1. Kingdom: Animalia Domain: Eukarya INVERTEBRATES!!!! 2007-2008 Domain
Bacteria
Archaea
Eukarya
Common ancestor

2. Animal Characteristics
Heterotrophs
must ingest others for nutrients
Multicellular
complex bodies
No cell walls
allows active movement
Sexual reproduction
no alternation of generations
no haploid gametophyte

3. Animal Evolution radial bilateral Ancestral Protist Cnidaria Nematoda
Annelida
Echinodermata
Porifera
Platyhelminthes
Mollusca
Arthropoda
Chordata
sponges
jellyfish
flatworms
roundworms
mollusks
segmented worms
insects spiders
starfish
vertebrates
body & brain
size,  mobility
backbone
redundancy,
specialization,  mobility
segmentation
 body size
endoskeleton
coelom
 digestive sys
radial
body cavity
body complexity
 digestive & repro sys
bilateral symmetry
distinct body plan; cephalization
tissues
specialized structure & function,
muscle & nerve tissue
multicellularity
specialization &  body complexity
bilateral
Ancestral Protist

4. Body Cavity acoelomate pseudocoelomate coelomate
ectoderm
Space for organ system development
increase digestive & reproductive systems
increase food capacity & digestion
increase gamete production
Coelem
mesoderm & endoderm interact during development
allows complex structures to develop in digestive system
ex. stomach
mesoderm
endoderm
pseudocoelomate
ectoderm
mesoderm
endoderm
pseudocoel
coelomate
ectoderm
mesoderm
coelom cavity
endoderm

5. Invertebrate: Porifera
food taken into each cell by endocytosis
Sponges
no distinct tissues or organs
do have specialized cells (amoebocytes and choanocytes)
no symmetry
sessile (as adults)

6. Invertebrate: Porifera
Sponges
Diffusion is the method used for circulation, gas exchange and excretion of wastes
Reproduction
Asexual – Fragmentation
Sexual – Hermaphrodites: release egg and sperm; produce flagellated, swimming larvae

7. Invertebrate: Cnidaria
Jellyfish, hydra, sea anemone, coral
tissues, but no organs
two cell layers
predators
tentacles surround gut opening
extracellular digestion
release enzymes into gastrovascular
cavity
absorption by cells of gastrodermis
Medusa = motile
Polyp = sessile

8. Cnidocytes of Cnidarians
hydra
Cnidocyte (stinging cell)
with nematocyst
trigger
discharged
nematocyst
undischarged
tentacles
mouth
sensory
cell
stinging cell

9. Invertebrate: Cnidaria
Nerve Net: not centralized, can respond equally on all sides
Use diffusion for circulation, gas exchange and excretion of wastes
Reproduction
Asexual – Budding (polyp)
Sexual – External fertilization/development (medusa)

10. Invertebrate: Platyhelminthes
Flatworms
tapeworm, planaria
mostly parasitic
bilaterally symmetrical
cephalization = concentration of nervouse system in anterior end
concentration of sense organs in head
Eye spots
Lateral flaps(smell)
increase specialization in body plan
Animals now face the world head on!
ectoderm
mesoderm
endoderm
acoelomate

11. Invertebrate: Platyhelminthes
Gastrovascular Cavity – one opening for mouth and anus
Use diffusion for transport and gas exchange
Protonephridia Network to excrete ammonia
Flame bulbs
Nephrostomes
Locomotion
Cilia used to move along mucus
Muscles used to undulate (swim)

12. Invertebrate: Nematoda
Roundworms
bilaterally symmetrical
many are parasitic
Hookworm
Nerve ring
Exhibits cephalization
Longitudinal muscles = thrashing motion
C. elegans

13. Invertebrate: Nematoda
Complete digestive system
tube running through length of body (mouth, esophagus, midgut, rectum, anus)
Midgut secretes enzymes and absorbs nutrients
Material circulate body in fluid of pseudocoelom
Gas exchange occurs by diffusion
Wastes collected by simple structures leading to excretory pores in body wall
Nitrogenous waste usually ammonia, but sometimes urea
Reproduction = sexual
Internal fertilization/external development
Zygote = resistant cell – can survive harsh environment
Rigid cuticle shed periodically

14. Invertebrate: Mollusca
slugs, snails, clams, squid
soft bodies, mostly protected by hard shells
General body plan:
Muscular foot (movement)
Visceral mass (contains internal organs)
Mantle (fold of tissue over visceral mass creating mantle cavity)
Nerve ring & nerve cords – exhibit cephalization
Locomotion via muscular foot, or jet propulsion

15. Invertebrate: Mollusca
Differentiated digestive tract
Radula: belt of curved teeth for scraping up food
Open circulatory System: 3-chambered heart pumps hemolymph
Gas exchange via gills in mantle cavity
Use countercurrent exchange
Nitrogenous waste removed by metanephridia
Nephridiopore discharge into mantle cavity
Reproduction: most gonochoristic (separate sexes)
Many snails
hermaphroditic
Ciliated larvae
= trochophore

16. Invertebrate: Annelida
Segmented worms
earthworms, leeches
segments
increase mobility
redundancy in body sections
Setae (Bristles) = traction for burrowing
Longitudinal + Circular muscles = peristaltic or slinky type movement
fan worm
leech

17. Invertebrate: Annelida
Complete Digestive tract (mouth, pharynx, esophagus, crop, gizzard, intestine, anus)
Closed cirulatory system
Separted body fluids (blood and interstitial)
hemoglobin as repiratory pigment
Moist skin = respiratory surface (gas exchange)

18. Invertebrate: Annelida
Excretory system = metanephridia in each segment
Nephrostome
Nephridiopore
Waste usually ammonia
Reproduction
Some asexual – regeneration
Sexual – hermaphrodites that cross fertilize

19. Invertebrate: Arthropoda
Spiders, insects, crustaceans
most successful animal phylum (most abundant on Earth)
segmented
specialized segments (head, thorax, abdomen)
allows jointed appendages specialized for swimming, walking or flying
exoskeleton
chitin + protein
Molting – shed exoskeleton periodically

20. Invertebrate: Arthropoda
Extensive cephalization
Well developed sense organs (eyes, olfactory, antennae)
Complete digestive tract (foregut, midgut, hindgut)
Excretory System
Malpighian tubules
Waste = uric acid (terrestrial)
Waste = ammonia/urea (aquatic)

21. Invertebrate: Arthropoda
Open circulatory system (hearts and body movement circulate hemolymph)
Gas exchange:
Gills (aquatic)
Book lungs (terrestrial)
Tracheal system (terrestrial)
Spiracles
Tracheae
Reproduction – Sexual
Internal fertilization/external development
Metamorphosis

22. Arthropod groups arachnids crustaceans insects 8 legs, 2 body parts
spiders, ticks, scorpions
crustaceans
gills, 2 pairs antennae
crab, lobster, barnacles, shrmp
insects
6 legs, 3 body parts

23. Invertebrate: Echinodermata
Starfish, sea urchins, sea cucumber
Bilateral larvae; radially symmetrical as adults
spiny endoskeleton
Nerve Ring with radial nerves
Short Digestive tract
Gills for gas exchange
Excretion:
Coelomocytes
Phagocytize wastes and
Carry to discharge sites

24. Invertebrate: Echinodermata
Circulation
Water Vascular system: madreporites take in water from environment; water flows through tubes terminating in tube feet (used for locomotion)
Hemal System: fluid moves through tubes due to peristalsis and cilia
Reproduction
Asexual – Regeneration
Sexual – external fertilization
and development

25. Invertebrate quick check…
Invertebrates: Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Mollusca, Arthropoda, Echinodermata
Which group includes snails, clams, and squid?
Which group is the sponges?
Which are the flatworms?
…segmented worms?
…roundworms?
Which group has jointed appendages & an exoskeleton?
Which two groups have radial symmetry?
What is the adaptive advantage of bilateral symmetry?
Which group has no symmetry?
Which group includes snails, clams, and squid? Mollusks
Which group is the sponges? Porifera
Which are the flatworms? Platyhelminthes
…segmented worms? Annelids
…roundworms? Nematodes
Which group has jointed appendages & an exoskeleton? Arthropods
Which two groups have radial symmetry? Cnidaria, Echinoderm
What is the adaptive advantage of bilateral symmetry? cephalization
Which group has no symmetry? Profiera

26. That’s the buzz! Any Questions?
That’s the buzz!
Any Questions?