Invertebrate Zoology Flashcards

# Invertebrate Zoology Flashcards ## Characteristics of Inverts Q: What are some general characteristics of invertebrates? A: - Lack a backbone - Diverse group including protozoans, cnidarians, annelids, and others - Can be microscopic or large (like giant squid) - Many have exoskeletons or hydrostatic skeletons - Often have segmented bodies - Diverse reproductive strategies ## Different ways to divide/classify inverts Q: What are some ways to classify invertebrates? A: - By body plan (radial vs. bilateral symmetry) - By presence/absence of a body cavity (acoelomates, pseudocoelomates, coelomates) - By developmental patterns (protostomes vs. deuterostomes) - By habitat (marine, freshwater, terrestrial) - By feeding strategy (filter feeders, predators, parasites, etc.) ## Taxonomic Classification Q: What are the major phyla of invertebrates discussed in the documents? A: - Protozoa (not a formal phylum, but a group of single-celled eukaryotes) - Cnidaria - Ctenophora - Annelida - (Note: This list is not exhaustive, as the documents focus on these groups) ## General characteristics of protists Q: What are some general characteristics of protists? A: - Unicellular eukaryotes without collagen or chitinous cell walls - Non-photosynthetic (in the context of protozoa) - Occur wherever there is moisture - Often in close relation to other organisms (mutualistic, commensal, or parasitic) - Typically small in size (<2μm) - Body bound by plasmalemma with outer ectoplasm and inner endoplasm - Contain many structures similar to metazoans (nuclei, chromosomes, mitochondria, etc.) ## Types of locomotion (including types of Pseudopida) Q: What are the main types of locomotion in protozoans? A: - Cilia: Short, hair-like projections that move in coordinated waves - Flagella: Long, whip-like structures often with mastigonemes - Pseudopodia: Temporary extensions of cytoplasm, including: - Lobopodia: Wide, round, blunt pseudopodia - Filopodia: Slim, branching, often non-crossing pseudopodia - Reticulopodia: Very thin, branching, often cross-linking pseudopodia - Axopodia: Filiform, straight, non-crossing pseudopodia ## Types of asexual and sexual reproduction in different groups Q: What are some types of asexual reproduction in protozoans? A: - Binary Fission: Cell splits into two cells of similar size - Budding: Cell splits into two cells of dissimilar size - Multiple fission: One cell produces 3+ similar cells at once - Plasmotomy: Multinucleate cells divide into two cells without undergoing mitosis Q: How do some protozoans reproduce sexually? A: - Conjugation: Exchange of micronuclei between two cells - Autogamy: Micronuclei fuse within an individual to form a new macronucleus before splitting ## Types of skeletons Q: What are the main types of skeletons found in invertebrates? A: - Hydrostatic skeleton: Fluid-filled cavity that allows muscle contraction and movement - Exoskeleton: Hard outer covering (e.g., in arthropods) - Endoskeleton: Internal supporting structure (e.g., in echinoderms) - Some invertebrates lack a true skeleton (e.g., some soft-bodied worms) ## Requirements of hydrostatic skeleton Q: What are the requirements for a hydrostatic skeleton? A: - Presence of a cavity housing an incompressible fluid that transmits pressure uniformly - Flexible outer membrane that surrounds fluid and allows deformation - Constant volume of liquid - Capability to form temporary attachments to substrate for movement ## Operation of hydrostatic skeleton Q: How does a hydrostatic skeleton operate? A: - Longitudinal and circular muscles alternate contraction - Changes in muscle contraction alter the diameter and length of the organism - This alternation of muscle contractions can create peristaltic movement - The incompressible fluid transmits force throughout the body ## General characteristics of Cnidarians (body forms, nematocysts, etc.) Q: What are some general characteristics of Cnidarians? A: - Radial symmetry along oral-aboral axis - Two basic body forms: polyp (sessile) and medusa (motile) - Possess stinging organelles called cnidae (nematocysts, spirocysts, ptychocysts) - Two tissue layers (epidermis and gastrodermis) with mesoglea in between - Gastrovascular cavity (coelenteron) for digestion and circulation - Tentacles surrounding the mouth for feeding and defense ## Forms of locomotion in Cnidaria Q: How do different Cnidarians move? A: - Medusae: Swimming by jet propulsion (contraction of the bell) - Polyps: Generally sessile, but some can: - Creep using their pedal disc - Somersault - Use muscular contractions for limited movement - Some sea anemones can detach and swim to escape predators ## Reproduction methods of Cnidaria Q: What are the main methods of reproduction in Cnidarians? A: Asexual: - Budding - Longitudinal fission - Transverse fission - Pedal laceration (in some anemones) Sexual: - Most are gonochoric (separate sexes) - External fertilization (release of gametes into water) - Some brood larvae internally - Produce planula larvae ## General life cycles of Cnidarians Q: What is the general life cycle pattern in many Cnidarians? A: - Alternation between polyp and medusa stages (metagenesis) - Typical cycle: 1. Adult medusa produces gametes 2. Fertilization produces planula larva 3. Planula settles and develops into polyp 4. Polyp (scyphistoma) undergoes strobilation 5. Ephyra larva released, develops into adult medusa - Some species lack medusa stage (e.g., Anthozoans) - Some species lack polyp stage (e.g., some hydrozoans) ## Features of colonial Cnidarians Q: What are some features of colonial Cnidarians? A: - Can be composed of polyps, medusae, or both - Often exhibit polymorphism (different types of zooids) - Types of zooids may include: - Gastrozooids (feeding) - Gonozooids (reproduction) - Dactylozooids (defense) - Pneumatophores (flotation in some species) - Connected by a common tissue (coenosarc) - May secrete a skeletal structure (e.g., coral exoskeletons) ## Feeding and nutrition of Cnidarians Q: How do Cnidarians feed? A: - Primarily carnivorous - Use tentacles with nematocysts to capture prey - Bring food to mouth using tentacles - Digestion begins in the coelenteron (gastrovascular cavity) - Both extracellular and intracellular digestion - Many species have symbiotic relationships with zooxanthellae for nutrition - Some filter feed using cilia or mucus ## Symbiotic relationships within Cnidarians Q: What are some examples of symbiotic relationships in Cnidarians? A: - Coral-zooxanthellae mutualism: Algae provide nutrients, corals provide shelter - Anemone-clownfish mutualism: Anemone provides protection, fish provides nutrients - Hydractinia-hermit crab: Hydroid colony on shell protects crab, gains mobility - Some anemones host symbiotic algae (zoochlorellae or zooxanthellae) - Certain hydroids live on shells of other animals (e.g., mollusks) ## Threats to Cnidarians Q: What are some major threats to Cnidarians, especially corals? A: - Coral bleaching due to increased water temperatures (climate change) - Ocean acidification affecting skeleton formation - Pollution and eutrophication leading to algal overgrowth