Slide 1 / 131 Slide 2 / 131 AP BIOLOGY Emergence of Organic Molecules Summer 2013 www.njctl.org Slide 3 / 131 Emergence of Organic Molecules Click on the topic to go to that section The Early Universe & Earth · · Organic Compounds · Development of Life
Slide 4 / 131 The Early Universe & Earth Return to Table of Contents Slide 5 / 131 The Beginning... Many scientists have provided evidence of an event called the "Big Bang". This event is said to have occurred about 14 billion years ago. Slide 6 / 131 Big Bang Theory This theory states that all of the mass in the universe was once compacted into one small point. The universe was then created by a massive explosion and it has been expanding ever since. photo: NASA
Slide 7 / 131 Big Bang Theory Every piece of matter in the universe came from this one point ... this one explosion. Since everything is made of matter, this means that the material that makes up everything in the universe came from this one point in time. Slide 8 / 131 Evidence Supporting the Big Bang Theory If no one was around 14 billion years ago, then how did this theory come about? In the early 1900's, an astronomer* named Edwin Hubble, discovered that various galaxies were spreading apart by measuring their location in the sky. Due to this finding, he concluded the entire universe must be expanding. *astronomer: a scientist who studies planets, stars, and galaxies Slide 9 / 131 Evidence Supporting the Big Bang Theory Scientists explain this phenomenon by claiming that the universe expanded from a single point. To visualize this, think of a stone that hits the surface of the water... The water will ripple out from that one point and expand larger and larger.
Slide 10 / 131 Our Expanding Universe The universe will continue to expand, as it always has since the Big Bang occurred. Stephen Hawking is one of the most famous physicists in the world today. He has researched and spoken on the expanding universe. Click here to hear Stephen Hawking talk about this idea, the expanding universe Slide 11 / 131 1 The Big Bang Theory... created all the elements on the periodic table A expanded all matter in the universe from a single point B states that the universe is expanding linearly C D is just a tv show Slide 11 (Answer) / 131 1 The Big Bang Theory... created all the elements on the periodic table A B expanded all matter in the universe from a single point C states that the universe is expanding linearly Answer is just a tv show D B [This object is a pull tab]
Slide 12 / 131 2When closely examined the universe appears red. This is due to... the short wavelength of red light A the high frequency of red light B the doppler effect as the universe expands C D the high percentage of red giant stars Slide 12 (Answer) / 131 2When closely examined the universe appears red. This is due to... the short wavelength of red light A B the high frequency of red light the doppler effect as the universe expands C the high percentage of red giant stars D Answer C [This object is a pull tab] Slide 13 / 131 The Early Universe The age of the universe is about 14 billion years. The age of Earth is about 4.6 billion years. The early universe was almost completely made of hydrogen (H 2 ) and helium (He). None of the heavier elements (above helium) existed at the dawn of the universe. Click here to see David Christian's explanation of the formation of the Universe
Slide 14 / 131 The Early Universe Earth formed about 10 billion years after the start of the universe, about 4.6 billion years ago. In those 10 billion years, generations of stars were born, and died. All the heavier atoms on the periodic table were created by nuclear fusion inside those stars, or when they exploded. Slide 15 / 131 The Early Universe When the early stars died explosively (novae and supernovae), those heavier elements were scattered into space. When Earth, and its solar system, formed, it was in a cloud of matter which included all the naturally occurring elements in the periodic table. No new elements have been created since Earth formed. This means that all the atoms in you and your world, other than hydrogen and helium, were once inside a star, long ago. Slide 16 / 131 3 Which came first? atoms A B electromagnetic force neutrons C quarks D
Slide 16 (Answer) / 131 3 Which came first? A atoms electromagnetic force B neutrons C Answer B quarks D [This object is a pull tab] Slide 17 / 131 4 Where did all the elements heavier than hydrogen and helium come from? A the Big Bang B the sun C stars that we see at night D stars that exploded long ago Slide 17 (Answer) / 131 4 Where did all the elements heavier than hydrogen and helium come from? A the Big Bang B the sun Answer C stars that we see at night D D stars that exploded long ago [This object is a pull tab]
Slide 18 / 131 5 Carbon was formed in nuclear fusion reactions such as... A 2H + He C He + He + He C B He + Li C C D 2H + Li C Slide 18 (Answer) / 131 5 Carbon was formed in nuclear fusion reactions such as... 2H + He C A B He + He + He C Answer B C He + Li C D 2H + Li C [This object is a pull tab] Slide 19 / 131 Early Earth Studies of volcanos suggest the early atmosphere of Earth was composed of a mix of chemical compounds. The most prevelant were: water vapor (H 2 O), · carbon dioxide (CO 2 ), · nitrogen (N 2 ), · hydrogen sulfide (H 2 S), · methane (CH 4 ), and · ammonia (NH 3 ). ·
Slide 20 / 131 UV Radiation Earth was also subject to intense lightning and ultraviolet radiation. It is ironic that life arose under conditions that included bombardment by UV radiation - Today, depletion of the ozone layer that protects us from this radiation is a major environmental concern! Slide 21 / 131 Oxygen in the Atmosphere Early Earth atmosphere contained practically no oxygen, as this gas is not expelled during volcanic eruptions. Oxygen gas first entered the atmosphere as a byproduct of photosynthesis. Initial oxygen production reacted with iron, producing banded iron formations. These geological formations have been used to date the evolution of photosynthesis to approximately 2.45 billion years ago. Slide 22 / 131 Early Earth's Oceans As Earth's crust cooled and solidified, water vapor condensed to create oceans. Water is thought to have been brought to Earth by comets in the early solar system.
Slide 23 / 131 6 Scientists hypothesize that Earth's early atmosphere contained substances such as: A oxygen, carbon dioxide and hydrogen gas B nitrogen, oxygen, and water vapor C water vapor, methane, and oxygen D ammonia, water vapor, and hydrogen gas Slide 23 (Answer) / 131 6 Scientists hypothesize that Earth's early atmosphere contained substances such as: A oxygen, carbon dioxide and hydrogen gas B nitrogen, oxygen, and water vapor C water vapor, methane, and oxygen Answer D ammonia, water vapor, and hydrogen gas D [This object is a pull tab] Slide 24 / 131 7 What is believed to have been the source of water for Earth? A nuclear fission B chemical reactions on Earth C electrolysis D comets
Slide 24 (Answer) / 131 7 What is believed to have been the source of water for Earth? A nuclear fission B chemical reactions on Earth C electrolysis Answer D D comets [This object is a pull tab] Slide 25 / 131 The Blue Planet Three-quarters of Earth’s surface is submerged in water. The abundance of water is the main reason the Earth is habitable. image courtesy NASA Slide 26 / 131 Water Molecules A water molecule consists of two hydrogen atoms covalently bonded to one oxygen atom. The more electronegative oxygen atom pulls the electrons from the hydrogen atoms toward it, resulting in an uneven distribution of charge. Slight Negative Charge Slight Positive Charge
Slide 27 / 131 Water: Polar Molecule Since a water molecule has a positive end and a negative end it is called a polar molecule. This property of water causes it to act like a magnet, attracting other molecules that have positive and negative poles. Slide 28 / 131 Properties of Water The polarity of water gives it several important properties that allowed life to emerge on Earth: · Ability to moderate temperature · Versatility as a solvent · Cohesive behavior Slide 29 / 131 Moderate Temperature Water has a very high specific heat. This means that a great amount of energy is needed to raise the temperature of water even a few degrees. Because of this, temperature on the Earth's surface can undergo extreme variations - between night and day, or between seasons - without its water freezing or boiling away. Why is this important in the development of life on Earth?
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