Invasive Aquatic Plant Indentification
Grade : 5 to 8
Length: one hour
Location: inside or outside
Subjects : life science, ecology
Topics: Botany- aquatic plant structure, invasive aquatic plant characteristics
Maine Learning Results
Middle Grades 5-8
A-1 Classifying Life Forms
Students will understand that there are similarities within the diversity of all living things. Students will be able to:
1. Compare systems of classifying organisms including systems used by scientists.
B-2 Ecology
Students will understand how living things depend on one another and on non-living aspects of the environment. Students will be able to:
2. Analyze how the finite resources in an ecosystem limit the types and populations of organisms within it.
E-2 Ecosystems
Students understand how plants and animals depend on each other and the environment they live in.
E1-Biodiversity
Students describe similarities and differences in the observable behaviors, features, and needs of plants and animals.
Objectives: Exercises in this lesson help students achieve the following objectives:
Students can describe the basic characteristics of aquatic plants by leaf type, pattern and arrangement and by location in the littoral zone.
Students will be able to use a simple dichotomous key in identifying aquatic plants.
Students will recognize the value of native plants and how invasive aquatic plants can disrupt the ecosystem.
Background
Aquatic plants have specialized physical and adaptive characteristics that enable them to succeed within a niche. Some of these adaptations are:
- Flexible leaves and often finely divided spongy and lack cuticle
- heterophylly – more than one leaf type
- stems are flexible, contain chlorophyll and spongy tissue
- height can vary dramatically within species
- diverse root systems allow dense mixed stands
- various over wintering strategies, e.g. rhizomes, tubers, turions, winter buds, whole plant
- most reproduce by clonal expansion, some produce seeds
In all environments organisms with similar needs may compete with one another for resources, including food, space, water, air, and shelter. For any particular environment, some kind of plants and animals survive well, some survive less well, and some cannot survive at all. In any particular environment, the growth and survival of organisms depend on the physical conditions. Students can explore adaptations of certain plants found in water- how plants remain at the surface to be near the sun for photosynthesis, how plants reproduce. These adaptations can be compared to common plants found on land.
Ecosystems can be reasonably stable over hundreds or thousands of years. As any population of organisms grows, it is held in check by one or more environmental factors: depletion of food or nesting sites, increased loss to increased numbers of predators, or parasites. Many natural and human processes affect the kind and distribution of aquatic plants. If a disaster such as flood or drought occurs, the damaged ecosystem is likely to recover in states that eventually result in a system similar to the original one. When catastrophic events or human activities alter a habitat, specialized plants, such as invasive weed species, often appear. Aquatic plants also impact, nutrient, chemical and temperature regimes and other biota in a lake or reservoir, especially in the littoral zone for more information go to Maine Center for Invasive Aquatic plants, Volunteer Lake Monitoring Program at http://mainevolunteerlakemonitors.org . Limiting factors of some common aquatic plants can be addressed. These same factors can be explored when a non-native aquatic plant is introduced to an ecosystem. A native and non-native aquatic plant can be compared for their different abilities to adapt in a particular location.
Materials
- 7-10 Picking Trays
- 6-12 Hand Lenses
- 3 Microscopes
- Petri dish - Several per station ( 5 Stations)
- Tweezers 6-10
- Work sheets
- 5 Plant identification key
- 5 Maine Aquatic Plant field guides
Procedure
- Describe the different living things within a given habitat. Students will learn to recognize common native plants in local lake habitats.
- Investigate the connection between major living and non-living components of a local ecosystem .Students can look at how aquatic plants exist in lake environments.
- Compare and contrast the life cycles, behavior, and structure of different plants. Students compare and contrast the structure and reproductive methods of aquatic plants
- Present information about aquatic plants and how they are classified. Define invasive aquatic plants.
- Divide students into small groups between the first three stations. Have students work through each of the stations rotating Station 1-3 dealing with plant structure. (See Worksheets- Friend or Foe, Simple Key for plant identification))
Station 1 - Leaf Arrangement - have a least one example of each type of leaf arrangement at this station along with tweezers and smaller dishes for looking a small samples. Label the trays A, B, C.
Station 2 – Leaf Type- Arrange plants in picking trays having at least one of each different leaf type. Label the trays A, B, C. Have tweezers, microscopes and Petri dishes available for close examination.
Station 3 - Leaf Patterns – Arrange plants in picking trays having a least one example of each leaf pattern. Label the trays A, B, C. Have a hand lenses tweezers and Petri dishes available to allow for closer inspection).
Plant identification –
Level 1 (Station 4) identify aquatic plants using a key.
Level 2 (Station 5 ) identify aquatic plants using a key and identify the invasive plant. Have identification keys and plants at each station along with several hand lenses and aquatic plant field guides.
Group Review of worksheets. Identify plants located at the stations and process students’ evidence and reasoning behind answers. If there are any discrepancies talk about how similar features can be misleading.
