Chapter 36 Arthropods1 Arthropods Chapter 36 722-735.
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Transcript of Chapter 36 Arthropods1 Arthropods Chapter 36 722-735.
Chapter 36 Arthropods 1
Arthropods
Chapter 36
722-735
Chapter 36 Arthropods 2
Objectives 36.1
• Describe the distinguishing characteristics of arthropods
• Explain the process of molting in an arthropod
• List the five major subphyla of the phylum arthropoda
Chapter 36 Arthropods 3
P. Arthropoda- “ jointed-foot”
Two-thirds of all animal species belong to the phylum Arthropoda. This phylum contains a variety of bilaterally symmetrical coelomates, including lobsters crabs, spiders, and insects. These animals have adapted to almost every environment on Earth
Holt cd- 2 segments
Chapter 36 Arthropods 4
characteristics
Appendages- legs, antennae, jointed extensions
Exoskeleton- protection and support
Made up of 3 layers secreted by the epidermis
1. Waxy outer layer- repels water, keeps from drying out
2. Middle layer- primary protection made up chitin (tough polysaccharide)
3. Inner layer- allows to move freely, flexible, muscles are attached
Chapter 36 Arthropods 5
characteristics
• Cephalization• Segmented antennae• Mouth parts• Compound eyes- many light detectors,
each has own lens• Open circulatory system• Molting- sheds exoskeleton and makes
new one – to grow (takes time to harden, soft shelled crabs)
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Chapter 36 Arthropods 8
Evolution and classification
• 545 million yrs ago• Exoskeleton• True coelom• Jointed appendages• Evolved from common ancestor, convergent
evolution (Trilobites)• Tagma- fused into larger parts
Holt cd-
Chapter 36 Arthropods 9
Chapter 36 Arthropods 10
5 subphyla
• based on appendages development• Mouth parts- mandibles (jaw like) and
chelicerae (pincher like)1. Trilobita2. Crustacea3. Chelicerata4. Myriapoda5. Hexopoda
Chapter 36 Arthropods 11
Objectives 36.2
• Describe the characteristics of crustaceans
• Compare aquatic crustaceans with terrestrial crustaceans
• Explain the function of the appendages on a crayfish
• Summarize digestion, respiration, circulation, excretion, and neural control in crayfish
Chapter 36 Arthropods 12
Subphylum Crustacea
The subphylum crustacea contains about 38000 known species. Crustaceans are abundant in oceans, lakes, and rivers, and a few species live on land. Some crustaceans are sessile, whiles others move by walking on legs, swimming with paddle-like appendages, or drifting with the currents.
Holt cd
Chapter 36 Arthropods 13
characteristics
• Diverse• 2 pair of antennae• Pair of jawlike chewing mouth parts- mandibles• Each body segment has pair of appendages• Some have 60 or more body segment• Most have 16-20 segments• Some breath by body, some have gills• Nauplius- free-swimming larva• Diverse in size, most small
Chapter 36 Arthropods 14
Types crustaceans
AquaticMarine environments (plankton, Copepods)• Fresh water- (water fleas, daphnia)• Barnacles- sessile as adults, free-
swimming as larva (cirri, feeding parts)Terrestrial isopods- (sow bugs, pill bugs)No waxy coat
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Crayfish-Order Decapods “ten feet”
• Have five pairs of legs – locomotion1. External structure-a. two major sections- 1. abdomen- 6 segments2. cephalothorax-head(5)thorax(8)Tagmata- segments fused together to make one
larger structureb. antennae- 2 pairs, feelers, tastec. chelipeds- back legs with pinchersd. swimmerets- create water currents and function
in reproductione. telson/uropods- posterior end is paddle like tail
Chapter 36 Arthropods 16
Crayfish-2. digestion- esophagus to stomach where teeth grind food
into paste and the digestive glands secret enzymes for digestion and absorption extra exits anus
3. respiration- feather like gills, as it walks legs circulate water across gills
4. circulation- open circulatory system5. Excretion- water is removed by excretory organs called
the green glandsdilute fluids are excreted by a pore at the base of the antennae
6. Neural control/ sensory organs- similar to annelidsHolt cdHave pair of ganglia, sense vibration and chemical in water
by sensory hairs, compound eye
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36.3 objectives
• List the characteristics of arachnids, as represented by spiders
• Explain the adaptations that spiders have for predatory life on land
• Identify the unique characteristics of scorpions, mites, and ticks
• Compare the characteristics of millipedes and centipedes
Chapter 36 Arthropods 20
Subphyla Chelicerata
• Nearly all members are terrestrial
- chelicerates, spider, scorpions, mites, sea spiders, and horseshoe crabs
• Lack antennae
• 6 pair of appendages
• Chelicerae- pinchers or fangs
• Major class is the arachnidae 70,000 species
Chapter 36 Arthropods 21
C. Arachnida
• Arachnids- spiders, scorpions, mites, and ticks
• Cephalothorax and abdomen• 6pairs of jointed appendages• One pair of chelicearae• One pair of pedipalps (hold food)• Four pair of walking legsHolt cd
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Anatomy of a spider• Range in length 0.5 mm to 9 cm • Narrow body• Fangs for venom• Poison glands• Simple eye/ single lens• Spinnerets- found at the tip of the
abdomen (3pairs), silk glands• Nervous, digestive, circulatory system
similar to most crustaceans
Chapter 36 Arthropods 23
Anatomy of a spider
• Book lungs- paired sacs in the abd w/ folds (look like a book)
• Tracheae- system of tubes carry air directly to the tissues from openings in the exoskeleton (spiracles)
• Some have both• Malpighian tubules- hollow projections of the
digestive tract that collect body fluids and wastes and carry them to the intestine
• Also help to conserve water (water gets reabsorbed)
Chapter 36 Arthropods 24
Life of spider
• Feed on insects• Some will catch fish, frogs and even birds• Some chase prey• Some hide and wait• Wait till get trapped in web• Immobilize prey by wrapping them in silk• Most not dangerous to human• 2 are: brown recluse, black widow
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scorpions
Differ from spiders in 2 ways1. Large pincer like pedipalps2. Segmented abdomen with large stinger on the
last segment
Hide during the day, hunt at nightInject venomOnly some fatal to humanTropical and semitropical regions, dry temperate or
desert regions
Chapter 36 Arthropods 27
Mites and ticks
• Most abundant specialized arachnids• 30000 species – of known species• Completely fused cephalothorax and abdomen• Small• Freshwater, marine, terrestrial • Chiggers- human host• Transfer disease- rocky mountain spotted fever
and lyme disease
Chapter 36 Arthropods 28
Sub phylum Myriapodamany feet
• Nearly all members are terrestrial
Class Diplopoda- millipeds
-2 pairs of legs on each body segment, except the last two
-Up too 100 body segments (200 legs)
-Short antennae
-Two groups of simple eyes (poor vision)
-Maxillas and mandibles to eat plants (good sense of smell)
Chapter 36 Arthropods 29
Sub phylum Myriapodamany feet
• Class chilopoda- centipedes• Few as 15 or 175 pairs of legs• 12 inches long• Poison claws• Long antennae• Two clusters of simple eyes• Eat earthworms, insects• Most not harmful to humans
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http://www.youtube.com/watch?v=-frk3pL620M&feature=related
Chapter 36 Arthropods 32
http://bioweb.uwlax.edu/zoolab/Table_of_Contents/Lab-7b/Crayfish_Sexes/crayfish_sexes.htm
1. Gonopods
2. Opening of the vas deferens
3. Opening of the oviduct
4. Seminal receptacle
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Chapter 36 Arthropods 34
Dissection of Crayfish
External
• http://www.youtube.com/watch?v=DRULKv9W6DM&feature=related
Internal
• http://www.youtube.com/watch?v=rpkiNLhCBMU
Chapter 36 Arthropods 35
Grasshopper Dissections
• http://www.ent.iastate.edu/ref/anatomy/ihop/
• http://wwwbio200.nsm.buffalo.edu/labs/tutor/Grasshopper/
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