ANIMAL DIVERSITY

YOU MUST KNOW… THE CHARACTERISTICS OF ANIMALS THE STAGES OF ANIMAL DEVELOPMENT HOW TO SORT THE ANIMAL PHYLA BASED ON SYMMETRY, DEVLOPMENT OF A BODY CAVITY, AND THE FATE OF THE BLASTOPORE

CONCEPT 32.1 ANIMALS ARE MULTICELLULAR, HETEROTROPHIC EUKARYOTES WITH TISSUES THAT DEVELOP FROM EMBRYONIC LAYERS

MOST HAVE MUSCLE AND NERVOUS TISSUE MOST REPRODUCE SEXUALLY, WITH FLAGELLATED SPERM AND A LARGE EGG UNITING TO FORM A DIPLOID ZYGOTE THE DIPLOID STAGE DOMINATES THE LIFE CYCLE

ZYGOTE – FERTILIZED EGG CLEAVAGES – SUCCESSIVE MITOTIC CELL DIVISIONS WITHOUT CELL GROWTH BETWEEN CYCLES BLASTULA – A HOLLOW BALL OF CELLS SURROUNDING A CAVITY CALLED THE BLASTOCOEL GASTRULA – AS BLASTULA IS “PUNCHED IN,” THE EMBRYONIC TISSUE LAYERS WILL FORM

ECTODERM – THE OUTER TISSUE LAYER ENDODERM – THE INNER TISSUE LAYER BLASTOPORE – THE OPENING INTO THE GASTRULA, IT WILL BECOME THE MOUTH IN PROTOSTOMES AND THE ANUS IN DEUTEROSTOMES ARCHENTERON – THE BLIND POUCH FORMED BY GASTRULATION

LARVAE – AN IMMATURE FORM DISTINCT FROM THE ADULT STAGE THAT WILL UNDERGO METAMORPHOSIS HOX GENES – ANIMALS SHARE THESE UNIQUE HOMEOBOX-CONTAINING FAMILY OF GENES THAT PLAY IMPORTANT ROLES IN DEVELOPMENT

CONCEPT 32.2 ANIMALS CAN BE CHARACTERIZED BY “BODY PLANS”

NO SYMMETRY – SPONGES RADIAL SYMMETRY – OCCURS IN JELLYFISH AND OTHER ORGANSIMS WHERE A LINE GOES THROUGH THE CENTRAL AXIS BILATERAL SYMMETRY – LOBSTERS, HUMANS, AND OTHER ORGANISMS WHERE A SINGLE LINE WOULD DIVIDE THE ANIMAL INTO TWO MIRROR IMAGE HALVES THERE IS ALSO A DORSAL AND VENTRAL SIDE, AND AN ANTERIOR AND POSTERIOR SIDE

CEPHALIZATION – CONCENTRATION OF SENSORY EQUIPMENT AT ONE END (USUALLY ANTERIOR OR HEAD END) ACOELOMATES – FLATWORMS, HAVE NO CAVITIES BETWEEN THEIR ALIMENTARY CANAL AND THE OUTER WALL OF THEIR BODIES PSEUDOCOELOMATES – TRIPLOBLASTIC ANIMALS (3 TISSUE LAYERS) WITH A CAVITY FORMED FROM THE MESODERM AND ENDODERM COELOMATES – POSSESS TRUE COELOM, A BODY CAVITY FILLED WITH FLUID AND THIS SPACE SEPARATES THE DIGESTIVE TRACT FROM THE OUTER BODY WALL. FORMS FROM TISSUE DERIVED FROM MESODERM ONLY.

FUNCTIONS OF THE BODY CAVITY CUSHION SUSPENDED ORGANS ACT AS A HYDROSTATIC SKELETON ENABLE INTERNAL ORGANS TO GROW AND MOVE INDEPENDENTLY

3 DIFFERENCES IN PROTOSTOMES AND DEUTEROSTOMES CLEAVAGE – PROTOSTOME BEGINS WITH SPIRAL, DETERMINATE CLEAVAGE AND DEUTEROSTOME BEGIN BY RADIAL, INDETERMINATE CLEAVAGE

PROTOSTOME any member of the lower invertebrate phyla the mouth appears before the anus during development, cleavage is spiral and determinate, and the coelom forms as a splitting of the mesoderm

DEUTEROSTOME a mouth that develops separately from the blastopore any member of the phyla (Chordata, Hemichordata, Echinodermata, Chaetognatha) the anus appears first, developing at or near the blastopore, cleavage is radial and indeterminate, and the mesoderm and coelom form from outgrowths of the primitive gut

COELOM FORMATION – BEGINS IN THE GASTRULA STAGE IN PROTOSTOMES AND THE COELOM FORMS FROM SPLITS IN THE MESODERM. IN DEUTEROSTOMES, THE COELOM FORMS FROM MESODERMAL OUTPOCKETINGS OF THE ARCHENTERON

FATE OF THE BLASTOPORE – IN PROTOSTOMES DEVELOPMENT, THE MOUTH FORMS FROM THE BLASTOPORE WHERE IN THE DEUTEROSTOME DEVELOPMENT, THE MOUTH FORMS FROM A SECONDARY OPENING