Scientists Through History Famous Scientists and their Accomplishments

Scientists Through History Famous Scientists and their Accomplishments : Time line of science

Aristotle Ø Classification of nature into groups, subgroups, and gave birth to the profession of taxonomy. l l Blooded (vertebrates) Bloodless (invertebrates) He created Nature’s scale and defined nature purpose: Inanimate to Living Beings (possibility of changing) to Plants and Living beings (mobile). Ø Worked out the hydrologic cycle Ø Described life cycles, species only born from same and reproduce the same. Ø

Leonardo da Vinci Ø Determined tree’s age by the # of rings in the trunk Ø Studied Anatomy Extensively l Studied heart and eye extensively Ø Tried to recreate birds flight. Ø Was the first one to propose a theory about the creation of fossils.

Antony van Leeuwenhoek First Simple Microscope First to observed unicellular organisms Able to calculate the size of bacteria, protozoa, sperm cells, stripped muscles and blood cells. Ø He built simple microscopes by grinding lenses Ø He laid the foundations of the detailed observation of the microscopic organisms Ø Discovered capillary systems Ø Opposed theory of spontaneous generation, proved this by showing fleas and mussels came from eggs Ø Ø Ø

Robert Hooke (XVIIc) Ø Published Microgaphia which is a record of his observations in microscopic organisms. Ø Devised compound microscope Ø Observed and coined the term cells, in cork. Ø Numerous other advances in Physics

Sir. Francis Bacon Ø Change in way of thinking Ø Substituted Aristotle’s deductive reasoning (general to particular) for an inductive reasoning (particular to general) (Novum Organum) nowadays known as the Scientific Method Ø First to develope Scientific Method

Nicholas Steno Ø Ø Ø Ø Made observations on the anatomy of the brain. First one to show that the heart has two independent pumps Discovered that fossils are petrified plants and animals Established some of the fundamental principles of stratigraphy. Rocks form in horizontal positions Law of Original Horizontality (Rock formed in Horizontal Layers) Law of Supperposition First use of geology by saying the rocks were divided by layers from different times.

Francesco Redi Ø Italian physician and poet. Ø Redi demonstrated in 1668 that rotting meat carefully kept from flies will not produce maggots, providing experimental evidence against theory of spontaneous generation.

George Cuvier Studied natural history and comparative anatomy Function determines form, as a theory of evolution. Ø Established extinction as fact. Ø Animals were immutable. Ø Classified animals by their skeletal structure Ø Ø l l Vertebrata Articulata Radiata Mollusca

Carolus Linnaeus Ø Considered the father of taxonomy Ø Several expeditions in Sweden Ø Created a binomial system for naming species Ø Studied hyloridization Ø Binomial nomenclature (genus then species)

Lazaro Spallanzani (1729 -1799) Ø An Italian naturalist, philosopher, and priest Ø Described the regeneration of organs in such animals as worms, snails, and frogs. Ø He attempted to induce frogs’ eggs to develop artificially by using vinegar and lemon juice

Thomas Malthus English Economist Ø Theories on population Ø l l Ø Ø Ø Plants arithmatic growth Animals geometric growth Relation of Food and Sex to populations – Positive Relation of Vice and Mersery to populations – Negative No perfect society, Darwin’s Statements about Malthus’s work – the strongest will survive Mathus said that man will overpopulate the earth

Jean-Baptiste Lamarck Ø Theory of evolution based on the use and lack of use of some organs Ø An organ is used becomes stronger then this characteristic will be passes on to offspring Ø Heredity Ø First to use term Biology Ø Theory of Transmutation – aquired traits can be inherited.

Adam Sedgwick Explored geology of Scotland presented his research Ø Proposed a new division of the geological timescale (the Devonian and the Cambrian) Ø Published “On the Silvarian and Cambrian systems, exhibiting the order in which the older sedimentary strata suceed each other in England Wales” Ø Strata, same strata exist separated in space but representing the same time. Ø Taught Darwin about Geology. Ø

Joseph Mendel Ø Ø Ø Studied botanics Used garden peas to study heredity Established the laws of segregation and independent assortment. First person to trace characteristics of succesive generations. Published experiments with Plants (Hybrids) l l Heredity character are independent They combine at random Characters dominant or recessive Antagonistic heredity factors never transmitted together

Thomas Henry Huxley He supported theory of evolution of Darwin and convinced people to accept it Ø First teacher of biology to use the laboratory method. Ø Supported Darwin’s theories Ø Punctuated evolution as opposed to Darwin, Gradual Ø I would rather be a man decended from apes than one afraid to face the truth Ø Jellyfish microbes in embryos of other organisms Ø

Louis Pasteur Found Vaccines for – rabies, anthrax (sheep), chicken cholera, silk worm diseases Ø Discovered- germ theory, spontaneous generation (living things from non-living) proposed and disproved Ø Created – First vaccines, pasteurization (heat killing organisms in milk), immunization Ø Gave birth to – stereochemistry, microbiology, bacteriology, virology Ø

Watson and Crick Ø Proposed the double helical structure of DNA Ø Analyzed and studied the structure of molecules that transmit the genetic characteristics from one generation to the next. Ø X ray defraction used to desifer structure of DNA.

Oparin Ø Ø Ø 1) Formation of the planet with gases in the atmosphere that could serve as the raw materials for life. The most widely accepted astronomical theory for the origin of the earth and the rest of the solar system is that the solar system formed about 4. 5 billion years ago from a diffuse dust cloud. 2) Random synthesis of simple organic molecules (such as amino acids that make up proteins) from the gases in the surrounding atmosphere. 3) Formation of larger, more complex molecules (Macromolecules) from the simple organic molecules, e. g. , the formation of simple proteins.

Oparin cont Ø Ø 4) Formation of coacervates - unique droplets containing the macromolecules , i. e. , a coacervate consists of chemicals suspended within a liquid surrounded by a membrane, e. g. a droplet consisting of chemicals in water surrounded by an oil layer membrane. 5) Development of some type of chemical organizers that function to give these droplets the ability to take in molecules, discharge other molecules, and control and maintain a characteristic chemical pattern. 6) Development of controlled reproduction to insure that resultant daughter cells have the same chemical capabilities. 7) Beginnings of evolutionary developments so that a group of cells could adapt to changes in the environment over time.

Sir Alexander Fleming (1881 1955) Ø Fleming had discovered the first antibiotic, penicillin Ø However, it was not until the research work of Florey and Chain that penicillin could be produced as a drug.