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Chapter 8 Life’s Structure and Classification
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8.1 Living Things
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1. Living Things are Organized A cell is the smallest unit of an organism that carries on the functions of life -orderly structure -contains instructions
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2. Living Things Grow & Develop Increase in the # of cells Increase in size of one cell Life Spans Mayfly = 1 dayHuman = 100 years Dog = 15 yearsTortoise = 180 years Horse= 30 yearsBristlecone = 4,600 years
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3. Living Things Respond The reaction to a stimulus is a response Movement Survival
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4. Living Things maintain homeostasis The regulation of an organism’s internal conditions Maintenance
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5. Living Things use Energy a) Directly -Plants get energy from sun & CO 2 b) Indirectly -humans get energy from food and drinks
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6. Living Things Reproduce 1. Sexual (male and female) 2. Asexual 1. Fission- protist divides into two parts 2. Budding- new organisms fall off of parent 3. Regeneration- regrow a lost part
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What do living things need? 7. A place to live 8. Water 9. Food
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8.2 Classification
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A. History Carolus Linnaeus (Swedish) Developed a system to classify organisms “binomial nomenclature” (2-part name) Latin Genus species Example: Homo sapiens
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B. Reasons for using scientific names 1. Avoid mistakes 2. Give descriptive information 3. Information can be easily organized 4. Universal (same in all languages) 5. Group organisms with similar history (like a family tree)
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C. Phylogeny How the organism has changed over time 1. Similarity in structure (skeletal) 2. Fossils 3. Hereditary information (DNA) 4. Early stages of development
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D. Dichotomous Key Field guide used to identify organisms Pick from two choices Narrow it down to the species
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E. Classification system Kingdom……animalia Phylum……..chordata Class ……….mammalia Order………..primate Family……….hominidae Genus……….Homo Species………sapiens Homo sapiens
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F. The 5 Kingdoms 1. Animals 2. Plants 3. Fungi 4. Bacteria 5. Protists
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8.3 Cell Structure
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A. History 1600’s Antonie Van Leeuwenhoek- 1 st microscope 1600’s Robert Hooke- Cells 1800’s Matthias Schleiden- Plants are made of cells 1800’s Theodor Schwann- Animals are made of cells 1800’s Rudolf Virchow- Cell Theory
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B. Cell Theory 1. All organisms are made up of one or more cells. 2. The cell is the basic unit of organization in organisms. 3. All cells come from cells.
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C. Types of Cells Prokaryotic One-celled organisms such as bacteria Eukaryotic Multicellular organisms such as plants and animals
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D. Cell Functions 1. take in nutrients 2. store, produce, and breakdown substances 3. take in and use energy
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E. Organization Cells- heart cell Tissues- heart lining Organs- heart Organ systems- circulatory system Organisms- human
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F. How are plant cells different? 1. have a cell wall- rigid 2. have chloroplasts- photosynthesis 3. larger vacuole- store water
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8.4 Viruses
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A. What are viruses? Strand of hereditary material surrounded by a protein coat Multiplies by making copies of itself with the help of a living thing…….Host Cell Variety of shapes (geometrical) Very small (microscopic)
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B. Life cycle of a virus 1. The virus attaches to a specific host cell. 2. The virus’s DNA enters the host cell. 3. The virus’s DNA causes the cell to make viral DNA and proteins. 4. New viruses form inside the host cell. 5. New viruses are released as the cell bursts open….go on to infect other healthy cells
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C. Latent Viruses Inactive viruses Virus information can be copied to other cells and be inactive for a long period of time….until it is activated Cold sores Herpes
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D. Infection of a virus Viruses can infect all kingdoms May be carried by wind May be inhaled Viruses fit host cells like a puzzle -Each type of virus attacks only one type of host cell
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E. Treatment & Prevention Antibiotics do not work against viruses Antiviral drugs can fight against a virus, but have side effects Prevention is the best defense: 1. vaccinations 2. improve sanitary conditions 3. controlling animals 4. separate patients w/disease
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F. Natural Immunity Body makes interferons 1. proteins that protect cells from viruses 2. form protective substances
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G. Vaccines Made from weakened viruses Cause your body to produce interferons to fight the infection These interferons are now part of your defense system Examples: measles, mumps, smallpox, chicken pox, polio, rabies, etc.
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H. A Deadly Virus HIV -Human Immunodeficiency Virus AIDS -Acquired Immune Deficiency Syndrome - “A weakened immune system”
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I. Gene Therapy use healthy genes from one organism insert them into a virus “infect” the person with defective genes the host cell now copies “healthy” genes prevents genetic disorders Cystic fibrosis Diabetes Etc.
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