Kingdom Animalia

• Formation of animals

  A spherical arrangement of cells in a colony might have become indented, forming a hollow cavity. This would have helped the organism capture and digest food. This same basic arrangement and indenting process can be still observed in the embryonic development of animals today. Some cells in the colony may also have become specialized for feeding. This double-layered arrangement of cells with a lining of specialized digestive cells is very similar to that of sponges, the simplest of all modern animals
• Major division among animal phyla

  Between those with radial symmetry and those with bilateral symmetry
• Kingdom Animalia

  • eukaryotic and multicellular
  • all are heterotrophic
  • use oxygen for aerobic respiration
  • no cell wall
  • their cell membranes are in direct contact with each other
  • mostly reproduce sexually
  • can be terrestrial or aquatic
• Humans belong to the deuterostomes phylum Chordata, almost entirely vertebrates. All other animals are referred to as invertebrates
• In deuterostomes

  The blastopore becomes the anus
• Invertebrates

  • Sponges and Cnidarians: Sea and freshwater; asymmetrical body plans and no tissues. Examples: sponges, jellyfish, corals, hydras
  • Worms: Tapeworms, flukes, planaria, earthworms
  • Molluscs: Clams, oysters, snails, octopuses, squids
  • Echinoderms: Sea stars, sea urchins
• Key innovation among animals

  • The development of nerve specialized cells allowing movement and the ability to sense changes in the environment. Animals in the porifera (sponges) are the only ones that do not have this key animal feature
• The common ancestor of all animals was likely a colonial, flagellated protist
• Animal Classification

  • Vertebrates: have a backbone; 5% of animals
  • Invertebrates: do not have a backbone; 95% of animals
• Animals with bilateral symmetry

  Further divided into protostomes and deuterostomes distinguished by different patterns of embryonic development
• In protostomes

  The blastopore becomes the mouth
• Arthropods


  • insects, spiders, crabs, lobsters, centipedes
• Sponges and Cnidarians

  • sponges, jellyfish, corals, hydras
• Deuterostome


  An animal with bilateral symmetry; during embryonic development, the anus forms before the mouth
• Blastopore


  The opening of the central cavity of an embryo in the early stage of development
• Fish

  • cod, salmon, goldfish, sharks
• Molluscs


  • Clams, oysters, snails, octopuses, squids
• Notochord


  A flexible rod found in some chordates; in most modern chordates it is replaced by vertebrae during embryonic development
• Reptiles

  • lizards, snakes, turtles, crocodiles
• Mammals

  • kangaroo, bears, cats, gorillas
• Vertebrates

  • Fish, Amphibians, Reptiles, Birds, Mammals
• Amphibians


  • frogs, toads, newts, salamanders
• Invertebrates

  • Sponges, Cnidarians, Worms, Molluscs, Echinoderms, Arthropods
• Worms

  • Tapeworms, flukes, planaria, earthworms
• Echinoderms


  • Sea stars, sea urchins, sea cucumbers, sand dollars
• Birds

  • chickadee, ostrich, hawk
• Vertebrate


  An animal with a backbone or notochord
• Protostome


  An animal with bilateral symmetry; during embryonic development, the mouth forms before the anus
• Invertebrate

  An animal that does not have a backbone; the great majority of animal species are invertebrates
• Coelom


  A body cavity present in some animals; contains the animal’s internal organs