1 / 27

Origin of Life

Origin of Life. Monday, March 9. How would you define life ?. Tuesday, March 10th. It is known that the continents once existed as one land mass known as Pangea. What is an explanation for the separation of this land mass into the continents we have today?. Wednesday, March 11 th.

danag
Download Presentation

Origin of Life

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Origin of Life

  2. Monday, March 9 How would you define life?

  3. Tuesday, March 10th • It is known that the continents once existed as one land mass known as Pangea. What is an explanation for the separation of this land mass into the continents we have today?

  4. Wednesday, March 11th What kind of evidence would you use to confirm humans relationships to mammals?

  5. John Kyrk Evolution Timeline • http://www.johnkyrk.com/evolution.html • As we scroll through the timeline write down interesting facts, questions, etc from each that we go through • Example: Hadean Era - Sun Ignites, Solar System Forms

  6. The evolutionary tree of life can be documented with evidence. The Origin of Life on Earth is another story… • Bacteria • Archae- • bacteria • Protista • Plantae • Fungi • Animalia • 0 • Cenozoic • Colonization of land • by animals • Mesozoic • Paleozoic • 500 • Appearance of animals • and land plants • First multicellular • organisms • 1000 • PROTEROZOIC • Oldest definite fossils • of eukaryotes • 1500 • 2000 • Appearance of oxygen • in atmosphere • PRECAMBRIAN • Millions of years ago • Oldest definite fossils • of prokaryotes • 2500 • 3000 • ARCHEAN • 3500 • Molten-hot surface of • earth becomes cooler • 4000 • 4500 • Formation of earth

  7. What is Life? • First we have to define LIFE… • Organized as cells • Respond to stimuli • Regulate internal processes • Homeostasis • Use energy to grow • Metabolism • Develop • Change & mature within lifetime • Reproduce • Heredity • DNA / RNA • Adaptation & Evolution

  8. The Origin of Life is Hypothesis • Special Creation • Was life created by a supernatural or divine force? • not testable • Extra-terrestrial Origin • Was the original source of organic (carbon) materials comets & meteorites striking early Earth? • testable • Spontaneous Abiotic Origin • Did life evolve spontaneously from inorganic molecules? • testable

  9. Conditions on Early Earth • What’s missingfrom thatatmosphere? • Reducing atmosphere • water vapor (H2O), CO2, N2, NO2, H2,NH3, CH4, H2S • lots of available H & its electron • no free oxygen • Energy source • lightning, UV radiation, volcanic • low O2 = organic molecules do not breakdown as quickly

  10. Electrodes discharge sparks • (lightning simulation) Origin of Organic Molecules • Water vapor • Abiotic synthesis • 1920Oparin & Haldane propose reducing atmosphere hypothesis • 1953Miller & Urey test hypothesis • formed organic compounds • amino acids • adenine • Mixture of gases • ("primitive • atmosphere") • Condenser • Water • Condensed liquid with complex, organic • molecules • Heated water • ("ocean")

  11. Stanley Miller Produced: • amino acids • hydrocarbons • nitrogen bases • other organics

  12. Key Events in the Origin of Life • Origin of Cells (Protobionts or “Protocells”) • lipid bubbles → separate inside from outside → metabolism & reproduction • Origin of Genetics • RNA is likely first genetic material • multiple functions: encodes information (self-replicating), enzyme, regulatory molecule, transport molecule (tRNA, mRNA) • makes inheritance possible • makes natural selection & evolution possible • Origin of Eukaryotes • endosymbiosis

  13. Protocells • A liposome is “giving birth” to a smaller liposome • Some liposomes could carry out metabolic reactions and export products (ie. phosphate and maltose) if the enzymes were carried through in the creation of new liposomes

  14. Origin of Genetics • RNA is likely first genetic material • multi-functional • codes information • self-replicating molecule • makes inheritance possible • natural selection & evolution • enzyme functions • ribozymes • replication • regulatory molecule • transport molecule • tRNA & mRNA

  15. Timeline • Key events in evolutionary history of life on Earth • 3.5–4.0 bya:life originated • 2.7 bya:free O2 = photosynthetic bacteria • 2 bya:first eukaryotes

  16. Prokaryotes • Dominated life on Earth from 3.5–2.0 bya • O2 in the Atmosphere • Oxygen begins to accumulate 2.7 bya • reducing —> oxidizing atmosphere • evidence is banded iron in rocks = rusting • makes aerobic respiration possible • photosynthetic • algae

  17. ~2 bya First Eukaryotes • Development of internal membranes • create internal micro-environments • advantage: specialization = increase efficiency • NATURAL SELECTION! • nuclear envelope • endoplasmicreticulum (ER) • nucleus • infolding of theplasma membrane • plasma • membrane • DNA • cell wall • plasma • membrane • Prokaryotic ancestor of eukaryotic cells • Prokaryotic • cell • Eukaryotic • cell

  18. 1st Endosymbiosis Evolution of eukaryotes origin ofmitochondria engulfed aerobic bacteria, but did not digest them mutually beneficial relationship natural selection! • internal membrane system • aerobic bacterium • mitochondrion • Endosymbiosis • Ancestral • eukaryotic cell • Eukaryotic cell • with mitochondrion

  19. 2nd Endosymbiosis Evolution of eukaryotes origin of chloroplasts engulfed photosynthetic bacteria, but did not digest them mutually beneficial relationship natural selection! • Eukaryotic • cell with • mitochondrion • photosyntheticbacterium • photosyntheticbacterium • chloroplast • Endosymbiosis • mitochondrion • Eukaryotic cell with • chloroplast & mitochondrion

  20. Evidence structural mitochondria & chloroplasts resemble bacterial structure genetic mitochondria & chloroplasts have their own circular DNA, like bacteria functional mitochondria & chloroplasts move freely within the cell mitochondria & chloroplasts reproduce independently from the cell • Theory of Endosymbiosis

  21. Diversification of Animals within 10–20 million years most of the major phyla of animals appear in fossil record Cambrian Explosion • 543 mya

  22. Precambrian Era • Longest of the eras • Comprises about 87% of the geological timescale • Mass Extinctions • Episode of large-scale extinction in which large #’s of species disappear in a few million years of less • At least 5 major mass extinctions throughout history: Ordovician, Devonian, Permian, Triassic, and Cretaceous

  23. Factors that Influence Evolution • Continental Drift: Movement of continents with respect to one another over the earths surface • Why do the continents drift? Plate Tectonics! • Plate Tectonics: Concept that the earths crust is divided into a # of fairly rigid plates

  24. HWE and population genetics • What has driven the diversity and unity of life? • Models of the origin of life • Macroevolution/Speciation • What is the end result of changes in populations (microevolution) over time? • How do times of ecological stress affect species diversity and the rate of speciation? Where have we been?

  25. Big idea #1 The process of evolution drives the diversity and unity of life.

  26. Multiple Choice Answers 2. C 5. C 7. C 8. A 9. B 10. B 20. C 58. B

More Related