Animal Diversity CHAPTER 32 & 33

What phylum?

Animalia Kingdom extends far beyond dogs, birds, and humans - vast array of diversity covers 1.3 million animal species - definition is not straight forward because of exceptions to every criterion 4 defining characteristics 1. nutritional mode – heterotrophs 2. Eukaryotic, multicellular 3. Specialized cells – nerve and muscle 4. Sexual Reproduction

Characterization by Body Plan Grade – group of animal species that share the same level of organizational complexity Body plan – set of morphological and developmental traits that define a grade a. Symmetry- radial (from the center) bilateral – half mirrored b. Tissues – germ layers – ectoderm, mesoderm, endoderm c. Body cavities – coelom – fluid filled space separates digestive tract from outer body wall

Protostomes & Deuterostomes

Protostome vs. Deuterostome Cleavage – (P) Spiral (diagonal), determinate (early fate) - (D)Radial (parallel or perpendicular), indeterminate (capacity to develop into complete embryo) Coelom Formation – (P) coelom forms from splits in mesoderm (D) coelom forms from mesodermal outpockets of digestive tube Fate of Blastopore – (P) mouth forms from blastopore (opening of digestive tube) (D) mouth forms from second opening; anus forms from blastopore

Invertebrates Animals without backbones comprise 95% of world’s known animal species Occupy almost every kind of habitat from hydrothermal vents to frozen tundra

Phylum Porifera Sponges - Sessile organisms usually to rocks or other surfaces - Can live in shallow or deep - many different colors - usually asymmetrical - lack true tissues Collar cells (choanocytes) line inner surface - contain flagellum - create wavelike current to circulate gallons of water each day - brings in food particles Amoebocytes - free moving cells - produce skeleton of spicules - digest and transfer nutrients Contain both male and female organs to cross fertilize to produce more offspring

Phylum Cnidaria Cnidarians - include coral, jellyfish, sea anemones Polyp (coral, anemones) – Cylinder, mouth at top – Tentacles face up – Sessile Medusa (jellyfish) – Umbrella-shaped – Tentacles hang down – Free-swimming Stinging cells (Cnidocytes) contain tentacles that sting and grasp prey Enzyme secreted Digestion completed by cells

Platyhelminthes Flatworms – include planarians, tapeworms and flukes - free living forms, most are parasitic - lack true body cavity - marine or freshwater inhabitants

Rotifera Rotifers – smaller than most protists - multicellular, specialized organ systems - alimentary canal – digestive tube with separate mouth and anus -parthenogenesis- reproduction that produces females from unfertilized eggs *can produce males but only live long enough to produce sperm and produce zygotes resistant to harsh conditions

Molluscs Second largest phylum next to Arthropods Soft body creatures Some produce shells; made of CaCO3 Common Features Visceral mass - contains all internal structures Specialized foot – used in digging, grasping, or creeping Mantle – covers soft body, enclosing internal organs, some produce shells Radula – rasplike scrapers used in feeding Classes Bivalvia Gastropoda Cephalopoda

Annelids Annelida meaning little rings; segmented worms Live in marine, freshwater, and damp soil Three classes Oligochaeta – earthworms Polychaeta – marine worms Hirudinea - leeches

Nematodes Nonsegmented worms or roundworms - body encased in a tough coat called a cuticle- sheds as it grows - alimentary canal - inhabit moist soil and decomposing matter in lakes and oceans * important role in decomposition and nutrient cycling - can be parasitic to plants and animals – “animals that act like viruses”

Arthropods Largest and most successful phylum - mainly insects Common features 1. hard exoskeleton 2. segmentation of body parts 3. jointed appendages - used to walk, feed, copulate, defense, and sensory reception

Arthropods Subphylum and examples a. Cheliceriforms – horseshoe crabs, spiders, scorpions, ticks b. Myriapoda – millipedes, centipedes c. Hexapoda – insects d. Crustacea – crabs, lobsters, shrimp

Phylum Echinodermata Common features Echino- meaning spiny derm- skin Radial symmetry from center of organisms Endoskeletons of calcium carbonate- spicules or spines Water vascular system- complex series of canals running throughout body with hydralic pressure causing water to enter and leave through tubes; aids in movement. Regeneration of body parts – sea stars

Phylum Echinoderma Types of Echinoderms Sea stars - Asteroidea Sea urchins - Echinodea Sea cucumbers - Holothuroidea Brittle stars - Ophiuroidea Feather stars - Crinoidea