Presentation on theme: "Compare and Contrast Why did scientist classify Pikaia as a chordate instead of as a worm Review What two aspects of evolutionary history does the cladogram."— Presentation transcript:
1 Compare and Contrast Why did scientist classify Pikaia as a chordate instead of as a worm Review What two aspects of evolutionary history does the cladogram of chordates showApply Concepts Recall what you learned about plant evolution in Ch 22. In what ways are chordate adaptations to life on land similar to plant adaptations. Based on the sequence of evolutionary change what was the first major adaptation of each
2 Ch 26 Animal Evolution and Diversity 26.2 Chordate Evolution and History
3 Embryological studies suggest that the most ancient chordates were related to the ancestors of echinoderms.
4 Earliest Chordates Pikaia Cambrian fossil First thought it was a worm but then determined that it had a notochord and paired muscles arranged in a series.
5 CartilageStrong connective tissue that is softer and more flexible than bone.
7 Nonvertebrate Chordates 550 million years agoTunicates and lanceletsTurnicatesAdults look like spongesLarval forms have all the key chordate characteristics.
8 Jawless Fishes 510 million years ago No true jaws or teeth, and their skeletons were made of cartilage.
9 Jawless FishesLampreys and hagfishes both lack vertebrae and have notochords as adultsLampreys are filter feeders as larvae and parasites as adultsHagfishes have pinkish gray, wormlike bodies, secrete incredible amounts of slime, and tie themselves into knots.
10 Sharks and Their Relatives Jaws make it possible to bite and chew plants and other animalsEvolved paired pectoral (anterior) and pelvic (posterior) finsPaired fins offered more control of body movementTail fins and powerful muscles gave greater thrust.
11 Chondrichthyes “Cartilaginous” fishes Sharks, rays, and skates Paired fins and tail fins.
12 Osteichthyes Bony Fishes Skeletons made of true bone Ray finned fishes Lobe finned fishes.
13 Ray-Finned FishesAquatic vertebrates with skeletons of true bone; most have paired fins, scales, and gillsMost fishes you are familiar withEels, catfish, walleye.
14 Lobe-Finned FishesBony fishes that evolved fleshy fins supported by larger, more substantial bonesLungfishes and coelacanthsOther ancient lobe-finned fishes evolved into the ancestors of tetrapodsFour-limbed vertebrates.
15 The Unique “Fishapod”Series of transitional fossils have been discovered that document the skeletal transformation from lobe-fins to limbs.
17 AmphibiansVertebrates that, with some exceptions, require water for reproduction, breathe with lungs as adults, have moist skin with mucous glands, and lack scales and claws.
18 Reptiles First vertebrates to evolve adaptations to drier conditions Vertebrate with dry, scaly skin, well-developed lungs, strong limbs, and shelled eggs that do not develop in water.
19 Current hypotheses about the relationships between living and extinct reptiles.
20 Enter the DinosaursTriassic and Jurassic periods saw a great adaptive radiation of reptilesLived all over the world, and they were diverse in appearance and in habit.
21 Exit the Dinosaurs End of the Cretaceous Period Worldwide mass extinction cause bySeries of natural disastersString of volcanic eruptionsFall in sea levelHuge asteroid smashing into what is now the Yucatán PeninsulaMany plant and animal groups went extinct.
22 Bird RootsSupport for hypothesis that birds evolved from a group of dinosaursArchaeopteryx shows both bird characteristics (flight feathers) and dinosaur characteristics (teeth and bony tail).
23 BirdsReptiles that regulate their internal body temperature (endothermy)Outer covering of feathers; strong yet lightweight bones; two legs covered with scales that are used for walking or perching; and front limbs modified into wings.
24 Bird clade is part of the clade containing dinosaurs Clade containing dinosaurs is part of a larger clade of reptilesModern birds are also reptiles.
25 MammalsMammary glands in females that produce milk to nourish young, and hairBreathe air, have four-chambered hearts, and regulate their internal body temperature.
26 The First Mammals Very small and resembled modern tree shrews Modern mammalian groups evolved during TriassicMammals diversified, increased in size, and occupied many niches after dinosaur extinction.
27 Modern Mammals Monotremes Marsupials Placental mammals Egg laying mammals- platypusMarsupialsBear live young that usually complete their development in an external pouchKangaroos, koalas, and wombatsPlacental mammalsEmbryos develop further while still inside the motherCare and nurse for young.