**Optional.** Scientific ideas about how life began
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Read this first
Table, The Miller–Urey experiment (NASA), with columns Part, What it stood for or gave
Flask of water, an early ocean; Methane, ammonia, hydrogen and water vapor, an early atmosphere, as Urey proposed; Electric sparks, lightning; Result in 1953, 5 amino acids identified; Re-analysis in 2008 of a sibling experiment, 22 amino acids.
A classmate says the Miller–Urey experiment created life in a flask. Which reply fits NASA, by Esme's reading?
- Correct; it made complete cells that held both DNA and RNA
- No; the flask stayed exactly as it started, with no new molecules
- Correct; bacteria grew in the flask within a few days after the sparks were sent
- No; it made amino acids, building blocks of proteins, not living cells
A pond, a tide pool, a hot spring and a seafloor vent chimney. A student says scientists know exactly how life began. Which reply fits NASA, by Jun's reading?
- Correct; vent tests in a lab made the first living cell from rock
- Correct; the 1953 experiment answered the whole question for good
- No; scientists have stopped studying the question altogether
- No; it is an open question, studied with lab chemistry and ancient fossils
RNA, DNA and a protein, with the jobs each can do. A student says the RNA world idea means DNA came first. Which reply fits NASA, by Kira's reading?
- No; it proposes RNA first, later replaced by DNA and proteins
- No; it proposes that stromatolites came first
- Correct; DNA came first, and then RNA was copied out from it later on
- Correct; proteins came first, then DNA, then RNA
Table, Early Earth timeline (NASA), with columns Event, When
Earth forms, about 4.5 billion years ago; Possible earliest signs of life, about 4 billion years ago; Pilbara stromatolites, Australia, about 3.5 billion years ago; Miller–Urey paper in Science, May 15, 1953.
Model scale: Earth's 4.5-billion-year history is one 24-hour day starting at midnight. About when would the 3.5-billion-year-old stromatolites appear, by Milo's math?
- About 1:00 a.m.
- About 5:20 a.m.
- About 6:40 p.m.
- About 3:30 a.m.
Model data: a stromatolite grew 0.4 mm a year for 2,500 years. How tall did it grow, by Noah's math?
- About 100 mm
- About 1,000 mm (1 m)
- About 2,500.4 mm
- About 6,250 mm
Which evidence best supports that life existed 3.5 billion years ago, by Pia's reading (NASA)?
- RNA strings that grew into full genes at a lab bench in 2016, on their own
- Pilbara stromatolites, built by microbial mats about 3.5 billion years ago
- Living bacteria found in the air of the giant planets
- Amino acids that formed in a flask of living bacteria in 1953
Table, The Miller–Urey experiment (NASA), with columns Part, What it stood for or gave
Flask of water, an early ocean; Methane, ammonia, hydrogen and water vapor, an early atmosphere, as Urey proposed; Electric sparks, lightning; Result in 1953, 5 amino acids identified; Re-analysis in 2008 of a sibling experiment, 22 amino acids.
Which result best supports that life's building blocks can form from simple chemicals, by Ren's reading (NASA)?
- DNA forms first in a cell, with no proteins needed
- Miller–Urey sparks made amino acids from water and simple gases
- Stromatolites formed from sea-floor sand with no microbes involved
- Living cells came out of the 1953 flask
A pond, a tide pool, a hot spring and a seafloor vent chimney. Two hypotheses: life began in a warm pond, or at a deep-sea vent. Which kind of evidence could help test them, by Tala's reading?
- Counting how many stars can be seen in the sky
- Assuming that the older idea must be the right one
- A vote on which idea sounds nicer to most people
- Lab tests of which setting forms and protects molecules like RNA
Table, Early Earth timeline (NASA), with columns Event, When
Earth forms, about 4.5 billion years ago; Possible earliest signs of life, about 4 billion years ago; Pilbara stromatolites, Australia, about 3.5 billion years ago; Miller–Urey paper in Science, May 15, 1953.
Which summary of the early-life timeline fits NASA, by Zee's reading?
- Earth is about 4.5 million years old, and its stromatolites are about 3.5 million
- Earth: about 4.5 billion years; life: maybe 4 billion; stromatolites: 3.5 billion
- Earth is about 3.5 billion years old; life began 4.5 billion years ago
- Life began about 3.5 billion years before Earth itself formed
Table, The Miller–Urey experiment (NASA), with columns Part, What it stood for or gave
Flask of water, an early ocean; Methane, ammonia, hydrogen and water vapor, an early atmosphere, as Urey proposed; Electric sparks, lightning; Result in 1953, 5 amino acids identified; Re-analysis in 2008 of a sibling experiment, 22 amino acids.
Which summary of the Miller–Urey experiment fits NASA, by Ari's reading?
- Sparks in water turned simple gases into stromatolites
- Sparks in oxygen-rich air made living bacteria in about a week, settling the question
- Sunlight on rocks made DNA and settled how life began
- Sparks in water and simple gases made amino acids, though early air may have differed
