Biology 120 Lab CerritosCollege

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)

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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