Biology The Study of Life
Brainstorm: What makes something living Brainstorm: What makes something living? What are the characteristics of living things? http://www.wordle.net/create
Class Brainstorm Block 3 Block 2
Characteristics of Living Things Composed of Cells Complex Organization Use Energy Grow/Develop Reproduce Homeostasis How do we know? complex organization: (cell parts, groups of cells, specific functions, size, lifespan)
The Microscope iphone of the 1600s allowed scientists to observe living tissues in detail many scientists built their own
Robert Hooke English Scientist Drew detailed sketches of his observations Compiled in Micrographia (1665) Observed thin slices of cork from cork oak trees named the structures cells!
Antonie van Leeuwenhoek Dutch scientist, lensmaker looked at pond scum, blood from different organisms, etc first to describe microorganisms 1674 called them animalcules! cells present in animals too!
And then… Hooke(1665) and Leeuwenhoek(1674) What were scientists doing for 200 years? 1830s Cell Theory was finally was proposed!
Spontaneous Generation Widely accepted belief: living things could come from non-living things Observations: rotting meat - maggots corn husks/dirty rags - mice muddy riverbank - frogs Conclusion: Living things could come from non-living things! (Spontaneous Generation)
Van Helmont Flemish chemist, psychologist, physician
Francesco Redi Italian physician, biologist, poet Challenged spontaneous generation (rotting meat - maggots) with controlled experiment (1668)
John Needham English biologist, botanist, Roman Catholic Priest Boiled meat infusions Looked at microorganisms Grew in both flasks, including sealed one Spontaneous generation of microorganisms? What was wrong with his experiment?
Lazzaro Spallanzani Italian biologist, physiologist, Catholic priest 1738 - Experiment to disprove spontaneous generation of microorganisms Critics: But you cut off the oxygen!
FINALLY: Louis Pasteur 1864 Used ``swan-necked`` flask Confirmed that new bacteria come only from existing bacteria!
Development of Cell Theory 1824 – Henri Dutrochet plants grow by increasing number of cells 1831 - Robert Brown described cell nucleus 1838 - Matthias Schleiden all plant parts are made of cells 1839 - Theodor Schwann all animal tissues are composed of cells 1858- Rudolf Virchow cells must arise from preexisting cells
Cell Theory All organisms are composed of one or more cells. The cell is the basic unit of life in all living things. All cells are produced by the division of preexisting cells.
Cells Video https://www.youtube.com/watch?v=gFuEo2ccTPA
Exit Slip Make a table to sort the following into living (biotic) and non-living (abiotic): Toenail Sun Hair Nerve Cell Leaf Fire Tree bark Water Algae Bacteria 2) How did the microscope contribute to the development of cell theory? 3) How did the swan-necked flask contribute to the development of cell theory? Biotic (living) Abiotic (non-living)