Invertebrates

• What is the definition of invertebrates?

  Animals without a vertebral column
• What is the main distinction between invertebrates and vertebrates?

  Invertebrates lack a backbone
• What are some examples of invertebrates?

  • Poriferans (sponges)
  • Cnidarians (jellyfish, corals)
  • Platyhelminths (flatworms)
  • Nematodes (roundworms)
  • Annelids (earthworms)
  • Molluscs (snails, squids)
  • Arthropods (insects, crustaceans)
  • Echinoderms (starfish)
• How many described animal species are there?

  Approximately 1.35 million
• During which period did many animal body plans evolve?

  The Cambrian period
• What are the major advances in animal architecture?

  • Multicellularity
  • Bilateral symmetry
  • Distinct body layers
  • Body cavity (coelom)
• From what are multicellular animals thought to have evolved?

  Colonial protists (choanoflagellates)
• What type of cells do animals have?

  Eukaryotic cells
• What is the primary carbohydrate stored by animals?

  Glycogen
• What is collagen and its significance in animals?

  Most abundant protein in animals' connective tissues
• What are the essential characteristics of all animals?

  • Movement
  • Adaptation
  • Reproduction
  • Growth
  • Feeding
  • Respiration
  • Irritability
  • Excretion
  • Death
• What are the types of body symmetry in animals?

  • Asymmetrical
  • Radial symmetry
  • Bilateral symmetry
• What are the body layers in diploblastic and triploblastic animals?

  • Diploblastic: Ectoderm, Endoderm
  • Triploblastic: Ectoderm, Endoderm, Mesoderm
• What is a coelom?

  A hollow space in the body
• How are triploblastic animals classified based on body cavities?

  • Acoelomates: No cavity
  • Pseudocoelomates: Cavity between gut and mesoderm
  • Coelomates: Cavity completely lined by mesoderm
• What are the advantages of having a body cavity (coelom)?

  Protection, cushioning, and organ development
• What are the two main groups of coelomates?

  • Protostomes: Mollusca, Annelida, Arthropoda
  • Deuterostomes: Echinodermata, Chordata
• What is the difference in egg cleavage between protostomes and deuterostomes?

  Protostomes: Spiral and determinate; Deuterostomes: Radial and indeterminate
• What are the characteristics of the Phylum Porifera?

  • Asymmetrical
  • No distinct body layers
  • Loose aggregate of cells
  • Water canal system
• What are the characteristics of the Phylum Cnidaria?

  • Radially symmetrical
  • Two body layers
  • Asexual and sexual reproduction
  • Specialized stinging cells (cnidocytes)
• What are the characteristics of the Phylum Platyhelminthes?

  • Bilateral symmetry
  • No coelom
  • Mouth opens to a blind sac
  • Propelled by cilia
• What is the body structure of Phylum Nematoda?

  Unsegmented, bilateral symmetry, pseudocoelomate
• What are the characteristics of the Phylum Annelida?

  • Segmented body
  • Triploblastic, protostome coelomates
  • Bilateral symmetry
  • Thin body wall for gas exchange
• What are the classes within Phylum Mollusca?

  • Gastropoda (snails, slugs)
  • Bivalvia (clams, mussels)
  • Cephalopoda (squids, octopuses)
• What are the characteristics of Phylum Arthropoda?

  • Largest phylum with >1 million species
  • Jointed limbs and appendages
  • Segmented body with specialized tagmata
  • Versatile exoskeleton
• What is the significance of crickets and mealworms as protein sources?

  High protein and lower production costs
• What are the characteristics of Phylum Echinodermata?

  • Deuterostomes
  • Radially symmetrical bodies
  • Unique water vascular system
  • Internal calcified skeleton
• What is the approximate time frame of the Cambrian Period?

  500 - 600 million years ago
• What is the estimated total number of animal species?

  Approximately 8.9 million
• Which of the following is NOT a characteristic of an animal?

  Prokaryotic structure
• Which of the following does NOT have a diploblastic structure?

  Frogs
• What is a correct characteristic of the Phylum Porifera?

  Loose aggregation of cells around a water canal system
• Which two statements are correct for Deuterostomes?

  Egg cleavage radial and indeterminate; Anus forms first
• What are the two correct features of the Phylum Cnidaria?

  Radially symmetrical; A mouth connected to a gastrovascular cavity