Download 2010 Chapter 24 Arthropods

ARTHRPPODS
Chapter 24
What is Entomology?
The study of insects
(and their near relatives).
Review of Zoological Nomenclature
Taxonomic Categories
Kingdom - Animalae
Phylum - Arthropoda
Class - Insecta
Order - Coleoptera
Family - Scarabaeidae
Genus - Popillia
Genus & species
Popillia japonica Newman
Characteristics of the Phylum
Arthropoda
24.1
• Segmented bodies (e.g., head, thorax,
abdomen).
• Paired appendages (e.g., legs, antennae) are
jointed.
• Chitinous exoskeletion that must be shed.
• Bilateral symmetry.
• The nervous system is dorsal (belly) and the
circulatory system is open and ventral
(back).
Arthropod Exoskeletons
• Joints are made of
stiff and flexible
cuticle to allow
movement.
• The exoskeleton is
made of many layers
of chitin.
– hard material that
protects the body
– must be shed in order
to grow
Arthropod Classification
– Crustaceans—live in oceans,
freshwater streams, and on land
– Chelicerates—specialized dagger-like
mouthparts
– Insects—most live on land,
have six legs
– Myriapods—
long bodies and
many pairs of
legs
24.2
Crustaceans
(Marine Arthropods)
– two distinct body sections, cephalothorax
and abdomen
– one pair of appendages per segment
– two pairs of antennae
– exoskeleton
– carapace
Crustacean Appendages
• Crustacean appendages are used for a variety
of functions.
– collecting and manipulating food
– attracting females
– Protection
– claws, antennae, walking legs, swimmerets,
and mandibles.
Types of Crustaceans.
– Decapods such as lobsters and crabs have ten
legs.
– Isopods such as pill bugs
have flattened bodies
and seven pairs of legs.
– Barnacles are sessile filter
feeders wrapped in a hard shell.
Chelicerate Arthropod Characters:
• Pincher-like mouthparts - chelicerae
• NO antennae
• Two body regions, usually cephalothorax & abdomen
• Four pairs of legs
• Horseshoe crabs and arachnids are
fangs
only living groups
poison gland
24.3
spinneret
Arachnids are the largest group of
chelicerates.
• There are three major groups of chelicerates.
– horseshoe crabs
– sea spiders
– arachnids
Arachnids -- Spiders
• All spiders make silk and produce venom.
Metamorphosis
CHANGE IN FORM FROM EGG
TO ADULT
INCOMPLETE
METAMORPHOUS
Incomplete
Insects change
shape gradually!
Complete
Metamorphosis
Four stages that
all look different
Insects with Complete
Metamorphosis
EGG  LARVA  PUPA  ADULT
•
•
•
•
beetles
bees, ants, wasps
Flies
butterflies
Insects with Incomplete
Metamorphosis
EGG  NYMPH  ADULT
• fleas
• grasshoppers &
crickets
Wings NOT
fully
developed