I thought so. :-)
[my post snipped]
>My real question on this side of things is about the change from one type
>of reprodution to another. ie if a creature was reproducing without any
>need for another creature to be involved, how did it become advantageous to
>need another? And how did it occur that all of the sudden a sex cell with
>only half the needed chromosomes came into being and survived? And did
>another creature happen to have the same problem at the same time, and
>these two mutated half cells bump into each other and form a whole knew
>creature with the genetically inherited trait of making the occasional half
>cell? I don't really understand how this could happen.
>
Due to the shuffling of genes, the phenomenon of cross-over etc. sexual
reproduction can produce a tremendously more genetically varied group of
organisms than can asexual reproduction. Thus when a virus comes along, a
few more of the sexually reproduced organisms have immunity. If everybody
has the same genome then if one individual has no resistance, probably no
one does. Genetic similarity is becoming a concern in the agricultural
community. Many of the wheats, ryes, rices, cows, sheep etc are becoming
genetically impoverished compared with their wild cousins. Because of
this, some professional worriers are becoming worried that an entire crop
could be wiped out quickly by one disease.
>
>>And how something would evolve from
>>>laying eggs in water to laying eggs on land, to not laying eggs at all!
>>
>>Each form of reproduction works in the peculiar environment to aid in the
>>survival of the species.
>
>Lets imagine an amphibian, who lays eggs in the water. How would this beast
>change from laying eggs in the water to laying eggs on land? The structure
>of the egg would have to change, the baby would have to change to be able
>to escape the new type of egg, the babys would have to be able to handle
>the land, and the egg laying process would have to change....
Lets look at what fossils are actually there and what the environment of
the earliest amniotes inhabited. First off, you must remember that fossil
eggs are very rare, even in the Pleistocene. Robert Carroll, Vertebrate
Paleontology and Evolution, 1988 (still a widespread text as I bought it
last year) says that the earliest amniote animals are found in the lower
Pennsylvanian of Nova Scotia (p. 193) It was about 10-12 cm long about the
same size as modern plethodontid salamnders that lay their eggs on land.
(p. 193, 194, 197) These salamanders hatch fully formed from eggs. The
eggs lack a extraembryonic membrane. According to Carroll, this limits
effective exchange of gas and water and limits the size of the egg.
Support against the force of gravity also limits the size of the egg
(imagine taking a chicken egg sans shell and laying it on the ground. It
would squish like a large water balloon laid on the ground.)
Support for this idea comes from the earliest egg found in the fossil
record. It is from the Lower Permian. It lacks a calcareous shell ( p.
198) But because of this lack some have suggested that it is not an egg but
most paleontologists apparently accept it. (Edwin H. Colbert, Evolution of
the Vertebrates, (New York: John Wiley and Sons, 1969), p. 110; George
Gaylord Simpson, Fossils and the History of Life, Scientific American
Books, 1983, p. 86)
Now, what kind of environment did the earliest amphibians live? Along the
moist shores. These are exactly the type of land that modern salamanders
above live and are able to lay their eggs on land. How do we know that they
lived in these humid environments? Because of the other animals they lived
with.
""Logan's 'Division 4', with a thickness of 2,539 feet, is the main
fossiliferous horizon with coal formation, and often abounds in fresh-water
bivalves, air-breathing snails, bivalve crustaceans, tiny worm tubes, and
bones and tracks of Amphibia; even rain-drop impressions are
preserved."~Louis V. Pirrson and Charles Schuchert, Textbook of Geology,
(New York: John Wiley and Sons, 1920), p. 783-784.
The environment is consistent with the presumed development of the egg.
>
>Could all this happen in one go? If not, what kind of changes could bring
>this about?
No, it didnt' happen in one go. Robert Carroll says
"According to Szarski, the first of the extraembryonic membranes to
evolve would have been the allantois. In modern amniotes, it develops as a
bladder to retain water that is otherwise lost from the embryo. Solutes
within the urine render its contents hypertonic relative to fresh water.
If the egg is laid on damp ground, water is drawn into the allantois by
osmosis. In modern reptiles such as many lizards and turtles that have
permeable egg shells, the water content within the egg may more than double
during development because because of absorption into the allantois.
With the development and enlargement of the allantois, the more
superficial layers of tissue that covered the embryo in the primitive state
were forced out from their original position and reflected over the body.
These layers form the chorion, which together with the surface of the
allantois serves for gas exchange. A further membrane, the amnion, forms a
fluid-filled chamber that surrounds the embryo. In order to fertilize eggs
laid on land, internal fertilization probably evolved early in amniote
evolution. Since copulatory organs are absent in the primitive living genus
Sphenodon and have apparently evolved separately in the ancestors of
lizards and crocodiles, they were almost certainly absent in the early
amniotes.
"A permeable membranous shell presumably evolved in conjunction with the
extraembryonic membranes. An object that was presumed to be the oldest
amniote eggs was described from the Lower Permian of Texas, but it lacks a
calcareous shell and the evidence that it is an egg is equivocal." Robert
J. Carroll, Vertebrate Paleontology and Evolution, (New York: W.H. Freeman,
1988), p. 197-198
>
>>>And why do bird have pretty colors? This is attractive to other birds, but
>>>it would also make them obvious to preditors.
>>
>>Not necessarily. Sometimes what we see as pretty colors are not the same
>>frequencies that the eyes of other species see.
>>
>>Wouldn't natural selection
>>>have made animals attracted to each other for qualities like camoflage,
>>>strength and speed, not things like a huge stupid peacock tail that slows
>>>you down?
>>
>>Then why did God create the stupid peacock tail feathers?
>
>
>I believe in a God who likes beauty, thats why we have art, because out
>creator has made beauty and made us to appreciate it. Peacock feathers are
>rad, I think they are heaps beautiful, and I'm sure God made them with that
>in mind.
Could it be that He also made them so that peacocks would be easy prey for
the predators? After all, it doesn't say in Scripture that God created
them for beauty but it does say:
Psalm 104:21 The young lions roar after their prey, and seek their meat
from God.
So I would conclude that your speculation that God made peacock feathers
for beauty is not as plausible as believing that God created them to slow
the peacock down.
>>>
>>>All these things are only secondary of course, and someone probably has
>>>thought of an answer, but I'm not really concerned about how it happened,
>>>the only thing I am concerned about is the fact that every day people are
>>>dying without know about Jesus. I think that stinks.
>>
>>I agree that people dying without Jesus stinks. But so does Christians
>>becoming atheists because other Christians decide that they won't pay any
>>attention to science! And if you aren't concerned with HOW it happened,
>>what are you doing on this list?
>
>You got me there, I think what I meant is I'm not that opinionated yet, I
>don't have enough reason to be dogmatic either way, as there are problems
>with both arguments. I don't know everything about the universe, and I dont
>thing the sum of human knowledge really knows that much either. Science is
>a changing thing, as we discover new stuff, our ideas change. Makes life
>more fun, I think, we will never know everything, so we can have fun trying
>to thing of whats really going on in the universe.
I like the above. You are absolutely correct that we will never know
everything but we do know some things and we must deal with the things that
we do know. God will hold us accountable for both the scriptural light we
are given but also for dealing honestly with the science we do know. He
will not hold us accountable for the science of the 21st or 22nd century
when our children and grand children will know more than we do. By not
dealing with what we do know we do aid in the defection of the
intellectuals from Christianity.
My plea to my fellow christians is to deal with the science of the late
20th century and to cease waiting for the science of tomorrow to pull our
cookies out of the fire. It probably won't.
glenn
Adam, Apes and Anthropology
Foundation, Fall and Flood
& lots of creation/evolution information
http://www.isource.net/~grmorton/dmd.htm