Introduction to Microbiology Lecture 7

Slides:



Advertisements
Similar presentations
Topic D.1 Evolution Origin of Life on Earth.
Advertisements

Origins of Life on Earth
IB Biology Option D Evolution.
Copyright Pearson Prentice Hall
How did life originate? Old hypothesis: “Organic soup” Old hypothesis: “Organic soup” Inorganic chemicals like methane, carbon dioxide and ammonia may.
14.2 The Origin of Life 9(D) Analyze and evaluate the evidence regarding formation of simple organic molecules and their organization into long complex.
Evolutionary History Chapter 20. Before life…  Chemical evolution:  The formation of small organic molecules preceded larger ones  Larger, more complex.
17-2 Earth’s Early History
Chapter 16. How Ancient Bacteria Changed the World Mounds of rock found near the Bahamas Contain photosynthetic prokaryotes.
Early Earth Notes. The earth was formed 4.6 billion years ago! So what was it like?
Early Earth. Earth formed 4.6 billion years ago oldest fossil organisms - prokaryotes dating back to 3.5 bya earliest prokaryotic cells lived in dense.
The History of Life Chapter 14. Early Earth Was inhospitable! Very hot due to: Meteoric impact Volcanic eruptions Radioactive decay Early atmosphere contained:
Chapter 25 The History of Life on Earth. Question u How have events in the Earth’s history contributed to life as we know it?
Copyright Pearson Prentice Hall
End Show Slide 1 of 36 Copyright Pearson Prentice Hall Origin of Life.
Origins of Life on Earth
Chapter 12 Section 1 How Did Life Begin? Grade 10 Biology Spring 2011.
The History of Life 14.1 Fossil Evidence of Change Land Environments The History of Life Chapter 14  Earth formed about 4.6 billion years ago.  Gravity.
Fossil Evidence of Change Land Environments The History of Life Section 1  Earth formed about 4.6 billion years ago.  Gravity pulled the densest elements.
Precambrian Life. Earth’s Atmosphere Today’s atmosphere and hydrosphere is different than Precambrian Today’s atmosphere: –Nitrogen (N2) –Abundant free.
Origin of Life Origin of the Solar System Earth is estimated to be ~4.6byo –Radiometric dating of rocks & meteors Nebula: cloud of gas & dust in space.
Chapter 26 Early Earth and the Origin of Life. Phylogeny Traces life backward to common ancestors. How did life get started?
Early Earth Conditions. Origin of Life Beliefs 1. Spontaneous Generation- idea that nonliving material can produce life ex. People believed decaying meat.
Intro to the History of Life Age of the Earth = 4.6 billion years Oldest fossils = 3.5 billion years –Prokaryotic type structures similar to spherical.
The History of Life Chapter 14. Early Earth Was inhospitable! Very hot due to: Meteoric impact Volcanic eruptions Radioactive decay Early atmosphere contained:
History of Life on Earth Chemical Evolution (prebiotic evolution) – most biologists believe that life developed from nonliving matter Alexander Oparin.
THE HISTORY OF LIFE ON EARTH PART 1 UNIVERSE TO EUKARYOTES.
Origin of Life on Earth.
Early Earth Conditions
Earth was very different billions of years ago 1. The most widely accepted hypothesis is the nebula hypothesis. The solar system formed by a condensing.
Ch 20 Origin of Life -Chemical Evolution: the decrease of the entropy of molecules (energy required) -Biological Evolution: formation and adaptation of.
Chapter 18.  Earth formed about _____________years ago (determined by _______________________)  Early atmosphere contained little or no oxygen (oldest.
Earth’s Early History and Evolution of Multicellular Life
The Archean Eon 3800 m.y. Subdivisions of the Archean - ERAS 3.8 Ga 3.6 Ga 3.2 Ga 2.8 Ga 2.5 Ga.
Origin of Life “…sparked by just the right combination of physical events & chemical processes…”
E VOLUTION – H ISTORY OF LIFE ON EARTH.  History of Life on Earth  Chemical Evolution (pre-biotic evolution) –  There are four processes needed for.
Life’s Origin and Early Evolution
FIRST SIGNS OF LIFE ON EARTH
The origin of (Eukaryotic) cells
Section 2: The Origin of Life
Lecture 61 – Lecture 62 The Origin of Life Ozgur Unal
FIRST SIGNS OF LIFE ON EARTH
Lecture Origin of Life Chapter 21 ~ The Origin and Evolutionary History of Life.
Chapter 12, Lesson 1-2 How did life begin? Age of the earth: 4.5 bya
Evolution – History of life on earth
LE1 – 05 - Origin of Life on Earth – Theories & Experiments
The Basic Chemicals of Life
Chapter 17.2: Earth’s Early History.
Chapter 12 History of Life
KEY CONCEPT The origin of life on Earth remains a puzzle.
Biology Concepts & Applications
Early Earth How old is earth? When did life first appear?
The Origin and Evolution of Life on Earth
History of Life on Earth
Origin of Life What do you think the first organism was like?
Earth’s Early History (Ch 19.3)
ORIGINS OF LIFE ON EARTH
Origins of Life AP Biology.
Outline 17-2: Earth's Early History
Early Earth and the Origin of Life
Evolution-Change Through Time
How Life Began Wake County Biology Curriculum.
The origin of Life.
Broad patterns of evolution
Origin of Life Page 96 Just write the red lettering into your notebook.
Going even further back!
Please take out Breeding Bunnies Lab to turn in
Origin of Life Just write the red lettering into your notebook.
Theories of Life Where and how did life begin?.
Presentation transcript:

Introduction to Microbiology Lecture 7 “Small creatures, big impacts” Lecture 7

Introduction to Microbiology Next lecture Everyone should read the paper “Tree of Life” 11:10- 11:45: Student evaluation Open discussion and questions Early ending if desired! Introduction to Microbiology

Introduction to Microbiology Lecture outline Early Earth Origin of life on Earth Introduction to Microbiology

Early Earth and Origin of Life

Early Earth and Origin of Life The Earth is ~ 4.5 billion years old First evidence for microbial life : found in rocks ~ 3.86 billion years old?? Scanning Electron Micrograph of Microfossil Prokaryotes from 3.45 Billion Year old rocks of the Barberton Greenstone belt of South Africa Early Earth and Origin of Life

Early Earth and Origin of Life Stromatolites Fossilized microbial mats layers of filamentous prokaryotes and trapped sediment Found in rocks 3.5 billion years old or younger Comparisons of ancient and modern stromatolites: Anoxygenic phototrophic filamentous bacteria formed ancient stromatolites (e.g. similar to Green non-sulfur Bacteria) Oxygenic phototrophic cyanobacteria dominate modern stromatolites Early Earth and Origin of Life

Conditions on early Earth Anoxic Surface temperatures of ~ 100ºC Abundant methane, carbon dioxide, nitrogen and ammonia Large reservoirs of sulfide (H2S and FeS) Frequently bombarded by meteorites Liquid water not possible Liquid water accumulated after Earth cooled Early life forms still heat tolerant Early Earth and Origin of Life

The first biomolecules Synthesis of biomolecules occurs spontaneously when gases and energy source present Intense UV radiation (no ozone layer), lightning, radioactivity, heat from meteorite impacts, volcanic eruptions Lab experiments- Amino acids, nucleotides and fatty acids can form abiotically Building blocks can polymerize Degradation does not occur due to lack of life Early Earth and Origin of Life

Urey-Miller experiment (1952) Early Earth and Origin of Life

Early Earth and Origin of Life Catalytic surfaces Surfaces of clay or pyrite Experiments with montmorillonite clay Lipid vesicles form from fatty acids Can enclose RNA Early Earth and Origin of Life Lipid vesicle RNA

Early Earth and Origin of Life The RNA world Self replicating RNA Catalytic RNAs (Ribozymes) catalyze several reactions including self replication Eventually DNA and proteins evolved DNA is more stable Proteins are better catalysts (higher specificity) Early Earth and Origin of Life

Surface origin hypothesis Contends that the first membrane-enclosed, self-replicating cells arose out of primordial soup rich in organic and inorganic compounds in ponds on Earth’s surface Dramatic temperature fluctuations and mixing from meteor impacts, dust clouds, and storms argue against this hypothesis Early Earth and Origin of Life

Sub-surface origin hypothesis States that life originated at hydrothermal springs on ocean floor Conditions would have been more stable Steady and abundant supply of energy (e.g., H2 and H2S) may have been available at these sites Early Earth and Origin of Life

Sub-surface origin hypothesis Early Earth and Origin of Life

Primitive life: energy sources No free oxygen: anoxic chemoautotrophs Early Earth and Origin of Life

Primitive life: carbon sources Likely C source: CO2 (abundant on early Earth) Produce enough C from chemoheterotrophs Autotrophic prokaryotes like Aquifex Hyperthermophile Contains small and simple genome Branches near root of evolutionary tree Early Earth and Origin of Life

Early Earth and Origin of Life Molecular oxygen Evolution of oxygenic photosynthesis Cyanobacteria appeared ~ 2.8 Ga Oxygen did not accumulate immediately due to large amounts of FeS Early Earth and Origin of Life Banded Iron Formation: Alternating Iron-rich and silica rich layers

Early Earth and Origin of Life

Early Earth and Origin of Life LUCA: Last Universal Common Ancestor Population of early cells from which cellular life may have diverged into ancestors of modern day Bacteria and Archaea Early Earth and Origin of Life

Endosymbiosis theory Early Earth and Origin of Life Well-supported hypothesis for origin of eukaryotic cells Contends that mitochondria and chloroplasts arose from symbiotic association of prokaryotes within another type of cell More in paper “Tree of Life” Early Earth and Origin of Life