Biology Notes

Biology Notes - Ashley Wandishin Chapter 1- A View of Life...

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Ashley Wandishin Chapter 1- A View of Life Biology - the science of life Evolution - populations of organisms have evolved through time from earlier forms of life. There are diverse life forms on this planet that are related and that the populations have evolved (changed over time), from earlier forms of life. Provides a framework for biology. Information transfer - information must be transmitted within organisms and among organisms. The survival and function of every cell and every organism depend on the orderly transmission of information. Evolution depends on the transmission of genetic information from one generation to another Energy for life- all life processes, including the thousands of chemical transactions that maintain life’s organization, require a continuous input of energy All organisms consist of basic units called cells (which are only formed from preexisting ones- cell theory ) Unicellular organisms consist of a single cell Multicellular organisms consist of billion of cells, life processes depend on the coordinated function of component cells that may be organized to form tissues, organs and organ systems Plasma membrane- a separator for the cell from the surrounding external environment DNA- (deoxyribonucleic acid) genetic instructions are encoded in this in most cells
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Organelles- the internal structures found within a cell specialized to perform specific functions Prokaryotic cells - exclusive to bacteria and to microscopic organisms called archaea, contain no nucleus or other membrane- enclosed organelles Eukaryotic cells- all the other organisms, contain a variety of organelles (including a nucleus [houses DNA]) within a membrane) Biological growth- involves an increase in the size of individual cells of an organism, in the number of cells, or in both Living organisms develop as well as grow Development- includes all the changes that take place during an organism’s life Metabolism- the sum of all the chemical activities of the organism Metabolic process occur continuously in every organism and they must be carefully regulated to maintain homeostasis (an appropriate, balanced internal environment) Homeostatic mechanisms help regulate the metabolism (e.g. glucose concentration in blood of complex animals) All forms of life respond to stimuli (physical or chemical changes in their internal or external environment)
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Responding to stimuli involves movement, though not always locomotion In simple organisms, the entire individual may be sensitive to stimuli Locomotion in some organisms happens through the process of amoeboid movement (slow oozing of the cell), cilia (tiny, hair-like extensions [beating of this]), or flagella (longer structures [rotation of this]) Most sponges, corals and oysters have free-swimming larval stages but most are sessile (do not move from place to place) as adults, so they use their cilia or flagella to moving the water around to obtain food and oxygen Simple organisms reproduce through asexual reproduction
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Biology Notes - Ashley Wandishin Chapter 1- A View of Life...

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