CHAPTER 3: PRODUCTS OF EVOLUTION: UNITY & DIVERSITY

KINGDOM ANIMALIA Characteristics- Eukaryotic Multicellular (with no cell wall like plants) Cell specialization- forming tissue Leads to higher level functions Heterotrophic through ingestion Sexual reproduction and development Movement and coordination

KINGDOM ANIMALIA Two main categories Criteria used to classify Invertebrates (without a backbone) Vertebrates- Chordates (with a backbone) Criteria used to classify Symmetry Germ or tissue layers Body cavities

INVEREBRATES 8 major phyla Classification based on embryonic development, symmetry, germ layers, and body cavity 97% of all animals are invertebrates All lack a backbone

PHYLUM PORIFERA (pore bearer) SPONGES- simplest animals Asymmetrical Little tissue specialization No germ layers No true coelom (body cavity) Sexual and asexual reproduction Most are sessile (not mobile) in adulthood

PHYLUM CNIDARIA Radial symmetry Two germ (cell) layers Epidermis gastrodermis Simple organ systems Three Classes of Cnidaria Class Hydrozoa- hydra, man-of-war Class Scyphozoa- jellyfish Class Anthozoa- sea anemones, coral

PHYLUM MOLLUSCA Characteristics 2nd most diverse phylum of animal Have a true coelom Fluid filled cavity that is completely surrounded by mesoderm Separates the gut from epidermis Allows a space where the circulatory, muscular, and eventually skeletal systems develop Body plan Bilaterally symmetrical Head-foot region- contains the mouth and a foot for moving Visceral mass region- contains internal organs Mantle- epidermis that secretes shell

PHYLUM MOLLUSCA THREE MAIN CLASSES Class Gastropoda- snails, slugs, etc. One or no shell Foot is near the gut Class Bivalvia- clams, oysters, scallops Two shells No distinct head, but big foot Class Cephalopoda- squid, octopuses Feet (tentacles) near the head No shell (except for the nautilus) Chromatophres- pigments for color change Squids- 10 tentacles Octopuses & other cephalopds- 8 tentacles

PHYLUM ANNELIDA Characteristics Three Main Classes Segmented Worms Bilaterally Symmetrical True coelom Simple organ systems Digetive- esophagus, crop, gizzard Circulatory- aortic arches Nervous- ventral nerve cord Setae- external bristles Parapodia- some have fleshy protrusions that are ‘like-feet’ Three Main Classes Class Oligochaeta- common earthworms Class Polychaeta- bristle worms Class Hirudinea- leeches

PHYLUM ARTHROPODA Most diverse phylum of animals Characteristics Bilaterally symmetrical True coelom Segmented bodies Jointed appendages (extensions)- ‘arthropods’ Exoskeletons High degree of cephalization- head development- antennae & mouth parts Compound eyes- made up of many small eyes Molting- shedding exoskeleton & growing new one

3 SUBPHYLA OF ARTHROPODA Subphylum Crustacea- Crustacians Crabs, lobsters, shrimp, crayfish, pill bugs Characteristics Mostly aquatic Two major body sections- Cephalothorax & abdomen Two pairs of appendages on the head Five pairs of walking legs One pair of appendages on each other body segment Subphylum Chelicerata Class Arachnida- spiders, scorpions, horseshoe crabs Characteristcs Terrestrial Four pair of walking legs- all on thorax

SUBPHYLUM UNIRAMIA Class Diplopoda- millipedes Two pairs of legs on each body segment Class Chilopoda- centipedes One pair of legs on each body segment Class Insecta- ¾ of all animal species Entomology- study of insects 15 major orders of insects Lice, termites, dragonflies, grasshoppers, beetles, flies, bees, ants, butterflies, fleas Characteristics- Mostly terrestrial Three body segments- head, thorax, & abdomen Three pairs of walking legs on the thorax One or two pairs of legs Exoskeleton Dorsal aorta Spiracles and tracheae for respiration Digestive system with crop and stomach Ventral nerve cord

PHYLUM ECHINODERMATA Characteristics Examples Radially symmetrical (mostly penta-radially Bilaterally symmetrical larvae Endoskeleton Water vascular system Tube feet Examples Starfish Sea lillies Brittle stars Sea urchins Sea cucumbers

PHYLUM CHORDATA SUBPHYLUM VERTEBRATA Characteristics Dorsal hollow nerve cord Vertebral column to protect nerve cord Cranium to protect the brain Bilaterally symmetrical True coelom Endoskeleton Highly developed nervous system & brain Highly developed senses

7 Major classes of vertebrates Class Agnatha- lampreys & hagfish No jaws Class Chondrichthyes- sharks & stingrays Cartilaginous skeletons Placoid scales Olfactory bulbs- good sense of smell Class Osteichthyes- All bony fish Bone skeleton Swim bladder Scales Four chambered heart- linear Class Amphibia- frogs, toads, salamanders Aquatic larval stage Moist, thin skin with no scales Three chambered heart

7 Major classes of vertebrates Class Reptilia- snakes, lizards, turtles, crocodiles Lay eggs Dry, scaly skin Three chambered heart Class Aves- birds Feathers Wings Beak Four chambered heart Class Mammalia- us, dogs, cats, bears, sheep, horses, rhinoceri, elephants, cows, rats, etc. Endothermy- internal body heat Hair Milk- mammary glands Placental birth Kangaroos have pouches- marsupials Duckbill platapus lays eggs- monotreme