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Chapter 2 It's Alive!! Or Is It?

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Section 1 Characteristics of Living Things

Section 2 The Necessities of Life

Concept Map


Section 1 Characteristics of Living Things Chapter 2

Bellringer

Pull out a blank piece of paper and brainstorm characteristics of living things. What does it mean to be alive.


Chapter 2

What You Will Learn

• Living things are composed of one or more cells.

• Living things sense and respond to changes in their environment.

• Living things produce offspring through sexual reproduction or asexual reproduction.



Chapter 2

What You Will Learn, continued

• The cells of living things contain DNA.

• Living things use energy.

• Living things grow and develop.



Chapter 2

1. Living Things Have Cells

• All living things have six characteristics in common. One characteristic is the presence of cells.

• A cell is the structural and functional unit of life.

• A cell is the smallest unit that can carry out the activities of life.



Chapter 2

Living Things Have Cells, continued

• In single-celled organisms, different parts of the cell perform different functions.

• In organisms with many cells, different kinds of cells perform specialized functions.



Chapter 2

2. Living Things Sense and Respond to Change

• A change that affects the activity of an organism is called a stimulus (plural, stimuli).– Ex. When you touch a hot stove your body reacts

to the stimuli

• Examples of stimuli include chemicals, gravity, light, sound, and hunger.



Chapter 2

Living Things Sense and Respond to Change, continued

• While conditions may change in the surrounding environment, an organism must maintain a constant internal environment to survive. This is called homeostasis.

• Different types of organisms achieve homeostasis in different ways.



Chapter 2

3. Living Things Reproduce

• A third characteristic shared by living things is the ability to produce offspring like themselves.

• In sexual reproduction, two parents produce offspring that share characteristics of both parents.

• In asexual reproduction, a single parent produces offspring that are identical to the parent. Most single-celled organisms, and some multi-celled organisms, reproduce asexually.



Section 1 Characteristics of Living Things Chapter 2


Chapter 2

4. Living Things Have DNA

• A fourth characteristic shared by all living things is the presence of deoxyribonucleic acid, or DNA, within the cells.

• When organisms reproduce, they pass on copies of their DNA to their offspring. This ensures the passing of traits to the offspring.

• The passing of traits is called heredity.



Chapter 2

5. Living Things Use Energy

• A fifth characteristic shared by living things is the use of energy to carry out the chemical activities of life.

• These chemical activities include growing, building cells, and moving materials in and out of cells.

• The sum of all the activities that an organism performs is called its metabolism.



Chapter 2

6. Living Things Grow and Develop

• The sixth and final characteristic shared by all living things is the ability to grow.

• As living things grow, they may also develop and change.

• Many organisms grow only during certain stages of their lives.



1. Write questions for your notes

2. Work on your section review

3. Work on your study guide, focusing on questions 1,2,3,4,9,10,12 and 13.

4. If finished with these three things, feel free to work on any homework you may have for a different class

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