Phylum Arthropoda

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Spiders, insects, centipedes, scorpions, shrimp,
crabs, lobsters, butterflies
Phylum Arthropoda

• Jointed appendages

The world arthropod population has been estimated
at a billion billion
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• Major Characteristics
• Segmented bodies covered in an exoskeleton
• of chitin (Carbohydrate).
• Protosome coelomate
• Three segments
• Head, Thorax, Abdomen

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Chitin

• Strong but flexible
• Nitrogenous polysaccharide.

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• Exoskeleton
• Protection
• helps prevent water loss
• provides framework for muscle attachment
• Does not grow. When the organism outgrows it, it
  molts.
• Gland digest inside of old exoskeleton and then
  other glands secrete a new skeleton.
• When new one is ready, organism pulls out of the
  old.

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Have more sensory apparatus than the annelids
gives them more speed and freedom of movement
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Groups of segments and their appendages have
become specialized for a variety of functions,
permitting efficient division of labor among
regions.
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Nervous System

• Arthropods have a well-developed nervous system.
  
• A brain is connected to a pair of ventral nerve
  cords with several segmental ganglia.

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Nervous System

• Chords meet in the head, where the ganglia from
  several anterior segments are fused into a
  cerebral ganglion (brain).
• Close to the antennae, eyes, and other sense
  organs concentrated on the head.

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Digestion

• Grasshopper
• Long tube containing crop gizzard
• Specialilzed mouth parts for tasting, biting
  crushing

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Reproduction
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• Metamorphosis (Insects)
• Adult stage and larval stage do not compete for
  food.

• Mouth Parts
• Many different types- enabled them to occupy any
  niche

• Short generation time

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• Metamorphosis.
• Process of changing shape and form.
• Two types
• Complete
• Larvae look completely different from adult
• Incomplete
• Larvae look like a
• small adult- lack sex organs

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• Metamorphosis is central to insect development.
• Larval stages specialized for eating and growing
  change morphology completely during the pupal
  stage and emerge as adults.

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Feeding Can be herbivores, carnivores, and
omnivores.
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• Respiration
• Most have tracheal tubes that extend throughout
  the body. Air enters through spiracles.
• Spiders- book lungs/gills.

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Tracheal tubes- respiration Complex mouth
parts Three parts specialized for diet
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chitin-lined tracheal system carries O2 from the
spiracles directly to the cells.
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Respiration
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Circulation Well developed heart with arteries
and vessels

• Open circulatory system in which hemolymph fluid
  is propelled by a heart through short arteries
  into sinuses (the hemocoel) surrounding tissues
  organs.
• Hemolymph returns to the heart through valved
  pores.

Hemocoel- internal cavity which bathes tissues
w/an O2 nutrient carrying fluid called
hemolymph
Open systems are also seen in mollusks
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In an open circulatory system, blood leaves the
blood and flows freely within the tissues. This
system is not very efficient because there is no
blood pressure to move blood rapidly through the
tissues. The oval line in the diagram below
represents an animals body.
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Removal of waste Malpighian tubules (outpockets
of the digestive tract) Aquatic Tubules
excrete directly into water
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Major Groups Classified based on number and
structure of body segments.4 subphylum, 10 classes
Subphylum Trilobita
All extinct Were marine arthropods about 500
million years ago. Became extinct 200 million
years ago.
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Subphylum Crustacea

• Lobster, crab, shrimp, Crayfish, Barnacles
• 4 classes
• Mainly aquatic (Marine and freshwater)
• Terrestrial -Pill bugs

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• 2 or 3 body segments
• Head-compound eyes
• 2 pairs of branched antennas
• Chewing mouth parts-mandibles
• 2 major body parts
• Cephalothorax
• -Fusion of head
• w/thorax
• -Covered by a carpace.
• 2. Abdomen

name is derived from the crusty exoskeleton
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• Head usually bears compound eyes and five pairs
  of appendages
• a. First two are antennae and antennules in
  front of the mouth, they have sensory functions.
• b. Three pairs (mandibles, first and second
  maxillae) lie behind mouth and are used in
  feeding.

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Spiders and their relatives 3 classes
Subphylum Chelicerata

• Have two mouth parts
• Cheliceras-fangs-stab and paralyze
• Pedipalps- to grab prey
• Two body segments
• Cephalothorax and abdomen
• Almost all have four pairs of walking legs
• Book lungs or book gills

Lycosid spider female with offspring
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Class Arachnida
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Spiders, scorpions, mites, ticks
Class Arachnida

• Spiders
• Book Lungs
• Inject digestive enzymes into prey
• All spiders produce silk- may not make webs
• Spin webs by forcing liquid silk through their
  spinnerets

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Class Arachnida

• Mites and Ticks
• Usually parasitic
• Mouth parts, usually needle-like, are used to dig
  into host tissue and suck blood.
• Ticks- Transmit bacteria that causes Lyme Disease
  Rocky mountain spotted fever
• Mites- chiggers can cause itching and painful
  rashes in humans.

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Class Arachnida
Scorpions Stingers can kill or paralyze prey.
Chew their prey.
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Insects and their relatives
Class Insecta
Beetles, Flies, Butterflies, Ants, Grasshoppers,
Fleas, Crickets, Mosquitoes, bees

• Three body regions
• Head, thorax, abdomen
• Three pairs of legs attached to thorax. Jumping,
  walking or capturing prey.
• Pair of antennae for sensing the environment
• Pair of compound eyes on head
• Two pairs of wings (chitin) on thorax
• Flying-wider variety habitats

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Insect Eyes
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• DOWNS
• Termites destroy wood
• Moths eat cloth
• Locusts destroy crops
• Cotton Boll Weevils
• Mosquitoes and diseases

• UPS
• Bees, butterflies, etc., pollinate crops
• Some produce silk, wax, honey
• Food

Insects and Humans
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Insects and communication Sounds- chirps,
buzz Light- Male fireflies Chemicals- Pheromones
(mate, danger, or alert)
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• Insect Societies
• Complex group that works together for the good of
  the colony.
• Different roles are preformed by groups called
  castes.
• Each castes has a different body form to carry
  out their specific task.

Carpenter ant castes, from left to right queen,
winged male, major worker, minor worker
Dances With Bees

• Bees Dance!
• Ants leave pheromone trails.

• Very sophisticated communication.

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ROUND DANCE-used when the source of food (nectar
or pollen) is less than 100 metres away
WAGGLE DANCE
Animation
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Class Diplopoda

• Millipedes
• Each body segment has two pairs of legs
• Detritivores- live under rocks and in decaying
  logs
• Some can secret unpleasant or toxic chemicals for
  defense.

slow-moving vegetarians scavengers
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Class Chilopoda

• Centipedes
• Each body segment has one pair of legs
• Carnivores
• Mouth parts contain venomous claws
• Live under rocks or in the soil
• Must live in moist environments because their
  spiracles cannot close and they lack a waterproof
  coating.

move rapidly and prey mostly on small
invertebrates.
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Anthropods
reproduceusing
havewell-developed
feedon
respireusing