Chapter 1
The
Nature of Life
Chapter 1
Are viruses organisms (living things)?
I. Characteristics of Life
A. List characteristics of all living things & nonliving things:
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| all have CARBON atoms | some nonliving things have carbon, such as, CO2 (carbon dioxide)& CO (carbon monoxide) |
| all living things use energy | don't use energy |
| have definite shape and size | |
| have a limited life span | |
| living things = organisms | |
| grow | |
| respond to changes in the environment | |
| some reproduce | |
| all have a metabolism | |
| living things are made of one or more cells. |
A. Scientists have been unable to agree upon a single definition of life. This syllabus characterizes life by the functions (fxn’s) that living organisms perform.
B. LIFE FUNCTIONS (processes) [in class students discussed examples of each processes]1. Nutrition includes the activities of an organism by which it obtains materials from its environment and processes them for its use.
a. heterotrophic nutrition- can NOT make own food, consumes other organisms
b. autotrophic nutrition- organisms that have the ability make their own organic food from inorganic material
2. Transport involves the absorption & distribution (circulation) of materials within an organism.
3. Respiration includes the exchange of gases AND those processes which provide the energy necessary for the maintenance of life functions.
a. aerobic- releases energy while using oxygen
b. anaerobic- releases energy without using oxygen
4. Excretion involves the removal of cellular (metabolic) waste products.
5. Synthesis involves those chemical activities by which large molecules are built from smaller ones. ex) assimilation- taking this material and combining it into your body-ATP.
6. Regulation involves the control coordination of the various activities of an organism.
7. Growth involves an increase in cell size and/or cell numbers. The process utilizes the products of synthesis.
8. Reproduction involves the production of new individuals. Species survival is dependent upon this life fxn.
a. sexual- involves 2 parents, offspring contains different genetic material
b. asexual- only 1 parent, offspring is a clone of parent
C. METABOLISM is the sum of all the life activities required to sustain life.
1. anabolism-building process
2. catabolism-breaking down process
D. HOMEOSTASIS in order for an organism’s metabolism to work properly, it must maintain a stable internal environment. This maintenance is known as homeostasis.
Life Function Interactive Quizzes
return to Mr. Buono's syllabus
