Ch. 14 – Origins of Life QUESTIONS OF THE DAY!!!! What do you think were the very first organisms? Why? What are the main elements that make up organisms? What are the building blocks of protein? What are the 4 biological macromolecules and what do they do? What evidence do you think we have to determine how life started on earth?
Ch. 14 – Origins of Life The Cosmic Calendar… If the history of the universe were condensed into a single calendar year
Ch. 14 – Origins of Life Life as we know it appeared the last month in the last few days of the Cosmic Calendar
Ch. 14 – Origins of Life Earth’s Age 4.2-4.6 billion years old 1.8 billion years ago life began Radioactive (radiometric) dating Uses radioactive isotopes and their breakdown to estimate approximate age (Review Ch. 6) Isotope: a radioactive atom w/different number of neutrons ( Carbon 12 is normal – 6 neutrons, 6 protons) (Carbon 14 is radioactive – 8 neutrons, 6 protons)
Ch. 14 – Origins of Life The isotopes release energy (radioactive) at a CONSTANT RATE. This determines the age. The release of energy is radioactive decay. The amount of time for ½ of the material to decay is called a HALF LIFE. EX: A. Start with 100g B. Half life is 50 years 25 g is left How old is the material?
Ch. 14 – Origins of Life Below is a graph representing the half life of Carbon 14 in animal tissue.
Ch. 14 – Origins of Life Miller and Urey Experimented to determine primitive atmospheres and origins of amino acids Primitive atmosphere of CH4, NH3, H2O, and H2 gases Gases combined and made amino acids Amino acids are the building blocks of protein.
Ch. 14 – Origins of Life 1st Organisms Anaerobic, prokaryotes, and heterotrophs
Ch. 14 – Origins of Life
Ch. 14 – Origins of Life Photosynthesis (sugar & oxygen) evolved (Autotrophs)(Ch.8) Eukaryotes and aerobic respiration develop in response to photosynthesis (Ch. 8)
Ch. 14 – Origins of Life Endosymbiosis – small things living in bigger things as a mutualistic relationship Mitochondria Chloroplasts
Ch. 14 – Origins of Life Fossil Record, Rock, and Early Life Fossil: traces of dead organisms that have been preserved in rock. Law of superposition Layer of rock (sediment) are deposited on existing layers
Ch. 14 – Origins of Life Cyanobacteria- the first organisms to undergo photosynthesis
Ch. 14 – Origins of Life Cambrian EXPLOSION! – Oxygen increased so diversity in life increased! (many new species appeared) More oxygen = more higher forms of animals The graph to the right shows the increase of oxygen as earth has aged.
Ch. 14 – Origins of Life