Scientists Through History provides a timeline of famous scientists and their accomplishments, including: - Aristotle established the foundations of taxonomy and defined nature's scale. - Leonardo da Vinci studied anatomy extensively and tried to recreate bird flight. - Antony van Leeuwenhoek invented the simple microscope and was the first to observe bacteria and other microorganisms. - Robert Hooke coined the term "cell" after observing cork under the microscope and made other advances in physics. - Charles Darwin developed the theory of evolution by natural selection, providing a mechanism by which species evolved over generations.

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

2. Aristotle
 Classification of nature into groups, subgroups,
and gave birth to the profession of taxonomy.
 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).
 Worked out the hydrologic cycle
 Described life cycles, species only born from
same and reproduce the same.

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

4. 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.
 He built simple microscopes by grinding lenses
 He laid the foundations of the detailed
observation of the microscopic organisms
 Discovered capillary systems
 Opposed the theory of spontaneous generation,
proved this by showing fleas and mussels came
from eggs

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

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

7. Nicholas Steno
 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.

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

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

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

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

12. Thomas Malthus
 English Economist
 Theories on population
 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

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

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

15. Joseph Mendel
 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)
 Heredity character are independent
 They combine at random
 Characters dominant or recessive
 Antagonistic heredity factors never transmitted together

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

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

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

19. Oparin
 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.

20. Oparin cont
 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.

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