Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Chapter 28 28.1 Arthropod? Chapter 2 A. What is an Arthropod? 1. Pollinate many of the flowering plants on Earth a. Some even spread disease 2. A typical arthropod is segmented, coelomate invertebrate, with bilateral symmetry 3. They have an exoskeleton, and jointed structures called appendages a. An appendage is any structure, that grows out of the body of an animal b. Highly adapted for a variety of purposes including sensing, walking, feeding and mating 4. Earliest known invertebrates to have jointed appendages Chapter 28 A. Arthropod ( cont ) 5. Jointed appendages are great because they allow more flexibility in the exoskeletons a. Better movement, and stronger animal 6. Exoskeleton a. Hard, thick, outer covering made of protein and chitin b. Some exoskeleton cover most of the body, others protects and support the internal tissues and a place for muscle attachment c. Some are covered by a waxy layer to protect from water lost Chapter 28 A. Arthropods ( cont ) 7. Some Molt the exoskeleton a. Because they are heavy structures, on most they must periodically shed the old b. A new soft exoskeleton form c. When molting occurs, the animal rear par t of body forces blood forward and the forward part of the body swells, splitting the old and the new exoskeleton hardens into a larger size allowing the animal to grow larger into the new shell D. About 4 to 7 times during their life Chapter 28 B. Segmentation in Arthropods 1. Segments have been fused into three body parts a. Parts are head, thorax and abdomen 2. In some arthropods the two body parts also fuse together Cephalothorax ( head and thorax fused together) 3. Based on this; Beetles have separate head and thorax and can move easier 4. Lobsters have a Cephalothorax and are limited in movement Chapter 28 C. Systems Chapter 28 1. Respiratory a. Quick creatures that run, fly, swim, dig, climb b. Some flies beat their wings as fast as 1000 times per second c. Efficient respiratory structures d. There are three types of respiratory structures 1 Gills, tracheal tubes, and book lungs e. Most insects have tracheal tubes which is a branching networks of hollow air passages that carry air throughout the body 1 Muscle activity helps pump the air through body 2 Air enters and leaves tubes through openings on the thorax and abdomen called spiracles f. Spiders have book lungs, air filled chambers that contain leaf-like plates 1 The stacked plates are like pages of a book Chapter 28 Chapter 28 C. Senses ( cont ) 2. Acute senses a. Quick movements because of strong muscular contractions b. So can respond to a variety of stimuli c. Movement, sound, and chemicals can be detected d. Antennae are also used for communication as well as pheromones 1 Pheromones are chemical odors given off that the antennae can sense e. Accurate vision is also important 1 Most have 1 pair of compound eyes, but some have simple eye 2 Simple eyes have only one lens 3 Compound eyes have many lenses Chapter 28 C. Systems (cont) 3. Nervous systems a. Well developed b. Consists of a double ventral nerve cord, and an anterior brain, and several ganglia c. Ganglia act as control centers for body section in which they are located 4. Other systems a. Circulatory 1 one or more hearts in an open circulatory system Blood flows out of the vessels, bathes the tissues of the body, and returns to heart through open body spaces Chatper 26 C. Systems ( cont ) 4. Other systems ( cont ) b. Digestive 1. Mouth, stomach, intestine, and anus 2. Have various glands that produce digestive enzymes 3. Mouth consists of mandibles ( jaws ) adapted for holding, chewing, sucking, or biting c. Excretion 1. Have malpighian tubes located in the abdomen a. Attached to intestine and empty it Chapter 28 Chapter 28 C. Systems ( cont ) 4. Other systems ( cont ) d. Muscular 1 muscles are attached to the inner surfaces of exoskeleton on both sides of the joint Chapter 28 C. Systems ( cont ) 5. Reproduction a. Separated sexes and internal reproduction in land and external in aquatic 1 Some like barnacles are hermaphrodites 2 Some including bees, exhibit parthenogenesis a Form of asexual reproduction in which a new individual develops from an unfertilized egg Chapter 28 D. Diversity 1. There are more arthropods species than all other animal species combined a. See problem-solving lab on page 766. Diversity Arachnids Class Arachnida Only two body regions First pair of appendages called chelicerae Located near mouth Modified pincers or fangs 2nd pair called pedipalps For handling food and sensing surroundings Diversity Spinnerets- structure used to make webs Other archnids Ticks, mites, scorpions Ticks and mites only have one body region Crustaceans Only arthropod to have two pair of antennae All have mandible for crushing food Move side to side Two compound eyes usually on stalks Diversity Many have 5 pair of walking legs Live in moist environment to aid in respiration Class Chilopoda- centipedes Carnivorous Have malpighian tubules for waste removal Class Diplopoda- millipedes Eat mostly plants Diversity Centipedes and millipedes have tracheal tubes instead of book lungs for gas exchange. Class insecta- the insects Mate only once (or some, a few times) during life Have internal fertilization Large number of eggs assures some will survive Diversity (insects) Metamorphosis- in some cases, adult insect does not look at all like the juvenile stage Series of chemically controlled changes Usually 4 stages: egg, larva, pupa and adult Pupa is a period of reorganization Ex. Caterpillar turning into a butterfly Complete metamorphosis is an advantage because adult does not compete with larva for food Diversity (insects) Incomplete metamorphosis Three stages: egg, nymph, adult Nymphs have same general appearance as adult but may lack some general features Success Success of arthropods can be attributed to Varied life cycles High reproductive output Structural adaptation Small size Hard exoskeleton Jointed appendages Most likely evolved from Annelids