Phylum Arthropoda

2. Animal Diversity: Invertebrates
by
Maryam Riasat
PHYLUM ARTHROPODA

4. General Characteristics
• Bilaterally Symmetrical
• Cells form up to the size of tissues and organs. Eat everything from plants to
animals
• Live everywhere in land, fresh water, salt water, and every other
environment
• Largest Phyla on earth
• More than 83% of all described animal species are arthropods

5. Support System
 Exoskeleton - made of protein and
chitin
• used for protection
• keeps joints attached
 Molting - sheds exoskeleton as it
grows
 Segmented body
• Head, thorax, abdomen
 Contain a range from 3 to 300 sets
of legs
 Contain 2 pairs of antennae

6. Respiratory System
• Aquatic arthropods possess gills for respiration
• Land arthropods have a tracheae and book lungs
as respiratory organs
• Air passes through the tracheae through
specialized openings in the exoskeleton called
spiracles

7. Circulatory System
• Open Circulatory System
• Body fluid called Hemolymph (Not blood)
• Hemolymph is pumped by the heart to sinuses called the
hemocoel
• Body fluid enters pores to the organs and is propelled through
arteries to the body

8. Nervous System
• Brain
• Ventral nerve cord
• Double chain of ganglia
along the ventral surface of
the arthropod
• At anterior end are 3 fused
pairs of dorsal ganglia,
constitutes the brain
• Much of the control of
arthropod's activities is in
the central ganglia

9. Digestive System
 Eat Everything
 Complete digestive system
 Specialized by segmentation
 Food enters through the mouth and flows into the mid-gut
where food is broken down and pushed to the anus.
 Specialized mouthparts
piercing, sucking or mandible, biting, chewing

10. Excretory System
 Excretory system made of
malpighian tubules and
green glands
 Malpighian tubules are
tubular network that
collects liquid wastes and
sends them to the hind gut
in the form of nitrogenous
wastes. Found in terrestrial
arthropods .
 Green glands collect and
excrete urine like kidneys.
Found in aquatic
arthropods.

11. Reproductive System
• Most reproduce sexually
o Internal fertilization
o External fertilization
• Some species reproduce through parthenogenesis
e.g. bees, wasps, ants and aphids
• Undergo metamorphosis
Complete egg – larva – pupa – adut
Incomplete egg – juvenile – adult

13. Taxonomic summary

14. Chelicerata
• Lives on land or in water
• Includes horseshoe crabs, spiders, scorpions,
ticks and mites
• Have chelicerae, which serve as pincers or
fangs
• They do not have antennae

15. Myriapods
• All Myriapods lives on land
• Head contains 3 appendages
for eating including
mandibles (jaw like
structure)
• Millipedes
o less than 1000 legs (2 pairs
per segment)
o herbivores
• Centipedes
o 1 pair of legs per segment
o carnivorous

16. Crustaceans
• Live in fresh and salt water
environments
• Crustacea is Latin word for
"Shell"
• Shell is made of calcium,
protein, and chitin
• Have anywhere from 16 to 60
segments, 2-3 pairs of legs
• Advanced crustaceans have
pincers
• Includes Crabs, Lobsters,
Barnacle, Shrimp

17. Hexapoda
• Includes insects
• Mostly live on land
• Contain 3 pairs of legs and2 pairs of wings
• There are more species of Hexapoda than all other
forms of life combined