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Mollusks and Echinoderms
Big Idea
Evolution of animals has led to new classification systems and complex body structures.
Essential Questions
Compare the essential functions of mollusks and echinoderms in general.
Compare the circulatory and digestive systems of phyla covered thus far (Porifera-Echinoderm).

Demonstrate safe and ethical procedures (e.g., use and care of technology, materials, organisms) and behavior in all science inquiry.
Record observations, notes, sketches, questions, and ideas using tools such as journals, charts, graphs, and computers.
Analyze, using a biological classification system (i.e., cladistics, phylogeny, morphology, DNA analysis), the degree of relatedness among various species.
Conduct a scientific investigation that is based on a research design.
Communicate results clearly and logically.
Describe the levels of organization of living things from cells, through tissues, organs, organ systems, organisms, populations, and communities to ecosystems.
Science & Engineering Practices
Planning and Carrying Out Investigations
Planning and carrying out in 9-12 builds on K-8 experiences and progresses to include investigations that provide evidence for and test conceptual, mathematical, physical, and empirical models.
  • Plan and conduct an investigation individually and collaboratively to produce data to serve as the basis for evidence, and in the design: decide on types, how much, and accuracy of data needed to produce reliable measurements and consider limitations on the precision of the data (e.g., number of trials, cost, risk, time), and refine the design accordingly. (HS-LS1-3)
Content/Core Ideas
  • Mollusks and echinoderms are further along the evolutionary chain than worms.  
  • Although Mollusks and Echinoderms have some traits in common such as three germ layers and a true coelom they are very different in mosts aspects.
  • Circulatory systems found in the 7 phyla covered thus far include: open circulatory systems, closed circulatory systems, diffusion and a water vascular system.  
  • Digestive systems vary depending on the use of intracellular digestion, extracellular digestion or both.
Learning Practices
CCSS.ELA-Literacy.RST.11-12.7 Integrate and evaluate multiple sources of information presented in diverse formats and media (e.g., quantitative data, video, multimedia) in order to address a question or solve a problem.

Design and use graphic organizers to show relationships between and within content topics (flowcharts, venn diagrams, cladograms, mind maps...).

Active Engagement Partner work:  Students work with partner(s) to solve basic problems, build models, think pair share...
Academic Vocabulary
Mollusk vocab
visceral mass                                
ganglion (pl. ganglia)              chromatophores
Echinoderm vocab
water-vascular system
tube foot
oral surface
aboral surface
ring canal
ampulla (pl. ampullae)
cardiac stomach
pyloric stomach
nerve ring
radial nerve
intracellular digestion
extracellular digestion
These are SOME ways for students to demonstrate knowledge and understanding of the content.
  • Design a cladogram showing the evolutionary advances from porifera to echinoderms.
  • Students will examine and compare the internal structures of a squid and sea star through dissection.
  • Students will create a graphic organizer that depicts the development of the circulatory and digestive systems of animals over time.