Phylum Arthropoda: Jointed Foot

Importance

-8 out of 10 animals are arthropods

-invaded every known ecosystem

-reproduce by the millions

-millions spent eliminating them

Taxonomy and Organization

Subphylum Chelicerata Phylum Arthropoda Subphylum Trilobita Subphylum Uniramia -Class Insecta -Class Diplopoda -Class Chilopoda Subphylum Chelicerata Subphylum Crustacea -Class Merostomata -Class Arachnida -Class Cirripedia -Class Malacostraca

Arthropod Characteristics

1. Exoskeleton: made of chitin -Molting: shedding the exoskeleton

2. Segmentation: head, thorax, abdomen (tagmatization)

3. Paired and jointed appendages

4. Metamorphosis – changing of the body forms throughout life cycle

5. Well developed sensory organs -compound eyes -antennae -pheromones

6. Prolific reproduction: short life span + high reproduction = rapid evolution

7. Complex behaviors and social interactions

Subphylum Trilobita: The trilobites -first arthropods -dominant in the Paleozoic Era -all extinct -no known ancestry

Subphylum Chelicerata: 2 Classes

Class Merostomata: horseshoe crabs

Class Merostomata: horseshoe crabs -circular shaped exoskeleton -five pairs of walking legs -small pair of chelicera (pinchers) -telson: long, triangular spiked tail -blue blood, used to test commercial drug purity

Class Arachnida: scorpions, spiders, mites, and ticks

-cephalothorax: head and thorax combined

-chelicera: fangs found in arachnids

-pedipalp: specialized feeding appendages

-book lungs: specialized respiratory organs

-ticks: blood sucking parasites; cause Lyme’s disease and Rocky Mt -ticks: blood sucking parasites; cause Lyme’s disease and Rocky Mt. Spotted fever

-scorpions: the oldest known terrestrial arthropods

Specimens: -black widow spider -black and yellow argiope -brown recluse -wolf spider -rose hair tarantula -mexican white-kneed tarantula -wood tick -emperor scorpion -desert scorpion

Subphylum Crustacea: 2 Classes

Class Cirripedia: barnacles -adults are sessile; attach to whales, rocks, wood -protected by a calcareous shell -cirri: appendages used to gather food Specimens: giant barnacles, goose necked barnacle

Class Malacostraca: crabs, lobsters, crayfish, and shrimp -ten walking legs -mostly marine -sexes are separate -open circulatory system

Specimens: -Blue crab -hermit crab -emerald crab -marsh crab -reef lobster -crayfish -fiddler crab

Subphylum Uniramia: 3 Classes

Class Chilopoda -arthropods with segmented, elongated bodies -one pair of legs per body segment Ex. Centipedes

Class Diplopoda -two pairs of legs per body segments

Class Insecta: Entomology: the study of insects -75% of all animal biodiversity are insects -biologists estimate that only 1/50th have been identified

Characteristics:

1. Three body segments

2. Three pairs of legs

3. One pair of antennae

4. Most have two pairs of wings – key to their success

5. Metamorphic life cycle

Negative Impact of Insects

1. Pests/tormentors: flies, gnats, mosquitoes

2. Disease vectors: mosquitoes, flies

3. Agricultural damage: crops and food

4. Property Damage: termites and ants

Positive Impacts of Insects

1. Plant Pollinators: mutualistic relationship 1. Plant Pollinators: mutualistic relationship. 65% of all plants are pollinated by insects

2. Ecological Importance: foundation of the food web

3. Economic Impact: honey, wax, dye, biodiversity

Insect Orders: most end in “ptera” - wing

Order Lepidoptera: “scale wing” -insects with two pairs of wings covered by colorful scales -moths and butterflies Ex. Monarch butterfly, polyphemus moth, luna moth, underwing moth

Order Coleoptera: “sheath wing” -insects with a hardened pair of forewings -the beetles Ex. Colarado potato beetle, stag beetle, June beetle, Japanese beetle

Order Hymenoptera: “membrane wing” -insects with two pairs of transparent wings -most carry toxins in their stinger Ex. Honey bee, bald-faced hornet

Order Orthoptera: “straight wing” -insects with straight wings Ex. Differential grasshopper, lubber grasshopper, red-legged grasshoppers

Order Diptera – “two wings” -insects with one pair of transparent wings Ex. Horsefly

Order Odonata: “toothed” -predatory insects with large mandibles and two pairs of transparent wings Ex. Green darner