Kingdom Animalia Lower Invertebrates. Characteristics: eukaryotic multicellular heterotrophic...
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Transcript of Kingdom Animalia Lower Invertebrates. Characteristics: eukaryotic multicellular heterotrophic...
Kingdom Animalia
Lower Invertebrates
Characteristics:
• eukaryotic• multicellular• heterotrophic consumers• no cell walls• sexual and asexual reproduction• locomotion• 99% invertebrates
Symmetry of body plan:asymmetry – no symmetryradial – central point; can be divided into equal
sectionsbilateral – can be divided into 2 mirrored halves
•cephalization – concentration of sense organs toward anterior end (associated with development
of a head)
• anterior – region of a bilaterally symmetrical organism toward the head end
• posterior – region of a bilaterally symmetricalorganism toward the tail end
• dorsal – back side of a bilaterally symmetricalorganism
• ventral – under side of a bilaterally symmetrical organism
• lateral – to the side of a bilaterally symmetricalorganism
A. Phylum Porifera• sponges• simplest animals• adults sessile, filter feeders (larvae are free-
swimming)• water vascular system – pumps large amts. of
water through porous body; all aquatic• asymmetrical
A. Phylum Porifera…cont• composed of spicules – framework of the sponge• classified by spicule composition:• reproduce sexually by egg and sperm• asexually by budding
B. Phylum Cnidaria• corals, jellyfish, anemones• radial symmetry• entirely aquatic (marine, few fw)• possess stinging cells (nematocysts) on tentacles• nerve net – simple nervous system
B. Phylum Cnidaria
• classified by life cycle stages:1) medusa – free swimming2) polyp – attached stage
• reproduction:asexually by buddingsexually by egg & sperm
C. Phylum Platyhelminthes• flatworms• incomplete digestive system (one opening)• bilateral symmetry
D. Phylum Nematoda
• roundworms• complete digestive system – 2 openings• bilateral symmetry• tube within a tube body plan• ex: Ascaris, hookworms, filarial worms,
eyeworms, Trichinella – cause trichinosis
E. Phylum Annelida• segmented worms• name means “little ring”• true coelom – fluid-filled body cavity• complete digestive system• all organ systems present• closed circulatory system – blood is confined
to vessels
E. Phylum Annelida• classified by their number of setae – bristles for
locomotion