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The Characteristics of Life
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History: Spontaneous Generation or Abiogenesis- 1 st proposed by Aristotle held that complex, living organisms are generated by decaying organic substances, e.g. that mice spontaneously appear in stored grain or maggots spontaneously appear in meat.
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The Characteristics of Life History: Was widely believed until the 19 th century. Several scientists performed experiments that disproved spontaneous generation Francisco Redi Lazzaro Spallanzani Louis Pasteur
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Redi’s Experiment Francisco Redi 1668
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Spallanzani’s Experiment Lazzaro Spallanzani 1746
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Pasteur’s Experiment Louis Pasteur 1859
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The Characteristics of Life History: Biogenesis- is the process of life forms producing other life forms e.g. a spider lays eggs, which form into spiders. The term is also used for the assertion that life can only be passed on by living things.
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The Characteristics of Life How can you tell if something is alive?
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The Characteristics of Life Biologists have devised a list of 5 characteristics that define life. Something can be considered alive ONLY if it displays ALL 5 of the characteristics.
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The Characteristics of Life Anything that possesses all 5 of the characteristics of life is called an organism.
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The 5 characteristics of life are: 1.Cellular Organization cell tissue organ system organism 2. Growth & Development 3. Reproduction 4. Adaptation to environment – response to a stimulus 5. Maintenance of Homeostasis
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The Characteristics of Life Organization: All living organisms have an organized structure Ex.-Cells form tissues -Tissues form organs -Organs form organ systems
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The Characteristics of Life All living organisms grow and develop during their life spans. Growth & Development:
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The Characteristics of Life Growth: an increase in the size of an organism due to an increase in the size and number of cells Development: all of the changes that take place throughout the life span of an organism
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The Characteristics of Life Reproduction: All living organisms are able to produce live offspring.
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The Characteristics of Life Adaptation to environment: All living organisms are able to adapt to their surroundings. They are able to react, or respond to an environmental condition, or stimulus.
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The Characteristics of Life Maintenance of Homeostasis: All living organisms are able to maintain a relatively constant internal environment. Homeostasis: The regulation of an organism’s internal environment to maintain conditions suitable for life.
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The Characteristics of Life Are bacteria alive? How about viruses?
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