Intro to Animal Diversity Chapter 32

Slide 2 of 17 Animalia – General Notes  1.3 million species  300K plant species  1.5 million fungi  >10 million bacteria  Animals ARE heterotrophs  Plantae? Fungi? Protista?  Animals are multicellular  Plantae? Fungi? Protista? Bacteria?

Slide 3 of 17 Animalia – General (Page 2)  Unique in the possession of muscular and nervous tissue  Lack cell walls  Held together by structural proteins such as collagen  Plants? Fungi? Bacteria? Protista?  Most reproduce sexually  Diploid stage is dominant in most

Slide 4 of 17 Fertilization  Zygote  (Mitosis) Cleavage  Blastula

Slide 5 of 17 Embryology Notes  Cleavage – rapid series of mitotic divisions w/o cell growth in between  What part(s) of the cell cycle would be proportionally reduced during cleavage? Extended?  Blastula – Hollow ball of cells  Cavity is called blastocoel  Gastrula – blastula gets “punched in”  Embryonic tissue layers form from gastrulation  Product of gastrulation called archenteron  Blastophore is the opening of the archenteron

Slide 6 of 17 2 Quick Things  Some animals have a larval stage  Immature, distinct form  Undergoes metamorphosis to become adult form  Hox genes  Common in animals  Genes that play an important role in development

Slide 7 of 17 Animal Body Plans  There are 3 main types of animal body plans:  No symmetry  Sponges  Radial symmetry  Jellyfish and many primitive animals  Central axis, and any cut through the axis results in mirror images

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Slide 9 of 17 Bilateral Symmetry  Most amphibians, reptiles, birds, and mammals  Produces a right and left sides that are mirror images of each other  Usually produces dorsal and ventral sides  Associated with cephalization  Anterior (head) end  Posterior (tail) end  Concentration of sensory equipment at one end  Usually anterior end

Slide 10 of 17 Coelomate  True coelom  Fluid-filled body cavity between digestive tract & outer body wall  True compartmentalization Pseudocoelomate  Triploblastic animals -- 3 tissue layers  Cavity formed from mesoderm + endoderm Acoelomate  No cavity between alimentary canal and outer body wall

Slide 11 of 17 Germ Layers  Give rise to the tissues and organs of the animal embryo  Ectoderm is the germ layer covering the embryo’s surface  Endoderm is the innermost germ layer and lines the developing digestive tube, called the archenteron

Slide 12 of 17 Germ Layers  Diploblastic animals have ectoderm and endoderm  Triploblastic animals also have an intervening mesoderm layer; these include all bilaterians  A pseudocoelom is a body cavity derived from the mesoderm and endoderm

Slide 13 of 17 Why a body cavity (coelom)?  The separation between body wall and digestive tract have advantages  Cushion suspended organs  From blunt force and other sources of physical trauma  Increased structural support  Skeletal structure or hydrostatic skeleton  Internal organs grow and move independently  Greater specialization = more advanced

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Slide 15 of 17 Coelom Formation  In protostome development, the splitting of solid masses of mesoderm forms the coelom  In deuterostome development, the mesoderm buds from the wall of the archenteron to form the coelom

Slide 16 of 17 Fate of the Blastophore  The blastopore forms during gastrulation and connects the archenteron to the exterior of the gastrula  In protostome development, the blastopore becomes the mouth  In deuterostome development, the blastopore becomes the anus

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