the history of life and earth
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The history of Life and earth. Early Ideas. Will rotting give rise to maggots ? Can mud produce live fish? Will a bag of wheat give birth to mice?. Spontaneous Generation . the idea that non-living material can produce life. Francesco Redi (1668). an Italian physician - PowerPoint PPT PresentationTRANSCRIPT
The Origin of Life
The history of Life and earthEarly IdeasWill rotting give rise to maggots ?
Can mud produce live fish?
Will a bag of wheat give birth to mice?
Spontaneous Generation the idea that non-living material can produce life
Francesco Redi (1668)an Italian physician disproved the common belief that decaying meat produced maggots
performed a controlled experiment
convinced many scientists that maggots and large organisms did not arise by spontaneous generation.
Redi placed decaying meat in several covered and uncovered jars
Over time, maggots filled the open jars but not the covered ones.
This showed that only flies produce flies.
Although Redi disproved the spontaneous generation of large organisms, many scientists still believed that microorganisms must arise spontaneously
They believed there must be some vital force in the air that caused microorganisms to arise
Louis Pasteur (1800s) designed an experiment to disprove spontaneous generation of microorganisms
set up an experiment where air but no microorganisms were allowed to contact a broth that contained nutrients
Who AM I?Whats wrong with you peopleliving things can not come from non living things. Living organisms dont just spontaneously generate.Francisco Redi
ResultsResults of Pasteur's experiment showed that:
Microorganisms do not simply arise in broth, even in the presence of air
Led to the idea of biogenesis living things can only come from other living things
VideoVideo
Simple Organic Moleculessimple organic molecules or molecules that contain carbon must have formed before the appearance of life
simple molecules must have been organized into complex organic molecules such as carbohydrates, proteins and nucleic acids
Who Am I?I think the energy from the sun, lightning, and Earths heat triggered chemical reactions to produce small organic molecules and a primordial soup in the oceans that formed the molecules of life.Alex OparinWho Am I?They call me biogenesis man! I also helped to disproved spontaneous generation by showing that microorganisms also dont spontaneously generate.Louis PasteurAlexander Oparin (1930s)Russian scientist
hypothesized that life began in the oceans
suggested that energy from the sun, lightning, and Earths heat triggered chemical reactions to produce small organic molecules
Believed that rain washed the molecules that formed into the ocean to form a primordial soup.
Stanley Miller & Harold Urey (1953)American scientists tested Oparins hypothesis
were the first to show that simple organic molecules could be made from inorganic compounds.
Who Am I?Its all about relationships you seethe eukaryotic needed the prokaryotic cells in order to come into existenceLynn MargulisEvolution of CellsFirst forms of life may have been prokaryotes
Organisms were most likely anaerobic
similar to Archaebacteria- prokaryotes that live in harsh environments like hot springs- do not require oxygen - autotrophicLynn Margulis (1960s)American biologist
proposed the endosymbiont theory
theory explains how eukaryote cells may have come into existence
Endosymbiont theory eukaryotes evolved through a symbiotic relationship between ancient prokaryotes.
This theory explains the origin of chloroplasts and mitochondria.
Three properties of chloroplasts and mitochondria shared with prokaryotes: circular DNA, similar ribosomes, reproduced by fission.
Four Requirements of LifeSimple organic molecules, the building blocks of life.A way to synthesize proteins from amino acids.A coding system for replicating proteins such as DNA.A way to form cells from molecules - membranesWho Am I?We believed that simple molecules came from simple inorganic compoundsMiller and UreyKnowledge checkWhich is an example of the theory of spontaneous generation? Tadpoles become frogs. A starfish can grow from a severed arm. Damp hay and corn create mice. From a tiny acorn, an oak can grow.Knowledge checkWhy do scientists believe that archea are the closest relatives to Earths first cells? They are eukaryotes. They contain DNA. They carry out photosynthesis. They live in extreme environments.Knowledge CheckWho is the scientist who showed that microscopic life is not produced by spontaneous generation?
Francesco RediStanley MillerLouis PasteurAlexander OparinWho Am I?Our Earth is the way that it is because of the forces that have been place on it for long periods of time.James HuttonJames Hutton (1785) Proposed that Earth was shaped by geological forces that took place over extremely long periods of time. He estimated the Earth to be millions of years old. He wrote the "Theory of the Earth.
Thomas Malthus (1798)The human population was growing faster than the space and food needed to provide for it. Natural disasters and forces of nature would solve the problem
Who am I?Giraffes now have long necks because they stretched over millions of yearsLamarackJean-Baptiste Lamarck (1809) principle of use and disuseA giraffe acquired its long neck because its ancestor stretched higher and higher into the trees to reach leaves, and that the animals increasingly lengthened neck was passed on to its offspring.
Structures will change and growor disappear be simply using or dis-using them
Charles Lyell (1833)
Wrote Principles of Geology, made Darwin ask himself: If the earth can change over time, then why cant the things on it? It must have taken life many, many years to change.
Charles DarwinWhat is a Theory? well-supported testable explanation of phenomena that have occurred in the natural world1859 Darwin published his book: On the Origin of SpeciesLife changes over time by the process of natural selection.
Natural Selection Ideastendency toward overproduction of offspring not all offspring produced will survive variations exist in any population variations are inherited individuals better suited to their environment live longer & produce more offspring than those less suited (survival of the fittest) entire population will change as it becomes better adapted to its environment
Who Am I?We will run out of resources soon, so we better have some natural disasters to control our population.Thomas MalthusWho AM I?I am the man of evolution. People know me for y ideas on natural selection and survival of the fittest. I also loved traveling to the G. islandsCharles Darwin