Animals. Invertebrate Diversity & Evolution

Animals Invertebrate Diversity & Evolution

Animal Characteristics Multicellular Heterotrophic (can be classified by their feeding strategies) Classified by feeding strategies Filter feeders (suspension feeders) Deposit feeders Fluid feeders Mass feeders

Animal Characteristics Heterotrophic (can be classified by their feeding strategies) Classified by what they eat Herbivores Carnivores Omnivores Detrivores Classified by what happens to the other organism Predator Parasites Endoparasite Ectoparasite

Animal Characteristics Lack a cell wall Motile at some point in life Reproduce sexually Most are diploid Fertilization is internal or external Respond quickly to a stimulus

Animal Evolution Trends Greater level of cellular organization & specialization Tissue to organs to organ systems Embryo development Blastula with blastocoel Gastrula (3 germ layers) Endoderm Ectoderm Mesoderm Diploblastic vs. triploblastic Cephalization (head & tail ends)

Tissue Layers

Animal Evolution Trends Development of a body cavity Acoelomate Pseudocoelomate Coelom Provides a hydrostatic skeleton Protostome- coelom forms within the space between the body wall & digestive cavity Blastopore & spiral cleavage Deuterostome- coelom forms as outgrowth of digestive cavity Radial cleavage Greater development of digestive system Incomplete digestion- waste leaves same opening as food goes in Complete digestion- special regions to breakdown & process food Body symmetry Asymmetry Radial symmetry Bilateral symmetry Brain size increases & becomes more sophisticated (seen in vertebrates)

Body Cavities

Protostomes vs. Deuterostomes

Symmetry

Endoskeleton vs. Exoskeleton

Phylum - Porifera Asymmetrical free form to definite shape aquatic- salt and freshwater varieties Variety of shapes and colors Invertebrates Sessile- they are anchored to a substrate (rock, etc.) Filter feeders = as the water passes through the organism it filters food from the water Tiny pores allow water to enter the ostia (interior cavity) Expels waste through a large center hole called the osculum (oscula) Asexual reproduction by budding and fragmentation Sexual reproduction- sponges release eggs and sperm in large amounts to increase the chance of fertilization Colonies of independent cells to multicellular Lack true organs and tissues 4 cell types Pinacocytes- flattened cells that cover the body surface Choanocytes- have flagella; maintain water flow through the sponge Amoebocytes- digest & distribute nutrients; produce reproductive cells Secrete spicules Porocytes- cells curl end to end to form the ostia pores Sponges

Phylum - Porifera Sponges

Phylum - Cnidaria marine invertebrates radial symmetry 1 body opening, gastrovascular cavity 2 body forms polyp- tube shaped body and a mouth surrounded by tentacles medusa- body shaped like an umbrella poison their prey by cnidocytes (tiny stinging cells) located on their tentacles darts called nematocysts contain specialized tissues contain a nerve net (a simple nervous system) contractile tissue asexual reproduction by budding sexual reproduction by external fertilization 2 body layers endoderm & ectoderm with mesoglea between layers Jellyfish, Anemone, Corals

Phylum - Cnidaria Class Hydrozoa- primitive polyps; hydra, physalia & obelia Class Scyphozoa- medusa forms; aurelia Class Anthozoa- advanced polyps; sea anemones & corals Jellyfish, Anemone, Corals

Phylum - Cnidaria Jellyfish, Anemone, Corals

Phylum - Platyhelminthes Acoelomates Bilaterally symmetrical with some cephalization Some have a nerve net & nerve cords Some have the beginnings of a central nervous system (the ganglion) Eyespot Specialized sense cells Size: 1 mm to several meters Most are hermaphroditic 1 body opening Planarians extend a muscular organ called the pharynx that releases enzymes to begin digesting food (the mouth is in the center of its body) Protonephridia transport wastes with the help of flame cells to exit through excretory pores Sexual reproduction by internal fertilization Hermaphroditic cross or self fertilization Asexual reproduction by regeneration Parasitic worms have hooks to keep the worm firmly attached to the host (tapeworms) can form cyst Tapeworms, Flukes, Planaria

Phylum - Platyhelminthes Class Turbellaria- free living flatworms; planaria Class Trematoda- parasites; flukes Class Cestoda- parasites; tapeworms

Phylum - Platyhelminthes Planaria

Phylum - Platyhelminthes Tapeworms, Flukes, Planaria

Phylum - Platyhelminthes Tapeworms

Phylum Nematoda Tapered at both ends Most are microscopic Free living C. elegans, Rhabditis, vinegar eels Parasitic varieties hookworms, heartworms, Trichinella Cuticle secreted by the hypodermis, thick outer covering for protection from the host organism Pseudocoelomate Provides a hydrostatic skeleton for muscle movement Tubelike, one-way digestive system 2 body openings: mouth and anus Well developed sense organs in free living species Sexual reproduction with separate sexes C. elegans

Phylum Nematoda Roundworms

Phylum Annelida Coelomates Invertebrates Exhibit metamerism Bilaterally symmetrical Digestive track with 2 body openings Contains a pharynx, esophagus, crop, gizzard and intestine Bristled setae on each segment used for movement Simple nervous system with a brain in some species Gas exchange occurs through moist skin 2 nephridia (waste removal organs) per segment Hermaphroditic Closed circulatory system (blood contained in vessels) with a heart Nephridia remove & excrete wastes Segmented Worms

Phylum Annelida Class Oligochaetes- earthworms * hermaphroditic Class Polychaetes- marine dwelling worms * separate sexes that shed gametes in water * have parapodia Class Hirudinea- leeches * NO setae or parapodia Segmented Worms

Phylum Annelida Segmented Worms

Phylum Annelida Parapodia

Phylum Annelida Segmented Worms

Phylum Mollusca bilaterally symmetrical coelomates supported by a hydrostatic skeleton digestive system with 2 body openings muscular foot for movement contain a mantle- a thin membrane that surrounds the internal organsthe mantle secretes the shell contain a radula- a tonguelike organ with rows of teeth sexual reproduction by external fertilization land mollusks tend to be hermaphroditic to increase chances of fertilization; most mollusks are separate sexes simple nervous systems with a brain and associated nerves 3 chambered hearts with an open circulatory system- blood moves through vessels and into open spaces around body organ larger mollusks have a closed circulatory system- blood moves through the body enclosed entirely in a series of blood vessels contain nephridia- waste removal organs gills for respiration - land snails and slugs have primitive lungs Squid, Octopus, Snails, Slugs, Shelled Animals

Phylum Mollusca Class Gastropoda- snails, slugs * use their radula * moist skin supplements gills or primitive lungs Snails & Slugs

Phylum Mollusca Class Bivalvia- clams, scallops, mussels & oysters * have 2 part shell attached at a hinge * have a muscular foot for movement or for anchoring the organism * have gills to aide in respiration & filter feeding Clams

Phylum Mollusca Class Polyplacophora- chitons * 8 calcium carbonate plates on the dorsal surface Chitons

Phylum Mollusca Class Cephalopoda- octopus & squid * predatory & marine dwelling * intelligent * grasping tentacles with chemosensory abilities * complex eye * capable of jet propulsion * have a closed circulatory system Squid & Octopus

Phylum Mollusca Squid, Octopus, Snails, Slugs, Shelled Animals

Phylum Arthropoda Have an exoskeleton Flexible appendages Watertight Must go through molting to grow Largest live in water Segmented Head Thorax Cephalothorax Abdomen Have respiratory system Gills Trachea Book lungs Insects, Arachnids, Crustaceans

Phylum Arthropoda Have open circulatory system Blood is called hemolymph & empties to the hemocoel Excretion through malpighian tubules Sensory organs Eyes Antennae for chemical & tactile sense Insects, Arachnids, Crustaceans

Phylum Arthropoda Subphylum Chelicerata- horseshoe crabs & arachnids * have chelicerae Arachnids (spiders, scorpions, ticks, mites) * pair of pedipalps & 8 walking legs * carnivorous * multiple pairs of simple eyes Spiders, scorpions, ticks, mites

Phylum Arthropoda Subphylum Crustacea- crustaceans (crabs, shrimp, crayfish) * have mandibulae * usually 2 pairs of antennae * compound eyes & gills Crabs, shrimp, crayfish

Phylum Arthropoda Subphylum Uniramia- insects, centipedes, milipedes * unbranched appendages * have mandibulae * can be divided into two subphyla: Insecta & Myriapoda Milipedes, centipedes

Phylum Arthropoda Insects * 3 pairs of legs & 2 pairs of wings * undergo metamorphosis * holometabolous- complete change in form * larvae to pupa to adult * hemimetabolous- incomplete change * nymphs resemble parents but do not have wings or reproductive organs

Phylum Arthropoda

Phylum Echinodermata All aquatic species Hard, spiny, bumpy endoskeletons Radial symmetry (pentaradial symmetry) Coelomates Coelomic fluid acts as circulatory system Water vascular system Move by hundreds of suction cup tipped appendages, tube feet Helps with respiration & feeding Water enters through the madreporite into the central canal Radial canals extend out from the central canal All have a mouth, stomach and intestines Central nerve ring Slow paced or sessile Able to regenerate Sexual reproduction with separate sexes Sheds gametes into the water Spiny Skinned Animals Starfish, Urchins, Sand Dollars

Phylum Echinodermata Class Asteroidea- sea stars Class Ophiuroidea- brittle stars & basket stars Class Echinoidea- sea urchins & sand dollars Class Holothuroidea- sea cucumbers Class Crinoidea- sea lilies & feather stars Spiny Skinned Animals Starfish, Urchins, Sand Dollars

Phylum Echinodermata Spiny Skinned Animals Starfish, Urchins, Sand Dollars