Arthropods
BIOL 1407
Phylum Arthropoda
• Cheliceriformes
– Horseshoe Crabs
– Arachnids: spiders, scorpions, ticks, mites
• Myriapoda: millipedes and centipedes
• Hexapoda: insects and springtails
• Crustacea: crabs, lobsters, barnacles, etc.
Cheliceriformes: Horseshoe Crabs
Cheliceriformes: Arachnids
Cheliceriformes: Arachnids
Video: Click on “Trapdoor Spider” and “An Amazing Web”
http://www.bbc.co.uk/sn/tvradio/programmes/lifeintheundergrowth/video.shtml
Myriapods
Millipede
Centipede
Hexapods: Insects
Photo Credit for Caterpillar: UNK Student, Vieques 2008
Videos: Click on “Titan Beetle”, “Moth and Lantern Bug”, “Feather-Legged
Bug”, “Bot Flies”, “Giant Asiatic Honeybees”, and “Mangrove Ants”.
http://www.bbc.co.uk/sn/tvradio/programmes/lifeintheundergrowth/video.shtml
Hexapods: Springtails
Photo
Credit:
Sarefo,
2005
Wikimedia
Commons
Video: Click on “Dancing Springtails”
http://www.bbc.co.uk/sn/tvradio/programmes/lifeintheundergrowth/video.shtml
Crustaceans
Photo Credit for Spiny Lobster: UNK Student, 2008,
Vieques
Crustaceans
Photo Credit for Artermia: Betsy Maxim, 2008
Characteristics of Arthropods
• Bilateral symmetry
• Triploblastic
• Coelomate
•
Photo Credit: Alvesgaspar, 2008, Wikimedia
Commons
Characteristics of Arthropods
• Segmentation
• Chitinous
Exoskeleton
•
Photo Credit for Striped Love Beetle: Adrian
Pingstone, 2005, Wikimedia Commons
Characteristics of Arthropods
• Jointed
Appendages
•
Photo Credit for Praying Mantis
in Defense Posture: Tibor
Duliskovich, 2007, Wikimedia
Commons
Characteristics of Arthropods
• Ecdysis
• Video of Cicada
Nymph Molting:
http://www.youtube.com/watch?v
=go4MqVq9HVM
•
Photo Credit: Macau500, 2004,
Wikimedia Commons
Characteristics of Arthropods
• Complete Digestive
System
• Open Circulatory
System
• Gills or book lungs or
tracheal tubes
• Centralized nervous
system
Metamorphosis
• Developmental
stage in insects
• Young feeding form
 adult
reproductive form
Incomplete Metamorphosis
• Young resemble
adults
• Smaller with different
proportions
•
•
Photo Credit for Eurydema oleraceum nymph:
James K. Lindsey, 2007, Wikimedia Commons
Photo Credit for Eurydema oleraceum adult:
Guido Gerding, 2006, Wikimedia Commons
Complete Metamorphosis
• Larval stages do not
resemble adults
• Pupa stage 
transformation
• Video:
http://www.youtube.com/watch?v=
GTUgUEpqBrA&feature=related
•
Photo Credit for Monarch Butterfly Pictures: Derek
Ramsey, 2006 (adult), 2007 (caterpillar), Wikimedia
Commons
Wings
Photo Credit: André Karwath, 2005, Wikimedia Commons
Complete Digestive System
Transport
• Open
Circulatory
System
• Heart =
Pump
• Vessels
• Hemolymph
= Fluid
Gas Exchange
•
•
•
•
Gills
Book Lungs
Tracheal Tubes
Respiratory Pigments
– Hemocyanin
(crustaceans and
horseshoe crabs)
–
Photo Credit for Terebellid Polychaete:
Matthias Buschmann, 2007, Wikimedia
Commons
Cellular Respiration
• Food is needed to
provide fuel for
cellular respiration
• Cellular
respiration:
– ATP
– Use O2
– Release CO2
CO2
O2
Surface-Area-to-Volume
• As body size ↑,
Surface Area
increases more
slowly than
Volume
increases
• Large bodies
have smaller
surface-area-tovolume ratio than
small bodies
Surface-Area-to-Volume
• Exchange occurs across surfaces
• Dependent upon surface area
• Folding ↑ Surface Area
Surface-Area-to-Volume
• Volume determines
demand for:
– Materials
– Energy
– Oxygen
• Volume generates:
– Metabolic Wastes
– Carbon Dioxide
Advantage of Folding
• Folding of internal
structures
increases surface
area
• Exchange rate
can meet
demands of
organism
Arthropod Excretory Systems:
Antennal Glands and Malpighian Tubules
Centralized
Nervous
System
The End
Unless otherwise specified, all images in this presentation came from:
Campbell, et al. 2008. Biology, 8th ed. Pearson Benjamin Cummings.