Evolution!!!! So..... it's only a theory eh?????
http://www.nap.edu/openbook.php?record_id=5787&page=5
Think, for example, of how people usually use the word "theory." Someone might refer to an idea and then add, "But that's only a theory." Or someone might preface a remark by saying, "My theory is …." In common usage, theory often means "guess" or ''hunch." In science, the word "theory" means something quite different. It refers to an overarching explanation that has been well substantiated. Science has many other powerful theories besides evolution. Cell theory says that all living things are composed of cells. The heliocentric theory says that the earth revolves around the sun rather than vice versa. Such concepts are supported by such abundant observational and experimental evidence that they are no longer
questioned in science.
Sometimes scientists themselves use the word "theory" loosely and apply it to tentative explanations that lack well-established evidence. But it is important to distinguish these casual uses of the word "theory" with its use to describe concepts such as evolution that are supported by overwhelming evidence. Scientists might wish that they had a word other than "theory" to apply to such enduring explanations of the natural world, but the term is too deeply engrained in science to be discarded.
As with all scientific knowledge, a theory can be refined or even replaced by an alternative theory in light of new and compelling evidence.
For example, Chapter 3 describes how the geocentric theory that the sun revolves around the earth was replaced by the heliocentric theory
of the earth's rotation on its axis and revolution around the sun. However, ideas are not referred to as "theories" in science unless they are supported by bodies of evidence that make their subsequent abandonment very unlikely. When a theory is supported by as much evidence as evolution, it is held with a very high degree of confidence.
In science, the word "hypothesis" conveys the tentativeness inherent in the common use of the word "theory." A hypothesis is a testable statement about the natural world. Through experiment and observation, hypotheses can be supported or rejected. As the earliest level of understanding,
hypotheses can be used to construct more complex inferences and explanations. Like "theory," the word "fact" has a different meaning in
science than it does in common usage. A scientific fact is an observation that has been confirmed over and over. However, observations are gathered by our senses, which can never be trusted entirely. Observations also can change with better technologies or with better ways of looking at data. For example, it was held as a scientific fact for many years that human cells have 24 pairs of chromosomes, until improved techniques of microscopy revealed that they actually have 23. Ironically, facts in science often are more susceptible to change than theories—which is one reason why the word "fact" is not much used in science.
Finally, "laws" in science are typically descriptions of how the physical world behaves under certain circumstances. For example, the laws of
motion describe how objects move when subjected to certain forces. These laws can be very useful in supporting hypotheses and theories, but like all elements of science they can be altered with new information and observations.
Think, for example, of how people usually use the word "theory." Someone might refer to an idea and then add, "But that's only a theory." Or someone might preface a remark by saying, "My theory is …." In common usage, theory often means "guess" or ''hunch." In science, the word "theory" means something quite different. It refers to an overarching explanation that has been well substantiated. Science has many other powerful theories besides evolution. Cell theory says that all living things are composed of cells. The heliocentric theory says that the earth revolves around the sun rather than vice versa. Such concepts are supported by such abundant observational and experimental evidence that they are no longer
questioned in science.
Sometimes scientists themselves use the word "theory" loosely and apply it to tentative explanations that lack well-established evidence. But it is important to distinguish these casual uses of the word "theory" with its use to describe concepts such as evolution that are supported by overwhelming evidence. Scientists might wish that they had a word other than "theory" to apply to such enduring explanations of the natural world, but the term is too deeply engrained in science to be discarded.
As with all scientific knowledge, a theory can be refined or even replaced by an alternative theory in light of new and compelling evidence.
For example, Chapter 3 describes how the geocentric theory that the sun revolves around the earth was replaced by the heliocentric theory
of the earth's rotation on its axis and revolution around the sun. However, ideas are not referred to as "theories" in science unless they are supported by bodies of evidence that make their subsequent abandonment very unlikely. When a theory is supported by as much evidence as evolution, it is held with a very high degree of confidence.
In science, the word "hypothesis" conveys the tentativeness inherent in the common use of the word "theory." A hypothesis is a testable statement about the natural world. Through experiment and observation, hypotheses can be supported or rejected. As the earliest level of understanding,
hypotheses can be used to construct more complex inferences and explanations. Like "theory," the word "fact" has a different meaning in
science than it does in common usage. A scientific fact is an observation that has been confirmed over and over. However, observations are gathered by our senses, which can never be trusted entirely. Observations also can change with better technologies or with better ways of looking at data. For example, it was held as a scientific fact for many years that human cells have 24 pairs of chromosomes, until improved techniques of microscopy revealed that they actually have 23. Ironically, facts in science often are more susceptible to change than theories—which is one reason why the word "fact" is not much used in science.
Finally, "laws" in science are typically descriptions of how the physical world behaves under certain circumstances. For example, the laws of
motion describe how objects move when subjected to certain forces. These laws can be very useful in supporting hypotheses and theories, but like all elements of science they can be altered with new information and observations.
Outline the theory of evolution by natural selection
"Evolution consists of changes in the heritable traits of a population of organisms as successive generations replace one another. It is populations of organisms that evolve, not individual organisms."
http://www.nas.edu/evolution/Definitions.html
http://www.nas.edu/evolution/Definitions.html
http://www.nap.edu/openbook.php?record_id=5787&page=2
Solving the Puzzle
The concept of biological evolution addresses both of
these fundamental questions. It accounts for the relatedness among organisms by
explaining that the millions of different species of plants, animals, and
microorganisms that live on earth today are related by descent from common
ancestors—like distant cousins. Organisms in nature typically produce more
offspring than can survive and reproduce given the constraints of food, space,
and other resources in the environment. These offspring often differ from one
another in ways that are heritable—that is, they can pass on the differences
genetically to their own offspring. If competing offspring have traits that are
advantageous in a given environment, they will survive and pass on those traits.
As differences continue to accumulate over generations, populations of organisms
diverge from their ancestors.
This straightforward process, which is a natural consequence
of biologically reproducing organisms competing for limited resources, is
responsible for one of the most magnificent chronicles known to science. Over
billions of years, it has led the earliest organisms on earth to diversify into
all of the plants, animals, and microorganisms that exist today. Though humans,
fish, and bacteria would seem to be so different as to defy comparison, they all
share some of the characteristics of their common ancestors.
Evolution also explains the great diversity of modern
species. Populations of organisms
Solving the Puzzle
The concept of biological evolution addresses both of
these fundamental questions. It accounts for the relatedness among organisms by
explaining that the millions of different species of plants, animals, and
microorganisms that live on earth today are related by descent from common
ancestors—like distant cousins. Organisms in nature typically produce more
offspring than can survive and reproduce given the constraints of food, space,
and other resources in the environment. These offspring often differ from one
another in ways that are heritable—that is, they can pass on the differences
genetically to their own offspring. If competing offspring have traits that are
advantageous in a given environment, they will survive and pass on those traits.
As differences continue to accumulate over generations, populations of organisms
diverge from their ancestors.
This straightforward process, which is a natural consequence
of biologically reproducing organisms competing for limited resources, is
responsible for one of the most magnificent chronicles known to science. Over
billions of years, it has led the earliest organisms on earth to diversify into
all of the plants, animals, and microorganisms that exist today. Though humans,
fish, and bacteria would seem to be so different as to defy comparison, they all
share some of the characteristics of their common ancestors.
Evolution also explains the great diversity of modern
species. Populations of organisms