1. Arthropods
Chapter 36
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
Waxy outer layer- repels water, keeps from drying out
Middle layer- primary protection made up chitin (tough polysaccharide)
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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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-
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10. 5 subphyla based on appendages development
Mouth parts- mandibles (jaw like) and chelicerae (pincher like)
Trilobita
Crustacea
Chelicerata
Myriapoda
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 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 segments
Some breath by body, some have gills
Nauplius- free-swimming larva
Diverse in size, most small
Chapter 36 Arthropods

14. Types crustaceans Aquatic Marine 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
Chapter 36 Arthropods

15. Crayfish- Order Decapods “ten feet”
Have five pairs of legs – locomotion
1. External structure-
a. two major sections-
abdomen- 6 segments
cephalothorax-head(5)thorax(8)
Tagmata- segments fused together to make one larger structure
b. antennae- 2 pairs, feelers, taste
c. chelipeds- back legs with pinchers
d. swimmerets- create water currents and function in reproduction
e. 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 system
5. Excretion- water is removed by excretory organs called the green glands
dilute fluids are excreted by a pore at the base of the antennae
6. Neural control/ sensory organs- similar to annelids
Holt cd
Have pair of ganglia, sense vibration and chemical in water by sensory hairs, compound eye
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19. 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 legs
Holt cd
Chapter 36 Arthropods

22. 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)
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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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26. scorpions Differ from spiders in 2 ways Large pincer like pedipalps
Segmented abdomen with large stinger on the last segment
Hide during the day, hunt at night
Inject venom
Only some fatal to human
Tropical 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 Myriapoda many 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 Myriapoda many 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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31.
Chapter 36 Arthropods

32. 2. Opening of the vas deferens
                          
   
       
 1. Gonopods
 2.  Opening of the vas deferens
 3.  Opening of the oviduct
 4.  Seminal receptacle
                                                         
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35. Dissection of Crayfish
External
Internal
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36. Grasshopper Dissections
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