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More Complex Invertebrate Animals:

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1 More Complex Invertebrate Animals:
Mollusks Annelids Arthropods Echinoderms

2 I. Mollusks: Snails, slugs, conch, Mussels, clams, scallops
Squid, octopus, chambered nautilus, cuttlefish

3 I. Characteristics of Mollusks: 2nd largest animal phylum
Arthropoda = largest from Latin molluscus, which means “soft. Many have soft bodies some have a hard shell.

4 Wide variety of organisms in this phylum:
Feeding- Some are sedentary filter feeders while others are fast-moving predators. Nervous system: Some are simple some are intelligent Circulatory system: Gastropoda & Bivalves have open while Cephalopoda has a closed system.

5 Have a body cavity completely lined by mesoderm tissue layer.
Mollusks are true coelmates. Have a body cavity completely lined by mesoderm tissue layer.

6 Mollusk Classes Gastropoda Bivalvia 3. Cephalopoda
(snails, slugs, albalone, conch) Bivalvia (clams, oysters, scallops) 3. Cephalopoda (octopuses, squid, cuttlefish, chambered nautiluses)

7 1. Class Gastropoda The largest & most diverse class of mollusks Most have a single shell. including snails, abalones, limpets and conchs. Slugs have no shell. Open circulatory system in which a heart pumps hemolymph from gills or lungs into the hemocoel (body cavity)

8 Mollusk Gastropod Body Plan
Divided into 2 main parts: Visceral mass which contains the heart and the organs of digestion, excretion, and reproduction Head-foot, which consists of: the head, contains the mouth with Radula- a tongue like feeding adaptation with tiny teeth that point backwards) and sensory structures the foot, a large, muscular organ for locomotion Other parts: Coelom -limited to space around heart. Mantle -a layer of epidermis that covers the visceral mass. (secretes the shell)

9 Gastropod body

10 Mollusk class: Gastropoda, snails

11 Phylum: Mollusk Class: Gastropoda Animal: Common garden slug

12 Conch shell

13 2. Class Bivalvia Aquatic mollusks (clams, oysters, & scallops)
Shell is divided into two valves connected by a hinge. Most are sessile filter feeders. Bivalves lack a distinct head

14 Clams Oysters attach to a hard surface
The mantle cavity of a clam is sealed except for a pair of hollow, fleshy tubes called siphons. Water enters through the incurrent siphon. Water leaves through the excurrent siphon. Other Bivalves Oysters attach to a hard surface Scallops can move through the water by repeatedly opening their valves and snapping them shut.

15 3. Class Cephalopoda Means “head-foot.” Free-swimming predators
Have tentacles & beaklike jaws on the head. Also- Have a closed circulatory system.

16 Squids Octopuses Chambered Nautiluses 10 tentacles.
Propels by pumping jets of water with the mantle through an excurrent siphon. Octopuses 8 tentacles They often crawl along the ocean bottom or lie in wait for prey. Chambered Nautiluses The only existing cephalopod with external shell. Shell is coiled & divided into chambers. The body is confined to the outermost chamber.

17 Caribbean reef squid (Venezuela)
Displays an aggressive zebra pattern to ward off other males competing for nearby females. This vivid species can display about three dozen different color patterns. (National Geographic)

18 In a cloud of greenish ink, a jumbo squid flees!
National geographic If all their dazzling color changes fail to deter a predator, squid use ink as a backup defense that helps them fade from view. Mexican fishermen catch some 100,000 tons (90,000 metric tons) of jumbos a year

19 Huge eye of the world's largest squid
About 11 inches across, researchers believe the colossal squid's eye is the biggest animal eye ever found. The 10m-long (34ft) specimen has also turned out to be female. Very little is known about colossal squid; only about 10 have ever been caught and brought to shore.

20 The giant squid remains largely a mystery to scientists despite being the biggest invertebrate on Earth. largest of these elusive giants ever found measured 59 feet (18 meters) in length and weighed nearly a ton (900 kg).

21 Small Squid (Calamari) Kalamarakia (discovergreek

22 Caribbean reef octopus hunting, making a balloon and scaring little fish out from under rocks to become dinner. Octopus briareus

23 An octopus swimming; an octopus moving between tide pools

24 But Octopus are tasty too!!!

25 Charred Octopus With Garlic, Chilli, Lemon And Olive Oil


27 A chambered Nautilus

28 The Chambered Nautilus: In which nature flawlessly executes constant mathematical form (It’s a physics thing) (Photo by John Lienhard)

29 Very Intelligent invertebrates:
Nervous system is very advanced. EXAMPLES: Dexterity, tool use and manipulation. Suction cups & arms are as efficient as human’s hand. Can learn through observation (choose colored balls) Can “Hide” & act like sea weed, Assess their prey. Complete & remember mazes & patterns ,

30 Many Cephalopods use pigments to hide & disguise themselves.
Blue-ringed octopus (size of a plum) this beak packs a deadly poison that'll kill a human in about 15 minutes.

31 Octopuses have blue “blood”
Octopuses have three hearts. Its blood has copper-rich protein (blue) hemocyanin for transporting oxygen. Although less efficient under normal conditions than the iron-rich hemoglobin of vertebrates, in cold conditions with low oxygen pressure, hemocyanin oxygen transportation is more efficient than hemoglobin oxygen transportation. The hemocyanin is dissolved in the plasma instead of being bound in red blood cells and gives the blood a blue color.

32 Octopuses: short life expectancy
some live for as little as six months. Larger species, such as the North Pacific Giant Octopus, may live for up to five years However, reproduction is a cause of death: males can only live for a few months after mating females die shortly after their eggs hatch. They neglect to eat during the (roughly) one month period spent taking care of their unhatched eggs, but they don't die of starvation. Endocrine secretions from the two optic glands are the cause of genetically-programmed death

33 Links

34 Phylum Annelida Segmented worms:
Earthworm Bristle worms Leeches

35 Segmented worms: Annelids
Annelids means little rings (many body segments). True coelom animals: have a body cavity that is divided into separate compartments by partitions. Other terms: Most have external bristles called setae Some have fleshy protrusions called parapodia

36 Class Oligochaeta Live in the soil or in fresh water Most familiar is the earthworm. Structure and Movement An earthworm’s body has over 100 nearly-identical segments. Circular and longitudinal muscles line the interior body wall. Locomotion is made possible by segmentation.

37 Earthworms

38 Earthworms Feeding /Digestion
Ingest soil as they burrow through it. Soil is moved through these structures: mouth pharynx esophagus crop gizzard intestine anus Earthworms play an important role in the condition of soil.

39 Closed circulatory system.
Contractions of the aortic arches and the dorsal blood vessel force blood through the vessels of the body Respiration and Excretion Oxygen and carbon dioxide diffuse through moist skin, Cellular wastes and excess water are excreted through nephridia. Neural Control Consists of a chain of ganglia connected by a ventral nerve cord. Sensory structures are found in all segments but are concentrated at the anterior end.

40 Reproduction Earthworms are hermaphrodites, but an individual worm cannot fertilize its own eggs. During mating, earthworms press their ventral surfaces together. Held together by their setae and by a film of mucus secreted by each worm’s clitellum. Fertilization occurs inside the tube, which forms a protective case for the young worms.

41 Earthworms reproducing


43 Earthworm diagrams

44 Earthworm links:

45 Class Polychaeta Leeches -have no setae or parapodia.
“many bristles” “feather duster worms” Polychaetes differ from other annelids in that they have antennae & specialized mouthparts. Class Hirudinea Hirudinea is the smallest class, consisting of about 500 species of leeches. Leeches -have no setae or parapodia. Many leeches are carnivores but some are parasites that suck blood from other animals.

46 Haemophagic Leeches Attach to their hosts & remain until they become full & they fall off to digest. Bodies are 34 segments. Have an anterior (oral) sucker formed from the first six segments of their body, used to connect to a host for feeding and releases an anaesthetic to remain unnoticed by the host. Use a combination of mucus and suction to stay attached and secrete an anti-clotting enzyme into the host's blood stream.

47 Leeches:

48 Famous Film Moment for leeches: Humphrey Bogart in The African Queen

49 How to Remove and Treat Leech Bites
Find the skinny end [the head end] and use your finger or fingernail to push it sideways off the bite point." - Authority Mark Siddall in the NOVA Science Internet site. You should avoid "remedies" such as simply pulling the leech from its moorings; plying it with salt, insect repellent, shampoo or vinegar; or heating it with a smoldering match, grass stem or cigarette. These techniques might cause the leech to discharge the contents of its gut, including bacteria, into the bite.  This might cause complications such as localized infection or even blood poisoning.

50 Leeches and a History of Medicine
For over 4000 years, the leech has been a familiar remedy, with Greek and Roman physicians praising the application of this clever invertebrate. 

51 In the 19th century leeches
were enjoying a golden age. Millions were raised for medical use as their fame as a cure-all ensued. The mid 1800s saw their constant use for local bloodletting. Druggists administered thousands of leeches to patients with anything from gumboils to facial discoloration. They were also put inside the mouth.

52 Leeches Today are bred in captivity in many institutions.
Leeches have found new fame in microsurgery, where doctors require the precision of the leech to drain congested blood from wounded sites. Plastic surgeons are particularly grateful for the contribution made by the leech, due to their use in the treatment of difficult grafts and reconstructive surgery.

53 III. Arthropods & Insects
“The real rulers of the Earth” Sources used include textbook, (Holt Modern Biology)

54 More than 83% of all animal species are arthropods.
That's about 160 million insects for each person on Earth. Have evolved to fill a variety of ecological niches — from tiny internal parasite to giant bird-eating predator.

55                                                                                                                                                                   Arthropods are a lot more than just delicious feasts and disgusting pests

56 5 Characteristics of all Arthropods

57 Segmented Body Each segment repeats the same set of structures (ie, a pair of legs, a set of breathing organs, & a set of nerves), sets of segments are grouped into a larger unit, such as the abdomen & cephalothorax.

58 Hard Exoskeleton Made of protein & Chitin (a polysaccharide)
Must molt many times as grows Enzymes digest the layer of exoskeleton inside soften & then shed. It takes a few days for the newly excreted exoskeleton to harden.

59 Jointed Legs All arthropods (arthro = joint, pod = foot) have jointed limbs. How can an animal with a rigid body covering move its legs? The exoskeleton is hard, but at the joints it is softer & bendable, (allowing movement in same way a suit of armor does).

60 Many pairs of limbs Tagma- are specialized segments

61 The five major subphyla of the phylum Arthropoda.

62 Arthropods usually divided into 5 subphyla based on:
differences in development in the structure of appendages, such as mouthparts.

63 1. Trilobites Extinct Many body appendages with one pair of appendages per segment Trilobites, living in shallow seas, flourished as swimmers, crawlers and burrowers for some 350 million years. Fossils found on all continents, entrapped in the hardened sediments of Ancient Seas.

64 2. Subphylum Myriapoda Means”many feet” Many body segments
One pair of branched antennae Many body segments Includes classes: Diplopoda (millipedes) Up to 100 body segments 2 pairs of legs on each segment Chilopoda (centipedes) In tropical regions can reach 12 inches long From 15 to 175 pairs of legs

65 3. Subphylum Crustacea Terrestrial & Marine
about 38,000 known species. Terrestrial & Marine so diverse their single defining characteristic is having two pairs of antennae. Most also have: a pair of mandibles a pair of appendages on each body segment some branched appendages 16 to 20 segments & several tagmata

66 a. Terrestrial Crustaceans
Sow bugs and pill bugs are terrestrial isopods. They lack adaptations for conserving water and live only in moist environments. They generally feed on decaying vegetation. Pill bugs roll into a ball when disturbed or threatened.

67 b. Aquatic Crustaceans (many species)
Copepods -important part of the ocean’s plankton. In freshwater, much of the plankton are water fleas such as Daphnia species. Barnacles are sessile as adults. Free-swimming barnacle larvae attach to surfaces and develop a shell that encloses the body. Barnacles use their cirri (singular, cirrus) to sweep food.

68 Types of barnacles http://www. marinebio
Balanus Barnacle with legs out, filter feeding on plankton Gooseneck Barnacles

69 More aquatic crustaceans
Order Decapoda -means“10 feet” Decapods have five pairs of legs Crayfish, lobsters, crabs, and shrimp are decapods Respiration through gills (see more about crayfish in handout & know parts for dissection lab)

70 4. Subphylum Chelicerata
Defined by presence of chelicerae The first pair of appendages Modified into pincer or fangs Class Arachnid- spiders, scorpions, mites, ticks Some important Parts : Chelicerae ( in spiders = fangs to inject poison) Pedipalps (hold food) 8 simple eyes at anterior of cephalothorax (NOT compound eyes!) Spinnerets- 3 pairs on tip of abdomen, for making silk Book lungs- like folds in a book= lots of surface area for gas exchange (some spiders use Tracheae for respiration instead) Malpighian Tubes- excretory tubes collect wastes, liquids. The liquid is reabsorbed (to conserve water) & waste is nearly solid.

71 Spiders-A full facial view of any spider shows its killing ability.
Two powerful chelicerae, protrude down Each chelicera bears a hinged fang. Both fangs have ducts that lead up to the venom glands within the head. Spiders fall into two groups, each being classified upon how they strike their prey. The fangs of Tarantulas are so hinged that they articulate in a front-to-back motion allowing them to strike their prey from above. Most other spiders have fangs that are hinged laterally, providing a left-to-right strike.

72 Fangs, Chelicerae of Zebra Jumping Spider Salticus scenicus
Spider Chelicerae Fangs and Chelicerae of Tarantula Spiderling Brachypelma smithi (Mexican Red-Knee Tarantula) Fangs, Chelicerae of Zebra Jumping Spider Salticus scenicus

73 Anatomy of a spider ** Mites and ticks differ from spiders because they have a fused cephalothorax and abdomen.

74 Life of a Spider Spiders feed on insects and other small animals. Many species are adapted to capture certain prey. Spiders rarely harm humans, but two species in the United States are dangerous: the black widow the brown recluse A male spider is usually smaller than the female. Females lay eggs in a silken case.

75 Brown recluse

76 Black widow spider

77 “Daddy long legs” Harvestmen are different from spiders:
Pholcus phalangioides – a real “spider” Harvestmen (Phalangium opili) Harvestmen are different from spiders: - in harvestmen the two main body sections (the abdomen with ten segments and cephalothorax) are nearly joined, so that they appear to be one oval structure; they also have no venom or silk glands. Mouth is different so that ingestion is not restricted to liquid, but chunks of food can be taken in. They have a single pair of eyes in the middle of their heads

78 Daddy long legs urban legend
Claims are that the harvestman is the most venomous animal in the world, but its fangs are too small to bite a human and therefore is not dangerous. This is untrue on several counts. None of the known species have venom glands or fangs The size of its mouth varies by species, but even those with relatively large jaws hardly ever bite humans or other large creatures, even in self-defense. The few known cases of actual bites did not involve envenomation, and had no lasting effect

79 Giant sea spider- new finds in Antarctica
Video link:

80 Camel spider “Urban legend”
Comments: NOT TRUE!! This scary-looking creature (actually, it's a pair of scary-looking creatures dangling end-to-end) is indeed commonly called a camel spider, but in fact it is neither a spider, strictly speaking (entomologists call it a solifugid), nor is it found only in the Middle East. Camel spiders reside in arid locales all over the world, including the southwestern United States. A typical specimen can grow to about the size of a child's hand, but, though they are known for being vicious predators, camel spiders are neither venomous nor a threat to human beings. For the record, they don't eat camels, either.

81 Common house spiders Excellent site to look up spiders!!

82 5. Subphylum Hexapoda Class Insecta
By many standards- the most successful group of animals on earth. Entomology- the study of insects & terrestrial arthropods. Body of an insect is divided into tagmata: Head Thorax Abdomen

83 “bugs” Because they dominate all terrestrial environments that support human life, insects are usually our most important competitors for food, fiber, and other natural resources.

84 Grasshopper Example organism Please note parts for dissection lab,.

85 The crayfish- next 4 pages are notes for dissection lab
an abundant freshwater crustacean that is structurally similar to lobsters, which are marine crustaceans. Crayfish, lobsters, crabs, and shrimp are decapods, or members of the order Decapoda. Decapoda means “10 feet.” Decapods have five pairs of legs that are used for locomotion.

86 External Structure The crayfish’s body is divided into
the cephalothorax, which is covered by the carapace and is divided into the head, which has five segments the thorax, which has eight segments the abdomen, which is is divided into six segments A pair of appendages is attached to each segment of the crayfish. Several pairs have specialized functions. These appendages include: Antennae Antennules Mandibles Maxillae Maxillipeds Chelipeds Walking legs Swimmerets

87 Crayfish -Parts for lab

88 Excretion Green glands assist in excretion of excess water that enters the body by osmosis. Digestion Digestive gland near the stomach secretes enzymes for digestion. Respiration gills. Circulation open. Nervous & Sensory Organs Many small sensory hairs. (sense water vibrations & chemicals) Compound eyes are set on two stalks.

89 Insects Factors responsible for their success include:
Entomologists classify insects into more than 25 orders based on characteristics such as: structure of mouthparts number of wings type of development Factors responsible for their success include: ability to fly -exoskeleton jointed appendages -small size large numbers offspring -short life span


91 Just how dominant are insects?

92 Comparison of 2 of the 5 groups of Arthropods

93 Insects as Food Insects are an important source of nutrition in many parts of the world In Mexico, dried grasshoppers are sold in village markets.  High in protein and low in fat, they may be fried or ground into meal and mixed with flour to make tortillas.  Sago grubs, the larvae of a wood-boring beetle, are considered a delicacy in Papua New Guinea.  The islanders boil the larvae or roast them over an open fire.  Ants, bees, termites, caterpillars, water bugs, beetle larvae, flies, crickets, katydids, cicadas, and dragonfly nymphs are among a long list of edible insects that provide nutrition for the people of Australia, Africa, South America, the Middle East, and China.  Americans and western Europeans appear to be unique in having a strong cultural taboo against insects as food. Silkworm pupae for human food in Thailand

94 A Recipe for Maggot Crispies
1/4 cup margarine 4 cups small marshmallows 3 cups crispy cereal 3 cups dry roasted maggots or mealworms In a saucepan, melt margarine and marshmallows. Remove from heat and stir in cereal and maggots. Spread mixture in a 9x13 greased pan and allow to cool.

95 Insect body – is divided into three tagmata:
Head -has mandibles and one pair of unbranched antennae. Thorax -has three pairs of jointed legs and, in many species, one or two pairs of wings. Abdomen -has 9 to 11 segments but neither wings nor legs in adults.

96 Humans & insects: Used for consumer products too: Example: cochineal
“Today, the textile industry has largely replaced cochineal with less expensive aniline dyes, but it is still used as a coloring agent in foods, beverages, cosmetics (especially lipsticks), and art products.”

97 Got Bugs?,2933,479233,00.htmlm

98 Insects and People Insects negatively affect humans by:
competing for food transmitting diseases destroying buildings & other manufactured products Insects benefit humans by: serving as food for other animals pollinating flowers making valuable products such as honey recycling nutrients in ecosystems

99 External Anatomy Grasshopper

100 Internal Anatomy Grasshopper

101 Grasshopper body- three tagmata:
The head mouthparts -labrum & labium are mouthparts that function like upper and lower lips, respectively. a pair of unbranched antennae pairs of simple and compound eyes. The thorax is composed of: Prothorax Mesothorax Metathorax The abdomen has upper and lower plates

102 Insect mouthparts

103 Circulation, Respiration, & Excretion
Insects have an open circulatory system that transports nutrients through the body. Gas exchange occurs by means of air-filled tracheae that reach deep into the body. Malpighian tubules remove cellular wastes from the hemolymph while conserving water.

104 Nervous system simple and compound eyes
The grasshopper’s central nervous system consists of a brain and a ventral nerve cord with ganglia located in each body segment. Nerves extend from the brain to sensory structures. Insect sensory structures include : simple and compound eyes sensory hairs on antennae and other body parts in some species, a sound-sensing tympanum

105 Reproduction Grasshoppers have separate sexes,
as do all insects. During mating, the male deposits sperm into the female’s seminal receptacle, where the eggs are fertilized internally. The last segment of the female’s abdomen forms the ovipositor, which she uses to lay fertilized eggs.

106 Most insects go through metamorphosis.
In incomplete metamorphosis, a nymph hatches from an egg and resembles the adult but has undeveloped reproductive organs and no wings. The nymph molts several times to become an adult. In complete metamorphosis, a wormlike larva called a caterpillar hatches from an egg and molts several times before becoming a pupa. The pupa molts to produce the adult, which resembles neither the larva nor the pupa.

107 Incomplete vs. Complete metamorphosis
-allows larvae and adults of the same species to avoid competing for space and food. -allows survival in periods of harsh weather or scant resources.

108 (Last phyla of invertebrates)
IV. Echinoderms (Last phyla of invertebrates) Starfish Sand Dollars sea urchins sea stars Brittle stars Sea cucumbers

109 Echinoderms are all benthic (bottom-dwellers)
endoskeleton of interlocking calcium carbonate plates and spines All true coelomates Nervous systems are poorly developed lack respiratory systems & circulatory systems (the water-vascular system takes over some of the functions of these systems)

110 Echinoderms water-vascular system of special structures that protrude & help the echinoderm breath, move, and defend itself. tube feet pedicellaria gills All echinoderms have a, a set of water-filled canals branching from a ring canal that encircles the gut. The canals lead to podia, or tube feet, which are sucker-like appendages that the echinoderm can use to move, grip the substrate, or manipulate objects. These tube feet are extended and retracted by hydraulic pressure in the water-vascular system.

111 Feeding: Some, like many starfish, are predators
sand dollars often feed on detritus crinoids are filter-feeders sea urchins scrape algae from rocks

112 Reproduction External fertilization; eggs and sperm are freely discharged into the water. A few sea urchins brood their eggs in special pouches, but most provide no parental care. Most echinoderms go through several planktonic larval stages before settling down



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