11-15_16Origin Life_Lecture 31&32

11-15_16Origin Life_Lecture 31&32 - The origin and...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
How many times did life originate? When did life first appear on Earth? How did life first arise on Earth? What were early life forms like? How did early life change Earth’s atmosphere? How did eukaryotic cells originate ? The origin and early evolution of life on planet Earth
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Question #1: How many times? future past
Background image of page 2
Charles Darwin’s great insights 1. Organisms share traits, showing evidence of common ancestry (e.g. p53) All life on Earth is related. A Tree of Life 2. New traits arise by descent with modification
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Statistical testing of alternative models strongly supports single ancestry (Theobald 2010) How many times did life originate? The available evidence says “once.”
Background image of page 4
When did life originate on Earth? fossils retained in ancient rocks dated using radioisotopic decay methods.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
1 Ka (kiloannum) = 1 thousand years ago 1 Ma (megannum) = 1 million years ago = 1000 Ka 1 Ga (gigannum) = 1 billion years ago = 1000 Ma Thinking about life’s origins requires large numbers 4 Eons
Background image of page 6
Origin of Universe (Big Bang Theory) 13.7 Ga Hadean Eon 4.5 Ga Earth forms, bombarded with space debris from formation of solar system
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Archaean Eon 3.5 Ga Oldest evidence prokaryotic life; Life arose 4.0-3.5 Ga
Background image of page 8
The Great Oxidation Event : Earth gets an oxygen- rich atmosphere thanks to photosynthetic cyanobacteria
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Cyanobacteria were very successful. Oxygen produced was initially absorbed by iron
Background image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 27

11-15_16Origin Life_Lecture 31&32 - The origin and...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online