1 Arthropods Chapter 31 Diversity of Arthropods –Arachnids –crustaceans –Centipedes and Millipedes –Insects What is an Arthropod? Characteristics of Arthropods

2 Diversity of Arthropods Arachnids Crustaceans Centipedes / Millipedes Insects

3 What is an Arthropod? Characteristics of Arthropods –Invertebrate –bilateral –exoskeleton –appendages (jointed Appendages)

4 Segmentation in Arthropods Head Thorax Abdomen

5 Body Segment fused Cephalotharax Abdomen

6 Exoskeleton Success of group attributed to this features hard thick outer layer made of protein called chitin Used as armor protection and support for muscle attachments Problems with exoskeleton

7 Jointed Appendages Multiple uses: senses, walking, feeding and mating Joints allow more powerful movement allow appendages to be used in multiple ways

8 Why they must Molt? Exoskeleton is heavy and bulky restricts speed of movement require that the exoskeleton be shed to allow growth (molting) During molting which may require a lot of time the animal is vulnerable

9 Gas Exchange Book Lungs Gills Tracheal Tubes

10 Arthropod Senses Movement, sound, or chemical can be detected by ANTENNAE - pheromomes Detect light with SIMPLE EYES Motion and some colors are detected by the COMPOUND EYES

11 Nervous System Well developed : – double ventral nerve cord, – anterior brain, –several ganglia - each segment has a set to help control the functions

12 Complex body systems Open circulatory system bathes the organs Complex digestive system Mouth parts have a great variety –holding –chewing –sucking/ biting Waste removed by malpighian tubules

13 Sucking mouth parts

14 Butterfly mouth part

15 Bee mouth part

16 Spider Fangs

17 More Spider fangs

18 Reproduction Sexual reproduction Some are hemaphrodites Parthenogenesis

19 Luber Grasshopper

20 Walking Stick

21 Special Mouth Parts

22 Butterfly

23 Crayfish’s External anatomy -cephalothorax - swimmeret - abdomen - uropods -Walking legs - mouth parts -claws(cheliped) mandible -antenna maxilla -antennules maxilliped

24 Crayfish’s Internal anatomy Digestive Circulatory –Esophagus- open system –stomach heart grastric mill dorsal artery –intestine –anus

25 Crayfish’s Internal Anatomy 2 Respiratory system –Gills –legs –bailers (maxilla) Excretory sytem –green gland –green gland pore

26 Questions A (100 words each) 1.Compare the digestive, respiratory, and reproductive system of Arachnids and Grasshoppers 2. What are 5 anatomical characteristics that only Arachnids have ? 3. How do joints affect the speed and power an animal has?