ARTHROPODS
HOLT CH. 29
PG. 701-711
ARTHROPOD CHARACTERISTICS

Segmented body
ARTHROPOD CHARACTERISTICS


Segmented body
Jointed appendages
ARTHROPOD CHARACTERISTICS



Segmented body
Jointed appendages
Hard external skeleton
ARTHROPOD CHARACTERISTICS




Segmented body
Jointed appendages
Hard external skeleton
Most have open circulatory system
ARTHROPOD CHARACTERISTICS





Segmented body
Jointed appendages
Hard external skeleton
Most have open circulatory system
Many have wings
SEGMENTED BODY

Individual body segments in larval stage
SEGMENTED BODY


Individual body segments in larval stage
Adults show 3 body segments




Head
Thorax (chest)
Abdomen
SOME display CEPHALOTHORAX (head and
chest fused together)
JOINTED APPENDAGES

APPENDAGE-structure that extends form
arthropod’s body wall
JOINTED APPENDAGES


APPENDAGE-structure that extends form
arthropod’s body wall
ARTHROPOD=“jointed foot”
EXOSKELETON

EXOSKELETON-made of carbohydrate
CHITIN-thin/flexible


Muscles attach
Appendages attach
EXOSKELETON

EXOSKELTON-made of carbohydrate
CHITIN-thin/flexible



Muscles attach
Appendages attach
WATERPROOF
EXOSKELETON

EXOSKELTON-made of carbohydrate
CHITIN-thin/flexible




Muscles attach
Appendages attach
WATERPROOF
PROTECTION
REPSIRATION AND
CIRCULATION

SPIRACLES-air enters body through these
openings
REPSIRATION AND
CIRCULATION


SPIRACLES-air enters body through these
openings
TRACHEA-tubes there air travels from
spiracles to bloodstream
REPSIRATION AND
CIRCULATION



SPIRACLES-air enters body through these
openings
TRACHEA-tubes there air travels from
spiracles to bloodstream
Aquatic arthropods breath with gills
REPSIRATION AND
CIRCULATION




SPIRACLES-air enters body through these
openings
TRACHEA-tubes there air travels from
spiracles to bloodstream
Aquatic arthropods breath with gills
OPEN CIRCULATORY SYSTEM
REPSIRATION AND
CIRCULATION





SPIRACLES-air enters body through these
openings
TRACHEA-tubes there air travels from
spiracles to bloodstream
Aquatic arthropods breath with gills
OPEN CIRCULATORY SYSTEM
Terrestrial arthropods breath with BOOK
LUNGS
FEEDING/DIGESTION/
EXCRETION

Many mouthparts/appendages for taking in
food
FEEDING/DIGESTION/
EXCRETION


Many mouthparts/appendages for taking in
food
MALPIGHIAN TUBULES-excretory system
of arthropods-
FEEDING/DIGESTION/
EXCRETION



Many mouthparts/appendages for taking in
food
MALPIGHIAN TUBULES-excretory system
of arthropodsWaste leaves through anus
COMPOUND EYE

Composed of thousands of individual visual
units
COMPOUND EYE


Composed of thousands of individual visual
units
SOME also have simple eyes (single
lenses)-see only light and dark, not images
LIFE CYCLE

Most reproduce sexually
LIFE CYCLE


Most reproduce sexually
Usually internal fertilization
LIFE CYCLE



Most reproduce sexually
Usually internal fertilization
Many have specialized reproductive organs
LIFE CYCLE




Most reproduce sexually
Usually internal fertilization
Many have specialized reproductive organs
MOLTING-shedding of exoskeleton to allow
for growth
GROUPS OF ARTHROPODS

4 main groups (SUBPHYLA of phyla
ARTHROPODA)
GROUPS OF ARTHROPODS

4 main groups (SUBPHYLA of phyla
ARTHROPODA)

HEXAPOD-insects
GROUPS OF ARTHROPODS

4 main groups (SUBPHYLA of phyla
ARTHROPODA)



HEXAPOD-insects
MYRIAPODA-millipeds/centipedes
CRUSTACEA-lobsters/shrimp
GROUPS OF ARTHROPODS

4 main groups (SUBPHYLA of phyla
ARTHROPODA)




HEXAPOD-insects
MYRIAPODA-millipeds/centipedes
CRUSTACEA-lobsters/shrimp
CHELICERATA-spiders
GROUPS OF ARTHROPODS

4 main groups (SUBPHYLA of phyla
ARTHROPODA)





HEXAPOD-insects
MYRIAPODA-millipeds/centipedes
CRUSTACEA-lobsters/shrimp
CHELICERATA-spiders
SEE PG. 705!!!
GROUPS OF ARTHROPODS

4 main groups (SUBPHYLA of phyla
ARTHROPODA)





HEXAPOD-insects
MYRIAPODA-millipeds/centipedes
CRUSTACEA-lobsters/shrimp
CHELICERATA-spiders
SEE PG. 705!!!
SUCCESS OF ARTHROPODS

More arthropods than all other animal
groups COMBINED
SUCCESS OF ARTHROPODS


More arthropods than all other animal
groups COMBINED
More than 5 million species identified (and
growing)
SUCCESS OF ARTHROPODS



More arthropods than all other animal
groups COMBINED
More than 5 million species identified (and
growing)
Exoskeleton provides protection (land and
water)
SUCCESS OF ARTHROPODS




More arthropods than all other animal
groups COMBINED
More than 5 million species identified (and
growing)
Exoskeleton provides protection (land and
water)
Wide range of food sources and habitats
ARACHNIDS

SUBPHYLUM CHELICERATA (spiders,
scorpions, mites, ticks and horseshoe
crabs)
ARACHNIDS


SUBPHYLUM CHELICERATA (spiders,
scorpions, mites, ticks and horseshoe
crabs)
Have appendages called CHELICERAE (1st
pair of appendages specialized for feeding)

Modified into pincers or fangs
ARACHNIDS


SUBPHYLUM CHELICERATA (spiders,
scorpions, mites, ticks and horseshoe crabs)
Have appendages called CHELICERAE (1st pair
of appendages specialized for feeding)



Modified into pincers or fangs
PEDIPALPS-2nd pair of appendages-catch and
handle prey
4 pair of WALKING LEGS
ARACHNIDS


SUBPHYLUM CHELICERATA (spiders,
scorpions, mites, ticks and horseshoe crabs)
Have appendages called CHELICERAE (1st pair
of appendages specialized for feeding)



Modified into pincers or fangs
PEDIPALPS-2nd pair of appendages-catch and
handle prey
4 pair of WALKING LEGS
ARACHNIDS


SUBPHYLUM CHELICERATA (spiders,
scorpions, mites, ticks and horseshoe crabs)
Have appendages called CHELICERAE (1st pair
of appendages specialized for feeding)





Modified into pincers or fangs
PEDIPALPS-2nd pair of appendages-catch and
handle prey
4 pair of WALKING LEGS
No antennae
CEPHALOTHORAX (head chest)
ARACHNIDS


SUBPHYLUM CHELICERATA (spiders, scorpions, mites,
ticks and horseshoe crabs)
Have appendages called CHELICERAE (1st pair of
appendages specialized for feeding)






Modified into pincers or fangs
PEDIPALPS-2nd pair of appendages-catch and handle prey
4 pair of WALKING LEGS
No antennae
CEPHALOTHORAX (head chest)
ABDOMEN (belly)
ARACHNIDS


SUBPHYLUM CHELICERATA (spiders, scorpions, mites,
ticks and horseshoe crabs)
Have appendages called CHELICERAE (1st pair of
appendages specialized for feeding)







Modified into pincers or fangs
PEDIPALPS-2nd pair of appendages-catch and handle prey
4 pair of WALKING LEGS
No antennae
CEPHALOTHORAX (head chest)
ABDOMEN (belly)
ARACHNIDS-largest class
ARACHNIDS


SUBPHYLUM CHELICERATA (spiders, scorpions, mites,
ticks and horseshoe crabs)
Have appendages called CHELICERAE (1st pair of
appendages specialized for feeding)







Modified into pincers or fangs
PEDIPALPS-2nd pair of appendages-catch and handle prey
4 pair of WALKING LEGS
No antennae
CEPHALOTHORAX (head chest)
ABDOMEN (belly)
ARACHNIDS-largest class
CLASS ARACHNIDA

All (except some mites) are carnivores
CLASS ARACHNIDA


All (except some mites) are carnivores
Most terrestrial
CLASS ARACHNIDA



All (except some mites) are carnivores
Most terrestrial
Don’t have jaws (consume only liquid food)
CLASS ARACHNIDA




All (except some mites) are carnivores
Most terrestrial
Don’t have jaws (consume only liquid food)
Enzymes turn prey into liquid (see pg. 710711)
CLASS ARACHNIDA





All (except some mites) are carnivores
Most terrestrial
Don’t have jaws (consume only liquid food)
Enzymes turn prey into liquid (see pg. 710711)
Most do more good than harm (predators of
insects)
SPIDERS

Chelicerae of spiders modified into fangs
SPIDERS


Chelicerae of spiders modified into fangs
Poison glands secrete toxins
(kills/paralyzes prey)
SPIDERS



Chelicerae of spiders modified into fangs
Poison glands secrete toxins
(kills/paralyzes prey)
2 poisonous species in US


BLACK WIDOW
BROWN RECLUSE
SPIDERS



Chelicerae of spiders modified into fangs
Poison glands secrete toxins
(kills/paralyzes prey)
2 poisonous species in US



BLACK WIDOW
BROWN RECLUSE
SPINNERETS-appendages at end of
abdomen-secrete sticky silk strands
BROWN RECLUSE
BLACK WIDOW
BLACK WIDOW VIDEO
SCORIONS/MITES/TICKS

SCORPIONS-segmented abdomen
ending in venomous stinger

Grasping pincers-seizing food and sexual
reproduction
SCORIONS/MITES/TICKS

SCORPIONS-segmented abdomen
ending in venomous stinger


Grasping pincers-seizing food and sexual
reproduction
MITES/TICKS-head, thorax and abdomen
fused into single unsegmented body


Most not harmful
Can spread viral/fungal infections (ex. Lyme’s
disease)
SCORIONS/MITES/TICKS

SCORPIONS-segmented abdomen ending in
venomous stinger


MITES/TICKS-head, thorax and abdomen fused
into single unsegmented body



Grasping pincers-seizing food and sexual reproduction
Most not harmful
Can spread viral/fungal infections (ex. Lyme’s disease)
HORSESHOE CRAB
Ancient group of invertebrates (400 million years)
SUBPHYLUM CRUSTACEA

Most marine, some fresh water
SUBPHYLUM CRUSTACEA
Most marine, some fresh water
 CEPHALOTHORAX (head chest) and
ABDOMEN

SUBPHYLUM CRUSTACEA
Most marine, some fresh water
 CEPHALOTHORAX (head chest) and
ABDOMEN
 Appendages on abdomen

SUBPHYLUM CRUSTACEA
Most marine, some fresh water
 CEPHALOTHORAX (head chest) and
ABDOMEN
 Appendages on abdomen
 Have mandibles for feeding and two
antennae

SUBPHYLUM CRUSTACEA
Most marine, some fresh water
 CEPHALOTHORAX (head chest) and
ABDOMEN
 Appendages on abdomen
 Have mandibles for feeding and two
antennae
 Breathe with gills

SUBPHYLUM CRUSTACEA






Most marine, some fresh water
CEPHALOTHORAX (head chest) and ABDOMEN
Appendages on abdomen
Have mandibles for feeding and two antennae
Breathe with gills
CARAPACE-exoskeleton of cephalothorax
SUBPHYLUM CRUSTACEA







Most marine, some fresh water
CEPHALOTHORAX (head chest) and ABDOMEN
Appendages on abdomen
Have mandibles for feeding and two antennae
Breathe with gills
CARAPACE-exoskeleton of cephalothorax
NAUPLIUS-larval form (molts to become adult)
TERRESTRIAL CRUSTACEANS

Sand fleas, isopods, land crabs (only
PARTIALLY adapted for land-tied to ocean)
AQUATIC CRUSTACEANS

Fairy shrimp, water fleas, copepods (most
abundant multicelled food source), krill,
barnacles (sessile),
AQUATIC CRUSTACEANS
Fairy shrimp, water fleas, copepods (most
abundant multicelled food source), krill,
barnacles (sessile),
 DECAPODS-crayfish, crabs, lobsters (5
pair legs)

AQUATIC CRUSTACEANS
Fairy shrimp, water fleas, copepods (most
abundant multicelled food source), krill,
barnacles (sessile),
 DECAPODS-crayfish, crabs, lobsters (5
pair legs)


CARAPACE-’hood’ over cephalothorax
AQUATIC CRUSTACEANS
Fairy shrimp, water fleas, copepods (most
abundant multicelled food source), krill,
barnacles (sessile),
 DECAPODS-crayfish, crabs, lobsters (5
pair legs)



CARAPACE-’hood’ over cephalothorax
LARVA=nauplius (MOLTS several times to allow
for growth)
AQUATIC CRUSTACEANS


Fairy shrimp, water fleas, copepods (most
abundant multicelled food source), krill, barnacles
(sessile),
DECAPODS-crayfish, crabs, lobsters (5 pair legs)



CARAPACE-’hood’ over cephalothorax
LARVA=nauplius (MOLTS several times to allow for
growth)
FOOD CHAIN-fairy shrimp, water fleas, krill
AQUATIC CRUSTACEANS


Fairy shrimp, water fleas, copepods (most
abundant multicelled food source), krill, barnacles
(sessile),
DECAPODS-crayfish, crabs, lobsters (5 pair legs)




CARAPACE-’hood’ over cephalothorax
LARVA=nauplius (MOLTS several times to allow for
growth)
FOOD CHAIN-fairy shrimp, water fleas, krill
SESSILE-barnacles
DECAPODS

LARGEST GROUP OF CRUSTACEANS

CHELIPEDS-pinchers
DECAPODS

LARGEST GROUP OF CRUSTACEANS



Shrimp, crayfish, crab, lobsters
CHELIPEDS-pinchers
SWIMMERETS-swimming legs on ventral
abdomen
DECAPODS

LARGEST GROUP OF CRUSTACEANS




Shrimp, crayfish, crab, lobsters
CHELIPEDS-pinchers
SWIMMERETS-swimming legs on ventral abdomen
UROPOD-flattened tail on posterior end (swim
backwards)