Download UNIT 3: Cellular Biology 3A: Origin of Life The Big Picture Evidence

UNIT 3: Cellular Biology
3A: Origin of Life
The Big Picture
Evidence supports that earth and the organisms that inhabit it have changed greatly over
time. The diversity of life is the result of ongoing evolutionary change. Species alive today
have evolved from ancient common ancestors. Cells are the basic units of structure and
function of all living things. Cells in a multicellular organism are interdependent upon each
other. Cells are dynamic and constantly work towards maintaining homeostasis. Processes
that occur at the cellular level provide the energy and basic structure organisms need to
survive.
1. How did life on Earth begin, and how has it changed over time?
2. How do we know that all living things are made of cells?
3. Why aren’t all cells identical?
4. What are similarities and differences between prokaryotic and eukaryotic cells, and
between different eukaryotic cells?
5. How did prokaryotic cells evolve into eukaryotic cells?
6. How do cell structures enable a cell to carry out basic life processes?
7. How does a cell transport materials across the cell membrane?
8. How does a cell use feedback mechanisms to maintain homeostasis both within itself
and as part of a multicellular organism?
9. How do organisms obtain the energy and they need to survive?
Prerequisite Knowledge…You should:
Understand basic chemistry and biochemistry.
Be familiar with basic cell structures.
Know that all living things are made of cells.
Recognize that organisms change over time and realize that fossils may help us track these
changes.
Suggested Resources…
Notes packets
Homework worksheets
Lab activity packets
PowerPoint presentations
Media resources (videos, images, Internet)
Textbook – Biology (Miller and Levine, 2010) (Sections 19.3, 18.3, 16.2, 1.1)
Websites: http://www.ucmp.berkeley.edu/exhibits/geologictime.php
The following information is found in your completed note packet.
By the conclusion of this unit, you should know the following:
1. Scientific evidence indicates that organic molecules and cells may have formed
spontaneously on ancient Earth.
2. Earth’s life forms evolved from earlier and distinctly different species.
3. The lack of free atmospheric oxygen and the abundance of energy on early Earth
facilitated the formation of organic compounds from inorganic precursors.
4. Simple organic compounds combined to form polymers or other complex organic
molecules, which in turn led to pre-cells (protocells). The ultimate result was the
origin of the earliest cells (probably heterotrophic anaerobic prokaryotes).
5. The “RNA world” hypothesis proposes that RNA existed by itself before DNA.
From this simple RNA-based system, several steps could have led to DNAdirected protein synthesis.
6. The endosymbiotic theory proposes that a symbiotic relationship evolved over
time between primitive eukaryotic cells and the prokaryotic cells within them.
Mitochondria and chloroplasts likely originated through endosymbiosis.
7. The evolution of O2-producing autotrophs transformed Earth's atmosphere to one
suitable for the evolution of aerobic metabolism and complex life
8. Aerobic cellular respiration produces more ATP per cycle than anaerobic cellular
respiration.
9. The development of the ozone layer contributed significantly to the cessation of
abiogenesis and the prevalence of biogenesis.
10. The reactions of aerobic cellular respiration take place in the cytoplasm and
mitochondria of a eukaryotic cell.
11. Compare and contrast aerobic and anaerobic cellular respiration.
12. Over time, continued evolution and endosymbiosis led to the development of
complex eukaryotic cells, and eventually a wide variety of multicellular
eukaryotes.
13. The development of sexual reproduction sped up evolutionary change because
sexual reproduction increases genetic variation.
14. General characteristics/examples of the 3 domains (Eukaryota, Bacteria, and
Archaea) and 6 kingdoms (Eubacteria, Archae-bacteria, Protista, Fungi, Plantae,
and Animalia).
The following are prompts (questions) to help prepare you
for the application of the material you learn this unit.
By the conclusion of this unit, you should be able to do the following:
1. Describe the conditions of the early Earth and the early atmosphere.
What were the conditions of the early Earth? What were the conditions of
the early atomosphere?
2. Differentiate between biogenesis and abiogenesis and justify why biogenesis
prevails over abiogenesis on modern earth.
What is the difference between biogenesis and abiogenesis? Why is
biogenesis the current belief on modern earth?
3. Explain how the conditions on early Earth may have led to the formation of
organic compounds, pre-cells (protocells) and to the first cells.
What were the conditions on early Earth that may have led to the
formation of organic compounds, protcells and to the first cells?
4. Analyze Miller and Urey’s experiment in terms of its purpose, design and
results.
What is the purpose of Miller and Urey’s experiment? How did they design
their experiment? What were the results of their experiment?
5. Rationalize the heterotroph hypothesis and the endosymbiotic theory.
What is the heterotroph hypothesis? How does the heterotroph hypothesis
support the endosymbiotic theory?
6. Infer whether the earliest life on Earth was likely aerobic or anaerobic.
Was the early life forms on earth aerobic or anaerobic? How did you come
to that conclusion?
7. Weigh the significance of the evolution of autotrophs in changing the
conditions on early Earth.
How did the first autotrophs change the conditions on early Earth? What
is the significance of the introduction of autotrophs?
8. Defend the significance of sexual reproduction in evolution.
How did the introduction of sexually reproducing organisms affect the
evolution of future organisms?
9. Provide evidence for the origin of mitochondria and chloroplasts.
Why do scientists believe that mitochondria and chloroplasts were once
living organisms?
10. Construct an approximate sequence/timing of major points in the evolution of life
on earth from the origin of Earth through the emergence of the human species.
When was the Earth first formed? What organisms evolved first? What
order did other organisms evolve. When did humans evolve?
11. Identify major characteristics and examples from the 3 domains and 6 kingdoms
discussed.
What are the 3 domains and the 6 kingdoms? What are the characteristics of the
domains and kingdoms? (i.e. heterotroph vs. autotroph, prokaryotic vs.
eukaryotic, unicellular vs. multicellular)
ORIGIN OF LIFE KEY TERMS
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Words Found in the Glossary
1) Heterotroph:
2) Autotroph:
3) Cellular Respiration:
4) Photosynthesis:
5) Ozone:
6) Polymers:
7) Anaerobic:
8) Aerobic:
9) Fossils:
10) Domains:
11) Kingdoms:
12) Ribonucleic Acid (RNA):
13) Proteins:
14) Eukaryote:
15) Prokaryote:
16) Mitochondrion:
17) Chloroplasts:
18) Endosymbiotic Theory:
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Words NOT Found in the Textbook
19) Abiogenesis:
20) Biogenesis:
21) Spontaneous Generation:
22) Big Bang Theory:
23) Primitive:
24) Atmosphere:
25) Oparin & Haldane:
26) Miller & Urey:
27) Protocells:
28) Ancestors:
29) Inorganic Matter:
30) Microspheres:
31) Anaerobic Heterotrophs:
32) Microfossils:
33) Multicellular: