Download 7th Grade Science: Chapter 6 Lesson 1: The Environment and

7th Grade Science: Chapter 6
Lesson 1: The Environment and Change Over Time
Describe how fossils form.
Mineralization: After an organism dies, its body could be buried under mud,
sand, or other sediments in a stream or river. If minerals in the water replace the
organism’s original material and harden into rock, a fossil forms. Minerals in water
also can filter into the mall spaces of a dead organism’s tissues and become rock
(Petrified wood).
Carbonization: A fossil forms when a dead organism is compressed over
time and pressure drives off the organism’s liquids and gases, and only the carbon
outline, or film, of the organism remains (Discuss the Biblical flood).
Molds and Casts: The impression of an organism in a rock is called a mold.
Sediments can later fill in a mold and harden to form a cast. A cast is a fossil copy of
an organism in a rock. A single organism can form both a mold and a cast. Molds and
casts show only external features of organisms.
Trace Fossils: A trace fossil is the preserved evidence of the activity of an
organism. The tracks of an organism can fossilize if they are filled with sediment
that hardens (A human track was fossilized inside of a dinosaur track, in Texas).
Original Material: In rare cases, the original tissues of an organism can be
preserved. Animals and even humans have been found preserved in ice and bogs
and insects have been found encased in amber (tree sap). Study Table 1 on Pg. 194195.
Explain how scientists date fossils.
Relative-age Dating: Scientists determine the relative order in which rock
layers were deposited. In an undisturbed rock formation, they “know” that the
bottom layers are oldest and the top layers are youngest. This dating helps scientists
determine the relative order in which species have appeared on Earth over time
(Floods).
Absolut-age Dating: This dating is based on natural radioactive decay and is
therefore considered to be more precise. In radioactive decay, unstable isotopes in
rocks change into stable isotopes over time. Scientists measure the ratio of unstable
isotopes to stable isotopes to find the age of a rock. This ratio is best measured in
igneous rock (lava or magma rock). Most fossils form in sedimentary rock, so
scientists will measure the age of the igneous rock above and below the sedimentary
layer where fossils are found to estimate the age of the fossils within that layer.
*Neither of these methods are accurate, because they use a laboratory tested
equation to calculate the age of something that has been left out in the elements for
a long period of time. Anything that can degrade the chemical and or biological
material within an organism or object will cause it to appear older. Scientists do not
account for these variables when they date rock, fossils, or anything else. Instead
they go to the opposite extreme and over estimate the age. This is another way of
promoting a belief in evolution, because they believe that the more time there is
involved in a scenario, the more likely evolution is to be true. This is because in the
thousands of years of known history, nothing has evolved the way that scientists
teach evolution. They base the fossil timeline and the age of the Earth on this over
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estimation of age and thus we have an Earth that is supposedly about 4 billion years
old. (Talk about the creation of Adam and the comparable age of the Earth.)
Explain how scientists believe fossils are evidence of biological evolution.
The fossil record is made up of all the fossils ever discovered on Earth. By
examining all of these fossils and already having a believe that the Theory of
Evolution is true, scientists believe that the fossil record shows that all living things
on Earth are related and that they change over time. They believe that based on how
fossil looks, they can closely recreate what a fossilized organism looked like.
Scientists believe that the fossil record only represents a small fraction of all the
organisms that ever lived on Earth.
*In reality, the fossil record can only show us what organisms were once
living. It cannot tell us if any of these organisms were once related or are related in
any way to the organisms that are alive today. It cannot even show us if organisms
evolved or changed over time to become the organisms that are alive today. When
we take what we already believe, even it has not and cannot be proven, and use it as
evidence or proof that something is a certain way, it is called circular logic (Talk
about the first dinosaur fossil that was found).
Lesson 2: Theory of Evolution by Natural Selection
Describe the history concerning Charles Darwin.
Charles Darwin was a scientist that studied birds and how they evolve.
Darwin was an English naturalist who, in the mid-1800’s, developed a theory of how
evolution works. A naturalist is a person who studies plants and animals by
observing them. Darwin spent many years observing plants and animals in their
natural habitats before developing his theory. A theory, according to the scientific
definition, is an explanation of the natural world that is well supported by evidence
(Evidence can be misinterpreted). Darwin was not the first to develop a theory of
evolution, but his theory is the one supposedly best supported by evidence today.
Darwin served as a naturalist on the HMS Beagle, a survey ship of the British navy.
During his voyage around the world, he observed and collected many plants and
animals. He was especially interested in the organisms he saw on the Galapagos
Islands. He saw that each island had a slightly different environment. Some were
dry, some were more humid, and others had mixed environments. Tortoises looked
different on each island. He also noticed that there was a variety of mockingbirds
and finches on the islands. He later determined that these differences made all of
these organisms different species of tortoises, mockingbirds, and finches. He
theorized that the characteristic differences between each species had a direct
relationship with the type of environment that it lived in. He also theorized that a
storm had brought a common ancestor of tortoise to one of the islands and the
tortoises evolved as they moved to different environments. A variation is a slight
difference in an inherited trait of individual members of a species. Variations arise
naturally in populations. They occur in the offspring as a result of sexual
reproduction. Variations are also caused by mutations, or changes in genes.
Mutations can lead to changes in phenotype or how a gene is expressed. These can
be passed on to future generations.
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Explain, according to scientist, how Darwin’s theory of evolution by natural
selection explains how species change over time.
Darwin did not know about genes. He did suspect that variations were the
key to the puzzle of how populations of tortoises and other organisms evolve.
Darwin developed the theory of evolution by natural selection based on his
observation of the different types of tortoises on the islands. Natural selection is the
process by which populations of organisms with variations that help them survive
in their environments live longer, compete better, and reproduce more than those
that do not have the variations. This explains how populations change as their
environments change. *It is important to note that organisms do not change from
one thing into another. A species is simply an individual with a different
characteristic. The theory of “macroevolution” is completely false.
Explain, according to scientists, how adaptations are evidence of natural
selection.
The accumulation of many similar variations, due to natural selection, can
lead to an adaptation. An adaptation is an inherited trait that increases an
organism’s chance of surviving and reproducing in its environment. Thus, if a
variation helps an organism survive in its environment, it increases in the
population through natural selection. This can be through camouflage, mimicry, long
necks, long and short beaks, etc. Artificial selection can be demonstrated in selective
breeding pets. *All of the “adaptations” that are expressed in any organism were
already present in the genes of the organisms that God created in the beginning.
Different organisms will express the traits that help them survive. They do not
create new genes or have gene mutations simply because the environment in which
they live. The environment can encourage the expression of specific genes due to the
simple fact that the organisms that best fit within that particular environment will
be most likely to survive. This is also not “survival of the fittest,” because that theory
teaches that a species or an organism will cease to exist by dying out or changing
into something new in order to survive. (Example: If you humans evolved from apes,
then that means apes were unable to survive and would thus disappear from the
Earth. However, there are still apes on Earth.)
Lesson 3: Biological Evidence of Evolution
Recall, according to scientist, the evidence from living species that supports
the theory that species descended from other species over time.
Scientists believe that studying comparative anatomy of similarities and
differences among structures of living species is evidence of common ancestry.
Homologous structures are body parts of organisms that are similar in structure and
position but different in function. The fact that a human arm, a cat forearm, a frog
leg, and bats and birds wings all look alike causes scientists to believe that they all
have a common ancestor. They say that the more similar two structures are to each
other, the more likely it is that the species have evolved from a recent common
ancestor. They in turn say that if two organisms have structures that are similar in
function, but different in structure then they are not related (a bird and a fly). This
actually points more to a common creator than a common ancestor (God compared
to an artist). They also say that vestigial structures are evidence of common
ancestry. These are body parts that have lost their original function through
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evolution. There is what appears to be a pelvis in dolphins and even in snakes that
supposedly were once a pelvis in a common ancestor, but now are not longer
needed. *In pythons, this so called vestigial structure actually has a completely
different function and is used in mating. Evidence that vestigial structures are not
what scientists claim them to be is the fact that pelvic bones are attached to other
bones. The bones in pythons and dolphins are not attached to any bones and server
other purposes. One more method is the study of the development of embryos from
fertilization to birth. This is called embryology. Figure 17 on Pg. 216 is supposedly
how they support their evidence. *This picture was originally placed in a scientific
magazine in the 1800’s, by a scientist that lied about his studies. He drew the picture
by memory rather that actually drawing them as he examined them. The scientific
community of the day proved his picture to be fact and removed it from all text. At
some point in the 1950’s when the study of evolution became popular in schools,
science textbooks began printing these pictures in their chapters about evolution
and presenting it as fact. No one has publicly refuted this lie to this day and thus
textbooks continue to print these pictures.
Describe, according to scientists, how Earth’s organisms are related.
Scientists claim that fossils, comparative anatomy, and embryology prove the
theory of evolution to be a fact and that all organisms on Earth are related through a
common ancestor. They believe that when genes sequences are compared it
provides strong evidence for evolution. *However, the fact that the number of
chromosomes are different for each different type of organism proves more that
they are not related. The similarities in DNA and the structure and codes of DNA
simply again points more to a common creator. When an organism has a mutation in
the genetic code that gives it more or less chromosomes than normal, the individual
is not able to reproduce and it is often life threatening. A mutated chromosome can
be passed on to the next generation at times, but again it is not beneficial to the
organism. Based on this evidence it is impossible for organisms to mutate into new
organisms by having chromosomes added to or subtracted from its genetic
sequence.
*The major problem with studying animals or life today is that most scientists
already assume that evolution is a fact, even though there is very little proof or
evidence for it. They begin a study assuming the “fact” of evolution and therefore all
results supposedly further prove evolution in their minds. Most science today is
performed with an evolutionary bias, rather than pure science, which allows the
evidence to speak for itself. In other words, scientists will say, “Because of evolution
is true, this (fill in the blank with any pre-conceived notion or idea) must be true, “
regardless of what the evidence says.
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