Ch. 36 - Arthropods

1. Ch. 36 - Arthropods • Phylum: Arthropoda • Means “jointed legs” • 75% of all animals belong to this phylum • Insects, lobsters, crabs, spiders, millipedes, & centipedes • Video • Video

2. Characteristics of Arthropods • 1. Appendages – legs, antennae • 2 appendages per segment • 2. Open circulatory system • 3. Digestive system • 4. Ventral nervous system • 5. Exoskeleton – protection & desiccation • Made of chitin • Video • Video

3. What is molting? • Shedding of the exoskeleton • Why do animals molt? • Every time an animal molts it enlarges or grows

4. What are some advantages & disadvantages of molting? • Protection, prevents desiccation • Must molt to grow, vulnerable after it molts

5. Crustacea subphylum • Crayfish, lobsters, crab, sow bugs, daphnia. • Mainly aquatic • Crayfish Characteristics • 2 main body parts • 1. Cephalothorax – head & thorax • 2. Abdomen – 7 segments • Last segment is the telson • Video • Video

6. Appendages of the Crayfish • 1. Chelipeds – pinchers • 2. Antennules – smaller (inside) • 3. Antenna – larger (outside) • 4. Walking legs – 4 along the thorax • 5. Swimmerets – along the abdomen • 6. Uropod – outside the telson

7. Digestive & Excretory Systems • First the crayfish tears the food with their maxillae & maxillipeds. • They chew their food with their mandibles • The food passes through the esophagus to the stomach.

8. The digestive glands absorb nutrients, then the undigested material enters the intestine, and then exits the anus. • Green glands are also used in the excretory system to remove waste; much like kidneys.

9. Circulatory & Respiratory Systems • Open Circulatory System • Dorsal heart that pumps blood to the body cavity to bath the organs. It is then pumped to the gills. • What do the gills do? • Large surface area for gas exchange • The gills are attached to each walking leg

10. Nervous System • Ventral nerve cord • Brain • Sense receptors  antennules, antennae, & compound eyes • A compound eye has many lenses • Do you have a compound eye?

11. Reproductive System • Usually mate in the fall • The male uses its swimmerets to transfer sperm to the female, where she keeps the sperm until spring. • The eggs are then fertilized and kept along the female’s swimmerets until they hatch.

12. Chelicerae - subphylum • Class: Arachnida • Spiders, mites, scorpions • Many use stingers or fangs with poison. • How do spiders catch their prey? • with webs or “trap doors” • Scorpions hunt at night and hide during the day. • Video

13. Only a few scorpions are poisonous enough to kill humans. • Mites and ticks are the most abundant in this class. • Ticks are parasitic and some carry diseases. • Lyme’s disease • Rocky mountain spotted fever. • Spider mites can damage and wipe out fruit trees or other trees.

14. Structure of a spider • 2 segments • 1. Cephalothorax • 2. Abdomen • Chelicerae – hollow fangs • Pedipaps – aid in chewing • 8 legs & eyes • Spiracles – openings for respiration

15. Book lung – air sacs in the abdomen for respiration. • Malpighian tubules – kidney-like excretory system. Removes wastes. • Spinnerets – spins silk for webs • Can also be used as silk balloons to fly away in young spiders. • Black widow & Brown Recluse • 2 poisonous spiders in Kansas • Video

16. Uniramia - subphylum • 2 classes • 1. Diplopoda – millipedes • Means “thousand feet” • 2 pair of legs per segment • 2. Chilopoda – centipedes • Means “hundred feet” • 1 pair of legs per segment • Some are poisonous • Video

17. Insects – 2nd Part of Ch. 39 • Most diverse and largest number of species of any class of organism. • They were present on earth before the dinosaurs, over 300 million years ago. • Differences from other arthropods • 1. 3 body segments  head, thorax, abdomen • Video

18. 2. Head has 1 pair of antennae • 3. Thorax has 3 pairs of legs & 1 or 2 pair of wings. • 4. No wings or legs attached to the abdomen.

19. Kingdom: Animalia • Phylum: Arthropoda • Class: Insecta (700,000 + species named) • What makes insect so successful? • Lots of them – adapt very well • Great diversity – several types • Reproduce rapidly • Small size & ability to fly (most)

20. Benefit of insects? • 1. Pollination – plants can’t reproduce without insects. We need plants to survive. • 2. Food – for other animals. Several animals rely on insects as a source of food. • 3. Industrial uses – silk & honey • What is the study of insects called? (E.C) • Entomology • Video

21. Grasshopper  External Structures • 3 Body Parts: • 1. Head • Labium – grasps the food ( bottom lip) • Mandible – chews the food (jaws) • Labrum – holds the food (upper lip) • Maxilla – extra jaws • 2. Thorax • 3 pairs of legs (6 total) • 2 pair of wings usually

22. 3 parts to the thorax • 1. Prothorax – pair of walking legs • 2. Mesothorax. – pair of walking legs • 3. Metathorax – pair of jumping legs • Forewings are attached to the mesothorax • Hindwings are attached to the metathorax

23. 3. Abdomen • Spiracle – for respiration • Tympanum – for hearing (eardrum) • Ovipositors – holds it eggs

24. GrasshopperInternal Structures • Digestive System • What do grasshoppers eat? • What are the mouth parts? • Food passage: esophaguscrop (storage) gizzard (grind) midgut (digested) hindgut (rectum & colon)  out the anus

25. Circulatory System • Open Circulatory System • An aorta is a large vessel that carries the blood on the dorsal side. • 2 Hearts along the aorta

26. Respiratory System • No lungs or gills • Use spiracles – openings along the abdomen • The spiracles lead to the trachea • Nervous System • Brain connected to a ventral nerve cord • Has simple and complex eyes

27. Have antennae • Tympanum for sensing sound • Reproductive System • The male deposits sperm into the seminal receptacle, which stores the sperm. • The female uses its ovipositors to deposit her eggs in the ground.

28. Types of Metamorphosis • Incomplete Metamorphosis • 1. Egg • 2. Nymph – immature form of an adult • 3. Adult – able to reproduce (wings)

29. Complete Metamorphosis • 1. Egg • 2. Larvae – catepillar stage • 3. Pupa – cocoon protects the pupa • 4. Adult – emerges from the pupa (butterfly) • Video

30. Defenses of Insects • What ways do insects use defenses? • 1. Stinger or bite – bee, wasp, ants • 2. Camouflage – blend into their surroundings. • Ex. Grasshopper, praying manthesis • Video • 3. Warning coloration – alert other animals that the insect might be poisonous.

31. Insect Behavior • Division of Labor among Bees • 1. Worker bee – female bees, most abundant. (8,000) - sterile • 2. Drone – male bees (100) • 3. Queen bee – the only fertile female • CHARACTERISTIS OF EACH BEE • Video

32. The worker bee produces royal jelly to feed the queen bee • The worker also secretes wax to make the hive. • The produces a pheromone called queen factor, which makes the other females sterile. • Round Dance – tells the other bees food is within 50 meters • Waggle Dance – tells the other bees food is greater than 50 meters.