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Evolution/fossils And Evolution.


Can you please Explain why the black variety of the peppered moth became more common in the industrial revolution.

Suggest how the effects of the tornado in Canada could have affected the characteristics of sparrows in future generations.

Explain how fossils provide evidence for evolution.

List three possible places in which life on Earth may have begun.

Peppered moth.... This partcular moth, in England, (I'm American) was common in two varieties.... a rather dark morph, and a rather light morph.  And until the 1740's at the beginning of the Industrial Revolution in England, i.e., before the very extensive burning of coal, the light one was predominant, tho the dark one did show up.  And because the trees were lighter before 1740, a bird could easily see the darker variety, and thus those were spotted first, and eaten first.  

As coal in England became more and more the source of power, the dust settled into the barks of the trees where this moth lived, or at least "roosted", and the bark itself became darker and darker.  Now, being a lighter colored moth had no advantage, so those were then more easily seen  by birds as the trees continued over the decades to get darker and darker.  After 1950. and after the killer fog that took the lives of so many folks in London, rules were passes to control the soot, with scrubbers in the smoke stacks, or in some instances, they were built to emit the smoke higher into the atmosphere.  Since 1950, the trees have been getting lighter and lighter, so we are seeing more and more the lighter morph over the darker morph.  Animals of all sorts change as pressures from the environment change.  This one is a classic example of evolution in action....first from lighter morph to darker morph, and now back to lighter morph. (In deserts with black soils and tan soils, we see the same thing in field mice in the Americas.... lighter ones get to stay alive longer if they live on the light tans of desert soils.  And the darker variety tend to stay alive longer on those volcanic soils that tend to be darker.

Sparrows in tornadoes anywhere....  This is a situation where only the strongest will survive in that area.  Several things happen with the deaths of many sparrows...... the area after the tornado has passed, is now vacant of "native" sparrows, and thus the void is filled with those unaffected by a tornado, living elsewhere.  Stray sparrows see the void, and move in.  If they were somewhat different than the native ones, they would now be the only ones living there.  The same thing happens to rattle snakes in the south west.  Kill a rattle snake, and after his scent is gone -- about two weeks, many move in, so where you had one, there would now be six or seven.

Evidence for evolution. Fossils, first of all, are relatively rare.  Few of them survive the millions of years required to become a fossil. It is interesting that we have so many.

It would be best if you had a look at a catalog from an outfit that makes copies of fossils for museums that may want an Australopithecus, but doesn't have one.  Even you could order any fossil.  Go to, and compare and contrast the skulls of man's nearest relatives..... other apes, and other earlier hominids.  When all we had was fossils this was the only way to prove heredity.  Now with the ability to glean DNA from almost any more or less recent fossil, heredity and closeness of ancestry is easily proven.  You'll like the catalog.  

Beginning life on Planet Earth.

We aren't really sure.  The land has changed places several times after the earth cooled, and oceans formed, and oxygen became available. Pangea  had continents located in different places than Gondwallaland.  The Indian continent crashed into what is now an area south of the Himilayas, and forced those mountains to rise.  We know this because on those mountains are the fossilized remains of ocean dwelling snails, and other mollusks.  We can see that the eastern side of S. America fits nicely into the "neck" of Africa.   Most scientists believe life started with blue-green algae, alive even today...stromatolites. Google them.   But prior to them clumps of RNA seemed to have come together.  It is when they separated, and then reformed each set with other clumps that reproduction began, and one of the definitions of life, is the ability to reproduce.... not to have babies, but to have cells divide and make new cells.  These for sure were not  yet cells. But they were alive.    Apart from looking up stromatolites, Google "The Economist + And Man Made Life."  Two men, Craig Venter and  Hamilton Smith, worked 15 years to make cells that would indeed divide.  And these cells HAD NO PARENT CELL!!!!!!  Read the article.  Hugely interesting.


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Elisabeth DeWald


I've been a public school teacher for 26 years. My major was history, but along the way, picked up minors in math, biology, zoology, and other life sciences. My whole life has been on one side of the desk or the other. Husband and Dad were both MDs so science and medicine was a natural for me. My dad once told me that I knew more medicine than most doctors. I can easily answer almost any life science question, most history questions, and lots of medical questions.


Taught math,history, science, geology, chemistry, biology in a public school setting

None at the present time


Majored in history in college, minored in all those subject mentioned. Masters degree in education. Grad courses, but no degree in religious studies, U of Chicago, Divinity School.

Awards and Honors
Award at my one of my colleges of Best Student, in History as a year end award.

Past/Present Clients
I tutored for two years in math. Math however, if not used daily fades. My area of competency is in honors first year algebra, at this point.

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