Chapters 29-31
 Type of Body Plan
 Sac plan- jellyfish/tapeworms- incomplete digestive system
 Tube-within-a-tube- complete digestive system with a
separate entrance for food and an exit for undigested material
 Type of Coelom
 Aceolomate- no body cavity (mesoderm but no coelom)
 Pseudoceolmate- coelom incompletely lined by mesoderm
 Coelomates- coelom completely lined with mesoderm either
 Protostome- blastopore becomes mouth
 Deuterostome- blastopore becomes anus
 Tissue organization
 Diploblastic with tissue organization
 Triploblastic with organ organization
 Segmentation
 Repetition of body parts along the length of the body
 Type of Symmetry
 Asymmetrical- no body shape (sponges)
 Radially symmetrical- organized circularly, with 2
identical halves no matter how the organism is sliced
longitudinally
 Bilaterally symmetrical- have definite right and left half
 Lack true tissue layers
 Sac like bodies perforated with pores
 Sessile filter feeders
 Body shaped maintained by spicules or spongin
 Develop only ectoderm and endoderm separated by
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mesoglea
Radially symmetrical
Tubular or bell-shaped marine or freshwater animals
Have nematocysts
Possess a gastrovascular cavity and a nerve net
Dimorphic
 Polyp- mouth is directed upward (asexual)
 Medusa- mouth is directed down (sexual)
 Develop only ectoderm and endoderm
 Radially symmetrical
 Free-swimming marine invertebrate
 Body is made of mesoglea
 May be bioluminescent
 Every remaining phyla has bilateral symmetry at some
point in their development.
 Known as ribbon worms
 Acoelomate
 Possess a “tube within a tube” body plan
 Primarily bottom dwelling marine organisms with
proboscis
 Known as flat worms
 Free-living or parasitic
 Acoelomate
 Possess epidermis, muscles, and reproductive organs
 Cephalization can occur, may have senses receptors or
nerve ladder
 Remaining phyla have a body cavity
 Roundworms
 Psuedocoelomate (body cavity is incompletely lined by
mesoderm)
 Prevalent in any environment
 May be free-living or parasitic
 Pseudocoelomate
 Predominately lives in fresh water
 May remain dormant in inhospitable environments
 Viewed by Leeuwenhoek
 2nd largest animal phylum
 Inhabit a variety of environments
 Reduced coelom
 Cephalization ranges from none to complex
 3 part body plan
 Visceral mass- internal organs
 Mantle- covering that lies to the sides of visceral mass
 Foot- muscular organ used for locomotion, attachment,
and food capture
 Segmented worms (internal septa)
 Majority found in marine environments
 Well developed coelom and hydrostatic skeleton
 Closed circulatory system
 Cephalization is apparent
 Excretory system includes nephridia
 Largest and most diverse phylum
 Adapted to every environment and mode of life
 Success is due to 5 characteristics
 Exoskeleton composed of chitin
 Segmentation modified for specialization of body
regions
 Well developed nervous system with a brain and ventral
nerve cord- head bears several sense organs
 Variety of respiratory organs
 Occurrence of metamorphosis
 Primarily bottom dwelling marine animals
 5 pointed radial symmetry
 Possess a water vascular system to aid in locomotion,
feeding, gas exchange, and sensory reception
 Do not have complex excretory, respiratory or
circulatory system
 Most possess 4 characteristics during life history to be
considered a chordate:
 Notochord- dorsal supporting rod
 Nerve cord- dorsal and tubular
 Pharyngeal pouches- usually seen only in embryonic
development. Some develop into functioning gills. In
humans, the first pair becomes the auditory tubes. The
second pair becomes tonsils. The third and fourth pairs
become the thymus gland and parathyroid glands
 Postanal tail
 Cephalochordata
 Notochord persists in adults
 Some gills persist in adults
 Notochord is replaced by vertebral column
 Skull that encloses the brain
 High degree of cephalization and complex sense
organs
 Development of jaw
 Large coelom and complete digestive tract
 Mainly marine cartilaginous fish
 5-7 gill slits
 Epidermal placoid scales
 May be filter feeders or predators
 Three well-developed senses
 Sense electric current generated by muscle movements
 Sense pressure caused by fish swimming by
 Keen sense of smell
 Bony fish
 Lobe-finned
 Fleshy fins
 Ray-finned
 fan shaped fins
 Most have swim bladder
 Single loop, closed cardiovascular system
 Well developed nervous system
 Live on land and in water
 Well developed pelvic and pectoral girdles
 Developed cerebral cortex
 Lungs as adults
 Smooth, nonscaly skin
 Ectotherms
 3 groups
 Salamanders and newts
 Frogs and toads
 Caecilians
 Ectothermic, thick keratinized skin, well developed
kidneys
 Developed means of reproduction that was not dependent
on water
 Internal fertilization
 Leathery, amniotic egg
 Alligators and Crocodiles-Majority live in fresh water
 Turtles- heavy shell fused to ribs and thoracic vertebrae,
lack teeth
 Lizards- clawed four feet, carnivorous
 Snakes- carnivorous with loosely attached jaw, Jacobson’s
organ, protective eye membrane, internal ears
 Legs have scales, feathers are modified reptilian scales
 Hard-shelled amniotic egg
 Four-chambered heart
 Air sacs in bones
 Enlarged sternum with keel for muscles to attach for
flying
 No bladder
 Endothermic
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Mammals have larger brain relative to body size
Teeth differentiate as premolars and molars
Efficient respiratory and circulatory systems
Presence of hair
Internal development
Newborn dependency
Milk-producing mammary glands
Endothermic
Divided in three groups
 Monotreme- egg laying
 Marsupial- pouch possessing
 Placental- developing embryo dependent on placenta