Campbell Essential Biology (7th Edition)
7th Edition
ISBN: 9780134765037
Author: Eric J. Simon, Jean L. Dickey, Jane B. Reece
Publisher: PEARSON
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Chapter 14, Problem 7SQ
A paleontologist estimates that when a particular rock formed, it contained 12 mg of the radioactive isotope potassium-40. The rock now contains 3 mg of potassium-40. The half-life of potassium-40 is 1.3 billion years. From this information, you can conclude that the rock is approximately _____ billion years old.
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A fossil is found to contain the radioactive parent and daughter isotopes uranium 235U, and lead 207Pb, in the ratio 12.5% to 87.5%. Assuming that no 207Pb was present when the fossil first formed, estimate the age of this sample.Please show some thought process and a therefore statement. Thank you very much, have a great day!
Radiometric dating does not measure the age of an individual atom. It is a measure of the age of a quantity of atoms—a statistic. As with any statistical measure, its values may deviate around an average (sampling error, Section 1.8). Imagine that one sample of rock is dated ten different ways. Nine of the tests yield an age close to 225,000 years. One test yields an age of 3.2 million years. Do the nine consistent results imply that the one that deviates is incorrect, or does the one odd result invalidate the nine that are consistent?
Which parent isotope is most useful for dating samples that are greater than 100 million years old?
a
potassium-40
b
lead-206
c
argon-40
d
uranium-238
Chapter 14 Solutions
Campbell Essential Biology (7th Edition)
Ch. 14 - Distinguish between microevolution, speciation,...Ch. 14 - Identify each of the following reproductive...Ch. 14 - Why is a small, isolated population more likely to...Ch. 14 - Many species of plants and animals adapted to...Ch. 14 - Mass extinctions a. cut the number of species to...Ch. 14 - Prob. 6SQCh. 14 - A paleontologist estimates that when a particular...Ch. 14 - Why are biologists careful to distinguish...Ch. 14 - In the three-domain system, which two domains...Ch. 14 - Prob. 10IMT
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- "Carbon 14 decays to carbon12. The half-life of the C14 isotope is 5730 years. 22920 years after an animal dies, ______ carbon 14 will have been replaced with carbon12 and only _____ will remain in a bone sample from the animals skeleton found by the archaeologists. " "More than 99 percent, less than 1 percent" "Three fourths (75 percent), one fourth (25 percent)" "15/16ths (94 percent), 1/16 (6 percent)" "62/64ths (97 percent), 2/64 (3 percent)"arrow_forwardSuppose a scientist finds a rock with an interesting fossil. Curious to know the age of the fossil, she takes the rock to a lab. The lab determines the amount of rubidium (Rb) and strontium (Sr) in the rock. The scientist is familiar with radiometric dating and knows that she can now calculate the age of the rock, 1, using an isochron. The Rb-Sr isochron equation is 87. Rb. [edr – 1] 86 °Sr. 87 87 Sro 86 Sro 86 Sr. 87. Rb 3.807 and 89.60. In a published table, she finds that Using the lab's values, she calculates the isotope ratios as 86 Sr. 87 = 0.7129. She also finds that the decay constant, 86 the ratio of strontium-87 to strontium-86 at the formation of the rock was Sro 2, for rubidium-87 is 1.42 x 10-11. Use the equation and provided data to calculate t. Put your answer in scientific notation and round to the nearest tenth. years x10 What is the approximate age of the rock in billions of years? Round to the nearest tenth. billions of years t =arrow_forwardThe most useful method for dating ancient calcium rich cave deposits would be Group of answer choices A: Argon-Argon Dating B: Paleomagnetic Reversals C: Electron Spin Resonance Dating D: Uranium-Thorium Dating E: Potassium-Argon Datingarrow_forward
- A rock sample which originally contained 400 grams of radioactive isotope X now contains 25 grams of the material. The half-life of isotope X is 10,000 years. How old is the rock sample? (Give your answer without any punctuation or lables. For example: 15000).arrow_forwardRadiometric dating _______. has a substantial error factor can only be used for dating animal fossils can be used to date sedimentary rock, but not fossils is basedon the premise that each isotope decays at a constant rate is unpredictable because of changes in temperature and pressurearrow_forwardFact or theory? Organisms that look similar have been observed to have differences when preserved in rocks of different ages.arrow_forward
- In radiometric dating, scientists use the half-life of a radioactive isotope, to determine the approximate age of rocks, and the fossils that are embedded in them. Half-life is the time it takes for half of a radioactive element to become stable.Uranium 238 (238U) is a radioactive element that decays into Lead (206Pb) after 4.5 billion years. 6) Scientists found a fossil in a layer of rock that tested as 1/8th U and 7/8th Pb. What is the approximate age of the fossil? A) 562 million years old B) 4.5 billion years old C) 9 billion years old D) 13.5 billion years old Not Gradedarrow_forwardIf the half-life of a radioisotope is 20,000 years, then a sample in which three-quarters of that radioisotope has decayed is _______ years old. a. 15,000 b. 26,667 c. 30,000 d. 40,000arrow_forwardTrue or false? Wrinkly textures in rock that formed from ancient biofilms living in marine sediments are considered trace fossils.arrow_forward
- Researchers looking for fossils of the earliest life forms face many hurdles. For example, few sedimentary rocks date back more than 3 billion years. Explain why so few remaining samples of these early rocks remain.arrow_forwardMatch the reliable age range of the right with the appropriate technique on the left. Thermoluminescence [ Choose] Choose] Ages greater than 1,000 years ago. Ages between 1,000 years ago and 600 kya. Ages greater than 100 kya Ages between 300 BP and 300 kya. Ages between 0- 50 kya. [Choose ] Uranium-Thorium K-Ar (Potassium-Argon) Fission Track [ Choose ] Radiocarbon (14C) [Choose ]arrow_forwardDuring the Paleozoic, many life forms developed hard parts (shells/bones/etc.). Why would it be useful for organisms to have hard parts?arrow_forward
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