Presentation is loading. Please wait.

Presentation is loading. Please wait.

Chapter 30 Arthropods Section 28.1 Summary – pages 741 - 746 Section 28.1 Summary – pages 741 - 746 segmented coelomate exoskeletonA typical arthropod.

Similar presentations


Presentation on theme: "Chapter 30 Arthropods Section 28.1 Summary – pages 741 - 746 Section 28.1 Summary – pages 741 - 746 segmented coelomate exoskeletonA typical arthropod."— Presentation transcript:

1

2 Chapter 30 Arthropods

3 Section 28.1 Summary – pages Section 28.1 Summary – pages segmented coelomate exoskeletonA typical arthropod is a segmented, coelomate invertebrate animal with bilateral symmetry, an exoskeleton, and jointed structures called appendages. A. Jointed appendages: “joint foot”=arthropoda An appendage is any structure, such as a leg, an antenna, or mouthpart that grows out of the body of an animal. I. Features of Arthropods

4 Section 28.1 Summary – pages Joints also allow powerful movements of appendages, and enable an appendage to be used in many different ways. Mouthparts have sucking, ripping or chewing parts What is an arthropod?

5 Section 28.2 Summary – pages Origins of Arthropods

6 Section 28.2 Summary – pages Origins of Arthropods Arthropods most likely evolved from an ancestor of the annelids. Oldest, best –preserved multicellular animal fossils 600 million years old trilobitesMost numerous early arthropod: trilobites -became extinct about 250 million years ago Lived in the sea Segmented bodies Jointed appendages First animals with eyes capable of forming images. scorpionsFirst terrestrial arthropods: scorpions

7 Section 28.2 Summary – pages The total number of arthropods Exceeds that of all other kinds of animals combined. 5,000,000 species More species of beetles than vertebrates. Size varies from 80 micrometers (parasitic mite)- to 3.6 m (giant crab found in the sea near Japan.)

8 Two main groups Arthropods with jaws 1.-Uniramia – (subphylum) insects chilopoda and diplopoda 2. Crustacea- (subphylum) shrimp, crab lobster Arthropods with fangs and pincers 1. Chelicerata (subphylum) – scorpions, mites, spiders ***Each subphyla represents a distinct evolutionary line. Two main groups Arthropods with jaws 1.-Uniramia – (subphylum) insects chilopoda and diplopoda 2. Crustacea- (subphylum) shrimp, crab lobster Arthropods with fangs and pincers 1. Chelicerata (subphylum) – scorpions, mites, spiders ***Each subphyla represents a distinct evolutionary line.

9 Section 28.1 Summary – pages Arthropod Body Plan Segmentation in arthropods Arthropod Body Plan Segmentation in arthropods In most groups of arthropods, segments have become fused into three body sections—head, thorax (mid body region), and abdomen. Individual body segments often exist only in larval stages. (ex: catepillar)

10 Section 28.1 Summary – pages In other groups, even these segments may be fused. Segmentation in arthropods Some arthropods have a head and a fused thorax and abdomen.

11 Section 28.1 Summary – pages In other groups, there is an abdomen and a fused head and thorax called a cephalothorax. Segmentation in arthropods Fusion of the body segments is related to movement and protection.

12 Section 28.1 Summary – pages A compound eye is a visual structure with many lenses. Arthropods have acute senses See motion much more quickly than humans.

13 Section 28.1 Summary – pages Accurate vision is also important to the active lives of arthropods. Most arthropods have one pair of large compound eyes and three to eight simple eyes. A simple eye is a visual structure with only one lens that is used for detecting light. In dragonflies and locusts, these simple eyes function as horizon detectors. –helps them stabilize their position in flight.

14 Section 28.1 Summary – pages The exoskeleton is a hard, thick, outer covering made of protein and chitin (KI tun). Brittle and can break easily Arthropod exoskeletons provide protection

15 Section 28.1 Summary – pages In other species, the exoskeleton is made of separate plates held together by hinges. Crustaceans : thick relatively inflexible exoskeleton. Insects and arachnids: soft and flexible exoskeleton. In some species, the exoskeleton is a continuous covering over most of the body. Arthropod exoskeletons provide protection

16 Section 28.1 Summary – pages In many aquatic species, the exoskeletons are reinforced with calcium carbonate. The exoskeleton protects and supports internal tissues and provides places for attachment of muscles. Arthropod exoskeletons provide protection

17 Section 28.1 Summary – pages First, they are relatively heavy structures. The larger an arthropod is, the thicker and heavier its exoskeleton must be to support its larger muscles. Exoskeletons have their disadvantages. Why arthropods must molt

18 Section 28.1 Summary – pages Why arthropods must molt A second and more important disadvantage is that exoskeletons cannot grow, so they must be shed periodically. Shedding the old exoskeleton is called molting.

19 Section 28.1 Summary – pages When the new exoskeleton is ready, the animal contracts muscles and takes in air or water. This causes the animal’s body to swell until the old exoskeleton splits open, usually along the back. Why arthropods must molt

20 Section 28.1 Summary – pages Thus, the new exoskeleton hardens in a larger size, allowing some room for the animal to continue to grow. Before the new exoskeleton hardens, the animal puffs up as a result of increased blood circulation to all parts of its body. Why arthropods must molt

21 Section 28.1 Summary – pages When the new exoskeleton is soft, arthropods cannot protect themselves from danger because they move by bracing muscles against the rigid exoskeleton. Most arthropods molt four to seven times in their lives before they become adults. Why arthropods must molt

22

23 Section 28.1 Summary – pages This large oxygen demand is needed to sustain the high levels of metabolism required for rapid movements. Respiration: Arthropods have efficient gas exchange Arthropods have efficient respiratory structures that ensure rapid oxygen delivery to cells.

24 Section 28.1 Summary – pages Three types of respiratory structures have evolved in arthropods: gills, tracheal tubes, and book lungs. Arthropods have efficient gas exchange

25 Section 28.1 Summary – pages Aquatic arthropods exchange gases through gills, which extract oxygen from water and release carbon dioxide into the water. Arthropods have efficient gas exchange

26 Section 28.1 Summary – pages Land arthropods have either a system of tracheal tubes or book lungs. Arthropods have efficient gas exchange

27 Section 28.1 Summary – pages Most insects have tracheal tubes, branching networks of hollow air passages that carry air throughout the body. Arthropods have efficient gas exchange

28 Section 28.1 Summary – pages Air enters and leaves the tracheal tubes through openings on the thorax and abdomen called spiracles. Muscle activity helps pump the air through the tracheal tubes. Arthropods have efficient gas exchange

29 Section 28.1 Summary – pages Most spiders and their relatives have book lungs, air-filled chambers that contain leaflike plates. Arthropods have efficient gas exchange

30 Section 28.1 Summary – pages The stacked plates of a book lung are arranged like pages of a book. Arthropods have efficient gas exchange

31 Section 28.1 Summary – pages Most terrestrial arthropods excrete wastes through Malpighian tubules. Slender, fingerlike extensions from the arthropods gut that are bathed in blood. In insects, the tubules are all located in the abdomen rather than in each segment. Malpighian tubules are attached to and empty into the intestine. Metabolic wastes remain in the gut and leave the body through the anus. Excretion:

32 Section 28.2 Summary – pages II. Spiders and other Arachnids

33 Section 28.2 Summary – pages Spiders, scorpions, mites, and ticks belong to the class Arachnida (uh RAK nud uh). Spiders are the largest group of arachnids. What is an arachnid? Spiders and other arachnids have only two body regions—the cephalothorax and the abdomen. They have no antennae Arachnids have six pairs of jointed appendages.

34

35 Section 28.2 Summary – pages The first pair of appendages, called chelicerae, is located near the mouth. chelicerae What is an arachnid?

36 Section 28.2 Summary – pages Chelicerae are often modified into pincers or fangs. Pincers are used to hold food, and fangs inject prey with poison. What is an arachnid?

37 Section 28.2 Summary – pages Spiders have no mandibles for chewing. Using a process of extracellular digestion, digestive enzymes from the spider’s mouth liquefy the internal organs of the captured prey. The spider then sucks up the liquefied food. What is an arachnid?

38 Section 28.2 Summary – pages The second pair of appendages, called the pedipalps, are adapted for handling food and for sensing. pedipalps What is an arachnid? Sometimes the pedipelps are for reproduction. Following the pedipalps, are 4 pairs of appendages called walking legs.

39 Section 28.2 Summary – pages Although all spiders spin silk, not all make webs. Spider silk is secreted by silk glands in the abdomen. What is an arachnid?

40 Section 28.2 Summary – pages As silk is secreted, it is spun into thread by structures called spinnerets, located at the rear of the spider. What is an arachnid?

41 Section 28.2 Summary – pages A Spider Spiders are predatory animals, feeding almost exclusively on other arthropods.(=carnivores) Simple eyes Legs Cocoon Silk glands Book Lungs Chelicerae Pedipalps

42 Section 28.2 Summary – pages Ticks and mites differ from spiders in that they have only one body section. tick Ticks, mites, and scorpions: Spider relatives

43 Section 28.2 Summary – pages The head, thorax, and abdomen are completely fused. Plant mites-Plant mites- while feeding may pass viral and fungal infections to plants. Dust mites-Dust mites- live in carpet, bedding, clothing. (cause allergies) ChiggersChiggers -known for their irritating bite TicksTicks feed on blood from reptiles, birds, and mammals. Ticks, mites, and scorpions: Spider relatives

44 Section 28.2 Summary – pages Mites feed on fungi, plants, and animals. They are so small that they often are not visible to the unaided human eye. Like ticks, mites can transmit diseases. Lyme disease is spread by deer ticks Ticks, mites, and scorpions: Spider relatives

45 Section 28.2 Summary – pages Scorpions are easily recognized by their many abdominal body segments and enlarged pincers.(=pedipalps) Ticks, mites, and scorpions: Spider relatives They have a long tail with a venomous stinger at the tip. Which is used to stun their prey.

46 Section 28.2 Summary – pages Flies, grasshoppers, lice, butterflies, bees, and beetles are just a few members of the class Insecta. Insects Insects have three body segments (head thorax and abdomen) and six legs. Head-Head- mandibles (chewing mouth part) pair of antennae, compound eyes Thorax-Thorax- ( composed of 3 fused segments.) 3 pair of jointed walking legs and some have wings that are attached to the thorax. AbdomenAbdomen- is composed of 9-11 segments

47 Section 28.1 Summary – pages Arthropods have other complex body systems The mandibles, together with other mouthparts are adapted for holding, chewing, sucking, or biting the various foods eaten by arthropods.

48 Section 28.2 Summary – pages A Grasshopper Wings Legs Eyes Antennae Nervous System Tympanum Malpighian tubules Spiracles

49 Section 28.2 Summary – pages Insects usually mate once during their lifetime. Insect reproduction/Life Cycle The eggs usually are fertilized internally. Some insects exhibit parthenogenesis, reproducing from unfertilized eggs.

50 Section 28.2 Summary – pages Most insects lay a large number of eggs, which increase the chances that some offspring will survive long enough to reproduce. Insect reproduction

51 Section 28.2 Summary – pages After eggs are laid, the insect embryo develops and the eggs hatch. In some wingless insects development is direct; the eggs hatch into miniature forms that look just like tiny adults. Metamorphosis: Change in body shape and form

52 Section 28.2 Summary – pages Metamorphosis: Change in body shape and form These insects go through successive molts until the adult size is reached. Eggs Nymph Molt Nymph Molt Adult

53 Section 28.2 Summary – pages In some cases, the adult insect bears little resemblance to its juvenile stage. Adult Egg Larva Pupa Metamorphosis: Change in body shape and form

54 Section 28.2 Summary – pages Insects that undergo metamorphosis usually go through four stages on their way to adulthood: egg, larva, pupa, and adult. This series of changes, controlled by chemical-substances in the animal, is called metamorphosis. Metamorphosis: Change in body shape and form

55 Section 28.2 Summary – pages The larva is the free-living, wormlike stage of an insect, often called a caterpillar. Metamorphosis: Change in body shape and form

56 Section 28.2 Summary – pages The pupa stage of insects is a period of reorganization in which the tissues and organs of the larva are broken down and replaced by adult tissues. Usually the insect does not move or feed during the pupa stage. After a period of time, a fully formed adult emerges from the pupa. Metamorphosis: Change in body shape and form

57 Section 28.2 Summary – pages The series of changes that occur as an insect goes through the egg, larva, pupa, and adult stages is known as complete metamorphosis. Complete metamorphosis is an advantage for arthropods because larvae do not compete with adults for the same food. Metamorphosis: Change in body shape and form

58 Section 28.2 Summary – pages Metamorphosis: Change in body shape and form pupa larvae adult fertilized egg The complete metamorphosis of a butterfly is illustrated.

59 Section 28.2 Summary – pages Other insects that undergo complete metamorphosis include ants, beetles, flies, and wasps. Metamorphosis: Change in body shape and form

60 Section 28.2 Summary – pages Incomplete metamorphosis has three stages Many insect species, as well as other arthropods, undergo a gradual or incomplete metamorphosis, in which the insect goes through only three stages of development. These three stages are egg, nymph, and adult.

61 Section 28.2 Summary – pages Incomplete metamorphosis has three stages A nymph, which hatches from an egg, has the same general appearance as the adult but is smaller and wingless. Eggs Nymph Molt Nymph Molt Adult

62 Section 28.2 Summary – pages Incomplete metamorphosis has three stages Nymphs cannot reproduce. As the nymph eats and grows, it molts several times. With each molt, it begins to resemble the adult more. Gradually, the nymph becomes an adult.

63 Section 28.2 Summary – pages Incomplete metamorphosis has three stages Grasshoppers and cockroaches are insects that undergo incomplete metamorphosis. Incomplete metamorphosis of a harlequin bug

64 Section 28.2 Summary – pages Two orders of insects, Hymenoptera (bees) and Isoptera (termites) have elaborate social systems. Social Insects They have division of labor. Each having their own job. (worker, drone, soldier, queen,king) caste.The role played by the individual in a colony is called its caste. Its Caste is determined by a combination of heredity, diet, hormones and pheromones

65 Section 28.2 Summary – pages Like spiders, millipedes and centipedes have Malpighian tubules for excreting wastes. Insect relatives Centipedes and Millipedes Insect relatives Centipedes and Millipedes In contrast to spiders, centipedes and millipedes have tracheal tubes rather than book lungs for gas exchange.

66 Section 28.2 Summary – pages Centipedes are carnivorous and eat soil arthropods, snails, slugs, and worms. Centipedes have one pair of legs /segment Centipedes and Millipedes The bites of some centipedes are painful to humans.

67 Section 28.2 Summary – pages A millipede eats mostly plants and dead material on damp forest floors. (herbivores) Centipedes and Millipedes Millipedes do not bite, but they can spray foul-smelling fluids from their defensive stink glands. Millipedes have 2 pair of legs /segment

68 Section 28.2 Summary – pages Members of the class Crustacea include crabs, lobsters, shrimps, crayfishes, water fleas, pill bugs, and barnacles. Barnacles are sessile Crustaceans Many have a distinctive larval form called a nauplius. The nauplius has 3 pair of branched appendages and undergoes a series of molts.(pg 680)

69 Section 28.2 Summary – pages Most crustaceans are aquatic and exchange gases as water flows over feathery gills. Shrimp, water fleas, ostracods,copepods Copepods are among the most abundant multi-cellular organism on earth and along with krill they are a major food source in the oceans. Sow bugs and pill bugs, two of the few terrestrial crustaceans, must live where there is moisture, which aids in gas exchange. Crustaceans

70 Section 28.2 Summary – pages Crustaceans (krus TAY shuns) this type have two pairs of antennae for sensing. 5 pairs of legs Anterior pair of legs are modified into large pincers called chelipeds. Cephalathorax (called a carapace) Uropods-flattened, paddle like appendages Telson- tail spine Decapods Swimmerets- are appendages attached to the underside for swimming and reproduction

71 Section 28.2 Summary – pages The first pair of walking legs are often modified into strong claws for defense. (Cheliped) claw legs Crustaceans


Download ppt "Chapter 30 Arthropods Section 28.1 Summary – pages 741 - 746 Section 28.1 Summary – pages 741 - 746 segmented coelomate exoskeletonA typical arthropod."

Similar presentations


Ads by Google