An understanding of plant growth and development is essential in understanding how and why alien plant species adversely affect the land and water quality of our environment.  In the previous Ecosystems Unit, students learned how biological diversity exists as an intricate web of populations uniquely adapted to the environmental conditions within particular communities.

Plants deal with their environment in different ways than animals do. Although we are surrounded by plants all our lives, most of us never realize just how alien they are. From the way they manufacture their food to the ways in which they respond to the environment, plants are quite different from animals.

An important reason for this difference is the sedentary lifestyle of plants. While some animals are sedentary, such as barnacles and sponges, most are quite able to move around. Thus, when conditions become uncomfortable, they may simply move away to another location. By contrast, plants are generally unable to move to a new location, but must rather cope with the circumstances in which they find themselves. For example, if a lion began to nibble on your leg, you would probably try to run away, however when a grasshopper begins to nibble on the leaf of a plant, the plant cannot simply run away. Instead plants must deal with the situation where they stand, by such means as producing noxious chemicals, growing spines, and generating sticky saps to deal with this problem.  Plants cannot move when they are too hot or too cold, or when they are thirsty, or when their environment dramatically changes.

Alien plant species become invasive because of a range of adaptations that allow them to survive a wide range of environmental changes.  When an environment is altered and disturbed, usually at the hand of humankind, the delicate web of environmental connections are broken, thus changing the conditions to which native plants and animals are adapted.  Alien plant species can often cope with these changes by mechanisms that allow them to establish themselves before the native species can recover.  By producing seed heads with thousands of seeds in each pod, by producing seeds that may germinate within a wider range of temperature and moisture conditions, by having rapid growth patterns that utilize soil nutrients before the native plants can use them, and by developing extensive root systems that rob native plants of precious water reserves, alien plants establish themselves in disturbed environments and crowd out the more finely adapted native species.

The following activities provide students with an introduction to these alien plants, provides them with skills to begin a basic inventory and research into alien plant species, presents opportunities to collect and preserve field specimens through plant pressing and photography, and to express their understanding of plants through both research and art.

Your Curriculum - Many life science curricula follow a pattern of exploration in the study of plants; from simple plant species to the complex flowering plants. The following lessons can be incorporated with your regular curriculum in Life Science, the biosphere, plant development units, and the characteristics of plants within their environment. When you combine these lessons with your own curriculum you take the first step to integrating invasive plants species as a unifying theme.

• When Is A Rose Not A Rose? - Defining Plants As Weeds - Research & Activities
• Tracking Aliens In The School Yard - Mapping
• Alien Wanted Posters - Photography               Sample WANTED poster
• Pressing Aliens - Collection
• Raising Aliens - Growing                      
• Make-Believe Alien - Assessment through Art

The glossary at the end of each lesson provides additional keywords that can assist you with background information for the integration of concepts similar to your own curriculum.

Last updated 10/24/03