1 (insects, crustaceans, spiders, mites)Diversity of Life -Arthropoda - (insects, crustaceans, spiders, mites)

2 Arthropoda - insects, crustaceans, spiders, mites,

3 Arthropoda - abundance

4 Arthropoda – Where did they come from?Peripatus

5 What about the Onychophora (“velvet worms” )?Annelid Arthropod Characteristics Characteristics -worm-like body -segmented legs (during embryogenesis) Peripatus -paired nephridia -open circulatory system - hemocoel - trachea - oral appendages

6 Arthropoda - What makes them all arthropods?Arthropods are • segmented coelomates • exoskeleton • jointed appendages

7 Arthropoda - two significant improvements in body architectureEXOSKELETON JOINTED APPENDAGES

8 Arthropoda - Exoskeletonheart digestive cavity ventral nerve cord

9 Arthropoda - ExoskeletonThe arthropod exoskeleton is made of chitin (also found in the cell walls of fungi) Chains of sugars - cross-linked with benzene N-acetyl - glucosamine Benzene rings

10 Arthropoda - Exoskeleton= Laid down in overlapping layers (like plywood)

11 Arthropoda - ExoskeletonAdvantages: Protection from drying - allowed invasion of land Protection from predators -

12 Arthropoda - ExoskeletonAdvantages: Protection from drying - allowed invasion of land Protection from predators - Disadvantages: Doesn’t permit growth - have to moult Doesn’t bend - need to insert breaks (joints) in it to permit movement

13 Arthropoda - Body SectionsThorax - locomotory Abdomen - digestion and reproduction Head - sensory and feeding

14 Arthropoda - ClassificationTHE MAIN GROUPS OF ARTHROPODS CHELICERIFORMES - spiders, mites, ticks, scorpions MYRIAPODA - centipedes and millipeds UNIRAMIA - insects CRUSTACEA - crabs, lobsters, shrimp

15 Arthropoda - CheliceriformesHorseshoe crab Spider Scorpion

16 Arthropoda - CheliceriformesCharacteristics 1. Chelicerae - feeding appendages 2. Head and thorax are fused - cephalothorax 3. Eight legs

17 Arthropoda - Myriapoda- millipedes and centipedes Characteristic - several pairs of legs

18 Arthropoda - Uniramia - the insectsMost common kind of animal - greatest number of species

19 Arthropoda - Uniramia - the insectsMost common kind of animal - greatest number of species

20 Arthropoda - Uniramia - the insectsMost common kind of animal - greatest number of species Characteristics - Six legs 2. Distinct head, thorax and abdomen

21 Arthropoda - Uniramia - the insectsCharacteristics 3. Wings Insects are the only invertebrates to have mastered flight

22 Arthropoda - Uniramia - the insectsCharacteristics - 3. Two kinds of life cycles Complete (or holometabolous) Egg larva pupa adult Incomplete (or hemimetabolous) Egg larva adult

23 Arthropoda - Crustacea - lobsters, crabs, barnacles

24 Arthropoda - Crustacea - lobsters, crabs, barnaclesCharacteristics - 1. Head and thorax are fused - cephalothorax

25 Arthropoda - Crustacea - lobsters, crabs, barnaclesCharacteristics - 2. 10 primary locomotory appendages

26 Arthropoda - Summary of characteristicsGroup Cheliceriformes Uniramia Myriapoda Crustacea Cephalothorax Yes No Number of legs 8 6 20+ 10 Flight Jointed appendages