Transcript Unit 3 Principles of Evolution

Remember:
Scientific Method
1. Observation
2. Hypothesis
3. Experiment & Collect Data
4. Conclusion
Cell Theory
1. living things are made of cells
2. cells are basic unit of structure & function
3. All cells arise from existing cells.
Theories on Early Earth
& Life’s Origin
What is a theory?
- an explanation that is supported by
evidence
Describe the Earth as theorized to have formed 4.6
Billion years ago (BYA)
- very hot
- N, CO2, H2O, methane, NO oxygen
4.4 BYA
- theorized to have cooled
- water vapor condenses
http://www.cosmographica.com/gallery/portfolio2007/content/bin/images/large/340_CometFlood.jpg
http://www.space-art.co.uk/images/artwork/formations/Early-Earth.jpg
Can scientists be sure that Earth formed this way?
No – physical process of Earth constantly
destroys and reforms rock
What evidence is there to support this theory?
Fossils – hardened remains of plants or
animals found in the earth’s crust
http://dangerdulcimer.com/fossil.jpg
http://images.google.com/imgres?imgurl=http://www.breckminerals.com/images/fossil4.jpg&imgrefurl=http://www.breckminerals.com/fossils.ht
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Fossils – hardened remains of plants or
animals found in the earth’s crust
Dating Fossils
1. Relative Dating – older fossils on
the lower levels, younger on top
2. Absolute Dating or radiometric dating –
measuring active chemicals in rocks
http://images.google.com/imgres?imgurl=http://evolution.berkeley.edu/evosite/lines/images/strat_column.gif&imgrefurl=http://evolution.berkeley.edu/evosite/lines/IIIAchronology.shtml&usg=__W60aIrR5yb93lThSoGij
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Radiometric Dating
• Using isotope half-life
– Ex. Potassium-40
• Potassium’s half life is 1.3billion
– Ex. Carbon-14 for dating < 50,000 years old
• Carbon’s half life is 5730years
http://www.google.com/imgres?imgurl=http://facstaff.gpc.edu/~pgore/myart/radgraph.gif&imgrefurl=http://facstaff.gpc.edu/~pgore/geology/geo102/radio.htm&usg=__y8NYQsrpFh7trBQATHlf
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%2Bdating%26um%3D1%26hl%3Den%26tbs%3Disch:1&ei=aKXaTIGPDIP98AbNo6WRCQ
Describe a theory of how life first began on Earth.
spontaneous generation – life came from nowhere
also called abiogenesis
Two people who discredited spontaneous generation.
1. Francesco Redi in 1600s with the meat
experiment
http://micro.digitalproteus.com/pics/spontaneousgeneration.jpg
2. Louis Pasteur in the 1800s with the sterile
broth experiment
http://vilenski.org/science/notebook/unit1/historyoflife/pastuer_image.jpg
From this point (Pasteur’s experiment) on Biogenesis,
the idea that life comes from life, stands accepted.
What are some other theories on how the 1st life formed?
1. Oparin’s Hypothesis
- energy from the sun triggered chemical
reactions of the gases in the air
- producing organic molecules
- these molecules fell into the ocean
- called primordial soup model
http://i8.photobucket.com/albums/a48/frogfishII/Miller.gif
2. Oparins Hypothesis Tested by Miller & Urey
- Created organic molecules
- Problems with this experiment
- lighting not in early earth
- hot & cold not at the
same time
3. Current ideas on origin of first life:
Organic chemicals 
information molecules 
complex molecules 
formation of protocell (p.383)
Process
Review: 2 types of cells
Prokaryote(“simple”)
Eukaryote
(“complex,” because have
________ like m_____ & ch_____)
Theories on the Development of Complex Organisms
(getting from a single celled organisim to multicellular)
-Estimated first organism using fossils
- cyanobacteria (cyano = blue green)
(bacteria = prokaryotic)
- see board
O2 trapped

photosyn
Cyanobacteria
O2  ozone  organisms that
created
breath oxygen
Eukaryotes believed to come later than Pro
and by the process of endosymbiosis
Endosymbiosis
- pre-eukaryotic (prokaryote)
bacteria engulfed another
(endocytosis), p.385
http://images.google.com/imgres?imgurl=http://evolution.berkeley.edu/evolibrary/images/endosymbiosis/endosymbiosis.gif&imgrefurl=http://evolution.berkeley.edu/evolibrary/article/_0/endosymbios
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1%26hl%3Den%26sa%3DN
Estimated Timeline of Earth and Organisms
- timeline
- chart
- Pangea picture
http://www.cyburbia.org/gallery/data/6457/pangea-continental-drift.gif
Two types of bacteria (prokaryotes):
1. eubacteria – have peptidoglycan in
its cell walls and a cell membrane,
bacteria that we “know”
2. archaebacteria – no peptidoglycan,
first bacteria, live in extreme
environments
Theories of Life on Early Land
Cyanobacteria 
oxygen 
ozone 
livable earth
Helpful Terminology:
mutualism –
mycorrhizae – fungus and plant
continental drift – (Pangea p.379), movement
off, relates to theories of evolution
6 Kingdoms
Eubacteria
Archaebacteria
Protists
Fungi
Plants
Animals
http://teachers.westport.k12.ct.us/resource/images/Five_king.jpg