Feb 14, 2016
• most diverse group of invertebrates (1,130,000 species)
• 75% of all animal species• jointed appendages – important characteristic• - adapted for walking, feeding, sensing, and
mating
• hard, thick, and made out of a carbohydrate called chitin
• land arthropods must have a waxy layer to protect against water loss
• Molting = shedding of the old exoskeleton
• molts need to occur for arthropod to increase in size or add appendages (legs)
• new, softer exoskeleton forms underneath old skeleton
• new exoskeleton will harden overtime
• 3 fused segments:• 1. head 2. thorax 3.abdomen
( fusion allows for better movement and protection)
• some arthropods have a fused head and thorax called a cephalothorax
Three types:
1.Gills- aquatic arthropods
2. Book lungs - spiders, horseshoe crab
- leaf-like plates filled w/ air
3. Tracheal tubes
- terrestrial insects
- branching network of hollow air passages
All respiration based on diffusion of gases (Oxygen/Carbon dioxide)
• Antennae -- detect movement, sound and chemicals; used for communication (moth, mosquito, bee)
• pheromones --chemical odor signals can be given off for communication
• Usually - one pair of compound eyes and 3-8 simple eyes
• simple eye = one lens used for detecting light
• compound eye = many lenses, detect movements and colors
• Consists of 2 ventral nerve cords, anterior “brain”, and several ganglia
• ganglia serve as control centers for specific body sections
• Open system, blood pumped by one or more hearts
• heartvessels tissues heart (through open body spaces)
• Complete gut• mouth parts called mandibles
(jaws)• adapted for chewing, holding,
sucking, or biting• spiders have chelicerae, 1st
appendage adapted for piercing or fangs
• spiders and crustaceans also have pedipalps, used for holding food, sensing, and even mating
Insect Digestive Tract
Esophagus Crop Gizzard Salivary gland Gastric ceaca Midgut Intestine Rectum anus
• Use Malphigian Tubules• located in abdomen• empty into intestine
• Muscles attached to inner surface of exoskeleton
• External fertilization– aquatic (water) • Internal fertilization– terrestrial (land)• some species exhibit parthenogenesis (asexual
reproduction—new insect develops from an unfertilized egg.) ex. Bees, ants, wasps
Incomplete Metamorphosisegg, nymph, adult
Grasshopper Anatomy
http://webs.lander.edu/rsfox/invertebrates/romalea.html
http://www.carolina.com/category/teacher+resources/dissection+activities+and+resources/grasshopper+dissection.do
Above is excellent picture
http://bugs.osu.edu/~bugdoc/Shetlar/462/462InsectMorphology/Morph03.htm
http://www.junglewalk.com/video/Grasshopper-movie.htm
http://insects.tamu.edu/imagegallery/video/
http://salinella.bio.uottawa.ca/digitalzoology/Arthropo/Default.php?FlashLabModule.swf?&Loadmoviename=../ArthTrac/Inse_Hopp_05_lb.swf?E?Md2ChapterMcp1?Md2Ch4SectionMcp1?Md2Ch4Sc2TopicMcp1
http://www.members.shaw.ca/jonesbiology1/bio11/units/ecology/grasshopperdissectionlab.PDF
Above anatomy of digestive tract