UNIT5 GENBIO DAY 1

UNIT 5: ANIMAL BIOLOGY

Introduction to the Phyla

  • Overview of general principles governing classification and characteristics of animals.

AGENDA

  • Integrate systems of classification into specific phyla of animals.

  • Compare and contrast biological processes in different animal groups.

Characteristics of Animals

  1. Multicellularity: Animals are composed of many cells known as multicellular organisms.

  2. Eukaryotic Cells: Animal cells are classified as eukaryotes, which means they contain a nucleus and organelles.

    • They lack a rigid cell wall and are only surrounded by a cell membrane.

  3. Heterotrophic Feeding: Animals obtain nutrients by feeding on other organisms (heterotrophs).

Detailed Characteristics

  • Multicellular and Specialized Cells: Animals consist of specialized cells that form complex tissues and organs.

  • Oxygen Requirement: All animals require oxygen for respiration.

  • Mobility: Most animals demonstrate some form of movement at some stage in their lives.

  • Reproduction: The majority reproduce sexually.

Linnaean System of Classification

  • Hierarchy: In the Linnaean classification system, as one moves from species to kingdom, the number of shared characteristics decreases. Conversely, common characteristics increase as you move down the hierarchy.

    • Hierarchy levels include:

      • Domain

      • Kingdom

      • Phylum

      • Class

      • Order

      • Family

      • Genus

      • Species

Phylum Overview

  1. Phylum Porifera:

    • Non-motile, multicellular organisms with a porous body, known as filter-feeders.

    • Characterized by lack of symmetry and poorly developed organ systems.

  2. Phylum Cnidaria:

    • Etymology: From Greek "cnidos" meaning stinging nettle.

    • Possess a hollow body cavity, radial symmetry, and live in colonies (e.g., corals) or solitary (sea anemones).

    • Two-cell layer structure.

  3. Phylum Platyhelminthes:

    • Flatworms: Flattened body structure, bilateral symmetry, capable of free-living and parasitic lifestyles.

    • Example: Planaria (free-living) and Fasciola hepatica (liver fluke parasite).

  4. Phylum Nematoda:

    • Roundworms: Cylindrical body, bilateral symmetry, can be parasitic (e.g., Ascaris lumbricoides) and cause diseases.

  5. Phylum Annelida:

    • Segmented Worms: Segmented cylindrical bodies that are bilaterally symmetrical and have a true body cavity.

  6. Phylum Mollusca:

    • Soft-bodied animals with bilateral symmetry and well-defined organ systems.

  7. Phylum Arthropoda:

    • Largest phylum characterized by jointed limbs, bilateral symmetry, and a diverse range of organisms including insects and crustaceans.

    • Examples include various classes like Insecta, Crustacea, etc.

  8. Phylum Echinodermata:

    • Radial symmetry, free-living marine animals with an endoskeleton made of calcium carbonate.

    • Example animals include sand dollars and starfish.

  9. Phylum Chordata:

    • Includes organisms with a closed circulatory system and well-developed organ systems.

    • Bilateral symmetry must be noted.