Transcript 12.3 Origin of Life

12.3 Origin of Life
Objective
Describe the conditions on Earth billions of years ago and
summarize the hypotheses of how life began.
• Objective Rubric
4. Student is able to describe the conditions on Earth
billions of years ago and summarize the hypotheses of how
life began and teach another student
3. Student is able to describe the conditions on Earth
billions of years ago and summarize the hypotheses of how
life began.
2. Student is able to describe the conditions on Earth
billions of years ago and summarize one hypothesis of how
life began with the use of notes/textbook
1. With help student is able to describe the conditions on
Earth billions of years ago
12.3 Origin of Life
KEY CONCEPT
The origin of life on Earth remains a puzzle.
12.3 Origin of Life
Earth was very different billions of years ago.
• There have been many hypotheses of Earth’s origins.
• The most widely accepted hypothesis of Earth’s origins is
the nebula hypothesis.
12.3 Origin of Life
Several sets of hypotheses propose how life began on
Earth.
• There are two organic molecule hypotheses.
– Miller-Urey experiment
electrodes
“atmosphere”
water
“ocean”
heat source
– meteorite hypothesis
amino acids
12.3 Origin of Life
• There are different hypotheses of early cell structure.
– iron-sulfide bubbles hypothesis
12.3 Origin of Life
• There are different hypotheses of early cell structure.
– lipid membrane hypothesis
12.3 Origin of Life
• A hypothesis proposes that RNA was the first genetic
material.
– Ribozymes are RNA
molecules that catalyze
their own replication.
– DNA needs enzymes to
replicate itself.
12.3 Origin of Life
Objective
Describe the conditions on Earth billions of years ago and
summarize the hypotheses of how life began.
• Objective Rubric
4. Student is able to describe the conditions on Earth
billions of years ago and summarize the hypotheses of how
life began and teach another student
3. Student is able to describe the conditions on Earth
billions of years ago and summarize the hypotheses of how
life began.
2. Student is able to describe the conditions on Earth
billions of years ago and summarize one hypothesis of how
life began with the use of notes/textbook
1. With help student is able to describe the conditions on
Earth billions of years ago