Download Arthropods

Arthropods
General Characteristics
• All have jointed legs
• Evolved from annelids (segmented worms)
• All have an exoskeleton made of chitin
• All have bilateral symmetry
WOW BEHAVIOR!
• All molt- shed skin to allow for growth (lobster
example)
• Spiders molt too
Body Arrangement
• All have 3 body segments – head, thorax
and abdomen
Arthropods all have an open
circulatory system
“Blood” is confined to vessels for only a small
portion of it’s circuit through the body.
FIVE CLASSES
•
•
•
•
•
Centipede – one pair of legs per segment
Millipede- two pair of legs per segment
Insects- 3 pair of legs per thorax
Arachnids- 4 pair of legs per thorax
Crustaceans-5 pair of legs per thorax
Centipedes
• Centipedes have 1
pair of legs per
body segment.
Legs
Defenses
Have large
poisonous fangs
on their first
appendages.
Centipede
• Name means 100 feet. Do
they have 100 feet?
Centipedes
• Have longer
antennae than
other animals in
the same class.
• Antennae are
sensory organs,
used for touch and
smell
Feeding
• Usually are
carnivorous, eating
other arthropods
• Eat snails, slugs, and
worms
Millipedes
Millipedes
• Millipedes have 2 pair
of legs per segment.
• Body has many
segments; as many
as 100
Millipedes
• Generally not
poisonous to humans
Millipedes
Name means 1000 feet. Does it have 1000 feet?
Millipedes
• Millipedes spit
cyanide acid at prey.
Insects
Far out!!
Insects have 3 pairs of legs on their thorax
INSECTS undergo metamorphosis
• Complete metamorphosis:
– Egg
– Larvae
– Pupa
– adult
INSECTS undergo metamorphosis
• Incomplete metamorphosis:
– Egg
– Nymph
– adult
Insects have 3 simple eyes
between two compound eyes
Insects breathe through holes in their sides
(usually the thorax) called spiracles
Many insects have camouflage
More Camouflage
Insects mimic environment
Flight was an evolutionary advantage to insects
• Damselfly goes from water to flight
Drosophila flight
Common blue damselfly
The miraculous honey bee!
• Honey bees and relationship to humans
Wild and wonderful
Praying Mantis at the snake buffet
Weevil family
Amazing Mantis!!
Wild and wonderful
Monarch butterfly
Swallow tail species
Viceroy butterfly
Arachnids
Arachnid Includes
Mites
Spiders
scorpions
Arachnids have 4 pairs (8)of legs
All spiders have 2 pair of
mouthparts
Spiders have fangs
Arachnids breathe by book lungs
Horseshoe Crabs are more closely related to arachnids
then to crustaceans.
Malpigian tubules are used as kidneys to filter the
“blood”
Arachnids produce a strong elastic silk from spinerettes to
build a web to capture their prey
Cephalothorax
Cephalothorax is the head attached to the thorax.
Vision
Only have simple eyes
Arachnids have poison to kill their prey
Brown Recluse
Arachnid feeding
Arachnids use enzymes
to dissolve food
before ingestion.
Camel Spider
Real spider
Trick photography
Crustaceans
Crustacean
• Crustaceans all
have a
cephalothorax
• Examples are
crayfish, shrimp,
lobster, and crabs
Most are aquatic
• EXCEPT – rolly polly (pill bugs)
Locomotion
Have 5 pairs of
appendages
Crustaceans have a
special appendage
used for swimming
called a swimmerets
Green Gland
Have an organ called
the green gland:
which regulates the
amount of salt and
water in the body
Carapace – hard outer shell – protects inner organs
Internal Anatomy
Amount of Legs
• All crustaceans have five pair of appendages
• And crustaceans have two pair of antennae
General Information
• Crustaceans breathe
though gills
• Mostly scavenge for
food
•
Some have a long
appendage called a
telson-tail