Friday, September 30, 2011
Honey Bee
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| Honey bee in the field |
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| Honey Bee From Egg to Adult |
In addition to the familiar European honey bee, there are six other recognized species of honey bees, including the Indian honey bee, Koschevnikov’s honey bee, the dwarf honey bee, the andreniform dwarf honey bee, the giant honey bee, and the mountain giant honey bee. The European, the Indian, and to some extent the dwarf honey bees are the species that have been domesticated, although the European honey bee is by far the most widespread domesticated bee and the only species kept in North America. There are many races of the European honey bee. The ones most popular in modern beekeeping are the Italian, Carniolan, and Caucasian. Most honey bees used in hives today are mixtures of these and sometimes other races. Africanized honey bees, also known as killer bees, are a hybrid of African and European races naturalized in the western hemisphere.
III. SOCIAL ORGANIZATION
The honey bee is a social insect that can survive only as a member of a community, or colony. The colony inhabits an enclosed cavity, its nest. Domesticated colonies are kept in artificial containers, usually wooden boxes, known as hives.
Castes
The honey bee community consists of three structurally different forms—the queen (reproductive female), the drone (male), and the worker (nonreproductive female). These castes are associated with different functions in the colony; each caste possesses its own special instincts geared to the needs of the colony.
| 1. | The Queen |
The queen is the only sexually productive
female in the colony and thus is the mother of all drones, workers, and future
queens. Her capacity for laying eggs is outstanding; her daily output often
exceeds 1500 eggs, the weight of which is equivalent to that of her own
body.
Anatomically, the queen is strikingly
different from the drones and workers. Her body is long, with a much larger
abdomen than a worker bee. Her mandibles, or jaws, contain sharp cutting teeth,
whereas her offspring have toothless jaws. The queen has a curved, smooth
stinger that she can use repeatedly without endangering her own life. In
contrast, the worker honey bees are armed with straight, barbed stingers, so
that when a worker stings, the barbed, needlesharp organ remains firmly anchored
in the flesh of its victim. In trying to withdraw the stinger, the bee tears its
internal organs and dies shortly thereafter. The queen bee lacks the working
tools possessed by worker bees, such as pollen baskets, beeswax-secreting
glands, and a well-developed honey sac. Her larval food consists almost entirely
of a secretion called royal jelly that is produced by worker bees. The average
lifespan of the queen is one to three years.
Workers bee
Worker bees are the most numerous members
of the colony. A healthy colony may contain 80,000 worker bees or more at its
peak growth in early summer. Workers build and maintain the nest and care for
the brood. They build the nest from wax secreted from glands in their abdomen.
The hexagonal cells, or compartments, constructed by the workers are arranged in
a latticework known as the comb. The cells of the comb provide the
internal structure of the nest and are used for storage of the developing young
bees and all the provisions used by the colony. Comb used for storage of honey
is called honeycomb. Workers leave the hive to gather nectar, pollen, water, and
propolis, a gummy substance used to seal and caulk the exterior of the nest.
They convert the nectar to honey, clean the comb, and feed the larvae, drones,
and the queen. They also ventilate the nest and when necessary, defend the
colony with their stings. Workers do not mate and therefore can not produce
fertile eggs. They occasionally lay infertile eggs, which give rise to
drones.
As with all bees, pollen is the principal
source of protein, fat, minerals, and vitamins, the food elements essential for
the growth and development of larvae of all three castes. Adult bees can subsist
on honey or sugar, a pure carbohydrate diet. Besides gathering and storing food
for all the members of the colony, the workers are responsible for maintaining
the brood at 33.9°C (93°F), the optimum temperature required for hatching the
eggs and rearing the young. When the nest or hive becomes too hot the workers
collectively ventilate it by fanning their wings. During cool weather, they
cluster tightly about the nursery and generate heat. The eggs, which are laid
one per cell, hatch in three days. The larvae are fed royal jelly for at least
two days and then pollen and nectar or honey. Each of the hundreds of larvae in
a nest or hive must be fed many times a day.
For the first three weeks of their adult
lives, the workers confine their labors to building the honeycomb, cleaning and
polishing the cells, feeding the young and the queen, controlling the
temperature, evaporating the water from the nectar until it thickens as honey,
and many other miscellaneous tasks. At the end of this period, they function as
field bees and defenders of the colony. The workers that develop early in the
season live extremely busy lives, which, from egg to death, last about six
weeks. Worker bees reared late in the fall usually live until spring, since they
have little to do in the winter except eat and keep warm. Unlike other species
of bees, honey bees do not hibernate; the colony survives the winter as a group
of active adult bees.
| 3. | The Drone Bee |
Drones are male honey bees. They are
stingless, defenseless, and unable to feed themselves—they are fed by worker
bees. Drones have no pollen baskets or wax glands and cannot secrete royal
jelly. Their one function is to mate with new queens. After mating, which always
takes place on the wing in the open air, a drone dies immediately. Early
investigators of the mating habits of the honey bee concluded that a queen mates
only once in her life. Recent scientific studies, however, have established that
she usually mates with six or more drones in the course of a few days. The
motile sperm of the drones find their way into a small, saclike organ, called
the spermatheca, in the queen’s abdomen. The sperm remain viable in this sac
throughout the life of the queen.
Drones are prevalent in colonies of bees
in the spring and summer months. As fall approaches, they are driven out of the
nests or hives by the workers and left to perish.
Thursday, September 29, 2011
Human Nutrition
Human Nutrition, study of how food affects the
health and survival of the human body. Human beings require food to
grow, reproduce, and maintain good health. Without
food, our bodies could not stay warm, build or repair tissue, or
maintain a heartbeat. Eating the right foods can help us avoid certain
diseases or recover faster when illness occurs. These and other
important functions are fueled by chemical substances in our food called
nutrients. Nutrients are classified as carbohydrates,
proteins, fats, vitamins, minerals, and
water.When we eat a meal, nutrients are released from food through digestion.
Digestion begins in the mouth by the action of chewing and the chemical activity
of saliva, a watery fluid that contains enzymes, certain proteins
that help break down food. Further digestion occurs as food travels through the
stomach and the small intestine, where digestive
enzymes and acids liquefy food and muscle contractions push it along the
digestive tract. Nutrients are absorbed from the inside of the small intestine
into the bloodstream and carried to the sites in the body where they are needed.
At these sites, several chemical reactions occur that ensure the
growth and function of body tissues. The parts of foods that are not absorbed
continue to move down the intestinal tract and are eliminated from the body as
feces.Once digested, carbohydrates, proteins, and fats provide the body with the
energy it needs to maintain its many functions. Scientists measure
this energy in kilocalories, the amount of energy needed to raise 1 kilogram of
water 1 degree Celsius. In nutrition discussions, scientists use the term
calorie instead of kilocalorie as the standard unit of measure in
nutrition.
ESSENTIAL NUTRIENTS
ESSENTIAL NUTRIENTS
Nutrients are classified as essential or
nonessential. Nonessential nutrients are manufactured in the body and do not
need to be obtained from food. Examples include cholesterol, a
fatlike substance present in all animal cells. Essential nutrients
must be obtained from food sources, because the body either does not produce
them or produces them in amounts too small to maintain growth and health.
Essential nutrients include water, carbohydrates, proteins, fats, vitamins, and
minerals.
An individual needs varying amounts of each
essential nutrient, depending upon such factors as gender and age. Specific
health conditions, such as pregnancy, breast-feeding,
illness, or drug use, make unusual demands on the body and increase its need for
nutrients. Dietary guidelines, which take many of these factors into account,
provide general guidance in meeting daily nutritional needs.
| WATER |
If the importance of a nutrient is judged
by how long we can do without it, water ranks as the most
important. A person can survive only eight to ten days without water, whereas it
takes weeks or even months to die from a lack of food. Water circulates through
our blood and lymphatic system, transporting
oxygen and nutrients to cells and removing wastes through
urine and sweat. Water also maintains the natural balance between
dissolved salts and water inside and outside of cells. Our
joints and soft tissues depend on the cushioning that water
provides for them. While water has no caloric value and therefore is not an
energy source, without it in our diets we could not digest or absorb the foods
we eat or eliminate the body’s digestive waste.
The human body is 65 percent water, and it
takes an average of eight to ten cups to replenish the water our bodies lose
each day. How much water a person needs depends largely on the volume of urine
and sweat lost daily, and water needs are increased if a person suffers from
diarrhea or vomiting or undergoes heavy physical
exercise. Water is replenished by drinking liquids, preferably those without
caffeine or alcohol, both of which increase the output
of urine and thus dehydrate the body. Many foods are also a good source of
water—fruits and vegetables, for instance, are 80 to
95 percent water; meats are made up of 50 percent water; and
grains, such as oats and rice, can have
as much as 35 percent water.
Carbohydrates
Carbohydrates are the human
body’s key source of energy, providing 4 calories of energy per
gram. When carbohydrates are broken down by the body, the sugar
glucose is produced; glucose is critical to help maintain tissue
protein, metabolize fat, and fuel the central nervous system.
Glucose is absorbed into the bloodstream
through the intestinal wall. Some of this glucose goes straight to work in our
brain cells and red blood cells, while the rest makes its way to
the liver and muscles, where it is stored as
glycogen (animal starch), and to fat cells, where it is stored as fat.
Glycogen is the body’s auxiliary energy source, tapped and converted back into
glucose when we need more energy. Although stored fat can also serve as a backup
source of energy, it is never converted into glucose. Fructose and
galactose, other sugar products resulting from the breakdown of carbohydrates,
go straight to the liver, where they are converted into glucose.
Starches and sugars are the major
carbohydrates. Common starch foods include whole-grain breads and cereals,
pasta, corn, beans, peas, and potatoes. Naturally occurring sugars are found in
fruits and many vegetables; milk products; and honey, maple sugar, and sugar
cane. Foods that contain starches and naturally occurring sugars are referred to
as complex carbohydrates, because their molecular complexity requires our bodies
to break them down into a simpler form to obtain the much-needed fuel, glucose.
Our bodies digest and absorb complex carbohydrates at a rate that helps maintain
the healthful levels of glucose already in the blood.
Wednesday, September 28, 2011
Common Chemistry Equations
Density:
Charles’s Law:
Ideal Gas Equation:
Molarity:
Molarity equation:
Molality:
pH:
CAT
Cat, small, mainly carnivorous animal, Felis silvestris catus, member of the family Felidae, popular as a household pet, and valuable for killing mice and rats. Like other members of the cat family, the domestic cat has retractile claws; keen hearing and smell; remarkable night vision; and a compact, muscular, and highly supple body. Cats possess excellent memory and exhibit considerable aptitude for learning by observation and experience. The natural life span of a domestic cat is about 15 years. There are an estimated 600 million house cats in the world.
ORIGIN OF SPECIES
Debate has surrounded the origin of the domestic cat. A common theory held that cats were first domesticated by ancient Egyptians perhaps as early as 2500 bc from the African or Near Eastern wildcat Felis silvestris libyca, also called the Caffre cat. Crusaders then transported the cat to Europe, where it interbred with the indigenous smaller wildcats Felis silvestris silvestris. The idea that domestic cats in different parts of the world had originated from, or interbred with, populations of local wildcats and other small cat species was proposed by a number of experts. For example, the longhaired breeds of domestic cats were said to come from the Asian Pallas’s cat, Felis manul.
ORIGIN OF SPECIES
Debate has surrounded the origin of the domestic cat. A common theory held that cats were first domesticated by ancient Egyptians perhaps as early as 2500 bc from the African or Near Eastern wildcat Felis silvestris libyca, also called the Caffre cat. Crusaders then transported the cat to Europe, where it interbred with the indigenous smaller wildcats Felis silvestris silvestris. The idea that domestic cats in different parts of the world had originated from, or interbred with, populations of local wildcats and other small cat species was proposed by a number of experts. For example, the longhaired breeds of domestic cats were said to come from the Asian Pallas’s cat, Felis manul.
However, a study published in 2007 compared
the mitochondrial DNA of domestic cats and wildcats
and concluded that the domestic cat derives only from Felis silvestris
libyca. Members of this particular subspecies of wildcat were domesticated
in the Middle East, likely around the time that farming villages first developed
in the Fertile Crescent region between 10,000 and 12,000 years ago.
Wildcats probably began associating with human settlements to prey on the
rodents and other pests attracted by stored grains and cereals. Some of the
wildcats then gave up their more aggressive wild behaviors to adapt to life with
people.
The DNA study indicates that at least five
individual female cats from the Middle East served as founders for all the
domestic cats that were later carried around the world by humans. This new DNA
evidence appears to contradict theories that domestic cats carry genes that come
from other types of small cats and from wildcats found in different parts of the
world. Some interbreeding between domestic cats and local wildcats probably took
place, however. Over the centuries, cats have remained virtually the same in
size, weighing about 3.6 kg (about 8 lb) when full-grown, and have preserved
their instinct for solitary hunting.
Wednesday, September 21, 2011
Heliophysics
We live in the extended atmosphere of an active star. While sunlight enables and sustains life, the Sun's variability produces streams of high energy particles and radiation that can harm life or alter its evolution.
Under the protective shield of a magnetic field and atmosphere, the Earth is an island in the Universe where life has developed and flourished. The origins and fate of life on Earth are intimately connected to the way the Earth responds to the Sun's variations.
Understanding the Sun, Heliosphere, and Planetary Environments as a single connected system is the goal of the Science Mission Directorate's Heliophysics Research Program. In addition to solar processes, our domain of study includes the interaction of solar plasma and radiation with Earth, the other planets, and the Galaxy. By analyzing the connections between the Sun, solar wind, planetary space environments, and our place in the Galaxy, we are uncovering the fundamental physical processes that occur throughout the Universe. Understanding the connections between the Sun and its planets will allow us to predict the impacts of solar variability on humans, technological systems, and even the presence of life itself.
We have already discovered ways to peer into the internal workings of the Sun and understand how the Earth's magnetosphere responds to solar activity. Our challenge now is to explore the full system of complex interactions that characterize the relationship of the Sun with the solar system. Understanding these connections is especially critical as we contemplate our destiny in the third millennium. Heliophysics is needed to facilitate the accelerated expansion of human experience beyond the confines of our Earthly home. Recent advances in technology allow us, for the first time, to realistically contemplate voyages beyond the solar system.
There are three primary objectives that define the multi-decadal studies needed:
- To understand the changing flow of energy and matter throughout the Sun, Heliosphere, and Planetary Environments.
- To explore the fundamental physical processes of space plasma systems.
- To define the origins and societal impacts of variability in the Earth-Sun System.
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