Introduction to Kingdom Animalia
Characteristics of Animals:
• Multi-cellular - specialization of cells and tissues
• Mobility - at least in some stage of the life cycle
• Heterotrophic - animals cannot make their own food
• Diploid body form - gametes form a very short haploid cellular stage
Animal Characteristics and why they matter:
• Organization
• Body Symmetry
• Presence or absence of body cavity
• Digestion
• Circulation
Here is the graphic I showed in class:
Use you textbook to understand all of these terms and to their significance. In particular, Table 25.1
does a good job of distilling the information.
Characteristics of Sponges (Porifera)
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Sessile
Motile Larva
No true tissues or organs
Asymmetrical
Filter Feeders
Hermaphroditic
Characteristics of Cnideria
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Radial Symmetry
Two tissue layers, but no true organs
Can have Nematocysts
Calcium carbonate an important component of corals
Form important symbiotic relationships with photosynthetic algae that form the basis of the coral
reef ecosystem.
Characteristics of Flat Worms (Platyhelminthes)
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Bilateral symmetry
Cephalization
True organs
No body cavity (acoelomate)
Characteristics of molluscs (Mollusca)
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Unsegmented soft body
Most have internal or external shell
Have a mantle (fold in the body wall that lines the shell), which excretes the shell
Muscular foot and/or tentacles
Calcium carbonate an important component of body
Cone snails: produce toxin called conotoxins which serve to disrupt signals in the nervous system
causing paralysis. One class of drugs has been synthesized, called Ziconotide, that relieves severe
chronic pain.
Characteristics of Round Worms (Nematoda)
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Unsegmented
Bilateral Symmetry
Molts
Important parasites of humans, particularly in tropical and sub-tropical areas.
Psuedocoelomate
Characteristics of segmented worms (Annelida)
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Long, cylindrical body
Body segmented both internally and externally
Have nervous, digestive and circulatory systems
Many species have a pair of leg-like appendages (not jointed) attached to every segment
Has body cavity (true coelum).
Characteristics of arachnids (Arthropoda: Chelicerates)
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Eight walking legs
Two body parts: cephalothorax (fused head and thorax) and abdomen
Biting or piercing jaws (chelicerae)
Simple eyes
No antenna
Characteristics of crustaceans (Arthropoda: Crustacea)
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body segmented with a hardened shell
Limbs generally with two branches
Two pairs of antennae
Body with 7 or more pairs of different appendages for feeding, locomotion and sex
Respiration by gills
Calcium carbonate an important component of the exoskeleton
Characteristics of insects (Arthropoda: Insecta)
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Six jointed legs
Skeleton outside the body
Body divided into three parts
Head has a pair of antennae
Mouthparts are adapted for particular diets
Characteristics of centipedes (Arthropoda: Myriapods)
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body divided into head with one pair of antennae and trunk with 15 - 191 pairs of legs
trunk segments all similar except for first pair, which is incorporated into head, modified as fangs
with a poison gland
almost exclusively predatory, mostly fast moving and aggressive
Characteristics of Echinoderms
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Adults have radial symmetry, larvae have bilateral symmetry
Endoskeleton
Has body cavity (true coelum)
Water vascular system
Separate sexes
Calcium carbonate an important component of body