In this chapter there are five sections that cover the basis of paleontology and the studies of fossils.
Section 1: Earth’s Story and Those Who First Listened
Vocabulary :
Uniformitarianism: A principle that states that geologic processes that occurred in the past can be explained by current geologic processes
Catastrophism: A principle that states that geologic changes occurs suddenly
Paleontology: The scientific study of fossils
Section 2: Relative Dating: Which Came First?
Vocabulary:
Relative Dating: Any method of determining whether an event or object is older or younger than other events or objects
Superposition: A principle that states that younger rocks lie above older rocks if the layers have not been disturbed
Geologic column: An arrangement of rock layers in which the oldest rocks are at the bottom
Unconformity: A break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time
Spotlight:
Types of Unconformities:
There is three types of unconformities in geology. These include disconformities,nonconformities,and angular unconformities. Disconformities are the most common and are found when a parallel layer of soil is missing. Also disconformities represent thousands to millions of years of missing time. Nonconformities represent millions ofyears of missing time and are found when a horizontal soil layer is gone. Angular unconformities represent millions of years of missing time and are found when layers that had been tilted or folded.
Section 3: Absolute Dating: A measure of Time
Protium, Deuterium, and Tritium have the same number of Protons(P) but a different number of Neutrons(N)
Absolute dating: Any method of measuring the age of any event or object in years
isotope: An atom that has the same number of protons (or the same atomic number) as other atoms of the same element do but that has a different number of neutrons (and thus a different atomic mass)
Radioactive decay: The process in wich a radioactive isotope tends to break down into a stable isotope of the same element or another element
Radiometric dating: A method of determining the age of an object by estimating the relative percentages of a radioactive (parent) isotope and a stable (daughter) isotope
Half-life: The time needed for half of a sample of a radioactive substance to undergo radioactive decay
Spotlight:
Types of Radiometric dating
There are four types of radiometric dating,these include:
Quote about the fossil record: “The phrase ‘the fossil record’ sounds impressive and authoritative. As used by some persons it becomes, as intended, intimidating, taking on the aura of esoteric truth as expounded by an elite class of specialists. But what is it, really, this fossil record? Only data in search of interpretation. All claims to the contrary that I know, and I know of several, are so much superstition.” ― Gareth J. Nelson
Chapter 5: Time Marches On
Vocabulary:
Geologic time scale: The standard method used to divide the Earth’s long natural history into manageable parts
Eon: The largest division of geologic time
Era: A unit of geologic time that includes two or more periods
Period: A unit of geologic time into which eras are divided
Epoch: A subdivision of a geologic period
Extinction: The death of every member of a species
One More Quote to finish this of (Quote of today):
“But just in proportion as this process of extermination has acted on an enormous scale, so must the number of intermediate varieties, which have formerly existed, be truly enormous. Why then is not every geological formation and every stratum full of such intermediate links? Geology assuredly does not reveal any such finely graduated organic chain; and this, perhaps, is the most obvious and serious objection which can be urged against the theory. The explanation lies, as I believe, in the extreme imperfection of the geological record.”
― Charles Darwin, The Origin of Species
When I talk about Backyard Sports I’m talking of the old ones:
Elidoger's Corner 