ANTH 2301 Quiz: Review 3

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Exam 3 Covers:
*Terms to Know:
In addition to the bold face terms in your book, the following are terms/concepts
you should know:
-Paleoanthropology
Taphonomy from the Greek taphos (death), is concerned with the processes
responsible for an organism becoming part of the fossil record and how these processes
influence information in the fossil record. Many taphonomic processes must be
considered when trying to understand fossilization. Events that affected the organism
during life like changes in rainfall, availability of food, and behavior for maximum
growth. Physical and chemical interactions that affect the organism from the time it is
buried until the time it is collected in the field
Fossil a fossil is any piece of evidence which bears upon the structure or way of
life of organism that lived in the past, a fossil may be bones that have become
mineralized or turned to stone, it can also be an ancient footprint or a discontinuity in the
soil created by a growing plant or burrowing animal. Fossils do not speak for themselves
but must be interpreted
*Who is Piltdown Man?
Physical characteristics, why was it put on our family tree?
A human cranium with an ape’s jaw. It was accepted because anthropologists and
scientists at the time wanted to believe that a larger brain was crucial to our distinction
and evolution as humans. Belief in false theory, wishful thinking, and cultural bias lead to
the accepting of Piltdown man as scientifically credible. Furthermore scientists were not
allowed to see the evidence and had to settle for plaster molds.
What evidence did it contradict?
Controversy, method used to reveal the hoax:
-Dating Techniques:
-Relative Dating Techniques: a dating technique which assigns a speculative
date to an artifact or fossil based upon many factors such as location, type, similarity,
geology, and association
-Biostratigraphy concerned with the recognition of fossils and the
relative position of their occurrences in space and time. Various fossil groups can be
found in different sedimentary environments. The two main environments are terrestrial
and marine
-Fluorine fluorine is an element that is found in most ground water
around the world. it can be used as a relative dating technique because skeletal remains
buried in the earth are subject to a wide range of chemical changes. One of these changes
can occur when percolating ground water comes into contact with a solution of minerals
drawn from local soils. This can cause a change in the mineral composition of the bone.
Hydroxyl ions are displaced wit ha form of soluble fluorides. These ions form
fluorapatite which is markedly less soluble.
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-Nitrogen occurs in bone in the form of protein collagen. It is lost slowly
during fossilization
-Absolute Dating Techniques:
-Radiometric (Chronometric) Dating we know that certain radioactive
elements discharge energy at a constant rate, known as the deca rate. Radium, for
example, slowly turns to lead. Once this steady decay rate is known, it is only a matter of
lab technology to determine how old a piece of radium is by measuring how much of it is
still radium and how much is lead
-Radio Carbon C-14 used to obtain age estimates on organic
materials. Was developed immediately following WW2 by Willard F. Libby and
coworkers. Radioactive carbon, produced when nitrogen 14 is bombarded by cosmic rays
in the atmosphere, drifts down to earth and is processed into the environment through
plants-animals-humans consumption of each other. When a living organism dies it stops
absorbing C14 and the C14 that is already in the body begins to disintegrate, scientists
study how much C14 has disintegrated and how much is left in the body
-Potassium-Argon measurement of the accumulation of argon in
a mineral. Measures the accumulation of argon in a substance from the decomposition of
potassium. It takes 1.3 billion years for half the potassium 40 in a given sample to decay
into argon, this method cannot be used to date material younger than 100,000 B.P.
-Argon-Argon - is a radioisotopic dating method that entails
measuring the ratio of two argon isotopes, argon-39 and argon-40.
-Dendrochronology - dating of past events (climatic changes) through
study of tree ring growth. Botanists, foresters and archaeologists began using this
technique during the early part of the 20th century. Discovered by A.E. Douglass from
the University of Arizona, who noted that the wide rings of certain species of trees were
produced during wet years and, inversely, narrow rings during dry seasons.
Each year a tree adds a layer of wood to its trunk and branches thus creating the annual
rings we see when viewing a cross section.
-Thermoluminescense - used for rocks, minerals and pottery. It dates
items between the years 300,000-10,000B.P. It is based on the fact that almost all natural
minerals are thermoluminescent. Energy absorbed from ionizing radiation frees electrons
to move through the crystal lattice and some are trapped at imperfections. Later heating
releases the trapped electrons, producing light
-Electron Spin Resonance - a chronometric dating method that estimates
dates from observation of radioactive atoms trapped in the calcite crystals present in a
number of materials such as bones and shells
*Which techniques are utilized on different types of fossils?
Volcanic ash potassium-argon, bone electron spin resonance, pottery -
thermoluminescence
Half-life
-Evolutionary Concepts:
-Anagenesis the transformation of an unbranched lineage of organisms to such
an extent that it is justifiably called a new species
-Cladogenesis the type of speciation in which branching of new forms from an
ancestral lineage occurs
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