Classification and Cells

Currently 1.8 million species of living organisms Classifying 15,000/year new species Many species have gone extinct Scientists believe million species Look at Figure 7 page 43 What characteristics may have been used to group these beetles? Section 2.2

Why do Scientists Classify? Classification Process of grouping things based on similarities Taxonomy Study of how living things are classified Also involves naming organisms

Naming System of Linnaeus Carolus Linnaeus a Swedish Naturalist in 1750’s Classified based on observable features Binomial Nomenclature Written in italics and Latin, first letter capitalized Two names Genus – similar, closely related species Species – group of organisms, physically similar that can mate

Levels of Classification Three Domains: 1. Eukarya – membrane bound nuclei –Protists, Fungi, Plants, Animals 2. Archaea – “ancient” 3. Bacteria – Prokaryotes – cells without a nucleus

6 Kingdoms Prokaryotes - microscopic no distinct nuclei now divided into 2 kingdoms 1. Archaebacteria - anaerobic (deep) 2. Eubacteria - everywhere 10,000 species 3. Protista – “odds and ends” eukaryote lacks a complex organ system and lives in moist environments 4. Fungi- multicellular, decomposers, mushrooms, molds, mildew 5. Plants - multicellular oxygen producers 6. Animals - Multicellular consumers, diverse, heterotrophs

Discovering Cells 2.3 Cell – basic unit of structure and function of living things

Microscope Magnifies small objects Invention allowed people to see cells Construct a flowchart stating showing how Hooke, Leeuwenhoek, Schleiden, Schwann and Virchow contributed to the scientific discovery of cells

Cell Theory 1. All living things are composed of cells 2. Cells are the basic unit of structure and function in living things 3. All cells are produced from other cells.

Light and Electron Microscopes Compound Microscope – using more than one lens –Multiply lenses together Resolution – how sharp it looks Electron Microscope – Use a beam of electrons instead of light to produce a magnified image

1. What does the red bar represent? What does the blue bar represent? 2. What percentage of the mammalian cell is made up of water? 3. Compare that to the water in the bacterial cell. 4. What kind of compound, proteins or nucleic acids is found in larger concentrations in the mammalian cell? 5. How do the bacterial and mammalian cell compare?