Section 6 - Characteristics of Living Things
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Review the information below, and answer the questions to follow. This material will be
included in your first test.
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Characteristics of Living Things
Scientists have identified certain characteristics that are found in all living things. If something in
question does not possess ALL of these characteristics, it is considered nonliving.
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1. All living things are made of one or more cells.
A. The cell is the basic unit of structure and function in living things.
B. Organisms may be unicellular (like bacteria) or multicellular (like plants).
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2. All living things display organization.
A. The levels of organization in biological systems begin with atoms and molecules and
increase in complexity.
B. Each organized structure in an organism has a specific function.
C. Levels of organization:
cell g tissue g organ g organ system g organism
a. Specialized cells are organized according to function into groups that work together,
called tissues.
b. Tissues are organized into organs.
c. Organs then comprise organ systems that work together to support an organism.
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3. All living things grow and develop.
A. Growth results in an increase in mass.
B. Development results in different abilities that the organism may acquire over time.
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4. All organisms reproduce.
A. Organisms reproduce and pass along traits from one generation to the next.
B. Reproduction may occur sexually or asexually.
a. In sexual reproduction, DNA from two parent organisms combines to create
offspring. This allows for various gene combinations.
b. In asexual reproduction, no DNA is combined. One parent reproduces to create
offspring with genetically identical DNA. Changes in DNA (causing genetic
variation) only occur by mutations to the DNA.
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5. All living things respond to stimuli.
A. Anything that is part of the internal or external environment that causes a reaction in the
organism is called a stimulus.
B. Reactions to external and internal stimuli are called responses. !
Section 6 - Characteristics of Living Things
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6. All living things require energy.
A. Energy is required for all life processes.
B. The process of using energy is called metabolism, and metabolic reactions occur
continuously.
C. Living things get their energy from food.
a. Most plants and some unicellular organisms use energy from sunlight to create their
own food to fuel cell processes (photosynthesis). These organisms are known as
producers or autotrophs.
b. Organisms that cannot make their own food get energy by consuming other
organisms. These organisms are known as consumers or heterotrophs.
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7. All living things maintain homeostasis.
A. Homeostasis is the regulation of an organism’s internal conditions to maintain stability
and therefore, life.
B. If anything happens within or to an organism that affects its normal state, processes to
restore the normal state will initiate. !
8. All living things possess adaptations that evolve over time.
A. An adaptation is any inherited characteristic that results from changes to a species over
time.
B. The theory of natural selection states that organisms with favorable traits will survive and
reproduce better that organisms who do not possess those traits.
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Answer the following questions on a separate sheet of paper. Remember to use the following
formatting:
- If typed, use size 12 Times New Roman font and single spacing. - If handwritten, print your responses neatly. - Leave one line of blank space between each response.
- Use the following heading in the top left corner of your response sheet:
Student Name
Pre-AP Biology
Summer Assignment, Section #
Date of completion (not the due date)
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Section 6 Review Questions:
1. Identify a nonliving thing. How can you be certain it is nonliving? Identify and describe 3
characteristics listed above displayed by the organism that confirm your prediction.
2. Identify a living thing. How can you be certain it is living? Identify and describe 3
characteristics listed above displayed by the organism that confirm your prediction.
3. What is the difference between an organism’s response and an adaptation it possesses?