Lesson Write-Up For Spring Quarter 2013
Your name: Gilene Young
Title of Lesson: Alien Invaders in California
Grade Level: 7th
Subject(s): Life Science/Biology
Summary:
The purpose of this lesson is to introduce the concept of invasive species and review some
of the most common non-native species present in California. First, students learn the
definitions of native and introduced species, including some of the ways that species may
come to live in a certain area. Second, students go through a series of pictures of different
species, and decide with a partner whether each species is native or introduced. This
section includes a number of species that are very familiar to the students. The answers are
reviewed as a class.
The students then learn the definition of invasive species and review some examples. The
final example is Argentine ants, which leads into the lab activity. Students are assigned the
role of an ant, a plant, or a horned lizard (which eats ants). In the first round, only native
harvester ants are present. Students who are ants travel among plants to forage, while
horned lizards occasionally attempt to “eat” an ant. At the end of the round, students tally
the condition of the plants and the number of surviving ants. In the second round, students
play both harvester ants and Argentine ants. Lizards do not eat Argentine ants. Again, the
condition of the plants and numbers of surviving ants of each species are recorded. Any
lizards that do not eat should also be tallied.
By the end of the activity, students should see that introduced Argentine ants can spread in
part because they lack natural biological controls such as predators. Harvester ant
populations will not be able to compete. This simulation allows the students to see for
themselves how invasive species can upset ecosystems and damage native species.
Time Required: 90 minutes
Cost to implement:
Materials:
Plastic headbands (36) - $2.50 per 6-pack
Pipe cleaners (green and brown) – about $5
Construction paper (green and brown)
Total: ~ $25
Learning Goals:
After this lesson, students should be able to:
1) Define native, introduced, and invasive species.
2) Explain some of the reasons why invasive species can be harmful.
3) Recognize common non-native species in California.
Level of Inquiry:
This lesson involves guided inquiry. During the group activity, students must guess
whether species are native or introduced based on prior knowledge. In the simulation lab,
students hypothesize about what will happen to the populations of plants, ants, and lizards.
They then collect data and evaluate their predictions. This activity requires that students
think about how species interact, how small changes can effect an entire ecosystem, and
how populations change over time.
Introduction / Motivation:
The lesson can begin with asking the students whether they have heard the term “invasive
species” before, and if they know of any examples. The group activity includes a large
number of species that the students see around them all the time, such as Western gulls,
palm trees, iceplant, and bird of paradise. Similarly, the simulation focuses on one of the
main pests of the Los Angeles area, the Argentine ant. This allows them to connect
personally to the material and better understand their immediate environment. For further
involvement, you can ask the students to collect and bring in ants to see if anyone can find
any native species. The majority of students will only find Argentine ants.
Lesson Background Concepts for Teachers:
[Review the basic concepts behind the lesson and explicitly explain how the lesson
illustrates the concepts. Place your lesson in context for the teacher].
This lesson is divided into four sections. First, the lecture defines the terms native and
introduced. The main concept here is the role of humans in establishing a species’ range.
This can be explained using examples such as black and Norway rats, which spread around
the world as stowaways on ships. In addition, the lecture should mention some of the ways
that species’ ranges are established, both naturally and with humans as the mechanism. In
the second section, students work with a partner to evaluate whether species are native or
introduced. These answers are discussed as a class, and prizes can be awarded for the
group that gets the most correct. For each species, discuss their original range, where they
currently live in California, and any interesting facts about the species.
Third, define the concept of invasive species. Not all introduced species are invasive.
Species are invasive only if they disrupt the ecosystem in some way. An excellent example
is iceplant, which was planted widely in California to stabilize the soil along railroads.
Iceplant actually speeds up coastal erosion and has been very detrimental to coastal
ecology in California. One of the most common invasive species in California is the
Argentine ant, which forms huge “super-colonies” that do not compete with each other.
Argentine ants displace most of the native ants in California, which affects other species as
well. For example, the coastal horned lizard does not eat Argentine ant, and has been
declining in areas where native ants have been replaced. This species interaction is the
focus of the lab activity.
Procedure:
1. Students are assigned roles
a. Ants (10-14 students)
b. Horned lizards (2-3 students)
c. Plants (remaining students)
2. Round 1
a. All ants are native harvester ants
b. Ants have a set period of time to collect leaves from the plants
c. Each leaf must be brought back to the ant nest before getting a second leaf
d. Lizards eat on the instructor’s cue (about 3-5 times) by tagging the closest
ant with a hand
e. At the end, count the number of surviving and dead ants and rate each plant’s
condition based on the number of remaining leaves
3. Round 2
a. Students switch roles
b. Half the ants become Argentine ants instead of harvester ants
c. Horned lizards eat only harvester ants
d. Same procedure as Round 1
4. Class discussion and wrap-up
Materials List
Approximately 180 green paper leaves (10 per plant)
Headband with attachments for each student:
 Ants: brown pipe cleaners as antennae
 Lizards: brown/black paper horns
 Plants: green pipe cleaners arranged like grass
Ants and lizards get pictures of their organism to tape to their shirt – 14 harvester ant
pictures, 7 Argentine ant pictures, and 3 lizard pictures.
Safety Issues:
Students must be kept orderly while outside.
Lesson Closure:
After the simulation activity, the students get a worksheet with wrap-up questions. This
wrap-up covers how the populations changed, the differences between Round 1 and Round
2, and the potential long-term effects of Argentine ants.
Assessment:
Pre-Activity Assessment:
Before starting the presentation, students share anything they might know about invasive
species. During the presentation, students are asked to define each concept before any
information is given to them. Often several answers can be combined to produce the full
correct definition, which is then shown on the slides.
Activity Embedded Assessment:
In the small group activity, students decide together whether each of 24 species is native to
California or introduced. The answers are reviewed as a class. During the simulation lab,
students write a hypothesis about how the presence of Argentine ants will affect the
ecosystem. They collect and record data on the survival of each species.
Post-Activity Assessment:
The students answer a set of wrap-up questions in a written assignment. The questions and
concepts can be reviewed as a class discussion. In addition, students can share a brief
reflection on what they did and what they learned during the activity.
Is this lesson based upon or modified from existing materials? If yes, please specify
source(s) and explain how related:
The simulation activity was heavily modified from a lesson plan on agricultural pests (see
below).
References:
http://www.nytimes.com/learning/teachers/lessons/20070619tuesday.html
A wide variety of internet resources were used to provide information on each species
discussed.
For the history of palm trees in Los Angeles:
http://www.kcet.org/updaily/socal_focus/history/la-as-subject/a-brief-history-of-palmtrees-in-southern-california.html
Attachments:
Powerpoint slides, including group activity
Activity worksheet
Wrap-up worksheet
Pictures to be printed out for lab
CA Science Standards addressed:
Students know both genetic variation and environmental factors are causes of evolution
and diversity of organisms.
Students know that extinction of a species occurs when the environment changes and the
adaptive characteristics of a species are insufficient for its survival.