Download Week 12 - CMS - Cerritos College

Biology 120 Lab
Cerritos College
The Animal Kingdom
Part I – The Lower Invertebrates
(rev. 08.17.03)
I. INTRODUCTION TO THE KINGDOM ANIMALIA
All animals are multicellular, eukaryotic heterotrophs.
A. SYMMETRY: Think "balance" – plane(s) by which an organism can be divided to give similar pieces.
RADIAL - _________________________________________________________________________
BILATERAL - ______________________________________________________________________
ASYMMETRY - ____________________________________________________________________
B. REPRODUCTION: The ability to "create" one's own kind.
SEXUAL - _________________________________________________________________________
MONOECIOUS - _______________________________________________________________
DIOECIOUS - __________________________________________________________________
ASEXUAL - ________________________________________________________________________
II. THE LOWER INVERTEBRATES
A. THE PHYLUM PORIFERA
THE SPONGES
Cellular level of organization. All are aquatic, most are marine. Most are asymmetrical (few have radial
symmetry). Reproduction is sexual, but asexual reproduction possible for some.
B. THE PHYLUM CNIDARIA [formerly known as COELENTERATA; refers to a sac-like body cavity]
All are aquatic, most are marine. Body consists of two tissues “glued together”. They have no “real”
organs. All have radial symmetry and have either of two (2) body forms:
POLYP – long body with tentacles
MEDUSA – short, bell-shaped body, with tentacles
Examples: jellies, hydra, sea anemones, and corals. There is sexual and asexual reproduction stages
in the “life cycle” of some. Medusae and Polyps in the “life cycle” of some. Toxicity of their venom varies.
1. SINGULAR CNIDARIANS: EXAMPLE – HYDRA [fresh water], JELLIES [marine], ANEMONES [marine]
EPIDERMIS - _________________________________________________________________________
GASTRODERMIS - ____________________________________________________________________
MESOGLIAL - ________________________________________________________________________
CNIDOBLAST - _______________________________________________________________________
TENTACLE - _________________________________________________________________________
2. COLONIAL CNIDARIANS: EXAMPLES – OBELIA & CORALS [marine]
REPRODUCTIVE POLYP - ______________________________________________________________
SEXUAL MEDUSAE - __________________________________________________________________
FEEDING POLYP - ____________________________________________________________________
EXOSKELETON - _____________________________________________________________________
C. THE PHYLUM PLATYHELMINTHES (Flatworms [platy = flat / helminthes = worms])
These worms are dorsoventrally flattened with Bilateral Symmetry. They are Acoelomic (lack a
body cavity) – They have a third tissue layer and also have an organ system level of organization
MESODERM (MID-LAYER TISSUE) - ___________________________________________________
CEPHALIZATION - __________________________________________________________________
TRUE ORGANS - ___________________________________________________________________
But, NO RESPIRATORY & CIRCULATORY SYSTEMS (gas exchanges by diffusions alone)
3 "CLASSES" WITHIN THE PHYLUM PLATYHELMINTHES
1. FLATWORMS (Turbellaria) – FREE LIVING WORMS
Reproduction is either asexual or sexual:
1. Asexual – transverse division and then regeneration (via mitosis) of "parts".
2. Sexual – monoecious with cross-fertilization.
EXAMPLE – PLANARIA WORMS (View live animals and model)
EYESPOTS – __________________________________________________________________
TOUCH AND CHEMORECEPTORS – ______________________________________________
PROBOSCIS – _________________________________________________________________
INCOMPLETE DIGESTIVE SYSTEM – _____________________________________________
2. TAPEWORMS (Trematoda)
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Intestinal parasites in host animal. No digestive system; no adult locomotion. Lots of fertilized
eggs produced. Monoecious – with self-fertilization
SCOLEX - _____________________________________________________________________
PROGLOTTIDS - _______________________________________________________________
CUTICLE - ____________________________________________________________________
3. FLUKES (Cestoda)
Parasitic on variety of host organs. Liver, brain, kidneys, blood, ... First host is an invertebrate and
final host is a vertebrate.
D. THE PHYLUM NEMATODA (Roundworms; name refers to a “thread-like” body)
Bilateral symmetry. All are Dioecious. Lifestyles: Some are free-living, but others are parasitic.
ADVANCEMENTS:
PSEUDOCOELOM -____________________________________________________________
COMPLETE DIGESTIVE SYSTEM - _______________________________________________
SEXUAL DIMORPHISM - ________________________________________________________
Females: larger than male (but size is relative term!)
Males: smaller than female & have a "Spicule" (useful distinction!) - _________________
_______________________________________________________________________
SOME MALADIES CAUSED BY PARASITIC ROUNDWORMS
ELEPHANTIASIS (FILARIAL WORM) - ______________________________________________
TRICHINOSIS (TRICHONELLA) - _________________________________________________
"HOOKWORMS"
"PINWORMS"
"WORMS" YOUR PET GETS
ADDITIONAL VOCABULARY:
FREE-LIVING - _____________________________________________________________________________
PARASITIC - ______________________________________________________________________________
SELF-FERTILIZATION - _____________________________________________________________________
CROSS-FERTILIZATION - ___________________________________________________________________
REGENERATION - __________________________________________________________________________
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