology textbooks and bird watchers' field guides may need to be changed.

Scientists believe birds, which first appeared roughly 150 million years ago, evolved from small-feathered carnivorous dinosaurs. Reddy, who worked with researchers at several other labs, said modern birds, as we know them evolved rapidly, probably within a few million years, into all of the forms we have seen. That happened 65 to 100 million years ago. Moreover, she said these quick changes have made bird evolution hard to pin down, and several smaller prior studies have led to conflicting results.

Researchers are not positively sure how any of these major bird groups were related to each other. They have tried to represent all of the major groups of birds and all of the major lineages. Their findings suggest birds can be grouped broadly into land birds, like water birds, the sparrow, like the penguin; and shore birds, like the seagull. However, there are many paradoxes within these groupings. For example, water-loving flamingos and some other aquatic birds did not evolve from water birds. Instead, they adapted to life on water. In addition, some flightless birds are grouped with birds that fly.

Reddy acknowledges the results are likely to stir debate in many circles, but she said she is confident in the findings. According to Reddy, it is a good study brings up as many questions as it answers.

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Human Genome to Change with Age

A study published in the Journal of the American Medical Association said individual human genomes change throughout a person's life influenced by environmental or nutritional factors that may explain why illnesses such as cancer come with age. Such changes could also be hereditary that might explain why some families are more affected by certain diseases than others are.

Researchers at Johns Hopkins University have found that the so-called epigenetic marks on the sequence of a person's DNA modify over the course of their life and the extent of such changes is similar among family members.

According to Andrew Feinberg, professor of molecular biology and genetics at the university, epigenetics might very well play a role in diseases like diabetes, autism and cancer. Epigenetics stands at the center of modern medicine because epigenetic changes, unlike DNA sequence that is the same in every cell, can occur because of dietary and other environmental exposure.

The team analyzed the DNA sequences from 600 people taking part in the AGES Reykjavik Study, formerly called the Reykjavik Heart Study in Iceland. Those participants supplied DNA samples in 1991, and then again between 2002 and 2005. Then, scientists measured the variations in the levels of methylation that is the main epigenetic modification, in 111 samples. In about a third of cases, the methylation levels had changed over the years.

Vilmundur Gudnason, a professor of cardiovascular genetics at the University of Iceland, said inappropriate methylation levels could contribute to disease. Moreover, he added too much might turn necessary genes off, too little might turn genes on at the wrong time or in the wrong cell.

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Hundreds of Young Penguins Found Dead in Brazil

Every year, Brazil airlifts dozens of penguins back to Patagonia or Antarctica. On last Friday, rescuers and penguin experts have reported that hundreds of young penguins swept from the icy shores of Patagonia and Antarctica are washing up dead on Rio de Janeiro's tropical beaches, Brazil. Rescuers and those who treat penguins are divided over the possible causes.

According to Eduardo Pimenta, supervisor for the state coastal protection and environment agency in the resort city of Cabo Frio, there are more than 400 penguins have been found dead on the beaches of Rio de Janeiro state over the past two months, most of them young. Moreover, he said that it is common here to find some penguins (both dead and alive) swept by strong ocean currents from the Strait of Magellan. However, this year is the worst.

A veterinarian at the Niteroi Zoo (the state's biggest zoo), Thiago Muniz, said that he believed over fishing has forced the penguins to swim further from shore to find fish to eat, but that leaves those penguins more vulnerable to getting caught up in the strong ocean currents. Muniz added, Niteroi has already received about 100 penguins for treatment this year and many are drenched in petroleum. The Campos oil field that supplies most of Brazil's oil lies offshore. Moreover, he said that he had not seen penguins suffering from the effects of other pollutants. However, he pointed out that already dead penguins are not brought in for treatment.

Pimenta pointed out pollution is to blame. He said that aside from the oil in the Campos basin, the pollution has been lowering the animals' immunity. Moreover, he added, the pollution has also been leaving them vulnerable to funguses and bacteria that attack those animals’ lungs.

Nevertheless, biologist Erli Costa of Rio de Janeiro's Federal University pointed out weather patterns could be involved. He did not think the levels of pollution are high enough to affect the birds so rapidly. According to his analysis, global warming that affects ocean currents and creates more cyclones, making the seas rougher. Moreover, he said the vast majority of penguins turning up are baby birds, which have just left the nest and are unable to out-swim the strong ocean currents they encounter while searching for food.

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Animal Life: The Story of Ant Colony

Ant is a common name for social insect of the family Formicidae, in the order Hymenoptera, which also includes the bees and the wasps. Unlike bees and wasps, some species of which are solitary, all ants are to be distinguished from the so-called white ants, or termites, constituting the separate order Isoptera.

In most ant species, males remain winged throughout life, and females are winged until after mating. Certain wingless females, called workers, are usually infertile. The fertilized female becomes the queen of the colony, with the main function of laying eggs. The males die after mating, and the workers gather food, care for the species of ants commonly consist of chambers and galleries excavated under stones or logs or underground; some species construct their nests in mounds of earth and vegetable matter or in decayed trees.

The ant family contains more than 4500 described species, widely distributed in temperate and tropical countries. The ant body consists of head, thorax, and abdomen, with the abdomen articulated to the thorax by means of an abdominal pedicel, or stalk.

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Albino: Lack Pigmentation in Living Creatures

Sometimes we see an animal or a plant without the normal pigmentation of its species, we called the as albino individualism. When an animal or a plant that raise without the pigment melanin, primary agent of normal human coloration, it is mean that the colorize item is absent in the tissues its. When albino is happened to the human, then the human will have pale skin, white or light yellow hair, and eyes that, although actually colorless, appear pink because the blood vessels of the retina are visible. This is happened to the albinos human because of enzyme tyrosinase that required for its formation, is lacking. Lacking the protection is photophobic (shunning light) and, in ordinary illumination, is inclined to squint. The absence of melanin in certain brain tissues is probably the case of the nystagmus (oscillation of the eyeballs), characteristic of most albinos.

Albinos occur in all races of humans, most frequently among certain Indian tribes of the southwestern U.S., but nowhere in large numbers. Albinism is transmitted as a recessive hereditary characteristic. Several types of partial albinism exist, including dominant piebald albinism, dominant white forelock, and chromosomal, sex-linked ocular albinism.

Animal albinism, similar to that of human in its cause, effects, and transmission, has been observed in most species of domestic animals and in a wide variety of other mammals and birds. The white rabbits, white rats, and white mice common in biological laboratories are true albinos. Forms of albinism occur in cold-blooded animals, but their causes are different. Albinism in frogs and certain salamanders, for example, is apparently caused by hormonal deficiency, because albinism can be cured by an injection of pituitary hormone. In fish, complete or spotty melanism (atypical black color) or albinism can be induced by merely severing certain nerves. Most cases of variations rather than the complete absence of pigmentation characteristic of albino mammals. Albinism in plants is always quickly fatal, because the plant cannot manufacture its food without the pigment chlorophyll.

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Animal in the Human Community

Ever since true humans appeared on earth, they have lived in close association with other animals. Throughout most of that time, human existed as hunter-gatherers who depended on wild animals for food and clothing. They also found a source of aesthetic pleasure and spiritual strength in the animal life about them. Evidence of this exists is the remarkable paintings of Paleolithic people in the caves of southern France. The religious practices of North American Indians involved the veneration of certain animals, such as the bear, wolf, and eagle, in an attempt to acquire the power, wisdom, courage, and speed that these animals supposedly possessed.

Human societies have continued to exhibit traces of these relationships. The aesthetic appeal of animals is expressed in the mosaics and frescoes of ancient Greece, Rome, and Egypt, in the paintings of the Renaissance masters, and in countless works of more recent artists. Mystical feelings toward animals are reflected in myths and folktales, moralistic fables involving animals, and anthropomorphic animal stories for children as well as the adoption of animal names for cars, sports teams, and so on.

Despite highly developed technology and agriculture and the domestication of many species, modern humans still depend on wild stocks of a variety of other animals, such as fish and shellfish, for food. Unmanaged commercial exploitation, however, has greatly reduced this resource and has driven some species to the edge of extinction. In addition, wild animals provide recreation in the form of sport hunting and sport fishing, bird watching, and visits to zoos and wildlife refuges.

As human advanced from hunting to an agriculture existence, relationships between humans and animals changed. Animals that preyed on livestock or that destroyed crops were reduced or exterminated and the alteration on the landscape eliminated habitats for many other species. As humans became more concentrated in cities, however, animals such as rats multiplied and became important carriers of disease.

Human domesticated some animals for food, clothing, power, and companionship. How this came about is a matter of speculation. Through protection and selective breeding, humans changed early-domesticated forms into highly productive dairy and beef cattle, sheep, swine, and poultry. Also contributing to human welfare are the dogs, cats, white rats and mice, guinea pigs, and rhesus monkeys that medical research has used to gain an understanding of human physiology and to develop drugs and procedures to combat human illnesses.

As human continue to spread across the earth, however, they encroach on or pollute the environments of many animals, reducing remaining habitats to smaller and smaller areas. Unless this trend is reversed, much of the world’s animal life faces extinction.

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Adaptive Radiation

Because the environment exerts such control over the adaptations that arise by natural selection-including the co-adaptations of different species evolving together, such as flowers and pollinators-the kind of organism that would fill a particular environmental niche ought to be predictable in general terms. An example of this process of adaptive radiation, or filling out of environmental niches by the development of new species, is provided by Australia. When Australia became a separate continent some 60 million years ago, only monotremes and marsupials lived there, with no competition from the placental mammals that were emerging on other continents. Although only two living monotremes are found in Australia today, the marsupials have filled most of the niches open to terrestrial mammals on that continent. Because Australian habitats resemble those in other parts of the world, marsupial equivalents can be found to the major placental herbivores, carnivores, and even rodents and moles.

This pattern can be observed on a restricted scale as well. sparsely populated islands for example, one species of bird might enterIn some the region, find little or no competition, and evolve rapidly into a number of species adapted to the available niches. A well-known instance of such adaptive radiation was discovered by Charles Darwin in Galapagos Islands. He presumed, probably correctly, that one species of finch colonized the islands thousands of years ago and gave rise to the 14 species of finch-like birds that exist there now. Thus, one finch behaves like a warbler, another like a woodpecker, and so on. The greatest differences in their appearance lie in the shapes of the bills, adapted to the types of food each species eats.

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Mechanisms of Adaptation

Evolutionary adaptations are the result of the competition among individuals of a particular species over many generations in response to an ever-changing environment, including other animals and plants. Certain traits are culled by natural selection favoring those individual organisms that produce the most offspring. This is such a broad concept that, theoretically, all the features of any animal or plant could be considered adaptive. For example, the leaves, trunk, and roots of a tree all arose by selection and help the individual tree in its competition for space, soil, and sunlight.

Biologists have been accused of assuming adaptiveness for all such features of a species, but few cases have actually been demonstrated. Indeed, biologists find it difficult to be certain arose by selection and hence can be called adaptive or whether it arose by chance and is selectively neutral. The best example of an evolutionary development with evidence for adaptation is mimicry. Biologists can show experimentally that some organisms escape predators by trying to be inconspicuous and blend into their environment and that other organism imitate the coloration of species distasteful to predators. These tested cases are only a handful, however, and many supposed cases of adaptation are simply assumed.

On the contrary, it is possible that some features of an organism may be retained because they are adaptive for special, limited reasons, even though they may be maladaptive on the whole. The large antlers of an elk or moose, for example, may be effective in sexual selection for mating but could well be maladaptive at all other times of the year. In addition, a species feature that now has one adaptive significant may have been produced as an adaptive to quite different circumstances. For example, lungs probably evolved in adaptation to life in water that sometimes ran low on oxygen. Fish with lungs were then “preadapted” in away that accidentally allowed their descendants to become terrestrial.

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Sex Cell and Their Origins

Sex cells are different from other body cells. A sex cell has just one function to perform and that is to pass on, by union with a cell from the partner in marriage, the spark of life from this generation to the next.

Male sex cells are produced in the testes-a man’s essential sex organs. Female sex cells are produced in the ovaries. Early in the life history of a human being-even before the time of his own birth-a certain bit of living tissue was set aside, as it were, for purposes of later parenthood.

In a boy, this highly specialized tissue developed into the testes. Even during childhood immature male sex cells are present in the testes. But only as a boy reaches early manhood do, these sex cells become mature enough to enable him to be a father. Beginning at this time (by the early teens) a young man’s testes produce enormous numbers of sex cells. The testes remain active in producing sex cells throughout the years of a man’s physical prime. Of course, most of them perish, for it takes only one male sex cell to unite with a female sex cell at the time of conception to initiate the life of a child.

In the case of a girl, the life perpetuating tissue is built into the ovaries-small glands located, one on the right and one on the left, within the lower abdominal cavity. The immature female sex cells contained in the ovaries lie dormant throughout the years of a girl’s childhood.

As a girl arrives at young womanhood, changes occur each month in the ovaries. Although there are thousands of immature sex cells, only a few respond each month to the influence of the hormones and, as they respond, grow rapidly. These few seem to compete with each other for a chance to arrive at full maturity and be liberated from the ovary. Usually only one out of the several is released during a particular month.

This one female sex cell, as it reaches full maturity, is located within a blister-like structure on the ovary’s surface. At just the right time this breaks open and the sex cell it contains escapes into the abdominal cavity. Remarkably, it is not lost here but is guided into the open end of the oviduct, a tube leading to the uterus.

The female sex cell is propelled through the oviduct toward the uterus by a multitude of microscopic fingers which have the effect of sweeping the sex cell on its way.

While the female sex cell is passing through the oviduct, it becomes available for union with a male sex cell if sexual intercourse has occurred at this time. If no male sex cells are available, the female cell passes on into the uterus and soon perishes. If it does unite with a male sex cell so that a new life is begun. The combined cell makes its way slowly through the remainder of the oviduct and lodges in the uterus where, in nine month, it develops into a full-term baby.

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The Conception of Life

Five-year-old Andra questioned her mother: “Mom, why did you tell the neighbor lady that baby brother Yogy looks like Pap? Pap, wasn’t even here when Yogy was born. He was on a trip to Bukit Tinggi. Remember?”

Obviously Andra was not yet acquainted with the facts of life. The actual beginning of a human life dates back nine months before birth to the occasion when the father and mother shared in making available the sex cells which, as they combined, provided the biological elements from which a new human life is formed.

In terms of the inherited traits parents pass on their children, the father’s influence is as great as the mother’s; each parent has contributed one sex cell from which the entire body of the child develops. From conception onward to the time of birth the mother’s relationship to the child is more important than that of the father, for it is within her body that the child develops. But in terms of parenthood, embracing the responsibility for bringing the child into existence, a child’s father and mother are involved equally.

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The Beginning of Life

The passing on of life from parent to child is one of the greatest privileges that come to men and women. Seeing one’s children grow and develop is one of life’s great satisfactions. A parent delights in the observation that his child is like himself.

With the privilege of parenthood comes responsibility for the child’s welfare. A parent’s care of the child does much to determine how strong and healthy the child will be. A parent’s influence on the child, both by word and example, does much to determine what the child’s intellect and character will be.

This passing on of life from one generation to the next has physical components as well as philosophical. In this section we are concerned mostly with the physical components of parenthood. We shall begin our study of the human body and human relationships with conception, the beginning of life, which occurs nine months before the birth of a baby.

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