Reproduction: A-Courting To Nature!
.... the same time he did not forget that all romance - animal and human -
is tied intimately to natural selection. Natural selection brought on the
evolution of males and females during prehistoric epochs when
environmental change was making life difficult for single-sex species such
as bacteria and algae. Generally, these reproduced by splitting into
identical copies of themselves. New generations were thus no better than
old ones at surviving in an altered world. With the emergence of the
sexes, howe .....
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Tiger Subspecies
.... seem to be obsessed with numbers and not
trends. Let me illustrate this with tigers. There are frequently requests as to
the exact number of tigers, or a tiger subspecies left in the world. That tells
you that there are people that care. But there are so little tigers left that
we can not even keep track of them. We should look at the trend that the
population is taking, rather than the number as a slice in time. Just as you
might say of a young member of the Hunt family, that they were very wealth .....
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Solar Energy - The Energy Of The Future?
.... beams of
sunlight are collected in a device called a solar furnace, which acts on
the same principles as a large magnifying glass. The solar furnace
takes the sunlight from a large area and by the use of lenses and mirrors
can focus the light into a very small area. Very elaborate solar
furnaces have machines that angle the mirrors and lenses to the sun all
day. This system can provide sizeable amounts of electricity and
create extremely high temperatures of over 6000 degrees Fahrenheit.
Solar energy .....
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Solar Cells
.... increase with the orbital radius.
When atoms bond together to form a solid, the electron energy levels merge
into bands. In electrical conductors, these bands are continuous but in
insulators and semiconductors there is an "energy gap", in which no
electron orbits can exist, between the inner valence band and outer
conduction band [Book 1]. Valence electrons help to bind together the atoms
in a solid by orbiting 2 adjacent nucleii, while conduction electrons,
being less closely bound to the nucleii, are .....
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The Keys To Unlocking Transitions In Water
.... less dense, than salt water,
unless the two are mixed by the tides or winds, the fresh water remains at the
surface, resulting in a salinity gradient. Tides force seawater inland as a
countercurrent and produce a saltwater wedge below the freshwater surface waters
(Bellamy 62).
Estuaries are always in a state of change and hardly ever in a steady
state. The principal energy source are tides, causing estuarine mixing, but wind,
wave motions, and river runoff can also be important locally (Braun 45). Salt
w .....
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Haloes Forecast Storms
.... changes direction, or refracts. The radius of the hale depends on
the amount of change in the direction of the sun's light. Usually this is
22 degrees. Since the sun is 1/2 of a degree across, the radius of the
halo is 44 sun-widths. Occasionally you may see a second halo at 46
degrees from the sun (that is, with a radius of 92 sun-widths). This is
produced by sunlight passing through both the side and bottom of each
crystal. Moonlight will also produce a halo, around the moon, with the
proper la .....
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Turkey Vultures
.... and the nearly extinct California condor-belong to a group of raptors
called New World vultures. Chromosome analysis shows that the New World
vultures are actually more closely related to storks than to the vultures of
Europe, Asia, and Africa.
Turkey vultures are remarkably successful birds. They range everywhere
from parts of Canada and much of the United States to South America. At home in
deserts, prairies and woodlands, they have even settled close to people in a
number of urban and suburban area .....
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How Technology Effects Modern America
.... is clear evidence that the supply of workers in the [unskilled
labor] categories already exceeds the demand for their services,” says L.
Mishel, Research Director of Welfare Reform Network.
In view of these facts, I wonder if these trends are good or bad for
society. “The danger of the information age is that while in the short run
it may be cheaper to replace workers with technology, in the long run it
is potentially self-destructive because there will not be enough
purchasing power to grow the .....
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Twinning In Cattle
.... be well
educated on how to handle twinning, in order for it to be successful for them.
Many agencies see twinning as an economic move upward. The American
Breeder Service has made efforts to produce semen as well as embryos with high
predicted breeding values available to producers. They have been recorded based
on twinning probabilities and ovulation rates. A large amount of work on
twinning has also been done by the Meat and Animal Research Center. Since the
early eighties, they have located cattle wi .....
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Turner Syndrome
.... may be diagnosed
with one of the following alternative names: 45 - X Syndrome, Bonnevie-
Ulrich Syndrome, Chromosome X, Monosomy X, Morgagni-Turner-Albright
Syndrome, Ovarian Dwarfism, Turner Type, among others.
SYNDROME CHARACTERISTICS A reduced growth in height is the commonest
visible characteristic of the syndrome, (the average adult height is 4
feet 8 inches) and may be the only sign before puberty. Their body
proportions are normal. Girls with this syndrome may have many middle ear
infections dur .....
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Virtual Reality - What It Is And How It Works
.... and entertainment uses among other things.
In order to create this alternate reality, however, you need to find ways
to create the illusion of reality with a piece of machinery known as the
computer. This is done with several computer-user interfaces used to
simulate the senses. Among these, are stereoscopic glasses to make the
simulated world look real, a 3D auditory display to give depth to sound,
sensor lined gloves to simulate tactile feedback, and head-trackers to
follow the orientation of the .....
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Wired Hands - A Brief Look At Robotics
.... while another pours
radioactive chemicals. Robots are ideal workers: they never get bored and
they work around the clock. What's even more important, they're flexible.
By altering its programming you can instruct a robot to take on different
tasks. This is largely what sets robots apart from other machines; try as
you might you can't make your washing machine do the dishes. Although some
critics complain that robots are stealing much-needed jobs away from people,
so far they've been given only the drea .....
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Vertebrate Adaptions For Terrestrial Life
.... present in all of the terrestrial
environment. Terrestrial vertebrates have developed lungs to solve this problem.
Air enters through the nasal passages, or the mouth, passes through the trachea,
then branches off at the two bronchi, and goes through many branching passages
called bronchioles, which end in alveoli. Alveoli are sack-like structures where
the circulatory system meets the respiratory system.
Since terrestrial vertebrates do not live in water, they need to develop
a means of conserving water .....
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UFOs: We Are Not Alone
.... airspeed of 1,700 mph he spotted nine circular aircraft flying in
formation and according to his estimate the aircraft were approximately the size
of a dc-4 airliner ( jackson 4).
This account was the first sighting to ever receive a great deal of
media attention. This sighting gave birth to the phrase "flying saucer" coined
by a reporter named bill begrette. Although not the first ufo sighting in
history, kenneth arnolds account is considered to be the first documented ufo
sighting. The following day .....
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Hypotheses Of The Effects Of Wolf Predation
.... preying on herbivores. Predation can have many possible effects on
the interrelations of populations. To draw any correlations between the effects
of these predator-prey interactions requires studies of a long duration, and
statistical analysis of large data sets representative of the populations as a
whole. Predation could limit the prey distribution and decrease abundance. Such
limitation may be desirable in the case of pest species, or undesirable to some
individuals as with game animals or endang .....
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