1. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 1 THE EARTH THROUGH TIME TENTH EDITION H A R O L D L. L E V I N

2. Life of the Paleozoic © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 2

3. FIGURE 10-1 Major events of the Paleozoic Era. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 3

4. In Paleozoic rocks, we find abundant fossils of multicellular organisms bearing shells. The fossil record is much improved at the beginning (the base of) Paleozoic strata. The pace of evolution appears to have quickened in the Paleozoic © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 4

5.  Representatives of most major invertebrate phyla were present during Paleozoic, including sponges, corals, bryozoans, brachiopods, molluscs, arthropods, and echinoderms.  Almost all of the common invertebrate phyla in existence today had appeared by Ordovician. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 5

6.  Vertebrates evolved during Paleozoic, including:  Fishes  Amphibians  Reptiles  Synapsids ("mammal-like reptiles")  The first vertebrates were jawless fishes, which are found in rocks as old as Cambrian in China. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 6

7.  An advanced lineage of fishes with primitive lungs and stout fins gave rise to the four- legged animals or tetrapods.  The transition from water-dwelling vertebrates to land-dwelling vertebrates depended on the evolution of the amniotic egg. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 7

8.  The first primitive land plants appeared near the end of Ordovician.  Vascular plants expanded across the land, forming great forests during Devonian.  The plants progressed from seedless, spore- bearing plants to plants with seeds but no flowers (gymnosperms). © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 8

9.  Several mass extinctions occurred during Paleozoic, including the largest extinction of all at the end of Permian.  Other mass extinctions occurred at the end of Ordovician and Devonian. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 9

10. Summary of invertebrate phyla © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 10

11. Summary of invertebrate phyla © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 11

12.  Paleozoic was a time of several adaptive radiations and extinctions.  Many geologic periods began with adaptive radiations (times of rapid evolution).  Several periods ended with extinction events of varying severity.  The extinction event at the end of Permian was the most extensive mass extinction in the history of life. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 12

13. Red arrows mark extinction events. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-94 13

14.  Multicellular animals evolved during Precambrian. Soft-bodied Ediacaran-type organisms ranged into Cambrian.  Soft-bodied fossils are infrequently preserved.  Preservation improved with the origin of hard parts. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 14

15.  The first animals with shells are called small shelly fossils.  Small shelly fossils are found at the base of Cambrian, and during Late Neoproterozoic.  Most disappeared during the Early Cambrian. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-2 15

16.  Many had phosphatic shells, few mm in size.  Shells and skeletal remains of primitive molluscs, sponges, and animals of uncertain classification, such as Cloudina, that secreted a calcareous tube. FIGURE 12-1 Tiny shell- bearing fossils from the Late Precambrian and Early Cambrian in Siberia. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 16

17.  The initial Paleozoic diversification is known as "the Cambrian explosion." Abrupt appearance of many types of animals about 535 million years ago, followed by rapid evolution.  During that episode of explosive evolution, all major invertebrate phyla appeared in the fossil record (except Bryozoa). © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 17

18.  Infaunal, burrowing animals evolved rapidly during Cambrian, as indicated by trace fossils and bioturbation (disruption of sedimentary structures by biological activity) of sediments.  The dramatic change in the character of the seafloor sediments (from undisturbed to highly burrowed) has been called the "Cambrian substrate revolution." © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 18

19.  No satisfying answers to why life diversified at the beginning of the Cambrian. The answer likely involves a number of factors.  Climate conditions became more favorable after the end of the Neoproterzoic glaciation.  Perhaps the glaciation produced an extinction event in the Ediacaran animals.  Extinction events of the Phanerozoic have been followed by rapid adaptive radiation © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 19

20. The extraordinarily well- preserved Middle Cambrian Burgess Shale fauna of Canada provides a window into the past to view the spectacular diversity of Middle Cambrian. Many soft-bodied organisms are preserved in black shale, along with the soft parts of animals with shells, such as legs and gills of trilobites. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 20

21. The significance of the Burgess Shale is that is records soft-bodied organisms, and the soft parts of organisms with shells. The finely detailed preservation reveals the extraordinary diversity and evolutionary complexity that existed near the beginning of Paleozoic. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 21

22. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-5 The Burgess Shale fauna. 22

23. 1. Several groups of arthropods, including trilobites and crustaceans 2. Sponges 3. Onycophorans 4. Crinoids 5. Molluscs 6. Corals 7. Three phyla of worms 8. Chordates (Pikaia) 9. Many others © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 23

24.  Location of the Burgess Shale fauna in British Columbia, Canada  C = Onycophoran, Aysheaia, intermediate in evolution between segmented worms and arthropods. D = Arthropod Leanchoila E= Arthropod Waptia © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-5 The Burgess Shale fauna. 24

25.  Chordates have a notochord or dorsal stiffening rod associated with a nerve chord, at some stage in their development.  In vertebrates, the notochord is surrounded by and usually replaced by a vertebral column during embryonic development.  Vertebrates are chordates, but Pikaia pre-dates the evolution of vertebrae. It is thought that vertebrates evolved from organisms similar to Pikaia.  Pikaia is a fish-like lower chordate from the Burgess Shale.  Modern representatives are called lancelets, such as the genus Amphioxus. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-13 25

26.  The giant predator of the Cambrian seas, Anomalocaris, up to 60 cm long.  Predators would have caused selective pressures on prey. The need to avoid being eaten probably encouraged the evolution of hard protective shells.  Predation probably also caused an increase in diversity of prey, as they evolved to better survive predation. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-8 Anomalocaris, “invertebrate equivalent of the dinosaurs.” 26

27.  Marrella, a "lace crab," is common in the Burgess Shale.  Hallucigenia, an onycophoran, was originally interpreted to walk on its spines, until claws were discovered on its "tentacles." © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-10 FIGURE 12-11 27

28.  Fossil sites containing abundant fossils with extraordinary preservation are called lagerstätten.  Both the Burgess Shale fauna and the Chengjiang fauna from China are considered to be lagerstätten. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 28

29.  In 1984, the Lower Cambrian Chengjiang fossil site was discovered in Yunnan Province, China.  More than 100 species of invertebrates have been found, with extraordinary preservation, including many soft bodied forms. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 29

30.  Jelly fish  Annelid worms  Cnidaria  Porifera (sponges)  Brachiopods  Arthropods  Early chordates similar to Pikaia  The world's oldest known fish (Myllokunmingia)  Other species of unknown phyla © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 30

31. The world's oldest known fish, Myllokunmingia, from the Maotianshan Shale near Chengjiang, in the Yunnan Province of China. 535 million years old. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 31

32.  Following a slight dip in diversity at the end of Cambrian, Ordovician seas experienced renewed diversification.  Global diversity tripled over a 25 million year time interval.  The number of genera increased rapidly, and the number of families increased from about 160 to 530.  The increase was particularly notable among trilobites, brachiopods, bivalve molluscs, gastropods, and corals. Why diversify?  Fragmented continents  Extensive seafloor spreading  Extensive warm nutrient rich seas fostering plankton growth resulting in an expansion of the base of the food chain. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 32

33.  An extinction event at the end of Ordovician led to an abrupt decline in diversity.  This extinction event was apparently related to the growth of glaciers in Gondwana, coupled with a reduction in shallow water habitat associated with the lowering of sea level. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 33

34. Red arrows mark extinction events © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 34

35. Diversification of marine animals occurred again at the beginning of Silurian. The period ended with only a slight drop in diversity. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 35

36.  During Devonian, there was continued diversification, but this ended with another fairly large extinction event, which extended over about 20 million years.  Roughly 70% of marine invertebrates disappeared.  Because of the long duration, the extinction is unlikely to have been caused by a sudden, catastrophic event. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 36

37.  During Early Carboniferous, diversity once again increased.  Diversity of marine animals remained fairly constant throughout Carboniferous and Permian.  Late Permian is marked by a catastrophic extinction event which resulted in the total disappearance of many animal groups. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 37

38. 1. Several Paleozoic periods ended with extinction events 2. The beginning of most Paleozoic periods were marked by adaptive radiations 3. Maximum diversity in Paleozoic seas was maintained roughly constant at between 1000 and 1500 genera 4. The largest extinction occurred at the end of Permian © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 38

39. 5. Recovery of diversity during Mesozoic was slow 6. Diversity increased rapidly during Cretaceous 7. Another mass extinction occurred at the end of Cretaceous 8. Diversity increased extremely rapidly, at unprecedented rates, at the beginning of Cenozoic 9. Diversity during Cretaceous and Cenozoic was much greater than during Paleozoic © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 39

40. Red arrows mark extinction events © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 40

41.  The principal groups of Paleozoic unicellular animals with a significant fossils record are the foraminifera and the radiolaria, which belong to Phylum Sarcodina.  These organisms are unicellular eukaryotic organisms, and belong to Kingdom Protista. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 41

42.  Name: Foraminifera means "hole bearer."  Chief characteristics:  Unicellular.  Related to the amoeba, with pseudopods.  Foraminifera build tiny shells (called tests) which grow by adding chambers.  Some species (called agglutinated foraminifera) construct tests of tiny particles of sediement. This is the most primitive test.  Other forams construct tests of calcium carbonate. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 42

43.  Geologic range: Cambrian to Holocene.  Modes of life:  Benthic or benthonic (bottom dwellers)  Planktic or planktonic (floaters). © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 43

44.  Fusulinids were abundant during Late Paleozoic (primarily Pennsylvanian and Permian).  Their tests were similar in size and shape to a grain of rice.  Their internal structure is complex and used to distinguish different species.  Important guide fossils during Pennsylvanian and Permian because they evolved rapidly, were abundant, and widespread geographically. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 44

45.  Chief characteristics:  Unicellular.  Test or shell composed of opaline silica  Ornate lattice-like skeleton  Often spherical or radially symmetrical with spines  Geologic range: Precambrian or Cambrian to Holocene. Rare during Early Paleozoic. More abundant during Mesozoic and Cenozoic.  Mode of life: Planktonic. Marine only. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 45

46.  Radiolarians are important constituents of chert at certain times in geologic history.  Their tests accumulate on the seafloor today to form radiolarian ooze, particularly in deep water, where any calcium carbonate shells would be dissolved. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 46

47.  The fossils of shell-bearing invertebrates that inhabited shallow seas are common in Paleozoic rocks.  Archaeocyathids, sponges, corals, bryozoans, trilobites, molluscs, and echinoderms.  Many were benthic (bottom dwellers), but others, such as graptolites, were planktonic. Currents carried them over wide areas.  As a result, they are useful index fossils for global stratigraphic correlation. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 47

48.  Name means "ancient cup"  Chief characteristics: Conical or vase-shaped skeletons made of calcium carbonate. Double-walled structure with partitions and pores.  Geologic range: Cambrian only. Extinct.  Mode of life: Attached to the sea floor. Reef-builders. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-17 Archaeocyathid skeleton. 48

49. Name means “pore-bearing,” or covered by tiny pores. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-21 Schematic diagram of a sponge with the simplest type of canal system. FIGURE 12-18 Early Paleozoic sponges. 49

50. Chief characteristics:  Globular, cylindrical, conical or irregular shape.  Basic structure is vase-like with pores and canals.  Interior may be hollow or filled with branching canals.  Solitary or colonial.  Skeletal elements are called spicules, and they may be separate or joined.  Composition may be calcareous, siliceous or organic material called spongin. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 50

51.  Corals, sea fans, jellyfish, and sea anemones.  Name: Cnidaria are named for stinging cells called cnidoblasts or cnidocytes.  Many are soft-bodied but only those which form hard skeletal structures are readily preservable as fossils. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-23 Common cnidarians. 51

52.  Geologic range: Late Precambrian (Proterozoic) to Holocene for the phylum.  The first corals were the tabulates.  Mode of life: Corals live attached to the sea floor, primarily in warm, shallow marine environments. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 52

53. 1. Radial symmetry 2. Mouth at the center of a ring of tentacles. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-24 53

54. 3. Body form may be polyp (attached to the bottom, with tentacles on top) or medusa (free-swimming, jellyfish). Diorama photograph courtesy of the U.S. National Museum of Natural History/ Smithsonian Institution.) © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 54

55. 1. May be solitary or colonial. Colonies are composed of many polyps living together. 2. Hard calcareous skeleton. The skeletal parts formed by polyps are called corallites. 3. The "cup," in which an individual coral polyp sits, is called the theca. Each theca is small, and roughly circular or hexagonal. 4. The theca is divided internally by vertical partitions called septae, arranged in a radial pattern. Harold Levin © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 55

56. 5. Types of corals are distinguished by presence or absence, and number of septae:  Rugose corals (or tetracorals) have septae arranged in multiples of four.  Tabulate corals lack septae.  Mesozoic and Cenozoic scleractinian corals (or hexacorals) have septae arranged in multiples of six. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 56

57.  Most rugose corals are solitary and conical (shaped like ice cream cones).  Septae are visible in the circular opening of the cone.  Some rugose corals are colonial, having hexagonal corallites with septae (such as Hexagonaria from Devonian of Michigan). Harold Levin © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 57

58.  Geologic range: Ordovician to Permian - all extinct.  Rugose corals were abundant during Devonian and Carboniferous, but became extinct during Late Permian. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 58

59.  Tabulate corals are colonial and resemble honeycombs or wasp nests.  They lack septae.  They have horizontal plates within the theca called tabulae. Tabulae are one of the main features of the tabulate corals. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. Harold Levin 59

60.  Geologic range: Ordovician to Permian - all extinct.  The principal Silurian reef formers.  They declined after Silurian and their reef-building role was assumed by the rugose corals. Harold Levin © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 60

61.  Modern corals are scleractinian corals. Scleractinian corals have septae are arranged in multiples of six, and are sometimes called hexacorals.  Scleractinian corals did not appear until after Paleozoic  Geologic range: Triassic to Holocene. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 61

62.  Name: Name means "moss" (bryo) + "animal" (zoa).  Chief characteristics:  Colonial (many microscopic individuals living physically united adjacent to one another).  The individuals are called zooids, and they are housed in a hard "capsule" called a zooecium.  The colony is called a zoarium. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 62

63.  Individual zooecia (plural of zooecium) are very tiny (about the size of a pin-hole, a millimeter or less in diameter). They are just large enough to be seen with the unaided eye.  Bryozoans may be distinguished from corals because of the apertures in the skeleton are much smaller. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 63

64. The bryozoan colony may resemble lace or a tiny net, may be delicately branching, finger-like, circular or dome-shaped. There are more than 4000 living species of bryozoans, and nearly 16,000 fossil species. Archimedes, from Mississippian rocks, has a cork-screw-like central axis with a fragile net-like colony around the outer edge. Harold Levin © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 64

65.  Geologic range: Ordovician to Holocene.  Mode of life: Widespread in marine environments. A few live in freshwater lakes and streams. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 65

66.  Name: Name means "arm" (brachio) + "foot" (pod).  Chief characteristics:  Bivalved (two shells), each with bilateral symmetry. The plane of symmetry passes through the center of each shell or valve.  The two valves differ in size and shape in most. Sometimes the larger valve will have an opening near the hinge line through which the pedicle extended in life. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 66

67. Soft parts include a lophophore consisting of coiled tentacles with cilia. The lophophore circulates water between the two valves, distributing oxygen and flushing out carbon dioxide. Water movements caused by the lophophore also transport food particles toward the mouth. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 67

68. Mode of life: Shallow marine environments. Generally attached to the sea floor. Inarticulate brachiopods are known to live in burrows in the sediment. Brachiopods are filter feeders. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-28 68

69.  Primitive brachiopods with phosphatic or chitinous valves.  No hinge. Spoon-shaped valves held together with muscles and soft parts.  Lingula is a well known genus  Geologic range:  Early Cambrian to Holocene © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 69

70.  Calcareous valves attached together with a hinge consisting of teeth and sockets.  Geologic range: Early Cambrian to Holocene  Spiny brachiopods (called productids) are characteristic of Carboniferous and Permian. Harold Levin © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 70

71.  Geologic range:  Early Cambrian to Holocene.  Very abundant during Paleozoic.  A few species (belonging to only three families) remain today. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 71

72.  Clams, oysters, snails, slugs, Nautilus, squid, octopus, cuttlefish  Name: Mollusca means " soft bodied." © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 72

73.  Chief characteristics:  Soft body enclosed within a calcium carbonate shell.  A few, like slugs and the octopus, have no shell.  Muscular part of body of clams and snails and some other groups of molluscs is called the foot. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 73

74.  Geologic range: Cambrian to Holocene  Mode of life: Marine, freshwater, or terrestrial.  They may: swim, float or drift, burrow into mud or sand, bore into wood or rock, attach themselves to rocks, or crawl. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 74

75. 1. Monoplacophorans (Neopilina) 2. Polyplacophorans or amphineurans (chitons) 3. Bivalves or pelecypods (clams, scallops) 4. Gastropods (snails and slugs) 5. Cephalopods (squid, octopus, Nautilus) 6. Scaphopods (tusk shells) © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 75

76. Chief characteristics:  Single shell resembling a flattened cone or cap.  Soft part anatomy shows pseudo-segmented arrangement of gills, muscles, and other organs. Suggests that the primitive mollusc was a segmented animal. Segmentation was lost secondarily.  Monoplacophorans are regarded as ancestral to bivalves, gastropods, and cephalopods. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-35 76

77.  Name: Monoplacophora means "single plate- bearer."  Geologic range: Cambrian-Holocene, but only known as fossils from Cambrian to Devonian. Living monoplacophorans found in deep water off Costa Rica in 1952 and named Neopilina. Considered to be a "living fossil." © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 77

78. Chief characteristics: Chitons have 8 overlapping plates covering an ovoid, flattened body. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-34 A common placophoran, the Atlantic Coast chiton. 78

79.  Name: Polyplacophora means "many plate- bearer."  Geologic range: Cambrian to Holocene © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 79

80.  Clams, oysters, scallops, mussels, rudists  Chief characteristics:  Skeleton consists of two calcareous valves connected by a hinge.  Bilateral symmetry; plane of symmetry passes between the two valves. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-36 Paleozoic bivalves. 80

81.  Name: Bivalvia means " two" (bi) + " shells" (valvia).  Geologic range: Early Cambrian to Holocene  Mode of life: Marine and freshwater. Many species are infaunal burrowers or borers, and others are epifaunal. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 81

82.  Snails and slugs  Chief characteristics:  Asymmetrical, spiral-coiled calcareous shell.  Name: means "stomach" (gastro) + "foot" (pod).  Geologic range: Early Cambrian to Holocene.  Mode of life: Marine, freshwater or terrestrial. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 82

83.  Squid, octopus, Nautilus, cuttlefish  Name: means " head" (kephale) + " foot" (pod).  Chief characteristics:  Symmetrical cone-shaped shell with internal partitions called septae  Shell may be straight or coiled in a spiral which lies in a plane.  Smooth or contorted sutures visible on the outside of some fossils mark the place where septae join the outer shell. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 83

84.  Geologic range: Late Cambrian to Holocene  Mode of life: Marine only; carnivorous (meat- eating) swimmers.  Types of Paleozoic cephalopods:  Nautiloids  Ammonoids  Coleoids © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 84

85.  The shells of nautiloid cephalopods have smoothly curved septa, which produce simple, straight or curved sutures.  Geologic range: Cambrian to Holocene Harold Levin © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 85

86.  Ammonoid cephalopods have complex, wrinkled or crenulated septa, which produce angular or dendritic sutures.  Geologic range: Devonian to Cretaceous - all extinct. Harold Levin © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 86

87.  There are three basic types of sutures in ammonoid shells:  Goniatite or goniatitic (septae have relatively simple, zig-zag undulations)  Ceratite or ceratitic (septae have smooth "hills" alternating with saw-toothed "valleys")  Ammonite or ammonitic (septae are complexly branching and tree-like or dendritic) © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 87

88. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-39 Cephalopod suture patterns. 88

89.  Belemnoids (belemnites)  Geologic range: Mississippian to Eocene - all extinct.  Sepioids (cuttlefish)  Geologic range: Jurassic to Holocene  Teuthoids (squid)  Geologic range: Jurassic to Holocene  Octopods (octopus)  Geologic range: Cretaceous to Holocene © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 89

90.  The belemnoids have an internal calcareous shell (which resembles a cigar in size, shape, and color) called a rostrum  The front part of this shell is chambered, as in the nautiloids and ammonoids.  The rostrum is made of fibrous calcite, arranged in concentric layers. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 90

91.  Tusk shells or tooth shells  Chief characteristics: Curved tubular shells open at both ends.  Geologic range: Ordovician to Holocene.  Mode of life: Marine. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 91

92.  Insects, spiders, shrimp, crabs, lobsters, barnacles, ostracodes, trilobites, eurypterids  Name: means "jointed" (arthro) + "foot" (pod).  Chief characteristics:  Segmented body with a hard exterior skeleton composed of chitin (organic material).  Paired, jointed legs.  Highly developed nervous system and sensory organs. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 92

93.  Geologic range: Cambrian to Holocene  Mode of life: Arthropods inhabit a wide range of environments. Most fossil forms are found in marine or freshwater sediments. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 93

94.  Trilobites - Cambrian to Permian  Horseshoe crabs - Silurian to Holocene  Eurypterids - Ordovician to Permian  Arachnids - Late Silurian to Holocene  Ostracodes - Cambrian to Holocene  Onychophorans - Cambrian to Holocene  Insects - Devonian to Holocene © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 94

95.  Chief characteristics:  Body has three-lobes  Skeleton composed of chitin, with calcium carbonate  Body is divided into three segments:  Rigid head segment - cephalon  Jointed, flexible middle section - thorax  Rigid tail piece - pygidium © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-42 95

96.  Name: Trilobite means "three" (tri) + "lobed" (lobus).  Geologic range: Cambrian to Permian  Mode of life: Exclusively marine. Most were bottom dwellers living in shallow shelf environments. Harold Levin © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 96

97.  Extinct scorpion-like or lobster-like arthropods.  Predators.  Up to 10 ft long.  Geologic range: Ordovician to Permian. Most are Silurian or Devonian.  Mode of life: Inhabited brackish estuaries. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 97

98.  Scorpions, spiders, ticks, and mites  Scorpions are the oldest arachnids with a fossil record.  Scorpions had evolved by Late Silurian. The earliest ones appear to have lived in the water, because their fossils have gills.  Scorpions, spiders, and mites are found in Devonian rocks.  Geologic range: Late Silurian to Holocene. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 98

99.  The ostracodes are mainly microscopic in size.  Tiny bivalved shell encasing a shrimp-like creature.  Geologic range: Cambrian to Holocene.  Mode of life: Both marine and freshwater. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 99

100.  Onychophorans share many characteristics of segmented annelid worms and arthropods, and are considered to be intermediate in evolution between the two groups.  Geologic range: Cambrian to Holocene The onycophoran, Aysheaia © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 100

101.  The insects are among the most diverse living group on Earth, but they are rarely found as fossils.  Body is divided into three parts, head, thorax, and abdomen.  Thorax has six legs.  The earliest insects were wingless.  Winged insects appeared by Pennsylvanian.  Geologic range: Middle Devonian to Holocene. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-46 101

102.  Starfish, sea urchins, sand dollars, crinoids, blastoids, and others  Name: Echinodermata means "spiny" (echinos) + "skin" (derma). © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-47 Representative living echinoderms. 102

103.  Chief characteristics: Calcite skeleton with five-part symmetry, superimposed on primitive bilateral symmetry.  Echinoderms have a water vascular system with water in a system of tubes within the body.  Tube feet are soft, movable parts of the water vascular system which project from the body and are used in locomotion, feeding, respiration, and sensory perception. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 103

104.  Geologic range: Cambrian to Holcene.  Mode of life: Exclusively marine. Some are attached to the sea floor by a stem with "roots" called holdfasts; others are free- moving bottom dwellers.  Similarity of embryos between echinoderms and chordates suggests that they may be derived from a common ancestral form. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 104

105.  Crinoids are animals which resemble flowers.  They consist of a calyx with arms, atop a stem of calcite disks called columnals.  The crinoid is attached to the sea floor by root-like holdfasts.  Some living crinoids are swimmers, and not attached.  Over 1000 genera are known. FIGURE 12-55 Crinoid in living position on the seafloor. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 105

106.  Geologic range: Middle Cambrian to Holocene.  Especially abundant during Mississippian. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 106

107.  Blastoids are extinct animals with an armless bud-like calyx on a stem.  About 95 genera are known.  A common genus is Pentremites.  Geologic range: Ordovician to Permian - all extinct. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-52 Some common Paleozoic blastoids. 107

108.  Starfish are star-shaped echinoderms with five arms.  About 430 genera are known.  Geologic range: Ordovician to Holocene. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-48 Partially dissected starfish showing elements of the water vascular system and other organs. 108

109.  Brittle stars have 5 arms, like starfish, but the arms are thin and serpent-like.  About 325 genera are known.  Geologic range: Ordovician to Holocene. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. FIGURE 12-47 Representative living echinoderms. 109

110.  Sand dollars and sea urchins  Echinoids are disk-shaped, biscuit-shaped, or globular.  Viewed from above, they may be circular or somewhat irregular in shape, but with a five- part symmetry.  About 765 genera are known.  Geologic range: Ordovician to Holocene. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 110

111.  Sea cucumbers  Soft-bodied echinoderms resembling cucumbers.  They have microscopic hard parts called sclerites in various shapes resembling hooks, wheels and anchors.  About 200 genera are known.  Geologic range: Middle Cambrian?; Middle Ordovician to Holocene © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 111

112.  Edrioasteroids  A group that was probably ancestral to starfish and sea urchins.  Globular, discoidal, or cylindrical tests (shells), many of which had concave surfaces.  Geologic range: Early Cambrian to Middle Pennsylvanian. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 112

113.  Cystoids  This primitive group had a calyx attached to the seafloor by a stem (like crinoids and blastoids).  Distinctive patterns of pores on the plates of the calyx.  Geologic range: Cambrian to Late Devonian. Most common during Ordovician and Silurian. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 113

114.  Echinoderms are closely related to chordates (the group that includes the vertebrates).  The early cell division, embryonic development, and larvae of echinoderms resemble those of chordates, and are different from those of other invertebrates.  Biochemistry of echinoderms is also similar to that of chordates (chemical similarities associated with muscle activity and chemistry of oxygen-carrying pigments in the blood). © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 114

115.  Chief characteristics:  Organic (chitinous) skeletons consisting of rows or lines of small tubes or cups, called thecae.  Tubes or cups branch off a main cord or tube called a stem or stipe.  Stipes may consist of one, two, or many branches.  Entire colony called a rhabdosome.  A filament at the lower end of the rhabdosome is called a nema. © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 115

116.  Most graptolites are found flattened and carbonized in black shales and mudstones.  Geologic range: Cambrian to Mississippian. (Most abundant during Ordovician and Silurian.)  Some living organisms which may be surviving descendants (living fossils) have been recovered in 1989 in the South Pacific and later in Bermuda.  Mode of Life: Planktonic (colonies attached to floats). © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 116

117. FIGURE 12-94 Five major mass extinction episodes. Source: After J. J. Sepkowski Jr., 1994, Geotimes,39(3): 15–17. FIGURE 12-2 Geologic time scale across the Proterozoic–Cambrian boundary. Source: Harold Levin. FIGURE 12-1 Tiny shell-bearing fossils from the Late Precambrian and Early Cambrian in Siberia. Source: Matthews, C., and Missarzhevsky, V., 1975, Small shelly fossils of late Precambrian and Early Cambrian age. Journal of the Geol. Society of London, 131:289-304. FIGURE 12-5 The Burgess Shale fauna. Source: Harold Levin. FIGURE 12-13 Reconstruction of Pikaia, the earliest known member of our own phylum, Chordata. Source: Harold Levin. FIGURE 12-8 Anomalocaris, “invertebrate equivalent of the dinosaurs.” Source: Harold Levin. FIGURE 12-10 Marrella, the most elegant and common arthropod in the Burgess Shale fauna. Source: Harold Levin. FIGURE 12-11 The early Cambrian Burgess Shale fossil Hallucigenia. Source: Harold Levin. FIGURE 12-17 Archaeocyathid skeleton. Source: Harold Levin. FIGURE 12-18 Early Paleozoic sponges. Source: Harold Levin. FIGURE 12-23 Common cnidarians. Source: Harold Levin. FIGURE 12-24 Medusaandpolypformsin cnidarians. Source: Harold Levin. FIGURE 12-28 Dwelling positions of articulate and inarticulate brachiopods. Source: Harold Levin. FIGURE 12-35 The monoplacophoran Pilina. Source: Harold Levin. FIGURE 12-34 A common placophoran, the Atlantic Coast chiton. Source: Harold Levin. FIGURE 12-36 Paleozoic bivalves. Source: Harold Levin. FIGURE 12-39 Cephalopod suture patterns. Source: Harold Levin. FIGURE 12-42 Trilobites. Source: Harold Levin. FIGURE 12-46 Mischoptera, a Pennsylvanian-age dragonfly. Source: Harold Levin. FIGURE 12-47 Representative living echinoderms. Source: Harold Levin. FIGURE 12-55 Crinoid in living position on the seafloor. Source: Harold Levin. FIGURE 12-52 Some common Paleozoic blastoids. Source: Harold Levin. FIGURE 12-48 (A) Partially dissected starfish showing elements of the water vascular system and other organs. Source: Harold Levin. IMAGE CREDITS © 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED. 117