Open system with a heart (one ventricle and one or two auricles).
Biology, 7th Grade Topic: Diversity, Structure, and Role in Nature 📂 Slide 1: Introduction Definition: Gastropods are the largest class of mollusks. Species: Over 100,000 known species. Habitat: Occupy sea, freshwater, and land. Key Feature: A single, often spiral-shaped shell. 📂 Slide 2: External Structure Open system with a heart (one ventricle and
Snails carry parasitic worms (e.g., Liver Fluke). 💡 Tips for your presentation: Habitat: Occupy sea, freshwater, and land
Most terrestrial snails (e.g., Grape Snails). 💡 Tips for your presentation: Most terrestrial snails
Provides protection; can be coiled (right or left-handed) or reduced (as in slugs). 📂 Slide 3: Internal Anatomy
Many marine species (separate males and females). Fertilization: Usually internal. Development: Direct (small snails hatch from eggs). Indirect (larval stage in some marine species). 📂 Slide 5: Diversity of Gastropods Grape Snail: A common land herbivore.