ARTHROPODS ARE ARTHROPODS ARE ALL AROUND US!ALL AROUND US!

CLASSIFICATION OF CLASSIFICATION OF LIFELIFE

KINGDOM ANIMALIAKINGDOM ANIMALIA

⇓⇓PHYLUM ARTHROPODAPHYLUM ARTHROPODA

KEY CHARACTERISTICSKEY CHARACTERISTICS

Chitinous exoskeletonChitinous exoskeleton Segmented bodiesSegmented bodies Jointed appendagesJointed appendages Bilateral symmetryBilateral symmetry Pair of compound eyesPair of compound eyes Brain in dorsal part of headBrain in dorsal part of head Ventral nerve cordVentral nerve cord Open circulatory system powered Open circulatory system powered by a single heartby a single heart

EXOSKELETONEXOSKELETON

Made up of carbohydrates Made up of carbohydrates (chitin)(chitin)– Some Crustaceans add CaCOSome Crustaceans add CaCO33

Excellent for protectionExcellent for protection WaterproofWaterproof Efficient movementEfficient movement Does not grow with the animalDoes not grow with the animal Restricts movementRestricts movement

APPENDAGESAPPENDAGES

AntennaeAntennae ClawsClaws Walking legsWalking legs WingsWings FlippersFlippers Other specialized featuresOther specialized features

NERVOUS SYSTEMNERVOUS SYSTEM

Well-developedWell-developed Brain that consists of a pair Brain that consists of a pair of ganglia in the head.of ganglia in the head.

Compound eyesCompound eyes Sense organsSense organs

>statocysts (help maintain >statocysts (help maintain balance)balance)

>chemical receptors>chemical receptors

CIRCULATORY SYSTEMCIRCULATORY SYSTEM

Open circulationOpen circulation Heart long and narrow and stretches Heart long and narrow and stretches along the abdomenalong the abdomen

When heart contracts, it pumps When heart contracts, it pumps blood through arteries that branch blood through arteries that branch into smaller vessels and enter the into smaller vessels and enter the tissues.tissues.

From the tissues, blood leaves the From the tissues, blood leaves the vessels and moves through spaces in vessels and moves through spaces in the tissues called sinuses. the tissues called sinuses.

Eventually, blood collects in a Eventually, blood collects in a large cavity surrounding the heart, large cavity surrounding the heart, from which it re-enters the heart from which it re-enters the heart through small openings and is through small openings and is pumped around again.pumped around again.

RESPIRATORY SYSTEMRESPIRATORY SYSTEM

takes place through the body takes place through the body surface, and/or by means of surface, and/or by means of gills, tracheae, or book gills, tracheae, or book lungs. lungs.

-some completely lack -some completely lack specialized specialized respiratory respiratory organsorgans

REPRODUCTIVE SYSTEMREPRODUCTIVE SYSTEM

Dioecious (separate gonads in Dioecious (separate gonads in males and females)males and females)

Fertilization is internal in Fertilization is internal in terrestrial forms; can be external terrestrial forms; can be external in some aquaticin some aquatic

Most lay eggsMost lay eggs

-development often proceeds -development often proceeds with with some form of metamorphosissome form of metamorphosis

- Parthogenesis in some (eggs hatch - Parthogenesis in some (eggs hatch without being previously without being previously fertilized)fertilized)

FEEDINGFEEDING

HerbivoreHerbivore CarnivoreCarnivore ParasiteParasite Filter feederFilter feeder Detritus feederDetritus feeder

DIGESTIVE/EXRETORY DIGESTIVE/EXRETORY SYSTEMSYSTEM

Undigested food becomes solid Undigested food becomes solid waste and leaves through anuswaste and leaves through anus

Dispose of N-containing waste by Dispose of N-containing waste by Malpighian tubules (bathed in Malpighian tubules (bathed in blood inside body sinuses)blood inside body sinuses)

-remove waste from blood, -remove waste from blood, concentrate concentrate them, and then them, and then excrete via anusexcrete via anus

Complete gutComplete gut

ARTHROPODA & SUBPHYLAARTHROPODA & SUBPHYLA

4 MAJOR SUBPHYLA4 MAJOR SUBPHYLA

Class Trilobita (extinct)Class Trilobita (extinct)

Class CrustaceaClass Crustacea

Class UniramiaClass Uniramia

Class Chelicerata Class Chelicerata (Cheliceramorpha)(Cheliceramorpha)

SUBPHYLUM TRILOBITASUBPHYLUM TRILOBITA

Extinct 245 million years ago Extinct 245 million years ago First appeared 540 million First appeared 540 million years agoyears ago

Closest living relative is Closest living relative is the horseshoe crabthe horseshoe crab

First animals with colour First animals with colour visionvision

Detritus feeders off ocean Detritus feeders off ocean floorfloor

Some were predatorySome were predatory

TRILOBITATRILOBITA

Lichas Paradoxides Triarthrus

SUBPHYLUM CRUSTACEASUBPHYLUM CRUSTACEA

Include brine shrimp, crabs, water fleas, lobsters, barnacles and their relatives, etc.

Primarily marine (salt water) Very diverse group Not very successful on land

CRUSTACEANSCRUSTACEANS

Not very successful on land:Not very successful on land:

-lack of a waxy, water--lack of a waxy, water-tight cuticle tight cuticle

-gills for respiration -gills for respiration

-larval stage -larval stage

CRUSTACEANSCRUSTACEANS

Hard exoskeletonHard exoskeleton

Two pairs of antennaeTwo pairs of antennae

MandiblesMandibles

CRUSTACEANSCRUSTACEANS

GillsGills-look like a row of -look like a row of feathers just under feathers just under

the the exoskeletonexoskeleton-formed from part -formed from part

of of the same appendages the same appendages that form that form

mouthparts mouthparts and legsand legs-movement of mouth -movement of mouth parts and other parts and other appendages keeps a appendages keeps a steady stream of steady stream of water moving over water moving over

the the gills.gills.

CRUSTACEANSCRUSTACEANS

Hairy hermit crab

CRUSTACEANSCRUSTACEANS

Dungeness CrabKing Crab

CRUSTACEANSCRUSTACEANS

Coonstripe/dock shrimp

CRUSTACEANSCRUSTACEANS

Japanese spider Japanese spider crab spans up to 4 crab spans up to 4 m (13 ft.). It is m (13 ft.). It is the largest the largest arthropodarthropod

SUBPHYLUM UNIRAMIASUBPHYLUM UNIRAMIA

Largest groupLargest group Includes insects, millipedes, Includes insects, millipedes, centipedes, and their centipedes, and their relatives relatives

One pair of antennae and One pair of antennae and appendages that do not branch appendages that do not branch ((uniramous appendagesuniramous appendages))

From spiracles, have From spiracles, have long branching tracheal long branching tracheal tubes that reach deep tubes that reach deep into the animals’ into the animals’ tissue.tissue.

Network of tracheal Network of tracheal tubes supplies oxygen by tubes supplies oxygen by diffusion to all body diffusion to all body tissues.tissues.

Work well in small Work well in small animalsanimals

UNIRAMIA - CLASS UNIRAMIA - CLASS DIPLOPODA: MILLIPEDESDIPLOPODA: MILLIPEDES

Octoglena anura Californiulus euphanusHarpaphe haydeniana

Characterized by long, wormlike body composed of many leg-bearing segments – are mainly detritivores

UNIRAMIA - CLASS UNIRAMIA - CLASS CHILOPODA: CENTIPEDESCHILOPODA: CENTIPEDES

Lithobius forficatus Scutigera coleoptrata “house centipede”

Scolopendra

Characterized by long, wormlike body composed of many leg-bearing segments – are mainly predators

UNIRAMIA - CLASS INSECTAUNIRAMIA - CLASS INSECTA

CHARACTERIZED BY: three part body:-head, thorax and abdomen-has three pairs of legs attached to the thorax.

INSECT COMMUNICATION:Use sound, visual, chemical (pheromones) and other types of signals.

UNIRAMIA SUBPHYLUM UNIRAMIA SUBPHYLUM CHELICERATACHELICERATA

includes arachnids, includes arachnids, horseshoe crabs, ticks and horseshoe crabs, ticks and numerous other animals which numerous other animals which have become extinct ever have become extinct ever since the Paleozoic era since the Paleozoic era

second most prominent class second most prominent class predators, parasites, or predators, parasites, or decomposers decomposers

do not care for their young do not care for their young producing large numbers of producing large numbers of offspring offspring

CHELICERATACHELICERATA

Live on land (except Live on land (except horseshoe crab)horseshoe crab)

Lack antennaeLack antennae Presence of chelicerae Presence of chelicerae (mouth parts modified to (mouth parts modified to grasp food or to poison prey grasp food or to poison prey with venom)with venom)

Most have pedipalps (2Most have pedipalps (2ndnd pair pair of appendages near mouth)of appendages near mouth)

2 body segments2 body segments Six appendagesSix appendages Other features: book lungs, Other features: book lungs, telson, spinnerets, stingerstelson, spinnerets, stingers

Horse shoe crabs:Horse shoe crabs:

-book gills-book gills

Spiders and relatives:Spiders and relatives:

-book lungs-book lungs

-contained inside a -contained inside a sac sac within the bodywithin the body

-opening (-opening (spiraclespiracle) ) connects sac connects sac

containing containing book lungs book lungs with fresh air with fresh air outside.outside.

-both of these structures -both of these structures several sheets of tissue several sheets of tissue are layered like pages in are layered like pages in a book.a book.

>increase surface >increase surface area for area for gas exchangegas exchange

CHELICERATA CLASS CHELICERATA CLASS ARACHNIDAARACHNIDA

Smeringurus mesaensis

Dermacentor occidentalis

Argiope bruennichi

HOW ARTHROPODS FIT HOW ARTHROPODS FIT INTO THE WORLD:INTO THE WORLD:

Direct and indirect source Direct and indirect source of foodof food

2/3 of flowering plants 2/3 of flowering plants depend on insects for depend on insects for pollinationpollination

Symbiotic relationshipsSymbiotic relationships AgricultureAgriculture Medications - allantoin Medications - allantoin heals wounds (maggots heals wounds (maggots produce)produce)

ChemicalsChemicals Famines and illnessesFamines and illnesses