SOME ARIZONA INVERTEBRATE ANIMALS. Phylum Mollusca = the mollusks – the clams, snail, slugs, ect . Represent the second largest animal phyla with most living in a marine environment. A. Characterized by: 1. Muscular foot: is the organ of locomotion that leaves a trail of slime .
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Phylum Mollusca = the mollusks – the clams, snail, slugs, ect. Represent the second largest animal phyla with most living in a marine environment.
A. Characterized by:
1. Muscular foot: is the organ of locomotion that leaves a trail of slime.
2. Mantle: this thin membranous covering secretes Ca++ deposits to form a shell.
3. Visceral mass: is the internal organs.
B. Class Gastropoda (“Stomach Foot”) Snails with a univalve shell or slugs with out a shell.
Desert snails (such as in the genus Helix) are only active during cool +moist season like the months of January+ February.
During the hot summer, they seek protected sites, pull back into their shell a+ secrete an impervious plug called an epiphragm.
The shell and the epiphragm allow some oxygen + moisture to pass through.
Snails tolerate desiccation of 40-45% of its body water, For humans, a loss of 10%body water results in nervous dysfunction and 18-20% is lethal.
Gastropods eat plants, using a rasp-like tongue known as a radula
C. Class Pelecypoda (“spade foot”) Clams with bivalve shell of right + left halves. Not found on land, but in ponds, streams, and canals.
II. Phylum Arthopoda (“jointed Foot”)- is the largest animal phylum consisting of nearly 90% of all animal species.
1. Bodies covered with a chitinous exoskeleton that is secreted by the epidermal cells.
a. Is a multilayered structure consisting of chitin, protein, + wax.
b. Functions include:
1. Protection- a suit of armor.
2. Reduction of water loss.
3. Framework for muscle attachment.
1. Heavy in proportion to total body weight.
2. Must be removed (molting) making the arthropod vulnerable.
2. Jointed appendages- necessary for movement + a lever system.
3. Special senses are many and well developed.
a. Propioceptors or position receptors.
b. Chemoreceptors or chemical receptors. Pheromones are chemical used to attract members of the same species.
c. Photoreceptors or light receptors.
d. Mechanoreceptors or receptors sensitive to touch, air movement + vibrations.
4. Thermoregulation- heterotherms + ectotherms.
5. Reproduction is mostly oviparous.
a. Internal fertilization- an important land adaptation preventing the dehydration of gametes (egg + sperm).
Male produces a spermatophore.
2. Insect Metamorphosis
Complete Metamorphosis Gradual Metamorphosis
1. Class- Arachnida- Characteristics include: 2 body regions, the cephlothorax + abdomen; 6 pair of walking legs; no antennae; simple eyes; chelicera for chewing food.
a. Order Scorpionida- elongated body with abdomen of 12 segments terminating in a venomous stinger segment known as thetelson; pedipalps with enlarged pincers; sensory pectins on ventral surface.
1.) Centruroidessculpturatus- bark scorpion
2.) Hadrurushirsutus + H. arizonesis- Desert hairy scorpion
3.) Vejovisspinigerus- striped – tail scorpion
b. Order Solpugida- sun “spiders” or wind “spiders”; massive chelicerae-like pincers; diurnal
c. OrderUropygi–Whipscorpions + vinegaroons; dark brow; massive pedipalps; elongated flagellum at the end of the abdomen; emits acetic acid spray when threatened; nocturnal, under rocks + litter by day.
d. Order Acarina- ticks + mites
e. OrderAraneae-spiders; abdomen with out segmentation; chelicerae small with venom duct.
1.) Family Theraphosidae-Tarantulas; large, hairy spiders with over 30 Arizona species: defends itself by hair flicking; venom not toxic to man.
2.) family Theridiidae- black widow; female with red hour glass on ventral surface of abdomen; highly toxic bite; around junk.
3.) family Lycosidae- wolf spider.
2. ClassChilopoda- Centipedes- Scolopendraheros-giant desert centipede; up to 8”; orange flattened body; one pair of legs/ body segment; dark head; venomous mouth parts + painful bite; carnivorous.
3. Class Diplopoda- Millipedes- Julus sp. Dark brown cylindrical body with 2 pair of legs/segment; non venomous; eat decaying plant matter.
4. Class Crustacea-2 pair antennae; breathe with gills; primarily aquatic.
a. Order Decapoda- crayfish/crawdads.
b. Order Isopoda- Pill bugs, terrestrial; feed on decaying material.
5. Class Insecta-insects-body divided into head, thorax, + abdomen; 3 pairs of legs attached to the thorax; 2 antennae; compound eye.
a. Order Thysanura-Silverfish
b. Order Odonata- Dragonflies + Damselflies
c. Orthoptera- Crickets, grasshoppers, mantids, cockroaches
f. Hemiptera-True Bugs
g. Homoptera- Cicadas, aphids
h. Neuroptera-Lacewings + ant lions
9. Coleoptera- Beetles- Forewings shell like; hind wings for flight. Some taxonomists estimate that every fifth species on this planet is a type of beetle!!
10. Lepidoptera-moths and butterflies
11. Diptera- Flies, mosquitos, gnats
12. Hymenoptera -Bees, wasp, and ants