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– 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

– 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– Two major body sections-

• Cephalothorax & abdomen

– Two pairs of appendages on the head– 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– 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 CHORDATASUBPHYLUM 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• Lay eggs• Feathers• Wings• Beak• Four chambered heart

– Class Mammalia- us, dogs, cats, bears, sheep, horses, rhinoceri, elephants, cows, rats, etc.

• Endothermy- internal body heat• Hair• Four chambered heart• Milk- mammary glands• Placental birth

– Kangaroos have pouches- marsupials– Duckbill platapus lays eggs- monotreme