Transcript The Earth`s History

5/18/15
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2. Review of Calendar
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and Go over tomorrow!
4. New Notes!
The Earth’s History
How long has the Earth
existed?
4.6 Billion Years
Rocks provide clues to the Earth’s
History.
Relative Age – older or younger
Uniformitarianism
A principle that assumes that forces that acted
upon the Earth’s crust in the past are the same
as those forces that are active today.
“The present is the key to the past.”
The Law of Superposition
The rock layers on the bottom of an
undisturbed rock exposure
oldest.
are usually the ______________
The rock layer is always
older
__________
than the process
that changed it.
younger
Intrusions are _____________
than the rock they move
through.
younger
Extrusions are _________
than
the rock that they move through.
Can U tell the sequence of events?
Fossils are naturally
________
preserved remains or
impressions of once living
things.
Nautiloid
Nautiloids are a large and
diverse group of marine
cephalopods (Mollusca)
belonging to the subclass
Nautiloidea that began in the
Late Cambrian and are
represented today by the living
Nautilus. Nautiloids flourished
during the early Paleozoic era,
where they constituted the main
predatory animals, and
developed an extraordinary
diversity of shell shapes and
forms. Some 2,500 species of
fossil nautiloids are known, but
only a handful of species survive
to the present day.
Trilobite
Trilobites ( /ˈtraɪləbaɪt/, /ˈtrɪləbaɪt/; meaning
"three lobes") are a well-known fossil group
of extinct marine arthropods that form the
class Trilobita. The first appearance of
trilobites in the fossil record defines the
base of the Atdabanian stage of the Early
Cambrian period (526 million years ago),
and they flourished throughout the lower
Paleozoic era before beginning a drawnout decline to extinction when, during the
Devonian, almost all trilobite orders, with
the sole exception of Proetida, died out.
Trilobites finally disappeared in the mass
extinction at the end of the Permian about
250 million years ago. The trilobites were
among the most successful of all early
animals, roaming the oceans for over 270
million years.[2]
Fossil sponge
Sponges are animals of the phylum Porifera ( /pɒˈrɪfərə/; meaning "pore
bearer").They are multicellular organisms which have bodies full of pores and
channels allowing water to circulate through them, consisting of jelly-like
mesohyl sandwiched between two thin layers of cells. Sponges have
unspecialized cells that can transform into other types and which often
migrate between the main cell layers and the mesohyl in the process.
Sponges do not have nervous, digestive or circulatory systems. Instead,
most rely on maintaining a constant water flow through their bodies to obtain
food, oxygen and remove wastes.
Coprolite
A coprolite is fossilized feces. Coprolites
are classified as trace fossils as opposed
to body fossils, as they give evidence for
the animal's behaviour (in this case, diet)
rather than morphology. The name is
derived from the Greek words κοπρος /
kopros meaning 'dung' and λιθος / lithos
meaning 'stone'.
What type of rock are fossils
found in?
Sedimentary
Geologic time is
divided into
time units
based upon the
fossil
________
record.
Correlation – matching up the rock
strata
Index fossils :
Have existed for a short period of time
Are found over a wide geographic area
Are easily recognizable
Heterotroph Hypothesis
Natural
selection
___________
individuals that
have traits that
better suit them to
their environment
would survive
longer and produce
more offspring.
Human Evolution
_______________
are buried
Unconformities
erosional surfaces.
Absolute age
__________________
is the
age of a rock unit, fossil or an
event expressed in units of time
(the exact age)
Radioactive Dating
The regular rate of nuclear
decay (half-life) of a radioactive
isotope allows us to find the
absolute age of rocks and
fossils.
Radioactive dating is a way to
determine the absolute age by
comparing the amounts of
isotope
_____________
to the amounts
decay
of _________
product.
Isotopes
___________
are
forms of an
element that
have more
neutrons in the
nucleus than
normal.
Draw this data table in the
empty space of your note
packet.