Name: _____________________________________
Period: _____ Seat #: _____ Date: _______________
Invasive Species Lab
Purpose: To observe the effects of an introduced invasive species on a native ecosystem.
Introduction:
Humans have moved hundreds of species all around the world, both on purpose and by accident.
Invasive species are non-native organisms that replace the species originally present in an environment.
Many of the species in Southern California today are invasive. For example, California has 245 different
species of native ants, but the most common ant in Southern California is the introduced Argentine ant.
Materials:
Harvester ant pictures/antennae
Argentine ant pictures/antennae
Horned lizard pictures/horns
Paper seeds
Nest buckets
Timer
Procedure:
1. For Round 1, you will be assigned one of 3 roles: harvester (native) ant, horned lizard, or purple
needle grass plant. For Round 2, we will add Argentine ants.
2. Students who are plants should hold 10 seeds each and stand in the designated spots.
3. Students who are ants will travel to and from the nest to forage (collect seeds).
4. Students who are lizards will occasionally “eat” ants by tagging them with a hand.
Rules:
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Ants may only take ONE seed at a time from each plant.
Ants must take each leaf back to the nest individually.
Ants who are eaten will sit down.
NO RUNNING!
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Plants must give ONE seed to each ant that visits.
o
o
Lizards can position themselves anywhere in the classroom, but may only move ONCE.
When the bell rings once, each lizard will eat ONE of the ants nearby. If there are no ants within
arm’s reach, the lizard does not eat. Lizards that do not eat by the end of the round will die.
Lizards can only eat native ants.
o
Results:
After each round, fill in the tables with information about the ant and plant populations. Evaluate plant
condition according to the list below.
7-10 seeds = Healthy (H)
4-6 seeds = Moderate damage (M)
1-3 seeds = Severe damage (S)
0 seeds = Dead (D)
Round 1
Plant
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
# of seeds
Condition
Number of harvester ants eaten: ______
Total number of harvester ants: ______
Number of severely damaged or dead plants: ______
Total number of plants: ______
Percentage of harvester ants eaten
Percentage of plants severely damaged or dead
Round 2
Make a hypothesis: Will more harvester ants or Argentine ants survive? _____________________
Plant
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
# of seeds
Condition
Number of harvester ants eaten: ______
Total number of harvester ants: ______
Number of Argentine ants eaten: ______
Total number of Argentine ants: ______
Number of severely damaged or dead plants: ______
Percentage of harvester ants eaten
Percentage of Argentine ants eaten
Percentage of plants severely damaged or dead
Total number of plants: ______
16