Unit 4:
Characteristics of Living Things
Objectives:
By the end of the lesson, students should be able to:
 To recognize and describe the characteristics of living things
Review
Review with students these six easily observable characteristics of living things:
1. movement (which may occur internally, or even at the cellular level)
2. growth and development
3. response to stimuli
4. reproduction
5. use of energy
6. cellular structure
Core Standards: Life Science
MS-LS14.
Use argument based on empirical evidence and scientific reasoning to support an
explanation for how characteristic animal behaviors and specialized plant
structures affect the probability of successful reproduction of animals and plants
respectively.
Misconceptions:
 All cells are the same size and shape
 There are no single celled organisms
 Some living parts of organisms are not made of cells
 Plants are not made of cells
 Cells do not eliminate waste
 Animal cells do not carry out essential life functions for themselves
Materials:
 a computer and projector
 a tech center (if available)
 student pages with sample answers (attached); also open to click on hyperlink
videos
 whole class or independently
Engagement:
Students will examine several objects in video format and list characteristics of life and a
description of the characteristics observed.
Exploration:
Student response sheets.
Explanation:
Defining "life" is a very difficult task, and scientists don’t all agree on a common list of the
characteristics of life. Some of the other characteristics that the students may discover in their
research, and which are often listed in textbooks, include those listed below. Many of these traits
are not limited to living things. For example, fire uses energy, grows, and can reproduce, but it is
not considered alive in part because it cannot evolve; its traits are necessary, but not sufficient,
for life. NASA scientist Bruce Jakosky, in his book The Search for Life on Other Planets,
provides a generally accepted definition of something being “alive” if it 1) utilizes energy from
some source to drive chemical reactions, 2) is capable of reproduction, and 3) can undergo
evolution.
Characteristics of Living Things
 All organisms use energy (metabolism).
 All organisms maintain a stable internal environment (homeostasis).
 All organisms detect and respond to select external stimuli.
 All organisms can engage in movement (which may occur internally, or even at the
cellular level).
 All organisms show growth and development; that is, specialization of cells or structures.
(Even unicellular organisms show a tiny amount of growth, and single cells repair and
use materials from the environment to replace internal structures as needed.)
 All organisms reproduce. (Even if an individual can’t reproduce, its species can.) In
addition, an individual’s cells are constantly reproducing themselves.
 All organisms have nucleic acid as the hereditary molecule.
 All organisms show adaptation, which occurs at the individual level and is tightly related
to homeostasis.
 All organisms are made of one or more cells.
 All organisms exhibit complex organization, grouping molecules together to form cells;
at a higher level, cells are organized into tissues, organs, and organ systems.
 All organisms exhibit evolution over time due to mutation and natural selection (which
operates at the species level).
Elaboration:
 Have students conduct Internet research on "characteristics of life." Do all sources agree
on the characteristics? Are there characteristics not covered in this activity? Do all
scientists agree on a common list of "characteristics of life"?
 What are the limitations of videos? Discuss which characteristics of life students are
unable to identify in the videos. How might they be able to observe these characteristics
in select organisms?
 If all of the characteristics of life are required to classify something as "alive," how can
we account for those individuals who are definitely alive, but that do not reproduce (for
example, people without children or a sterile mule)?
 Is a virus alive? Ask students to keep in mind the information from this activity, and to
conduct Internet research to discover how scientists answer this question.
Evaluation:
Accuracy in student recordings.
Characteristics of Life Data Table
Sample Answers
Category
Characteristics of Life
C. elegans
(Caenorhabditis elegans)
Movement, use of energy,
reproduction
Video: Moving C. elegans
Sea Urchins
(Lytechinus pictus)
Growth and development, made
of cells
The cell divides twice to
become four cells. The new
cells are smaller than the
original cells.
Reproduction, movement
The sea urchin sperm swim to
the egg; the egg raises a
membrane.
Movement, use of energy, cells
The white blood cells move
around a lot, which requires
energy.
Movement, made of cells
Green spots move inside the
cells; leaf cells surrounded by
walls.
Movement, made of cells,
growth and development
The stem cells in the first video
move a lot. The specialized
heart cells developed from
embryonic stem cells.
Movement, use of energy
The amoeba uses energy to
move around.
Growth and development,
movement, reproduction, made
of cells
The cells of the embryo divide
into more cells, and the embryo
develops into a baby fish that
moves a lot inside the egg.
Video: Sea urchin cell division
Sea Urchins
(Lytechinus pictus)
Video: Sea urchin fertilization
Blood Cells
Video: Human white blood cells
Cellular Structure and Function
Video: Elodea leaf cells
Stem Cells
Videos: Compare Mouse
embryonic stem cells—movie
1 with Heart cells grown from
mouse embryonic stem cells—
movie 1
Cell Motility
Video: Crawling Amoeba
Zebrafish
(Danio rerio)
Video: Zebrafish development
Description of Observed
Characteristics
The worms crawl to locate
their food (source of energy);
their eggs are visible.
Name
Date
Observing the Characteristics of Life
In this activity, you’ll identify observable characteristics of life in videos of various
organisms and describe those characteristics.
Review
What are six easily observable characteristics of living things?
1.
2.
3.
4.
5.
6.
To Do and Notice
If your teacher is displaying the videos:
Record one or more of the characteristics that you observe for each category and describe it
on the data table that follows.
If you are doing this activity independently:
1. On the data table, click on each category name in turn.
2.
Read the introduction, then play the video.
3.
Record one or more of the characteristics that you observe for each category and
describe it on your data table.
continued
Name
Date
Characteristics of Life Data Table
Category
C. elegans
(Caenorhabditis elegans)
Video: Moving C. elegans
Sea Urchins
(Lytechinus pictus)
Video: Sea urchin cell division
Sea Urchins
(Lytechinus pictus)
Video: Sea urchin fertilization
Blood Cells
Video: Human white blood cells
Cellular Structure and Function
Video: Elodea leaf cells
Stem Cells
Videos: Compare Mouse
embryonic stem cells—movie
1 with Heart cells grown from
mouse embryonic stem cells—
movie 1
Cell Motility
Video: Crawling Amoeba
Zebrafish
(Danio rerio)
Video: Zebrafish development
Characteristics of Life
Description of Observed
Characteristics