The Origin of Life Origins of Life: ◊ The origin of life remains a matter of speculation. We will look at four alternate views: • Panspermia • Undersea Thermal Vents • Primordial Soup • Creationism Panspermia • Life’s origins did not originate on Earth, but originated elsewhere in the universe. • Proposes that cellular life reached Earth “seeded” inside a meteor which hit a long time ago. Criticisms of Panspermia Theory • The odds of an organism surviving inside a meteor for thousands of years are not high. • Unlikely that organisms would be able to withstand the high energy impacts of bodies into the Earth or other planetary objects. Undersea Thermal Vents • Life originated deep beneath the surface of the ocean at deep sea hydrothermal vents. • These vents release hot gaseous substances from the center of the earth Found ecosystems thriving in the depths of the ocean. Because life had been found to exist where it previously was thought unable to, many scientists began to ask questions as to whether or not this was where life may have originated on the earth. Criticisms of Hydrothermal Vent Theory • On the molecular level, the chances of life originating at deep sea thermal vents is not likely. • It is known that organic molecules are unstable at high temperatures, and are destroyed as quickly as they are produced. It has been estimated that life could not have arisen in the ocean unless the temperature was less than 25oC, or 77oF. Primordial Soup • The Primordial Soup Theory states that life began in a warm pond/ocean from a combination of chemicals that forms amino acids, which then make proteins. This is suppose to happen at least 3.8 billion to 3.55 billion years ago. • The basic building blocks of life (amino acids) came from simple molecule which formed in the atmosphere (without oxygen). • This was then energized by lightning and the rain from the atmosphere created the "organic soup". Abiogenesis - ･ Abiogenesis (Greek a-bio-genesis, "non biological origins") is the hypothetical generation of life from non-living matter. Today the term is primarily used to refer to hypotheses of the origin of life from a primordial soup. Biogenesis - is the process of lifeforms producing other lifeforms. ◊e.g. a spider lays eggs, which form into spiders. The Miller-Urey Experiment (1950s) They mixed gases thought to be present on primitive earth: Methane(CH4) Ammonia(NH3) Water(H2O) Hydrogen (H2) No Oxygen They then electrically sparked the mixture to signify lightning. The results were amino acids, the building blocks of proteins. Criticisms of Primordial Soup • Amino acids have to become protein • a. 1 protein = 100amino acids of 20 varieties • b. 10130 combinations of amino acids • c. Hard to hit the right protein by accident • d. Amino acids are building blocks, not the assembled structure • Early atmosphere contain different gases than those used by Miller/Urey (Experiments with true atmospheric gases did not produce abundant amino acids) • 2nd Law of Thermodynamics • a. System becomes less and less organized over time • b. Means amino acids cannot form protein spontaneously (more and more organized) • Primordial soup too dilute to achieve anything • a. Cannot spontaneously generate proteins • b. No mechanism to concentrate and make protein Creationism • The word "creationism" is used to describe all groups who believe that a supernatural being created the universe. • Scientific Creationism - the belief that the account of creation in the early chapters of Genesis is scientifically as well as religiously valid and that it can be supported by scientific evidence apart from scriptural authority. Creationism • Creationism is a broad category. Some forms of creationism include: ◊ Young Earth Creationism - literal belief of Genesis. ◊ Old Earth Creationism - no literal belief of Genesis. ◊ Intelligent design (ID) - believe that a "Designer" (God) is necessary to explain life's complexity. ◊ Evolutionary creationism - believe that God guides nature and evolution. ◊ Theistic evolution - believe that God is responsible for creating the universe and laws of science, and thus creating evolution. Creationism • There are other creation myths, not of Judeo- Christian origin: ◊Vedic Creationism - Believes the life and the universe have always existed (Hindu) ◊Raelian Creationism - Believe life was created by ET scientists. ◊Wingmakers - Modern myth centered on scientific discovery of human spiritual links to a creator (“James” from NYC) Creation • There is no single creation story among Aboriginal peoples, who have a diverse mythology. • For example, among the First Nations peoples, eight unique stories of genesis exist and have been adapted in several forms: the earth diver, world parent, emergence, conflict, robbery, rebirth of corpse, two creators and their contests, and the brother myth.
Pages to are hidden for
"Evolution"Please download to view full document