Fig. 15-CO, p. 406

Fig. 15-1, p. 408

Fig. 15-1, p. 408

Carbon dioxide

Rel

ativ

e co

nce

ntr

atio

n

4.5 3.5 2.5 1.5 0.5 0Time

(billions of years ago)

Animals arise

Oxygen begins to accumulate in the atmosphere

Oxygen-producing cyano bacteria get their start

First microscopic life begins consuming carbon dioxide

Greenhouse warming due to high carbon dioxide level compensates for the faint, young sun

Oxygen

Fig. 15-2a, p. 409

Fig. 15-2b, p. 409

Fig. 15-2c, p. 409

Table 15-1, p. 409

Fig. 15-3, p. 410

Fig. 15-3a, p. 410

Fig. 15-3b-d, p. 410

Water outSpicules

Amoeboid cellPore

MesogleaCentral cavity Flattened

surface cells

c

Flagellum Microvilli Nucleus

Water ind Collar cell

b

Fig. 15-3b-d, p. 410

Water out

Central cavity

Water inCollar cell

Flagellum

Flattened surface cells

MesogleaPore

Amoeboid cell

Spicules

Stepped Art

NucleusMicrovilli

Fig. 15-4, p. 411

Fig. 15-5, p. 411

Fig. 15-6a, p. 412

Fig. 15-6b, p. 412

Fig. 15-6b, p. 412

Tentacles with stinging cells

Epidermal tissue Mouth

Digestive cavity

Interior partition

Symbiotic zooxanthellae

Mesenteric filaments

Layers of calcium carbonate forming a skeleton

b

Fig. 15-7, p. 413

Box 15-1, p. 414

Fig. 15-8, p. 415

Fig. 15-9, p. 415

Fig. 15-10, p. 416

Fig. 15-10, p. 416

Clam

Digestive tract

FootSnail

Shell

Squid

Fig. 15-11, p. 416

Fig. 15-12, p. 416

Fig. 15-13, p. 417

Fig. 15-13, p. 417

Left gill

Left mantleMuscle Shell Muscle

Mouth

Exhalant flow

Inhalant flow

Foot Right mantle

Sand and debris being

rejected

InhalantPalps String of

mucus

Fig. 15-14, p. 417

Fig. 15-15a, p. 418

Fig. 15-15b, p. 418

Fig. 15-16, p. 418

Fig. 15-16, p. 418

Vertebrates (with endoskeletons)

Siz

e

Arthropods (with exoskeletons)

Age

Fig. 15-17a, p. 419

Fig. 15-17b, p. 419

Fig. 15-18a, p. 420

Fig. 15-18b, p. 420

Fig. 15-19, p. 421

Fig. 15-19, p. 421

Sieve plate

Ring canal

Radial canal

Ampulla

Stone canal

Transverse canal

Tube feet

Fig. 15-20, p. 421

Fig. 15-21a, p. 422

Fig. 15-21a, p. 422

Oral opening

Atrial opening

Pharynx with slits

Fig. 15-21b, p. 422

Fig. 15-22, p. 422

Fig. 15-23, p. 423

Fig. 15-23, p. 423

Lancelets (like

Amphioxus)

Jawless fishes

Cartilaginous fishes

Bony fishesTunicates Amphibians Reptiles Birds Mammals

Recent

135

375

Uro-chordates

Cephalo- chordates

Ancestral vertebrates

500

Millions of years

agoAncestral chordates (probably filter feeders)

Fig. 15-24a, p. 424

Fig. 15-24b, p. 424

Fig. 15-25, p. 425

Fig. 15-26, p. 426

Fig. 15-27, p. 426

Fig. 15-28, p. 426

Fig. 15-29, p. 427

Fig. 15-29, p. 427

Moray eel (1.5 m, 5 ft)

Sunfish (to 2 m, 6.6 ft)

Lionfish (15 cm, 6 in.)

Weedy seadragon

(25 cm, 10 in.)

Scrawled cowfish (10 cm, 4 in.)

Redfish Typical form of

teleost fish (25 cm, 10 in.)

Fig. 15-30a-c, p. 428

Fig. 15-30a-c, p. 428

Disk

Sphere

Teardrop

a

b

c

Fig. 15-30d, p. 428

Fig. 15-31, p. 428

Fig. 15-31, p. 428

1 3

22

Path of motion3

1

a

Eel-like fishes

Moving hinge

1 2

5

3 4

4 3

5 1 2

b Advanced fishes

Path of motion

Fig. 15-32, p. 429

Fig. 15-32, p. 429

Oxygen-enriched blood Oxygen-poor blood

Gill archGill membrane

a

b

c

Fig. 15-33, p. 430

Fig. 15-33a, p. 430

Salinity of fresh water = 00‰ Salinity of body fluids = 8‰–10‰ Internal fluids are

saltier than the surrounding waterWater gain by

osmosis

Does not drink

Salt absorbed by gillsLarge volume of diluted urine removes excess water

a Freshwater fish

Fig. 15-33b, p. 430

Salinity of seawater = 35‰ Salinity of body fluids = 8‰–14‰

External environment is saltier than body fluids

Water loss by osmosis

Drinks seawater

Salt excreted by special glands in gills Very small amount of urine

produced by kidneys to conserve water

b Marine fish

Fig. 15-34, p. 431

Fig. 15-35, p. 432

Fig. 15-36, p. 432

Fig. 15-37, p. 433

Fig. 15-38a, p. 435

Fig. 15-38b, p. 435

Fig. 15-39a, p. 436

Fig. 15-39a, p. 436

Humpback whale

Bowhead whale

Right whale Minke whale

Blue whale

Fin whale

Feeding on krill

Sei whale

Gray whaleMysticetes (baleen whales)

Fig. 15-39b, p. 437

Fig. 15-39b, p. 437

Atlantic white-sided

dolphin

Common dolphin

Harbor porpoise

Killer whale

Beluga whale Bottle-nosed dolphin

False killer whaleCuvier’s beaked

whalePilot whale

Narwhal

Pygmy sperm whale Sperm

whale

Squid

Baird’s beaked whale

0 5 10 15 20 25 30 m

0 10 20 30 40 50 60 70 80 90 100 ftOdontocetes (toothed whales)

Fig. 15-40, p. 438

Fig. 15-40, p. 438

Returning echoes

Short high-frequency

sound pulses

Fig. 15-41a, p. 439

Fig. 15-41b, p. 439

Fig. 15-42, p. 439

Fig. 15-43a, p. 440

Fig. 15-43b, p. 440

Fig. 15-44, p. 441

Fig. 15-45, p. 441

Fig. 15-46, p. 442