1. End Show Slide 1 of 38 Copyright Pearson Prentice Hall Biology

2. End Show Slide 2 of 38 Copyright Pearson Prentice Hall 28-1 Introduction to the Arthropods

3. End Show 28-1 Introduction to the Arthropods Slide 3 of 38 Copyright Pearson Prentice Hall What Is an Arthropod? What are the main features of arthropods?

4. End Show 28-1 Introduction to the Arthropods Slide 4 of 38 Copyright Pearson Prentice Hall What Is an Arthropod? Arthropods have a segmented body, a tough exoskeleton, and jointed appendages. Arthropods include insects, crabs, centipedes, and spiders.

5. End Show 28-1 Introduction to the Arthropods Slide 5 of 38 Copyright Pearson Prentice Hall What Is an Arthropod? Arthropods are surrounded by a tough external covering, or exoskeleton. The exoskeleton is made from protein and chitin. Chitin is a carbohydrate.

6. End Show 28-1 Introduction to the Arthropods Slide 6 of 38 Copyright Pearson Prentice Hall What Is an Arthropod? All arthropods have jointed appendages. Appendages are structures that extend from the body wall. Legs and antennae are appendages.

7. End Show 28-1 Introduction to the Arthropods Slide 7 of 38 Copyright Pearson Prentice Hall Evolution of Arthropods What are the important trends in arthropod evolution?

8. End Show 28-1 Introduction to the Arthropods Slide 8 of 38 Copyright Pearson Prentice Hall Evolution of Arthropods A typical primitive arthropod was composed of many identical segments, each carrying a pair of appendages. Fossilized Trilobites

9. End Show 28-1 Introduction to the Arthropods Slide 9 of 38 Copyright Pearson Prentice Hall Evolution of Arthropods This early body plan was modified gradually. Body segments were lost or fused over time.

10. End Show 28-1 Introduction to the Arthropods Slide 10 of 38 Copyright Pearson Prentice Hall Evolution of Arthropods The evolution of arthropods has led to fewer body segments and highly specialized appendages for feeding, movement, and other functions.

11. End Show 28-1 Introduction to the Arthropods Slide 11 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Arthropods use complex organ systems to carry out different essential functions. Organ systems are interrelated; the functioning of one system depends on that of other systems.

12. End Show 28-1 Introduction to the Arthropods Slide 12 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Feeding Arthropods include herbivores, carnivores, and omnivores. There are filter feeders, detritivores, and parasites. The mouthparts of arthropods are adapted to the type of food the arthropod eats.

13. End Show 28-1 Introduction to the Arthropods Slide 13 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Respiration Most terrestrial arthropods breathe through a network of branching tracheal tubes that extend throughout the body. Tracheal tubes

14. End Show 28-1 Introduction to the Arthropods Slide 14 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Air enters and leaves the tracheal tubes through spiracles, which are small openings located along the side of the body. Spiracles

15. End Show 28-1 Introduction to the Arthropods Slide 15 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Other terrestrial arthropods, such as spiders, respire using book lungs. Book lungs are organs that have layers of respiratory tissue stacked like pages of a book. Spiracles Airflow Book lung

16. End Show 28-1 Introduction to the Arthropods Slide 16 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Most aquatic arthropods, such as lobsters and crabs, respire through featherlike gills. Horseshoe crabs respire through book gills.

17. End Show 28-1 Introduction to the Arthropods Slide 17 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Circulation Arthropods have an open circulatory system. The heart pumps blood through arteries that branch and enter the tissues. Heart

18. End Show 28-1 Introduction to the Arthropods Slide 18 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Blood leaves the blood vessels and moves through sinuses, or cavities. Blood collects in a large sinus surrounding the heart and re-enters the heart. Heart

19. End Show 28-1 Introduction to the Arthropods Slide 19 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Excretion Most terrestrial arthropods dispose of nitrogenous wastes using Malpighian tubules.

20. End Show 28-1 Introduction to the Arthropods Slide 20 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Malpighian tubules are saclike organs that extract wastes from the blood and then add them to digestive wastes. Malpighian tubules

21. End Show 28-1 Introduction to the Arthropods Slide 21 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods In aquatic arthropods, diffusion moves wastes from the body into the surrounding water.

22. End Show 28-1 Introduction to the Arthropods Slide 22 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Response Most arthropods have a well-developed nervous system. All arthropods have a brain. Brain

23. End Show 28-1 Introduction to the Arthropods Slide 23 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Two nerves connect the brain to a ventral nerve cord. Nerve cord

24. End Show 28-1 Introduction to the Arthropods Slide 24 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Along this nerve cord are several groups of nerve cells called ganglia. These ganglia coordinate the movements of individual legs and wings. Ganglia

25. End Show 28-1 Introduction to the Arthropods Slide 25 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Most arthropods have sophisticated sense organs such as compound eyes. Compound eyes may have more than 2000 separate lenses and can detect color and motion very well. Compound eyes

26. End Show 28-1 Introduction to the Arthropods Slide 26 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Movement Arthropods move using well-developed groups of muscles that are coordinated and controlled by the nervous system. Muscles generate force by contracting and then pulling on the exoskeleton.

27. End Show 28-1 Introduction to the Arthropods Slide 27 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods At each body joint, different muscles either flex (bend) or extend (straighten) the joint. Flexed Extended

28. End Show 28-1 Introduction to the Arthropods Slide 28 of 38 Copyright Pearson Prentice Hall Form and Function in Arthropods Reproduction Terrestrial arthropods have internal fertilization. In some species, males deposit sperm inside females. In other species, the males deposit a sperm packet that is picked up by the females. Aquatic arthropods may have internal or external fertilization.

29. End Show 28-1 Introduction to the Arthropods Slide 29 of 38 Copyright Pearson Prentice Hall Growth and Development in Arthropods What happens when an arthropod outgrows its exoskeleton?

30. End Show 28-1 Introduction to the Arthropods Slide 30 of 38 Copyright Pearson Prentice Hall Growth and Development in Arthropods When they outgrow their exoskeletons, arthropods undergo periods of molting. During molting, an arthropod sheds its entire exoskeleton and manufactures a larger one to take its place.

31. End Show 28-1 Introduction to the Arthropods Slide 31 of 38 Copyright Pearson Prentice Hall Growth and Development in Arthropods Molting is controlled by the arthropod's endocrine system. Most arthropods molt several times. The arthropod is vulnerable to predators while its shell is soft.

32. End Show 28-1 Introduction to the Arthropods Slide 32 of 38 Copyright Pearson Prentice Hall Growth and Development in Arthropods Skin glands digest the inner part of the exoskeleton, and other glands secrete a new skeleton. When the new exoskeleton is ready, the animal pulls itself out of what remains of the original skeleton.

33. End Show - or - Continue to: Click to Launch: Slide 33 of 38 Copyright Pearson Prentice Hall 28–1

34. End Show Slide 34 of 38 Copyright Pearson Prentice Hall 28–1 The mouthparts of arthropods are a.similar in all species. b.adapted to enable different species to eat different foods. c.adapted to enable different species to respire in different ways. d.useful for locomotion as well as feeding.

35. End Show Slide 35 of 38 Copyright Pearson Prentice Hall 28–1 Arthropods have open circulatory systems, which means that blood a.leaves the blood vessels, flows through sinuses, and then returns to the heart. b.flows from the heart directly into sinuses and then returns to the heart. c.never leaves the circulatory system. d.vessels open to the external environment.

36. End Show Slide 36 of 38 Copyright Pearson Prentice Hall 28–1 Characteristics which define the arthropods include a.an endoskeleton made of chitin and jointed appendages. b.an endoskeleton made of chitin and six pairs of appendages. c.an exoskeleton made of chitin and jointed appendages. d.an exoskeleton made of chitin and Malpighian tubules.

37. End Show Slide 37 of 38 Copyright Pearson Prentice Hall 28–1 What type(s) of fertilization do terrestrial arthropods have? a.internal b.external c.both internal and external d.hermaphroditic

38. End Show Slide 38 of 38 Copyright Pearson Prentice Hall 28–1 What happens to the exoskeleton of an arthropod as the animal grows? a.It remains soft until the animal reaches adulthood. b.It develops additional body segments. c.It softens and stretches to a larger size. d.It is discarded and replaced by a new, larger exoskeleton.

39. END OF SECTION