1. Chapter 12 Life of the Paleozoic REPLACE FIGURE (Chapter cover art)

2. Paleozoic overview REPLACE FIGURE (Fig. 10-1)

3. Paleozoic Fossil Record Paleozoic rocks, we find abundant fossils of multicellular organisms bearing shells. 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.

4. Paleozoic Invertebrates Representatives of most major invertebrate phyla were present during Paleozoic, including sponges, corals, bryozoans, brachiopods, molluscs, arthropods, and echinoderms.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.Almost all of the common invertebrate phyla in existence today had appeared by Ordovician.

5. Paleozoic Vertebrates Vertebrates evolved during Paleozoic, including: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.The first vertebrates were jawless fishes, which are found in rocks as old as Cambrian in China.

6. Paleozoic Vertebrates An advanced lineage of fishes with primitive lungs and stout fins gave rise to the four-legged animals or tetrapods.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.The transition from water-dwelling vertebrates to land-dwelling vertebrates depended on the evolution of the amniotic egg.

7. Paleozoic Plants The first primitive land plants appeared near the end of Ordovician.The first primitive land plants appeared near the end of Ordovician. Vascular plants expanded across the land, forming great forests during Devonian.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).The plants progressed from seedless, spore-bearing plants to plants with seeds but no flowers (gymnosperms).

8. Paleozoic Extinctions Several mass extinctions occurred during Paleozoic, including the largest extinction of all at the end of Permian.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.Other mass extinctions occurred at the end of Ordovician and Devonian.

9. Paleozoic Life Summary of invertebrate phyla REPLACE FIGURE (Fig. 12-1)

10. Paleozoic life includes some Precambrian forms, which survived into Paleozoic, as well as more advanced forms: –Unicellular eukaryotes –Animals InvertebratesInvertebrates VertebratesVertebrates –Plants

11. Adaptive Radiations and Extinctions Paleozoic was a time of several adaptive radiations and extinctions.Paleozoic was a time of several adaptive radiations and extinctions. Many geologic periods began with adaptive radiations (times of rapid evolution).Many geologic periods began with adaptive radiations (times of rapid evolution). Several periods ended with extinction events of varying severity.Several periods ended with extinction events of varying severity. The extinction event at the end of Permian was the worst mass extinction in the history of life.The extinction event at the end of Permian was the worst mass extinction in the history of life.

12. Diversity during Paleozoic Red arrows mark extinction events REPLACE FIGURE (Fig. 12-92)

13. Soft-bodied Animals Multicellular animals evolved during Precambrian. Soft-bodied Ediacaran-type organisms ranged into Cambrian.Multicellular animals evolved during Precambrian. Soft-bodied Ediacaran-type organisms ranged into Cambrian. Soft-bodied fossils are infrequently preserved.Soft-bodied fossils are infrequently preserved. Preservation improved with the origin of hard parts.Preservation improved with the origin of hard parts.

14. The first animals with shells are called small shelly fossils.The first animals with shells are called small shelly fossils. Small shelly fossils are found at the base of Cambrian, and during Late Neoproterozoic.Small shelly fossils are found at the base of Cambrian, and during Late Neoproterozoic. Most disappeared by at the top of the first stage within Lower Cambrian.Most disappeared by at the top of the first stage within Lower Cambrian. REPLACE FIGURE (Fig. 12-2)

15. Small Shelly Fossils Many had phosphatic shells, few mm in size.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.Shells and skeletal remains of primitive molluscs, sponges, and animals of uncertain classification, such as Cloudina, that secreted a calcareous tube. REPLACE FIGURE (Fig. 12-1) REPLACE FIGURE (Fig. 9-30)

16. Cambrian Diversification 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.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).During that episode of explosive evolution, all major invertebrate phyla appeared in the fossil record (except Bryozoa).

17. Cambrian Substrate Revolution Infaunal, burrowing animals evolved rapidly during Cambrian, as indicated by trace fossils and bioturbation of sediments.Infaunal, burrowing animals evolved rapidly during Cambrian, as indicated by trace fossils and bioturbation of sediments. The dramatic change in the character of the seafloor sediments (from undisturbed to highly burrowed) has been called the "Cambrian substrate revolution."The dramatic change in the character of the seafloor sediments (from undisturbed to highly burrowed) has been called the "Cambrian substrate revolution."

18. Soft-Bodied Fossils in the Burgess Shale 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.

19. Soft-Bodied Fossils in the Burgess Shale 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.

20. Animals in the Burgess Shale 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

21. Stratigraphic setting of the Cambrian Burgess Shale REPLACE FIGURE (Fig. 12-5)

22. Location of the Burgess Shale fauna in British Columbia, CanadaLocation 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 WaptiaC = Onycophoran, Aysheaia, intermediate in evolution between segmented worms and arthropods. D = Arthropod Leanchoila E= Arthropod Waptia REPLACE FIGURE (Fig. 12-5)

23. Pikaia - One of the Oldest Chordates Pikaia is a fish-like lower chordate from the Burgess Shale.Pikaia is a fish-like lower chordate from the Burgess Shale. Modern representatives are called lancelets, such as the genus Amphioxus.Modern representatives are called lancelets, such as the genus Amphioxus. REPLACE FIGURE (Fig. 12-12)

24. Chordates Chordates have a notochord or dorsal stiffening rod associated with a nerve chord, at some stage in their development.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.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.Vertebrates are chordates, but Pikaia pre-dates the evolution of vertebrae. It is thought that vertebrates evolved from organisms similar to Pikaia.It is thought that vertebrates evolved from organisms similar to Pikaia.

25. Predators in the Cambrian Seas The giant predator of the Cambrian seas, Anomalocaris, up to 60 cm long.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.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.Predation probably also caused an increase in diversity of prey, as they evolved to better survive predation. REPLACE FIGURE (Fig. 12-8)

26. Other Burgess Shale Animals Marrella, a "lace crab," is common in the Burgess Shale.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."Hallucigenia, an onycophoran, was originally interpreted to walk on its spines, until claws were discovered on its "tentacles." REPLACE FIGURE (Fig. 12-10) REPLACE FIGURE (Fig. 12-11)

27. The Significance of the Burgess Shale The significance of the Burgess Shale is that it 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.

28. Exceptional Preservation Fossil sites containing abundant fossils with extraordinary preservation are called lagerstätten.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.Both the Burgess Shale fauna and the Chengjiang fauna from China are considered to be lagerstätten.

29. The Chengjiang fauna In 1984, the Lower Cambrian Chengjiang fossil site was discovered in Yunnan Province, China.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.More than 100 species of invertebrates have been found, with extraordinary preservation, including many soft bodied forms.

30. The Chengjiang fauna Jelly fishJelly fish Annelid wormsAnnelid worms CnidariaCnidaria Porifera (sponges)Porifera (sponges) BrachiopodsBrachiopods ArthropodsArthropods Early chordates similar to PikaiaEarly chordates similar to Pikaia The world's oldest known fish (Myllokunmingia)The world's oldest known fish (Myllokunmingia) Other species of unknown phylaOther species of unknown phyla

31. Oldest Known Fish The world's oldest known fish, Myllokunmingia, from the Maotianshan Shale near Chengjiang, in the Yunnan Province of China. 535 million years old. REPLACE FIGURE (Fig. 12-13)

32. Ordovician Diversity Following a slight dip in diversity at the end of Cambrian, Ordovician seas experienced renewed diversification.Following a slight dip in diversity at the end of Cambrian, Ordovician seas experienced renewed diversification. Global diversity tripled.Global diversity tripled. The number of genera increased rapidly, and the number of families increased from about 160 to 530.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.The increase was particularly notable among trilobites, brachiopods, bivalve molluscs, gastropods, and corals.

33. Late Ordovician Extinction An extinction event at the end of Ordovician led to an abrupt decline in diversity.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.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.

34. Diversity and extinction during Paleozoic Red arrows mark extinction events REPLACE FIGURE (Fig. 12-92)

35. Silurian Diversity Diversification of marine animals occurred again at the beginning of Silurian. The period ended with only a slight drop in diversity.

36. Devonian Diversity During Devonian, there was continued diversification, but this ended with another fairly large extinction event, which extended over about 20 million years.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.Roughly 70% of marine invertebrates disappeared. Because of the long duration, the extinction is unlikely to have been caused by a sudden, catastrophic event.Because of the long duration, the extinction is unlikely to have been caused by a sudden, catastrophic event.

37. Carboniferous-Permian Diversity During Early Carboniferous, diversity once again increased.During Early Carboniferous, diversity once again increased. Diversity of marine animals remained fairly constant throughout Carboniferous and Permian.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.Late Permian is marked by a catastrophic extinction event which resulted in the total disappearance of many animal groups.

38. Overview of Changes in Diversity Through Time 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

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

40. Diversity during Paleozoic Red arrows mark extinction events REPLACE FIGURE (Fig. 12-92)

41. Unicellular Organisms in the Paleozoic Seas The principal groups of Paleozoic unicellular animals with a significant fossils record are the foraminifera and the radiolaria, which belong to Phylum Sarcodina.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.These organisms are unicellular eukaryotic organisms, and belong to Kingdom Protista.

42. Foraminifera Name: Foraminifera means "hole bearer."Name: Foraminifera means "hole bearer." Chief characteristics: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.

43. Foraminifera Geologic range: Cambrian to Holocene.Geologic range: Cambrian to Holocene. Modes of life:Modes of life: –Benthic or benthonic (bottom dwellers) –Planktic or planktonic (floaters).

44. Fusulinid foraminifera (fusulinids) Fusulinids were abundant during Late Paleozoic (primarily Pennsylvanian and Permian).Fusulinids were abundant during Late Paleozoic (primarily Pennsylvanian and Permian). Their tests were similar in size and shape to a grain of rice.Their tests were similar in size and shape to a grain of rice. Their internal structure is complex and used to distinguish different species.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.Important guide fossils during Pennsylvanian and Permian because they evolved rapidly, were abundant, and widespread geographically.

45. Radiolaria Chief characteristics: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.Geologic range: Precambrian or Cambrian to Holocene. Rare during Early Paleozoic. More abundant during Mesozoic and Cenozoic. Mode of life: Planktonic. Marine only.Mode of life: Planktonic. Marine only.

46. Radiolaria and the Rock Record Radiolarians are important constituents of chert at certain times in geologic history.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.Their tests accumulate on the seafloor today to form radiolarian ooze, particularly in deep water, where any calcium carbonate shells would be dissolved.

47. Marine Invertebrates in the Paleozoic Seas The fossils of shell-bearing invertebrates that inhabited shallow seas are common in Paleozoic rocks.The fossils of shell-bearing invertebrates that inhabited shallow seas are common in Paleozoic rocks. Archaeocyathids, sponges, corals, bryozoans, trilobites, molluscs, and echinoderms.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.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.As a result, they are useful index fossils for global stratigraphic correlation.

48. Phylum Archaeocyatha Name means "ancient cup"Name means "ancient cup" Chief characteristics: Conical or vase-shaped skeletons made of calcium carbonate. Double-walled structure with partitions and pores.Chief characteristics: Conical or vase-shaped skeletons made of calcium carbonate. Double-walled structure with partitions and pores. Geologic range: Cambrian only. Extinct.Geologic range: Cambrian only. Extinct. Mode of life: Attached to the sea floor. Reef-builders.Mode of life: Attached to the sea floor. Reef-builders. REPLACE FIGURE (Fig. 12-16)

49. Phylum Porifera - The Sponges Name means "pore-bearing." Covered by tiny pores. REPLACE FIGURE (Fig. 12-17) REPLACE FIGURE (Fig. 12-20)

50. Phylum Porifera - The Sponges 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.

51. Phylum Cnidaria Corals, sea fans, jellyfish, and sea anemones.Corals, sea fans, jellyfish, and sea anemones. Name: Cnidaria are named for stinging cells called cnidoblasts or cnidocytes.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.Many are soft-bodied but only those which form hard skeletal structures are readily preservable as fossils. REPLACE FIGURE (Fig. 12-22)

52. Phylum Cnidaria Geologic range: Late Precambrian (Proterozoic) to Holocene for the phylum.Geologic range: Late Precambrian (Proterozoic) to Holocene for the phylum. The first corals were the tabulates.The first corals were the tabulates. Mode of life: Corals live attached to the sea floor, primarily in warm, shallow marine environments.Mode of life: Corals live attached to the sea floor, primarily in warm, shallow marine environments.

53. Phylum Cnidaria – Chief Characteristics 1.Radial symmetry 2.Mouth at the center of a ring of tentacles. REPLACE FIGURE (Fig. 12-23)

54. Phylum Cnidaria – Chief Characteristics 3.Body form may be polyp (attached to the bottom, with tentacles on top) or medusa (free- swimming, jellyfish). REPLACE FIGURE (Fig. 12-25d)

55. Chief Characteristics of Corals 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. REPLACE FIGURE (Fig. 12-25a)

56. Chief Characteristics of Corals 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.

57. Rugose Corals Most rugose corals are solitary and conical (shaped like ice cream cones).Most rugose corals are solitary and conical (shaped like ice cream cones). Septae are visible in the circular opening of the cone.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).Some rugose corals are colonial, having hexagonal corallites with septae (such as Hexagonaria from Devonian of Michigan). REPLACE FIGURE (Fig. 12-25a, b, c)

58. Rugose Corals Geologic range: Ordovician to Permian - all extinct.Geologic range: Ordovician to Permian - all extinct. Rugose corals were abundant during Devonian and Carboniferous, but became extinct during Late Permian.Rugose corals were abundant during Devonian and Carboniferous, but became extinct during Late Permian.

59. Tabulate Corals Tabulate corals are colonial and resemble honeycombs or wasp nests.Tabulate corals are colonial and resemble honeycombs or wasp nests. They lack septae.They lack septae. They have horizontal plates within the theca called tabulae. Tabulae are one of the main features of the tabulate corals.They have horizontal plates within the theca called tabulae. Tabulae are one of the main features of the tabulate corals. REPLACE FIGURE (Fig. 12-24)

60. Tabulate Corals Geologic range: Ordovician to Permian - all extinct.Geologic range: Ordovician to Permian - all extinct. The principal Silurian reef formers.The principal Silurian reef formers. They declined after Silurian and their reef- building role was assumed by the rugose corals.They declined after Silurian and their reef- building role was assumed by the rugose corals. REPLACE FIGURE (Fig. 12-24b)

61. Modern Corals Modern corals are scleractinian corals. Scleractinian corals have septae are arranged in multiples of six, and are sometimes called hexacorals.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 PaleozoicScleractinian corals did not appear until after Paleozoic Geologic range: Triassic to Holocene.Geologic range: Triassic to Holocene.

62. Phylum Bryozoa Name: Name means "moss" (bryo) + "animal" (zoa).Name: Name means "moss" (bryo) + "animal" (zoa). Chief characteristics: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.

63. Phylum Bryozoa 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.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.Bryozoans may be distinguished from corals because of the apertures in the skeleton are much smaller.

64. Phylum Bryozoa 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. REPLACE FIGURE (Fig. 12-26a, b)

65. Phylum Bryozoa Geologic range: Ordovician to Holocene.Geologic range: Ordovician to Holocene. Mode of life: Widespread in marine environments. A few live in freshwater lakes and streams.Mode of life: Widespread in marine environments. A few live in freshwater lakes and streams.

66. Phylum Bryozoa Archimedes, from Mississippian rocks, has a cork-screw-like central axis with a fragile net-like colony around the outer edge. REPLACE FIGURE (Fig. 12-26c)

67. Phylum Brachiopoda Name: Name means "arm" (brachio) + "foot" (pod).Name: Name means "arm" (brachio) + "foot" (pod). Chief characteristics: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.

68. Phylum Brachiopoda 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.

69. Phylum Brachiopoda 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. REPLACE FIGURE (Fig. 12-27)

70. Phylum Brachiopoda Geologic range:Geologic range: –Early Cambrian to Holocene. –Very abundant during Paleozoic. –A few species (belonging to only three families) remain today.

71. Inarticulate Brachiopods Primitive brachiopods with phosphatic or chitinous valves.Primitive brachiopods with phosphatic or chitinous valves. No hinge. Spoon-shaped valves held together with muscles and soft parts.No hinge. Spoon-shaped valves held together with muscles and soft parts. Lingula is a well known genusLingula is a well known genus Geologic range:Geologic range: –Early Cambrian to Holocene REPLACE FIGURE (Fig. 12-28)

72. Articulate Brachiopods Calcareous valves attached together with a hinge consisting of teeth and sockets.Calcareous valves attached together with a hinge consisting of teeth and sockets. Geologic range: Early Cambrian to HoloceneGeologic range: Early Cambrian to Holocene Spiny brachiopods (called productids) are characteristic of Carboniferous and Permian.Spiny brachiopods (called productids) are characteristic of Carboniferous and Permian. REPLACE FIGURE (Fig. 12-29a, c, e)

73. Phylum Mollusca Clams, oysters, snails, slugs, Nautilus, squid, octopus, cuttlefishClams, oysters, snails, slugs, Nautilus, squid, octopus, cuttlefish Name: Mollusca means " soft bodied."Name: Mollusca means " soft bodied." REPLACE FIGURE (Fig. 12-32)

74. Phylum Mollusca Chief characteristics: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.

75. Phylum Mollusca Geologic range: Cambrian to HoloceneGeologic range: Cambrian to Holocene Mode of life: Marine, freshwater, or terrestrial.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.They may: swim, float or drift, burrow into mud or sand, bore into wood or rock, attach themselves to rocks, or crawl.

76. Types of Molluscs 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)

77. Class Monoplacophora 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. REPLACE FIGURE (Fig. 12-41)

78. Class Monoplacophora Name: Monoplacophora means "single plate-bearer."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."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."

79. Class Amphineura or Polyplacophora – The Chitons Chief characteristics: Chitons have 8 overlapping plates covering an ovoid, flattened body. REPLACE FIGURE (Fig. 12-33)

80. Class Amphineura or Polyplacophora – The Chitons Name: Polyplacophora means "many plate-bearer."Name: Polyplacophora means "many plate-bearer." Geologic range: Cambrian to HoloceneGeologic range: Cambrian to Holocene

81. Class Bivalvia or Pelecypoda Clams, oysters, scallops, mussels, rudistsClams, oysters, scallops, mussels, rudists Chief characteristics:Chief characteristics: –Skeleton consists of two calcareous valves connected by a hinge. –Bilateral symmetry; plane of symmetry passes between the two valves. REPLACE FIGURE (Fig. 12-35)

82. Class Bivalvia or Pelecypoda Name: Bivalvia means " two" (bi) + " shells" (valvia).Name: Bivalvia means " two" (bi) + " shells" (valvia). Geologic range: Early Cambrian to HoloceneGeologic range: Early Cambrian to Holocene Mode of life: Marine and freshwater. Many species are infaunal burrowers or borers, and others are epifaunal.Mode of life: Marine and freshwater. Many species are infaunal burrowers or borers, and others are epifaunal.

83. Class Gastropoda Snails and slugsSnails and slugs Chief characteristics:Chief characteristics: –Asymmetrical, spiral-coiled calcareous shell. Name: means "stomach" (gastro) + "foot" (pod).Name: means "stomach" (gastro) + "foot" (pod). Geologic range: Early Cambrian to Holocene.Geologic range: Early Cambrian to Holocene. Mode of life: Marine, freshwater or terrestrial.Mode of life: Marine, freshwater or terrestrial. REPLACE FIGURE (Fig. 12-36)

84. Class Cephalopoda Squid, octopus, Nautilus, cuttlefishSquid, octopus, Nautilus, cuttlefish Name: means " head" (kephale) + " foot" (pod).Name: means " head" (kephale) + " foot" (pod). Chief characteristics: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.

85. Class Cephalopoda Geologic range: Late Cambrian to HoloceneGeologic range: Late Cambrian to Holocene Mode of life: Marine only; carnivorous (meat-eating) swimmers.Mode of life: Marine only; carnivorous (meat-eating) swimmers. Types of Paleozoic cephalopods:Types of Paleozoic cephalopods: –Nautiloids –Ammonoids –Coleoids

86. Nautiloid Cephalopods The shells of nautiloid cephalopods have smoothly curved septa, which produce simple, straight or curved sutures.The shells of nautiloid cephalopods have smoothly curved septa, which produce simple, straight or curved sutures. Geologic range: Cambrian to HoloceneGeologic range: Cambrian to Holocene REPLACE FIGURE (Fig. 12-39)

87. Ammonoid Cephalopods Ammonoid cephalopods have complex, wrinkled or crenulated septa, which produce angular or dendritic sutures.Ammonoid cephalopods have complex, wrinkled or crenulated septa, which produce angular or dendritic sutures. Geologic range: Devonian to Cretaceous - all extinct.Geologic range: Devonian to Cretaceous - all extinct. REPLACE FIGURE (Fig. 12-39b)

88. Ammonoid Cephalopods There are three basic types of sutures in ammonoid shells: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)

89. Types of Sutures in Cephalopods REPLACE FIGURE (Fig. 12-38)

90. Subclass Coleoidea Belemnoids (belemnites)Belemnoids (belemnites) –Geologic range: Mississippian to Eocene - all extinct. Sepioids (cuttlefish)Sepioids (cuttlefish) –Geologic range: Jurassic to Holocene Teuthoids (squid)Teuthoids (squid) –Geologic range: Jurassic to Holocene Octopods (octopus)Octopods (octopus) –Geologic range: Cretaceous to Holocene

91. Order Belemnoidea - Belemnoids The belemnoids have an internal calcareous shell (which resembles a cigar in size, shape, and color) called a rostrumThe 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 front part of this shell is chambered, as in the nautiloids and ammonoids. The rostrum is made of fibrous calcite, arranged in concentric layers.The rostrum is made of fibrous calcite, arranged in concentric layers. REPLACE FIGURE (Fig. 6-51a)

92. Class Scaphopoda Tusk shells or tooth shellsTusk shells or tooth shells Chief characteristics: Curved tubular shells open at both ends.Chief characteristics: Curved tubular shells open at both ends. Geologic range: Ordovician to Holocene.Geologic range: Ordovician to Holocene. Mode of life: Marine.Mode of life: Marine.

93. Phylum Arthropoda Insects, spiders, shrimp, crabs, lobsters, barnacles, ostracodes, trilobites, eurypteridsInsects, spiders, shrimp, crabs, lobsters, barnacles, ostracodes, trilobites, eurypterids Name: means "jointed" (arthro) + "foot" (pod).Name: means "jointed" (arthro) + "foot" (pod). Chief characteristics:Chief characteristics: –Segmented body with a hard exterior skeleton composed of chitin (organic material). –Paired, jointed legs. –Highly developed nervous system and sensory organs.

94. Phylum Arthropoda Geologic range: Cambrian to HoloceneGeologic range: Cambrian to Holocene Mode of life: Arthropods inhabit a wide range of environments. Most fossil forms are found in marine or freshwater sediments.Mode of life: Arthropods inhabit a wide range of environments. Most fossil forms are found in marine or freshwater sediments.

95. Paleozoic Arthropods and Their Geologic Ranges Trilobites - Cambrian to PermianTrilobites - Cambrian to Permian Horseshoe crabs - Silurian to HoloceneHorseshoe crabs - Silurian to Holocene Eurypterids - Ordovician to PermianEurypterids - Ordovician to Permian Arachnids - Late Silurian to HoloceneArachnids - Late Silurian to Holocene Ostracodes - Cambrian to HoloceneOstracodes - Cambrian to Holocene Onychophorans - Cambrian to HoloceneOnychophorans - Cambrian to Holocene Insects - Devonian to HoloceneInsects - Devonian to Holocene

96. Subphylum Trilobita - Trilobites Chief characteristics:Chief characteristics: –Body has three-lobes –Skeleton composed of chitin, with calcium carbonate –Body is divided into three segments: Rigid head segment - cephalonRigid head segment - cephalon Jointed, flexible middle section - thoraxJointed, flexible middle section - thorax Rigid tail piece - pygidiumRigid tail piece - pygidium REPLACE FIGURE (Fig. 12-41a)

97. Subphylum Trilobita - Trilobites Name: Trilobite means "three" (tri) + "lobed" (lobus).Name: Trilobite means "three" (tri) + "lobed" (lobus). Geologic range: Cambrian to PermianGeologic range: Cambrian to Permian Mode of life: Exclusively marine. Most were bottom dwellers living in shallow shelf environments.Mode of life: Exclusively marine. Most were bottom dwellers living in shallow shelf environments. REPLACE FIGURE (Fig. 12-41b)

98. Class Eurypterida - Eurypterids Extinct scorpion-like or lobster-like arthropods.Extinct scorpion-like or lobster-like arthropods. Predators.Predators. Up to 10 ft long.Up to 10 ft long. Geologic range: Ordovician to Permian. Most are Silurian or Devonian.Geologic range: Ordovician to Permian. Most are Silurian or Devonian. Mode of life: Inhabited brackish estuaries.Mode of life: Inhabited brackish estuaries. REPLACE FIGURE (Fig. 10-30) REPLACE FIGURE (Fig. 12-44)

99. Class Arachnida - Arachnids Scorpions, spiders, ticks, and mitesScorpions, spiders, ticks, and mites Scorpions are the oldest arachnids with a fossil record.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 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.Scorpions, spiders, and mites are found in Devonian rocks. Geologic range: Late Silurian to Holocene.Geologic range: Late Silurian to Holocene.

100. Class Ostracoda -Ostracodes The ostracodes are mainly microscopic in size.The ostracodes are mainly microscopic in size. Tiny bivalved shell encasing a shrimp-like creature.Tiny bivalved shell encasing a shrimp-like creature. Geologic range: Cambrian to Holocene.Geologic range: Cambrian to Holocene. Mode of life: Both marine and freshwater.Mode of life: Both marine and freshwater. REPLACE FIGURE (Fig. 12-43)

101. Class Onychophora Onychophorans share many characteristics of segmented annelid worms and arthropods, and are considered to be intermediate in evolution between the two groups.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 HoloceneGeologic range: Cambrian to Holocene The onycophoran, Aysheaia REPLACE FIGURE (Fig. 12-5c)

102. Class Hexapoda - Insects The insects are among the most diverse living group on Earth, but they are rarely found as fossils.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.Body is divided into three parts, head, thorax, and abdomen. Thorax has six legs.Thorax has six legs. The earliest insects were wingless.The earliest insects were wingless. Winged insects appeared by Pennsylvanian.Winged insects appeared by Pennsylvanian. Geologic range: Middle Devonian to Holocene.Geologic range: Middle Devonian to Holocene. REPLACE FIGURE (Fig. 12-45)

103. Phylum Echinodermata Starfish, sea urchins, sand dollars, crinoids, blastoids, and othersStarfish, sea urchins, sand dollars, crinoids, blastoids, and others Name: Echinodermata means "spiny" (echinos) + "skin" (derma).Name: Echinodermata means "spiny" (echinos) + "skin" (derma). REPLACE FIGURE (Fig. 12-47b)

104. Phylum Echinodermata Chief characteristics: Calcite skeleton with five- part symmetry, superimposed on primitive bilateral symmetry.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.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.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.

105. Phylum Echinodermata Geologic range: Cambrian to Holcene.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.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.Similarity of embryos between echinoderms and chordates suggests that they may be derived from a common ancestral form.

106. Class Crinoidea - Crinoids Crinoids are animals which resemble flowers.Crinoids are animals which resemble flowers. They consist of a calyx with arms, atop a stem of calcite disks called columnals.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.The crinoid is attached to the sea floor by root-like holdfasts. Some living crinoids are swimmers, and not attached.Some living crinoids are swimmers, and not attached. Over 1000 genera are known.Over 1000 genera are known. REPLACE FIGURE (Fig. 12-54)

107. Crinoids Geologic range: Middle Cambrian to Holocene.Geologic range: Middle Cambrian to Holocene. Especially abundant during Mississippian.Especially abundant during Mississippian. REPLACE FIGURE (Fig. 12-50) REPLACE FIGURE (Fig. 12-53a)

108. Class Blastoidea - Blastoids Blastoids are extinct animals with an armless bud-like calyx on a stem.Blastoids are extinct animals with an armless bud-like calyx on a stem. About 95 genera are known.About 95 genera are known. A common genus is Pentremites.A common genus is Pentremites. Geologic range: Ordovician to Permian - all extinct.Geologic range: Ordovician to Permian - all extinct. REPLACE FIGURE (Fig. 12-51)

109. Class Asteroidea - Starfish Starfish are star-shaped echinoderms with five arms.Starfish are star-shaped echinoderms with five arms. About 430 genera are known.About 430 genera are known. Geologic range: Ordovician to Holocene.Geologic range: Ordovician to Holocene. REPLACE FIGURE (Fig. 12-47a)

110. Class Ophiuroidea – Brittle Stars Brittle stars have 5 arms, like starfish, but the arms are thin and serpent-like.Brittle stars have 5 arms, like starfish, but the arms are thin and serpent-like. About 325 genera are known.About 325 genera are known. Geologic range: Ordovician to Holocene.Geologic range: Ordovician to Holocene. REPLACE FIGURE (Part of Fig. 12-46)

111. Class Echninodea Sand dollars and sea urchinsSand dollars and sea urchins Echinoids are disk-shaped, biscuit- shaped, or globular.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.Viewed from above, they may be circular or somewhat irregular in shape, but with a five-part symmetry. About 765 genera are known.About 765 genera are known. Geologic range: Ordovician to Holocene.Geologic range: Ordovician to Holocene.

112. Class Holothuroidea Sea cucumbersSea cucumbers Soft-bodied echinoderms resembling cucumbers.Soft-bodied echinoderms resembling cucumbers. They have microscopic hard parts called sclerites in various shapes resembling hooks, wheels and anchors.They have microscopic hard parts called sclerites in various shapes resembling hooks, wheels and anchors. About 200 genera are known.About 200 genera are known. Geologic range: Middle Cambrian?; Middle Ordovician to HoloceneGeologic range: Middle Cambrian?; Middle Ordovician to Holocene

113. Class Edrioasteroidea EdrioasteroidsEdrioasteroids A group that was probably ancestral to starfish and sea urchins.A group that was probably ancestral to starfish and sea urchins. Globular, discoidal, or cylindrical tests (shells), many of which had concave surfaces.Globular, discoidal, or cylindrical tests (shells), many of which had concave surfaces. Geologic range: Early Cambrian to Middle Pennsylvanian.Geologic range: Early Cambrian to Middle Pennsylvanian. REPLACE FIGURE (Fig. 12-49)

114. Class Cystoidea CystoidsCystoids This primitive group had a calyx attached to the seafloor by a stem (like crinoids and blastoids).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.Distinctive patterns of pores on the plates of the calyx. Geologic range: Cambrian to Late Devonian. Most common during Ordovician and Silurian.Geologic range: Cambrian to Late Devonian. Most common during Ordovician and Silurian.

115. The Echinoderm-Backbone Connection Echinoderms are closely related to chordates (the group that includes the vertebrates).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.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).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).

116. Phylum Hemichordata Class Graptolithina - Graptolites Name: Graptolite means "write" (grapto) + "stone" (lithos), because they resemble pencil marks on rock.Name: Graptolite means "write" (grapto) + "stone" (lithos), because they resemble pencil marks on rock. REPLACE FIGURE (Fig. 10-21) REPLACE FIGURE (Fig. 12-57)

117. Graptolites Chief characteristics: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.

118. Graptolites Most graptolites are found flattened and carbonized in black shales and mudstones.Most graptolites are found flattened and carbonized in black shales and mudstones. Geologic range: Cambrian to Mississippian. (Most abundant during Ordovician and Silurian.)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.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).Mode of Life: Planktonic (colonies attached to floats).