Phylum Arthropoda

1. Phylum Arthropoda

2. What do animals do to survive? Eukaryoticcells Heterotrophs Essentialfunctions Feeding Respiration Circulation Excretion Response Movement Reproduction Section 26-1 All Animals have are carry out with such as No cell walls

3. The Arthropod Exoskeleton • Epidermis secretes an external skeleton called the exoskeleton • Advantages of possessing an exoskeleton: • provides strong support • provides rigid levers that muscles can attach to and pull against • offers protection • serves as a barrier to prevent internal tissues from drying out; important because many arthropods live on land • serves as a barrier to prevent infection

4. Structure of the Exoskeleton • Composed of the polysaccharide chitin and protein - glycoprotein • Outer surface called the epicuticle;contains waxes • The thicker portion is called the procuticle: • exocuticle • endocuticle • In the exocuticle, the glycoprotein chains are cross linked; process is called tanning epicuticle exocuticle procuticle endocuticle epidermis

5. Molting • In order to grow the arthropod must shed its exoskeleton, and secrete a new and larger one - moltingor ecdysis.

6. Arthropod Respiratory Advances • Special respiratory structures allow the arthropods to metabolize more efficiently and thus move rapidly • High metabolic rates require rapid oxygen delivery, and arthropods can accomplish this with respiratory organs that have a large surface area for collecting oxygen quickly

7. Gills • Many aquatic arthropods (crabs and lobsters) have gills, which are typically modifications of appendages or outgrowths of the body wall - folds of tissue with a large surface area

8. Tracheae • Gas exchange organs among terrestrial arthropods is usually internal; invaginations of the integument • Insects have tracheae,branching networks of hollow air conducting tubes such that air is sent to every cell in every tissue

9. Book Lungs • Spiders have book lungs,chambers with leaf-like plates for exchanging gases; air flows over the plates and blood flows through them

10. Respiration and Circulatory System • Extensive surface areas are needed to supply the large oxygen demands of most arthropods • Gills can occur both inside and outside of the of the carapace • Circulatory System • Open circulatory system as in molluscs, hearts vary in structure but do exist • Blood is pumped into empty spaces bathing the tissues in blood Phylum Arthropoda

11. Acute Senses • Arthropods have a well-developed nervous system that is of the same overall design as the annelids; anterior brain and a double, ventral hollow nerve cord. • The sensory receptors of arthropods are usually associated with modifications of the chitinous exoskeleton • The head usually bears various kinds of sense organs (e.g. antennae) with extreme sensitivity

12. Arthropod Vision • Simple eyes • Light sensitive cells share a common lens • Compound eyes • Thousand of closely packed units called ommatidia Phylum Arthropoda

13. Compound & Simple Eyes Phylum Arthropoda

14. Acute Senses cont. • Many arthropods have compound eyes - eyes that are composed of many visual units called facets (ommatidia); capable of color vision and detecting the slightest movements of prey or predators • Some eyes are simple eyes with only a few photoreceptors; however, they are capable of forming crude images

15. Digestive System Divided into 3 main regions: foregut, midgut, and hindgut • Foregut and the hindgut are lined with chitin • Foregut is involved with ingestion, mechanical breakdown, and storage • Hindgut is involved with water absorption and formation of the feces • Midgut is not lined with chitin; involved with digestion and absorption • Outpockets (e.g. digestive glands) increase the surface area for digestion and absorption

16. Digestive system • Most arthropods have three main regions: foregut, midgut and hindgut Phylum Arthropoda

17. Internal Transport and Excretion • Open circulatory system • Many crustaceans possess an excretory organ called the green gland (antennal gland),which filters fluid from the blood • Most insects and spiders have a excretory system called malpighian tubules

18. Reproduction • Sexes are separate; fertilization is external in aquatic forms, internal among the terrestrial forms

19. Arthropod Diversity

20. Subphylum Chelicerata • Lack antennae • Body is usually composed of two regions: cephalothoraxand abdomen • Cephalothorax is usually covered dorsally by the carapace • Six pairs of appendages: first pair are modified feeding structures - chelicerae • Second pair are called pedipalps • Four additional pairs of appendages are walking legs • No abdominal appendages • Some have compound eyes, usually have simple eyes capable of forming crude images.

21. Class Meristomata (e.g., Horeshoe crabs) • Marine chelicerates, common off of the Atlantic and Gulf coasts • Large dorsal carapace bearing compound eyes • Possess chelicerae, pedipalps, and 4 pair of walking legs (all but the last pair are chelate • Abdomen terminates in a long tail called the telson; used to turn the animal right side up • Possess a series of gill plates called book gills

22. Class Arachnida • Among spiders, the cephalothorax and abdomen shows no external segmentation; tagma are joined by a narrow pedicel • Respiration is accomplished via book lungs, tracheae, or both • Usually have 8 simple eyes; at the very least they detect motion; for some of the predatory forms, they are capable of forming crude images • Many species have evolved poison glands associated with the chelicerae Black widow Brown recluse

23. Class Arachnida cont. • Many of the spiders and mites are capable of producing silk; produced by silk glands that open to the exterior part of the abdomen through spinnerets • Silk is used to build webs for trapping prey, nests which serve as retreats, and egg cases; it is also used to form a dragline • Most spiders are predaceous and have all kinds of sensory hairs and relatively well-developed eyes for motion detection Orb web construction

24. Prey capture among the spiders • Some species are cursorial predators,those that stalk and ambush their prey; they usually have well-developed eyes Jumping spider • Others are web building spiders,those that construct various kinds of webs made of silk to trap their prey • Eyes are not as well developed as cursorial predators, but they have a battery of sensory hairs for detecting vibrations Grass spider

25. SubPhylum Crustacea • Possess 2 pair of antennae: First pair is homologous to those of insects; second pair is unique to the crustaceans • Second antennae have various functions, including sensory, locomotion or feeding. • The head bears a pair of compound eyes and 3 pairs of mouthparts: a pair of mandibles, and 2 pairs ofmaxillae; used for food handling • Trunk varies considerably among classes • Primitively, the first three pairs of thoracic segments are maxillipeds;function in handling food • Also, there are usually 5 pairs of appendages strengthened for walking (walking legs) and protection (chelipeds,pincer-like claws)

26. SubPhylum Crustacea cont. • Abdomen is also highly variable, but it is primitively large • Groups with a well-developed abdomen usually possess six pairs of appendages: Five pairs of structures called swimmerets (=pleopods);one pair of structures called uropods, • Uropods together with the terminal telson form a tail fan than can serve as rudders during locomotion

27. SubPhylum Crustacea cont. • Primitively many of the appendages of the crustaceans are biramous: there is an outer exopodand an inner endopod • They usually have an extremely hardened exoskeleton, which is impregnated with calcium carbonate - carapace

28. Class Insecta cont. • Mouthparts are highly modified depending on the group you are discussing • Mosquitoes have pointed mouthparts for piercing and sucking; grasshoppers have mouthparts that are well adapted for chewing; butterflies for siphoning; flies for sponging

29. Class Insecta con’t • Thorax is composed of 3 segments and each one has a pair of legs; the last two segments also have a pair of wings. • Wings of insects are modified portions of the exoskeleton • 1st pair is usually tough and leathery and fold over the inner pair for protection. • Abdomen does not have appendages; terminal portions do harbor the reproductive structures

30. Most insects undergo metamorphosis Incomplete Metamorphosis (Hemimetabolous) • Early developmental stages are very similar to the adults; only the wings and the reproductive structures gradually develop • The immature stages are called nymphs • Thus development is egg----> nymphs ----> adult

31. Complete Metamorphosis (Holometabolous) • Each of the developmental stages is structurally and functionally very different • The egg develops into an immature larva; eats voraciously • Followed by a transitional stage - pupa,contained within cocoon • Metamorphosis occurs within the pupal exoskeleton, yielding a sexually mature adult

32. Invertebrate feeding and digestion • Invertebrates can either have intracellular or extracellular digestion: • Intracellular meaning that food is digested within each individual cell of the organism. • Examples: Sponges • Extracellular means that digestion occurs inside a digestive tract or cavity, then absorbed into the body. • Examples: mollusks, worms, arthropods, echinoderms

33. Invertebrate Digestive Systems Section 29-2 Intestine Gizzard Crop Mouth/anus Pharynx Mouth Gastrovascularcavity Annelid Anus Gastrovascularcavity Cnidarian Arthropod Crop Pharynx Anus Pharynx Mouth Rectum Mouth/anus Stomachanddigestive glands Flatworm Intestine

34. Vertebrate Digestive Systems • The digestive systems of many vertebrates have organs that are well adapted for different feeding habits. • Carnivores, such as sharks have short digestive tracts that produce fast-acting digestive enzymes. • Herbivores have long intestines that have large colonies of bacteria that help in digesting the cellulose fibers in plant tissues.

35. The Digestive Systems of Vertebrates Section 33-3 Shark Salamander Lizard Pigeon Cow Esophagus Stomach Intestine Liver Gallbladder Pancreas Cloaca Crop Gizzard Cecum Rectum

36. Aquatic invertebrates Respiration in animals • Aquatic animals have natural moist respiratory surfaces, and some respire through diffusion through their skin and others use gills. Terrestrial Invertebrates • There are many different respiratory specialized organs in terrestrial invertebrates. • Spiders use parallel book lungs • Insects use openings called spiracles where air enters the body and passes through a network of tracheal tubes for gas exchange • Snails have a mantel cavity that is lined with moist tissue and an extensive surface area of blood vessels.

37. Invertebrate Respiratory Systems Section 29-2 Trachealtubes Gill Siphons Movement of water Spiracles Insect Mollusk Airflow Booklung Spider

38. Vertebrate respiratory systems • Chordates have one of two basic structures for respiration: • Gills – for aquatic chordates • Example: tunicates, fish and amphibians • Lungs - for terrestrial chordates • Examples: adult amphibians, reptiles, birds, and mammals

39. Aquatic Gills Section 33-3 • Water flows through the mouth then over the gills where oxygen is removed • Carbon dioxide and water are then pumped out through the operculum Vertebrate Lungs Nostrils, mouth, and throat Trachea Lung Air sac Salamander Lizard Primate Pigeon

40. Open circulatory systems Invertebrate Circulatory systems • Invertebrate circulatory system can range from a system where cells simply do diffusion to take in oxygen or systems with many hearts and even systems with one heart. • Blood is pumped through a system of vessels BUT is only partially contained in these vessels. Most of the time the blood is pumped through open cavities. • This system is beneficial to arthropods and mollusks because the blood comes into direct contact organs and tissues. Closed circulatory systems • A closed system forces blood through vessels that extend throughout the body of the organism. Since the system is “closed” the blood never leaves the vessels. • This system is beneficial to larger organisms because the blood is kept at a higher pressure which allows for more efficient circulation within the organism.

41. Invertebrate Circulatory Systems Section 29-2 Heartlike structure Hearts Small vessels in tissues Heart Bloodvessels Sinusesand organs Bloodvessels Heartlikestructures Insect:Open Circulatory System Annelid:Closed Circulatory System

42. Vertebrate circulatory systems • Chordate circulatory systems range from a single loop system (found in organisms with gills) to double loop systems. Double-Loop Circulatory System Single-LoopCirculatory System FISHES CROCODILIANS, BIRDS,AND MAMMALS MOST REPTILES

43. Aquatic Invertebrate excretion • Some aquatic invertebrates simply diffuse ammonia out their bodies into the surrounding water where it is diluted and carried away. • Example: sponges, cnidarians, and some round worms. • Other aquatic invertebrates swell up with water, dilute the wastes and excrete the wastes through tiny pores in their skin. Terrestrial Invertebrate excretion • Many terrestrial invertebrates convert ammonia into urea. • Urea is a simpler nitrogenous compound that is much less toxic than ammonia. • This urea is eliminated from the body in urine

44. Invertebrate Excretory Systems Section 29-2 Flamecells Flatworm Excretorytubules Nephrostome Excretory pore Flame cell Excretory tubule Nephridia Digestive tract Annelid Malpighian tubules Arthropod

45. Vertebrate Excretion • Aquatic vertebrates kidneys and rely on gill slits to release excretory wastes into surrounding water for dilution. • Terrestrial vertebrates rely on the kidney’s to filter out the ammonia and change it into urea and send it to be released in urine.

46. Nervous system • All animals respond to their environment through specialized cells called nerve cells. • In most animals nerve cells hook together to form the nervous system. • Nervous systems can range from fairly simple to extremely complex. • The arrangement of nerve cells from phylum to phylum can be dramatically different.

47. Invertebrate Nervous Systems Section 29-2 Vertebrate Nervous Systems Arthropod Brain Ganglia Ganglia Brain Flatworm Mollusk