Principles of Biology II Lab Four Recitation Notes

Principles of Biology II Lab Four Recitation Notes

Overview of Lab Four and Test Coverage

  • The lab recitation is for Principles of Biology II, specifically lab number four.

  • Preparation for the first test:

    • The test will cover topics from labs one through four.

  • Emphasis on safety rules:

    • Safety rule sheets were distributed in class; crucial to review those.

  • Focus on class notes:

    • Materials covered in lectures and recitations are fair game for questions on tests.

    • Materials not covered in class (e.g., PowerPoints, lab manuals) will not be tested.

Review of Chapter 7: The Animal Kingdom

  • Familiarity with Chapter 7 of the Photo Atlas (eighth edition) is essential, especially the introduction to the animal kingdom and its chart listing nine phyla.

  • The phylogenetic tree of the animal kingdom will be discussed in detail.

    • Various organisms will be analyzed, starting from simpler to more complex animals.

  • Characteristics defining the animal kingdom:

    • Kingdom Animalia includes multicellular, eukaryotic, heterotrophic organisms.

    • Classification criteria include:

    • Body symmetry (e.g., asymmetry, radial symmetry, bilateral symmetry)

    • Tissue organization

    • Body cavity structure

    • Organ function

Basic Definitions and Concepts

  • Tissue: A group of similar cells performing a common function.

  • Symmetry (Types):

    • Asymmetry: No symmetrical arrangement (e.g., sponges).

    • Radial Symmetry: Symmetrical around a central axis (e.g., sea anemone). Any cut along the central axis produces mirror images.

    • Bilateral Symmetry: Symmetrical halves; different structures (e.g., turtles) can be seen when cut longitudinally versus laterally.

  • Directional Terms:

    • Anterior (toward the head)

    • Posterior (away from the head)

    • Dorsal (top)

    • Ventral (bottom)

Phylum Porifera (Sponges)

  • Characteristics of Phylum Porifera:

    • Simplest animals, lacking tissues and organs, composed of cells only.

    • Exhibit asymmetry.

  • Feeding method:

    • Filter feeders: Filter water to remove food particles through pores (ostia) leading to a central cavity called the spongocoel.

  • Cell Types:

    • Choanocytes: Flagellated cells lining the spongocoel that help move water and filter food particles.

    • Amoebocytes: Mobile cells involved in digestion and nutrient distribution within sponges.

  • Examples of sponges discussed: Grantia and glass sponges (e.g., Eupectella).

Phylum Cnidaria (Jellyfish, Corals, Sea Anemones)

  • Characteristics of Phylum Cnidaria:

    • Marine carnivores with radial symmetry.

    • Capture prey using specialized stinging cells known as nematocytes.

  • Classes within Phylum Cnidaria:

    • Class Hydrozoa: Includes Hydra and Obelia, characterized by both polyp and medusa forms.

    • Class Scyphozoa: Dominated by jellyfish, focusing on the medusa form with gastrovascular cavity divided into pouches.

    • Class Anthozoa: Includes sea anemones and corals, existing only in polyp form with a hard skeleton made of calcium carbonate (CaCO₃).

Symmetrical Body Plans

  • Two general body plans:

    • Sac Body Plan: Exhibited by sponges, cnidarians, and flatworms (one body opening).

    • Tube Within a Tube Body Plan: Displayed by roundworms and further animal phyla (two openings: mouth and anus).

Phylum Platyhelminthes (Flatworms)

  • Description and characteristics:

    • Known as flatworms, with bilateral symmetry and no body cavity (acoelomates).

    • Notable representatives include planarians, flukes, and tapeworms.

    • Capable of regeneration; some, like Planaria, display hemiphrasis and light sensitivity through eyespots.

Phylum Nematoda (Roundworms)

  • Characteristics:

    • Roundworms exhibit bilateral symmetry with a complete digestive system (tube within a tube), having distinct mouth and anus.

    • Examples include Ascaris (a parasitic roundworm).

Phylum Rotifera (Rotifers)

  • Features:

    • Found in freshwater; have a differentiated body structure (head, body, foot) and a complete digestive system.

Practical Lab Components

  • Students will observe samples in the lab for hands-on learning:

    • Specimens from each discussed phylum will be shown, including aquatic and microscopic views.

    • Encourage active comparison between live organisms and the material learned in class and lab manual.

Photo Atlas Reference Points

  • Important pages include:

    • Pg. 151: Various sponge structures (e.g., Grantia).

    • Pg. 158-159: Cnidarians, including hydras, jellyfish, and corals.

    • Emphasize diagrams of body plans, including polyp and medusa forms.

  • Utilize the atlas for visual representation of structures and as reference material during lab exercises.