Earth Flashcards

the same phenomenon is sought again, preferably by independent

investigation, and the interpretation given it confirmed or discarded by means of novel

analysis and experimentation.

scientists attempt to abstract the information into the form that is simplest,

most easily recalled, and most esthetically pleasing--the combination called elegance--

while yielding the largest amount of information with the least amount of effort.

a parsimonious explanation is the one that

requires the fewest ad hoc assumptions and when two theories are equally good in

explaining a particular set of phenomena, the one that is more parsimonious is favored.

if something can be properly measured, using universally accepted scales,

generalizations about it will be rendered less ambiguous.

the best science stimulates further discovery, often in unpredictable new

directions, whose content confirms or modifies the parent formulation.

there must exist a way in which a scientific concepts (theories) can be

shown to be wrong.

If entirely new facts emerge, entirely

new concepts will likely be needed to accommodate them. This may lead to sudden and

dramatic, changes in concepts

This represented a paradigm shift from the Ptolemaic model of heavens (earth at center of the

1. Religion/Theology--invoke the supernatural, revelation, authority

2. Philosophy--logic from first assumptions (truth, justice, morality)

3. Science--natural processes, observations, order (rational, materialistic, testable)

Applies a SCIENTIFIC (rational, natural) approach to the problem of the age of the earth. If

human history equals earth history, we can reconstruct the earth’s time scale using written

documents.

4004 BC

-Supplement the revealed theology of the Bible.

-Identify the perfection, the order and harmony of nature as evidence for God’s design.

the term “fossil” was applied to anything (including minerals) found in the earth. Those

objects that we today recognize as once living organisms were thought to represent not

natural, but represent supernatural objects placed in the earth by the devil or some other

supernatural being either as symbols of some living objects or as representations of nonliving

things.

fossils are found in rx. How do they get inside rx? Rx were thought to be permanent.

explaining how sedimentary rocks form. Important

breakthrough--rocks are no longer seen as permanent!

as a deist, believes in harmony of the universe, a “designer”, and a purpose. (teleology)

physical universe and the laws that govern it, and these laws then produced what exists and

continue to produce what will come next. In this scheme, God doesn’t need to hang around to

supervise; the laws will take care of everything.

1. The Divine is held to be the first cause of the world.

2. Deism distinguishes the world and the Divine as effect and cause.

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3. “God is apart from the creation which He brought into being, and unconcerned as to the details

of its working. Having made Nature, He allows it to run its own course without

interference on His part.”

4. Deist rely solely on nature, scripture (revealed theology) is of no importance.

--processes are cyclical (time’s cycle), in fact, perfectly so, such that when we go from

the same part of one cycle to the same part of another cycle we cannot tell them apart and

so time is indecipherable, indeterminate:

The lower layers are tilted almost vertically,

and above an intervening layer lie horizontal

layers.

It states that if we are to understand past phenomena, we must accept that there

are certain laws and processes of nature that are time invariant (do not change with time). That

means that we can study those laws and processes today using experiments and observations and

invoke them in the past—“the present is the key to the past”.

Uniformitarianism: “present as the key to the past”+ gradualism

the notion that changes occurred in the past at the same rates as

they do today, and that those changes were cyclical, i.e., they always returned you back to the

same state (ala Hutton).

when rock layers are ordered from bottom to top, particular types (species) of fossils are

found in only one part of stratigraphic column (particular layers)

sequence, the sequence of fossils likewise can be ordered into a TEMPORAL sequence.

One explanation was that the fossils represented organisms that had yet to be discovered by

naturalists: they were living out there somewhere, but had not yet been found. Another

explanation was that fossils represented organisms that were no longer around, i.e., they were

extinct.

1. examines wooly mammoth

2. compares IN DETAIL to modern elephants

3. finds differences between mammoth and modern elephants to be greater than differences

between modern species of elephants, therefore mammoth is a distinct species.

4. the idea something the size of a mammoth is yet be discovered alive, can be rejected, therefore

concludes that mammoth MUST be EXTINCT species.

In order to do the above, Cuvier had to be able to compare IN DETAIL fossils to living

organisms. To do this he had to acquire knowledge of ANATOMY of many types of organisms

(not just human anatomy). He is thus recognized as the founder of Comparative Anatomy.

1. Biology: Uniformity of state CANNOT be correct-->the biological state of the earth has

changed through time. That is, there is a “time’s arrow” in the organic composition of the earth

2. Use fossils for dating rock layers (late 1700’s, early 1800’s) establishment of GEOLOGICAL

TIMES SCALE (early to late 1800’s)

Imagine a giraffe having to reach ever

higher to get food during its life. This continued

reaching would stretch its neck, such that although it

came from parents with a shorter neck, during its life

its neck got a little longer than the neck of its

ancestors

Lamarck argued that the traits modified

through uses and disuse are passed from parent to

offspring and thus a species can undergo change. In

fact, he viewed the extinctions that Cuvier had

demonstrated not as a complete disappearance of a

species, but rather as a transmutation of an ancient

species to a new one

Lamarck’s ideas were well-known but were rejected almost immediately, mainly because there

was no empirical data (observations) to support it. In fact, Lamarck was made fun of by Cuvier

who described him as someone who believed that if you bring “a hen near water it will become a

stork”.

has occurred by branching (different species

share common ancestral species)—

Evolution (what Darwin more descriptively called "Descent with Modification") embodies 2

separable aspects:

A. Change within a lineage (Modification = Anagenesis)

and many of these are endemic.

mainland (but still distinct from each other). The principle applies widely that island

inhabitants are most closely related to the inhabitants of a region from which

underlying structure shared by

different things: topology vs.

function of tetrapod limbs

The

bones are not identical, they have

been modified as a result of

millions of years of evolution. The

degree of similarity in basic

structure is so great, however, that

reflects common ancestry rather

than independent origins.

The early stages of development are the same (or similar) in organisms that are very

different from each other as adults. This is so because the organisms shared a common

ancestor that had those early stages stages. Through the process of descent with

modification, the later stages of development in diverged from each other.

There is usually a difference in form between embryo and adult.

diverged in the adult.

They served a purpose in an ancestor that had a different life habit. They are retained because

they are not “maladaptive” (they do not reduce fitness; they are adaptively neutral) and therefore

they are not eliminated quickly.

he argued it was random)

Some individuals do not survive to reproduce, elimination of individuals is nonrandom

which claimed that the intrinsic rate of

growth of human populations exceeds the rate of growth in food supply and this leads to

competition for those resources. A “balance” is reached, but this can only happen if not all the

offspring reach adulthood.

• Law 2: Populations tends to increase exponentially

Deduction 1: Populations always tend to outrun food supplies

Deduction 2: More offspring born than can survive

Deduction 3: Will always be competition for food (= resources)

Those that survive have some advantage over

those that die, so those advantageous traits will become more frequent in the population than the

disadvantageous traits,

Natural Selection is quite different from mechanisms proposed before, such as Lamackism. In

natural selection, it is not individuals that evolve, but populations.

small, incremental changes between generations. To Darwin, continued, gradual

accumulation of such small changes could lead to large changes over many generations

the mutations are random

Darwin argued that if selective breeding by

humans can produce the huge varieties of dogs and pigeons in just centuries, Natural Selection

operating more slowly but having 1000 to 100000 times more time could lead to the diversity of

organisms.

Theoretically, this blending was a smooth spectrum of infinite possible outcomes like with paint,

where two with still other colors. If this was how heredity worked, new genetic variations would

quickly be diluted out of a population. They could not accumulate as the theory of evolution

required. evolution and natural selection  needed time to prove true (and thats why blending is incorrect) darwins biggest problem

Mendel crossed a

round with a wrinkled seed plant and in

the next generation got plants that

produced round seeds plant. Obviously,

this result was alone enough to refute

When he crossed individuals from the F1

generation with each other (all roundseed

producers), in the subsequent

generation (F2) he got some plants that

produced round seeds and some wrinkled

seeds. The ratio of round to wrinkled

plants was 3 to 1.

1. Dominant vs. recessive traits.

2. Inheritance is particulate (not

blending).

3. Information about characters carried

on genes.

4. Two copies of a “gene” carried for

each trait -- one from each parent

(alleles).

5. Law of segregation: genes segregate

during gamete formation (1/2

gametes carry one allele (gene), 1/2 carry other).

6. Law of independent assortment: genes for different traits are inherited independently of one

another (true for genes carried on different chromosomes).

genetic composition of individual.

appearance of individual.

alternative forms of same gene

organisms whose chromosomes come in pairs.

pairs of chromosomes with same genes in same order.

two homologous chromosomes with the same/different allele.

neck due to stretching).

So why were these ancestors of

the varied Cambrian forms not being recovered?

Darwin’s theory required that the earth be very old—anything shorter than a billion years would

not provide sufficient time for life on earth to evolve from simple beginnings and a single origin

to the complex and diverse life that characterizes the present earth given the mechanism of

natural selection.

can be caused by copying errors (shuffling, duplication) in the genetic material during

cell division, by exposure to ultraviolet or ionizing radiation, chemical mutagens, or viruses.

evolution.

geographically isolation.

This form

speciation which occurs when populations get separated geographically

(allo-other; patry—fatherland)