Fossil Record and Radiometric Dating

Which of the following conclusions can be drawn from the selection below?

Dating of the fossils contributes to a clearer timeline of evolutionary history. Older methods of dating were more subjective, often an educated hypothesis based on the evidence available. However, the fossils in the Turkana region can be dated more accurately because they are found in the sedimentary rock between datable layers of tuff.

• Layers of sedimentary rock and tuff allow scientists to identify fossils with more accuracy than in the past.

• Layers of tuff provide the ideal medium for the preservation of fossils found in the Turkana region.

• Layers of sedimentary rock and tuff work in tandem to provide more accurate fossil dating.

• Layers of sedimentary rock yield less information about fossils than tuff in the Turkana region.

Tags

NGSS.MS-ESS1-4

Read the following sentence from the article.

In the Koobi Fora formation, bands of sedimentary rock are interspersed with layers of tuff, a sign of times when tectonic and volcanic activity dominated the landscape.

Which sentence from the article BEST supports this idea?

• This process of material deposition and erosion as well as the rise and fall in the lake levels due to environmental changes slowly added layers to the geologic record found in the Turkana Basin.

• The area has also been dominated by different landscapes over the span of Turkana's history — flood plains, forests and grasslands, an active volcano, and lakes.

• During the Pliocene geologic epoch (5.3 to 2.6 million years ago), tectonic activity left blocks of land at higher elevations than the surrounding land.

• The layers of volcanic rock are extremely important to reconstructing the history of the Turkana Basin because they allow scientists to calculate the age of hominin fossils found in the region.

Tags

NGSS.MS-ESS1-4

NGSS.MS-ESS2-2

"Radiometric dating" is a key term in the article. How does the author refine the meaning of this term over the course of the article?

• by introducing the Koobi Fora geologic formation, and showing how scientists have constructed an evolutionary timeline of the area

• by describing how tuff is created, and explaining how scientists look at the relationship between isotopes in the rock in order to determine age

• by reconstructing the history of the Turkana Basin, and explaining how tectonic activity relates directly to the decay of unstable isotopes

• by explaining how different layers of rock are formed in Koobi Fora, and showing how each layer relates to the law of superposition

Read the sentence from the article.

The climate of the region was once more humid, which may have been favorable for early humans and hominins to have flourished there.

What does the word "flourished" convey in the sentence?

• a sense of permanence

• a sense of assurance

• a sense of affluence

• a sense of success

What is the meaning of Sedimentary rock?

• rock that are formed by the accumulation or deposition of small particles.

• A lucky rock which have the power called "sedimentary"(superpower) to live.

• A candy.

• Three types of sedimentary rocks are organic, clastic, Chemical.

What is the meaning of deposition in science?

• the action of deposing someone, especially a monarch.

• geological process in which sediments, soil & rocks are added to a landmass

• witnesses sworn out-of-court testimony.

• All of the above

Tags

NGSS.MS-ESS2-2

What relationship seems to exist between the approximate age of fossils and rock layers and their depth in the earth?

• a sense of affluence

• a sense of assurance

• Following the law of superposition in geology, older fossils and rocks are found in lower strata than younger fossils and rock layers.

• Tectonic activity left some areas of land uplifted, and erosional forces from the lake, nearby rivers, and other forms of weathering exposed rock, even older rock layers, as outcroppings in the landscape. This made the fossils easier for researchers to find. The volcanic material in tuff layers also makes it possible to get a more accurate date for the fossils.

Tags

NGSS.MS-ESS1-4

NGSS.MS-LS4-1

True or False: Bones of ancient humans, our hominin ancestors, and other animal species were buried in the sediment, and eventually became fossilized and preserved in the rocks.

• True

• False

Tags

NGSS.MS-LS4-1

NGSS.MS-LS4-2