© 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED - PowerPoint Presentation

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© 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED - PPT Presentation

1 THE EARTH THROUGH TIME TENTH EDITION H A R O L D L L E V I N Chapter 12 Life of the Paleozoic 2013 JOHN WILEY amp SONS INC ALL RIGHTS RESERVED 2 Paleozoic overview FIGURE 101 Major events of the Paleozoic Era ID: 755755

wiley john sons amp john wiley amp sons rights reserved 2013 cambrian figure range paleozoic geologic harold levin called

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Slide1

THE EARTH THROUGH TIME

TENTH EDITION

H A R O L D L. L E V I NSlide2

Chapter 12Life of the Paleozoic

2Slide3

Paleozoic overview

FIGURE 10-1 Major events of the Paleozoic Era.

3Slide4

Paleozoic Fossil Record 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

4Slide5

Paleozoic InvertebratesRepresentatives 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.

5Slide6

Paleozoic VertebratesVertebrates evolved during Paleozoic, including:

FishesAmphibiansReptilesSynapsids ("mammal-like reptiles")

The first vertebrates were

jawless fishes

, which are found in rocks as old as Cambrian in China.

6Slide7

Paleozoic VertebratesAn 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

7Slide8

Paleozoic PlantsThe 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).

8Slide9

Paleozoic ExtinctionsSeveral 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

9Slide10

Paleozoic Life Summary of invertebrate phyla

10Slide11

Paleozoic Life cont.

Summary of invertebrate phyla

11Slide12

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).

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.

12Slide13

Diversity during Paleozoic Red arrows mark extinction events.

FIGURE

12-94

13Slide14

Soft-bodied AnimalsMulticellular 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

14Slide15

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.

Small Shelly Fossils

FIGURE

12-2

15Slide16

Small Shelly FossilsMany 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.

16Slide17

Cambrian DiversificationThe 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).

17Slide18

Cambrian Substrate RevolutionInfaunal, 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

18Slide19

Why the Cambrian Explosion?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

19Slide20

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.

20Slide21

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.

21Slide22

Stratigraphic setting of the Cambrian Burgess Shale

FIGURE 12-5 The Burgess Shale fauna.

22Slide23

Animals in the Burgess Shale Several groups of arthropods, including trilobites and crustaceans

Sponges Onycophorans Crinoids

Molluscs

Corals

Three phyla of worms

Chordates (

Pikaia

)

Many others

23Slide24

Location of the Burgess Shale fauna in British Columbia, CanadaC = Onycophoran, Aysheaia, intermediate in evolution between segmented worms and arthropods.D = Arthropod Leanchoila

E= Arthropod Waptia

Animals in the Burgess Shale

FIGURE 12-5 The Burgess Shale fauna.

24Slide25

Animals in the Burgess Shale: Chordates

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

FIGURE

12-13

25Slide26

Predators in the Cambrian Seas

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.

FIGURE 12-8

Anomalocaris

, “invertebrate equivalent of

the dinosaurs.”

26Slide27

Other Burgess Shale AnimalsMarrella,

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."

FIGURE 12-10

FIGURE

12-11

27Slide28

Exceptional PreservationFossil 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.

28Slide29

The Chengjiang fauna 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.

29Slide30

The Chengjiang fauna Jelly fish

Annelid wormsCnidaria Porifera (sponges) Brachiopods ArthropodsEarly chordates similar to Pikaia

The world's oldest known fish

(

Myllokunmingia

)

Other species of unknown phyla

30Slide31

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.

31Slide32

Ordovician Diversity

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.

32Slide33

Late Ordovician ExtinctionAn 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.

33Slide34

Diversity and extinction during Paleozoic Red arrows mark extinction events

34Slide35

Silurian Diversity Diversification of marine animals occurred again at the beginning of Silurian.

The period ended with only a slight drop in diversity.

35Slide36

Devonian Diversity 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.

36Slide37

Carboniferous-Permian Diversity 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

37Slide38

Overview of Changes in Diversity Through Time

Several Paleozoic periods ended with extinction events The beginning of most Paleozoic periods were marked by

adaptive radiations

Maximum diversity in Paleozoic seas was maintained roughly constant at between 1000 and 1500 genera

The largest extinction occurred at the end of Permian

38Slide39

Recovery of diversity during Mesozoic was slow Diversity increased rapidly during Cretaceous Another mass extinction occurred at the end of Cretaceous

Diversity increased extremely rapidly, at unprecedented rates, at the beginning of Cenozoic Diversity during Cretaceous and Cenozoic was much greater than during Paleozoic

Overview of Changes in

Diversity Through Time

39Slide40

Red arrows mark extinction events

Overview of Changes in

Diversity Through Time

40Slide41

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.

These organisms are

unicellular eukaryotic organisms

, and belong to

Kingdom Protista

41Slide42

Foraminifera 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.

42Slide43

Foraminifera

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

43Slide44

Fusulinid foraminifera (fusulinids)

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.

44Slide45

Radiolaria

Chief characteristics: Unicellular. Test or shell composed of opaline silicaOrnate 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

45Slide46

Radiolaria and the Rock RecordRadiolarians 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.

46Slide47

Marine Invertebrates in the Paleozoic Seas 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

47Slide48

Phylum Archaeocyatha 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.

FIGURE 12-17

Archaeocyathid

skeleton.

48Slide49

Phylum Porifera - The Sponges

Name means “pore-bearing,” or covered by tiny pores.

FIGURE 12-21 Schematic diagram of a sponge with

the simplest

type of canal system.

FIGURE 12-18 Early Paleozoic sponges.

49Slide50

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

50Slide51

Phylum CnidariaCorals, 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.

FIGURE 12-23 Common cnidarians.

51Slide52

Phylum CnidariaG

eologic 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.

52Slide53

Phylum Cnidaria – Chief Characteristics

Radial symmetryMouth at the center of a ring of tentacles.

FIGURE 12-24

53Slide54

Phylum Cnidaria – Chief Characteristics

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.)

54Slide55

Chief Characteristics of CoralsMay be

solitary or colonial. Colonies are composed of many polyps living together. Hard calcareous skeleton. The skeletal parts formed by polyps are called corallites

The "cup," in which an individual coral polyp sits, is called the

theca

. Each theca is small, and roughly circular or hexagonal.

The theca is divided internally by vertical partitions called

septae

, arranged in a radial pattern.

Harold Levin

55Slide56

Chief Characteristics of CoralsTypes 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.

56Slide57

Rugose

Corals

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

57Slide58

Rugose CoralsGeologic range: Ordovician to Permian - all extinct.

Rugose corals were abundant during Devonian and Carboniferous, but became extinct during Late Permian.

58Slide59

Tabulate CoralsTabulate 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.

Harold Levin

59Slide60

Tabulate CoralsGeologic 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

60Slide61

Modern CoralsModern 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.

61Slide62

Phylum BryozoaName

: 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

62Slide63

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

63Slide64

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.

Archimedes,

from

Mississippian rocks

, has a

cork-screw-like central axis

with a fragile net-like colony around the outer edge.

Harold Levin

64Slide65

Phylum BryozoaGeologic range

: Ordovician to Holocene. Mode of life: Widespread in marine environments. A few live in freshwater lakes and streams.

65Slide66

Phylum BrachiopodaName:

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.

66Slide67

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.

67Slide68

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

FIGURE 12-28

68Slide69

Inarticulate Brachiopods Primitive brachiopods with phosphatic or chitinous valves

.No hinge. Spoon-shaped valves held together with muscles and soft parts.Lingula is a well known genusGeologic range: Early Cambrian to Holocene

69Slide70

Articulate Brachiopods Calcareous valves attached together with a hinge consisting of teeth and sockets.

Geologic range: Early Cambrian to HoloceneSpiny brachiopods (called productids) are characteristic of Carboniferous and Permian.

Harold Levin

70Slide71

Phylum BrachiopodaGeologic range

: Early Cambrian to Holocene. Very abundant during Paleozoic. A few species (belonging to only three families) remain today.

71Slide72

Phylum Mollusca Clams, oysters, snails, slugs,

Nautilus, squid, octopus, cuttlefish Name: Mollusca means " soft bodied."

72Slide73

Phylum MolluscaChief 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.

73Slide74

Phylum MolluscaGeologic 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.

74Slide75

Types of Molluscs

Monoplacophorans (Neopilina)Polyplacophorans or amphineurans (chitons)Bivalves or pelecypods (clams, scallops)Gastropods (snails and slugs)

Cephalopods (squid, octopus,

Nautilus

)

Scaphopods (tusk shells)

75Slide76

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.

FIGURE 12-35

76Slide77

Class Monoplacophora 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."

77Slide78

Class Amphineura or Polyplacophora – The Chitons

Chief characteristics: Chitons have 8 overlapping plates covering an ovoid, flattened body.

FIGURE 12-34 A common

placophoran

the Atlantic Coast

chiton

78Slide79

Class Amphineura or Polyplacophora – The Chitons

Name: Polyplacophora means "many plate-bearer." Geologic range: Cambrian to Holocene

79Slide80

Class Bivalvia or Pelecypoda

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.

FIGURE 12-36 Paleozoic bivalves

80Slide81

Class Bivalvia or Pelecypoda

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.

81Slide82

Class GastropodaSnails 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.

82Slide83

Class CephalopodaSquid, 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

83Slide84

Class CephalopodaGeologic range

: Late Cambrian to Holocene Mode of life: Marine only; carnivorous (meat-eating) swimmers.

Types of Paleozoic cephalopods:

Nautiloids

Ammonoids

Coleoids

84Slide85

Nautiloid CephalopodsThe shells of nautiloid cephalopods have smoothly curved septa, which produce simple, straight or curved sutures.

Geologic range: Cambrian to Holocene

Harold Levin

85Slide86

Ammonoid CephalopodsAmmonoid cephalopods have complex, wrinkled or crenulated septa, which produce angular or dendritic sutures.

Geologic range: Devonian to Cretaceous - all extinct.

Harold Levin

86Slide87

Ammonoid CephalopodsThere are three basic types of sutures in ammonoid shells:

Goniatite or goniatitic (septae have relatively simple, zig-zag undulations) Ceratite

ceratitic

(septae have smooth "hills" alternating with saw-toothed "valleys")

Ammonite

ammonitic

(septae are complexly branching and tree-like or dendritic)

87Slide88

Types of Sutures in Cephalopods

FIGURE 12-39 Cephalopod suture patterns.

88Slide89

Subclass ColeoideaBelemnoids (belemnites)

Geologic range: Mississippian to Eocene - all extinct. Sepioids (cuttlefish)Geologic range: Jurassic to HoloceneTeuthoids (squid)

Geologic range

: Jurassic to Holocene

Octopods (octopus)

Geologic range

: Cretaceous to Holocene

89Slide90

Order Belemnoidea - Belemnoids

The belemnoids have an internal calcareous shell (which resembles a cigar in size, shape, and color) called a rostrumThe front part of this shell is chambered, as in the nautiloids and ammonoids. The rostrum is made of fibrous calcite, arranged in concentric layers.

90Slide91

Class ScaphopodaTusk shells or tooth shells

Chief characteristics: Curved tubular shells open at both ends. Geologic range: Ordovician to Holocene. Mode of life

: Marine.

91Slide92

Phylum ArthropodaInsects, 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.

92Slide93

Phylum ArthropodaGeologic range

: Cambrian to HoloceneMode of life: Arthropods inhabit a wide range of environments. Most fossil forms are found in marine or freshwater sediments.

93Slide94

Paleozoic Arthropods and Their Geologic Ranges

Trilobites - Cambrian to PermianHorseshoe crabs - Silurian to HoloceneEurypterids - Ordovician to PermianArachnids - Late Silurian to HoloceneOstracodes - Cambrian to Holocene Onychophorans - Cambrian to HoloceneInsects - Devonian to Holocene

94Slide95

Subphylum Trilobita - Trilobites

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

FIGURE 12-42

95Slide96

Subphylum Trilobita - TrilobitesName

: 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

96Slide97

Class

Eurypterida - EurypteridsExtinct 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.

97Slide98

Class Arachnida - ArachnidsScorpions, 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.

98Slide99

Class Ostracoda -Ostracodes

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.

99Slide100

Class OnychophoraOnychophorans 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 HoloceneThe onycophoran,

Aysheaia

100Slide101

Class Hexapoda - InsectsThe 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.

FIGURE

12-46

101Slide102

Phylum Echinodermata Starfish, sea urchins, sand dollars, crinoids,

blastoids, and others Name: Echinodermata means "spiny" (echinos) + "skin" (derma).

FIGURE 12-47 Representative living echinoderms.

102Slide103

Phylum Echinodermata

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.

103Slide104

Phylum EchinodermataGeologic 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.

104Slide105

Class Crinoidea - Crinoids

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

105Slide106

CrinoidsGeologic range: Middle Cambrian to Holocene.

Especially abundant during Mississippian.

106Slide107

Class Blastoidea - Blastoids

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.

FIGURE 12-52 Some common Paleozoic

blastoids

107Slide108

Class Asteroidea - StarfishStarfish are star-shaped echinoderms with five arms.

About 430 genera are known. Geologic range: Ordovician to Holocene.

FIGURE 12-48

Partially

dissected starfish

showing elements

of the water vascular system and other organs.

108Slide109

Class Ophiuroidea – Brittle StarsBrittle stars have 5 arms, like starfish, but the arms are thin and serpent-like.

About 325 genera are known. Geologic range: Ordovician to Holocene.

FIGURE 12-47 Representative living echinoderms.

109Slide110

Class EchninodeaSand 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.

110Slide111

Class HolothuroideaSea 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

111Slide112

Class EdrioasteroideaEdrioasteroids

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.

112Slide113

Class CystoideaCystoids

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.

113Slide114

The Echinoderm-Backbone Connection 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).

114Slide115

GraptolitesChief 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

115Slide116

GraptolitesMost 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).

116Slide117

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 LatePrecambrian 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

117

© 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED - PowerPoint Presentation

© 2013 JOHN WILEY & SONS, INC. ALL RIGHTS RESERVED - PPT Presentation

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