Higher level of assessment and knowledge. Analysis with tehnology data.
Structure and Functions of Nucleic Acids : DNA RNA Proteins,
Nucleotides. Summary of Cell Parts and Function. Definition of Diffusion
, Osmosis, Mediated Transport Mechanism, Facilitative Diffusion and
Active transport. Comparison of Membrane Transport Mechanisms.
Today, scientists obtain the absolute dates of rocks using
radiometric methods. These radiometric methods use radioactive minerals
in rocks as geological clocks. The principle involved here is that the
atoms of some chemical elements have different forms, called isotopes.
These isotopes break down over time in a process scientists call
radioactive decay.
RADIOACTIVE DECAY
CALCULATING RADIOACTIVE DECAY
ASSUMPTIONS MADE BY SCIENTISTS
Assumption 1: Conditions at Time Zero
With regard to the volcanic lavas
that erupted, flowed, and cooled to form rocks in the unobserved past,
evolutionary geologists simply assume that none of the daughter argon-40
atoms was in the lava rocks.
For the other radioactive “clocks,” it is assumed that
by analyzing multiple samples of a rock body, or unit, today it is
possible to determine how much of the daughter isotopes (lead,
strontium, or neodymium) were present when the rock formed.
Yet lava flows that have occurred in the present have
been tested soon after they erupted, and they invariably contained much
more argon-40 than expected.
For example, when a sample of the lava in the Mt. St. Helens crater
(that had been observed to form and cool in 1986) (Figure 1) was
analyzed in 1996, it contained so much argon-40 that it had a calculated
“age” of 350,000 years!
Similarly, lava flows on the sides of Mt. Ngauruhoe, New Zealand, known to be less than 50 years old, yielded “ages” of up to 3.5 million years.
So
it is logical to conclude that if recent lava flows of known age yield
incorrect old potassium-argon ages due to the extra argon-40 that they
inherited from the erupting volcanoes, then ancient lava flows of
unknown ages could likewise have inherited extra argon-40 and yield
excessively old ages.
There are similar problems with the other radioactive “clocks.” For example, consider the dating of Grand Canyon’s basalts
(rocks formed by lava cooling at the earth’s surface). We find places
on the North Rim where volcanoes erupted after the Canyon was formed,
sending lavas cascading over the walls and down into the Canyon.
Obviously, these eruptions took place very recently,
after the Canyon’s layers were deposited. These basalts yield ages of
up to 1 million years based on the amounts of potassium and argon
isotopes in the rocks. But when we date the rocks using the rubidium and
strontium isotopes, we get an age of 1.143 billion years. This is the
same age that we get for the basalt layers deep below the walls of the
eastern Grand Canyon.
How could both lavas—one at the top and one at the
bottom of the Canyon—be the same age based on these parent and daughter
isotopes? One solution is that both the recent and early lava flows
inherited the same rubidium-strontium chemistry—not age—from the same
source, deep in the earth’s upper mantle. This source already had both
rubidium and strontium.
To make matters even worse for the claimed reliability
of these radiometric dating methods, these same basalts that flowed
from the top of the Canyon yield a samarium-neodymium age of about 916
million years,5 and a uranium-lead age of about 2.6 billion years!
According to the evolutionary theory, homologous features are
programmed by similar genes. Gene sequence similarity would indicate
common ancestry since such similarities are unlikely to originate
independently through random mutations. If the bones of the human arm
evolved from the same precursors as the wing of a bat and the hoof of a
horse as evolution teaches, then we should be able to trace these
alleged homologies to the DNA that codes for them. Some geneticists
thought this knowledge would allow them to find the chemical formula
needed to produce an arm, leg, or other structure. But once biologists
acquired a greater understanding of genetics, they found that what are
labeled as homologous structures in different species often are produced
by quite different genes.
Homology predicted that features produced by similar
genetic sequences are phylogenetically homologous. There are now so many
exceptions to this prediction that the concept of genetic homology
cannot now be said to be a rule, but the exception. The classic example
is mutations in certain homeotic genes41 which can cause wholesale
changes in morphology such as producing two pairs of wings instead of
the normal single pair, or replacing a fly’ antenna with a leg (or can
even cause eyes to develop on the fly’ leg). Genes that produce results
similar to the homeotic genes for flies’ wings have been found in most
other animal kinds, including mammals and humans.
In another example, the gene that controls mouse eye
colour also happens to control the mouse’ physical size; but the gene
that controls the fruit fly’ eye colour controls not the fruit fly’
size, but female sex organ morphology.43 Although mice and flies share a
similar gene (called eyeless) which functions to control their eye
development, the fly’ multifaceted eye is profoundly different from a
mouse’ mammal eye. In both the fly Antennapedia and mouse eyeless,
similar homeotic genes control development of structures which are not
homologous by either the post-Darwinian phylogenetic or the classical
morphological definition.
The finding that similar genes regulate such radically
different structures strongly argues against the concept of homology.
So many genes used in higher organisms have multiple effects that Ernst
Mayr once suggested that genes which control only a single
characteristic are rare or nonexistent. The finding that a consistent
one-gene/one-characteristic correspondence does not exist has been a
major set back to the Darwinian interpretation of homology. Because
evolutionary biologists have failed to provide a biological basis for
their homology research findings, Roth concluded ‘that the title of de
Beer’ 1971 essay|--|Homology, an unsolved problem|--|remains an accurate
description … . The relationships between processes at genetic,
developmental, gross phenotypic and evolutionary levels remain a black
box’.45 Research at the molecular level has failed to demonstrate the
expected correspondence between gene product changes and the organismal
changes predicted by evolution.
Evolution by DNA mutations ‘is largely uncoupled from morphological
evolution’.46 An example of this is the large morphological
dissimilarity that exists between humans and chimpanzees despite a high
similarity in their DNA. In short we now know:
“ … in general the homology of structures such as
organs or modules cannot be ascribed to inheritance of homologous genes
or sets of genes. Consequently, organ homology cannot be reduced to gene
homology. Van Valen recognizes this too and therefore suggests, as an
alternative, to reduce homology to a continuity of [developmental]
information. Information is not the same as genotypic nucleic acid. But
what it is exactly, and how it is continuous, is still an unsolved
problem.”
Evolutionary Naturalism or an Intelligent Designer?