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The National Science Education Standards (1996. National Research Council. Washington D.C.) comprise an integrated set of standards for science teaching, professional development for teachers of science, assessment in science education, science content, science education programs, and science education systems with the ultimate goal of developing a scientifically literate populace. While the value of C-Fern as a model system make it useful for many of the standard sets, here we focus on the application C-Fern in the Science as Inquiry and the Life Science Content Standards.

Science as Inquiry

As a central focus of the National Standards, inquiry-based learning requires that students be given the opportunity to develop skills in asking questions, designing and conducting investigations, using tools to collect data, critically evaluating experimental results and communicating the results and implications of scientific studies. Several features make C-Fern ideal for inquiry-based and individual or group experimental approaches. During the rapid two-week development of C-Fern, from spores to sexually mature gametophytes, many biological processes are easily observed, manipulated and measured. For instance, spore germination (absolute or over time) can be quantified and used to assess the organism's responses to environmental stresses. Also, changes in gametophyte sex ratio (pheromone-based) can be quantified to assess the effects of manipulations, treatments or genotypes within a population. Observations of these and other simple but varied features provide opportunities to ask and refine many types of questions. In addition, because C-Fern gametophytes are small, i.e., 0.5 - 3 mm at maturity, large populations consisting of hundreds of individuals can be cultured in small (60x20 mm) Petri dishes. Rapid development of gametophytes means that experiments can be repeated easily and successive experiments can be easily extended over time. These properties make it possible to generate very large data sets for individual and classroom-level experimentation and thus provide an excellent foundation in sampling techniques, quantitative measurements, statistical treatment of data and interpretation and communication of results.

Life Science Content Standards The broad applicability of C-Fern for a variety of classroom uses means that it can be applied and integrated into several of the Content Standards. Life Science standards focus on the science facts, concepts, principles, theories, and models that are important for all students to know, understand, and use. In the following Table, the bulleted list highlights some of the specific C-Fern attributes that are relevant to each standard category.

 

 

Life Science Standards

 

Levels K - 4

Levels 5 - 8

Levels 9 - 12

Characteristics of organisms
Structure and function in living systems
The cell
  • plant form and function
  • basic requirements for plant growth
  • C-Fern exists as two independent organisms
  • gametophytes allow easy visualization of cell structure and differentiation
  • comparative studies of gametophyte and sporophyte structure and function
  • structure and function in gametophyte tissues -vegetative, meristematic, absorptive/anchoring, specialized sperm cells
  • cell motility (sperm)
  • chemotaxis (sperm)
  • spores as single-celled propagules
  • Life cycles of organisms
    Reproduction and heredity
    Molecular basis of heredity
  • sexual and asexual reproduction
  • non-flowering plant reproduction
  • C-Fern clearly shows the relationship of all aspects of sexual reproduction
  • genetic studies with C-Fern allow examination of both haploid (gametophytic) and diploid (sporophytic) ratios
  • a wide variety of mutant stocks allows extended investigation of the effects of mutation
  • although structure and function are very different, C-Fern gametophytes and sporophytes contain the same genetic instructions
  • gametophytes have ½ the chromosomes of the sporophyte
  • sexual differentiation in gametophytes is related to a chemical control of gene expression
  • mutants exist that have altered responses to the chemical (pheromone) that controls sexual type
  • Organisms and environment
    Regulation and behavior
    Biological evolution
  • responses to changes in environment (C-Fern can be grown both terrestrially and aquatically)
  • changes in sex ratio in response to population size and/or environment
  • changes in sporophyte growth in response to aquatic vs. terrestrial environment
  • ferns have adapted for a specific lifestyle
  • C-Fern has specialized adaptations for a ‘semi-aquatic’ lifestyle
  •  
    Populations and ecosystems
    Matter, energy, and organization of living systems
     
  • the effect of population size on sex ratio or early sporophyte development
  • C-Fern is autotrophic and exhibits distinct adaptations for photosynthesis and related activities
  • C-Fern gametophyte and sporophyte generations are independently autotrophic
  •  
    Diversity and adaptation of organisms
    Behavior of organisms
     
  • the structure and function of the C-Fern life cycle relative to other plants
  • adaptation to different environments
  • chemotaxis by C-Fern sperm shows behavior at the single cell level
  • C-Fern shows typical plant responses to the environment
  • population pressures influence development in both gametophytes and sporophytes