Animal Evolution: Chordate and Vertebrate Evolution and Diversity (Learning Outline) 1. Distinguishing features of the phylum Chordata and representative organisms. 2. Highlights of evolutionary steps of aquatic chordates and vertebrate animals 3. Highlights of evolutionary steps of land vertebrates. 4. Place chordates in order of appearance on earth. 5. For organisms covered in class or lab, place each in its classification grouping, relation to others, and know their major evolutionary features.
Phyla Sponges Cnidarians Flatworms Round worms Molluscs Annelids Arthropods Echinoderms Chordates Segmentation No Body Cavity (No coelom) Mouth from First Embryonic Opening Mouth from Second Embryonic Opening Organ Systems (Coelom) Body Cavity (Pseudocoelom) Tube within Tube Radial Symmetry Bilateral Symmetry Sac Body Plan Multicellular Level of Organization
Phylum Chordata, is distinguished by four features A dorsal hollow nerve cord A stiff notochord* Pharyngeal slits A muscular post-anal tail Includes invertebrates and vertebrates (*) A long flexible rod of cells that supports the body of chordates and vertebrate embryos and is in effect a primitive backbone
Tunicates Lancelets Hagfishes Lampreys Sharks, rays Chordates Craniates Vertebrates Jawed vertebrates Tetrapods Amniotes Ray-finned fishes Lobe-fins Amphibians Reptiles Mammals Milk Amniotic egg Legs Lobed fins Lungs or lung derivatives Jaws Vertebral column Invertebrates Ancestral chordate Brain Head Chordates
Tunicates - Sea Squirts Fossil record- appeared in early Cambrian Period Marine invertebrates with pharyngeal slits for suspension feeding Excurrent siphon Dorsal, hollow nerve cord Pharyngeal slits Mouth Adult (about 3 cm high) Larva http://www.youtube.com/watch?v=n8arukwpjae
Lancelets Small eel-like organisms that live in the ocean Filter feeders and use cilia to filter food out of the water. Anchor their tails in the sand and let the water wash over their mouths. Have a nerve cord, brain Head Notochord but no vertebrae Mouth Pharynx Pharyngeal slits Digestive tract Water exit Segmental muscles Anus Dorsal, hollow nerve cord Post-anal tail http://www.youtube.com/watch?v=gpnpxsancly
Jawless fish- Lamprey Vertebrates Adult has toothed, funnel-like sucking mouth No jaws No paired fins Skeleton made of cartilage http://www.youtube.com/watch?v=9jq6ohjpequ
Sharks and Rays Jaws Flexible skeleton made of car tilage Paired fins Uncovered gills Internal fertilization
Bony fishes: sub groups ray-finned fishes lobe-finned fishes
Bony Fishes- ray-finned fishes (most fish) - Skeleton reinforced with a hard matrix of calcium phosphate - Operculi that move water over the gills - A buoyant air-filled swim bladder Gills Bony skeleton Dorsal fin Operculum Pectoral fin Heart Anal fin Swim bladder Pelvic fin Rainbow trout, a ray-fin
Eels are bony fish that have a muscular, snake-like body
Bony Fishes- Lobe-finned fishes Muscular fins supported by bones
Tetrapod
Amphibians Tetrapods two pairs of limbs allowing movement on land Most reproduce in water External Fertilization and embryos and larval development take place in water Examples: Salamanders, frogs and toads
Amniotes Tetrapod vertebrates Adapted to survive in a terrestrial environment. Internal fertilization Have an amnion during the embryologic stage Egg-laying reptiles and birds and some early mammals Internal gestation and milk (Mammals)
Reptiles are amniotes tetrapods with a terrestrially adapted egg Terrestrial adaptations of reptiles include Waterproof scales Internal fertilization shelled, amniotic egg
Dinosaurs, the most diverse reptiles to inhabit land Some of the largest animals ever to inhabit land May have been endothermic, producing their own body heat Living reptiles other than birds are ectothermic
Birds wings, feathers, and endothermic metabolism flight adaptations Evolved from a small, two-legged ectothermic dinosaurs. Wing claw (like dinosaur) Teeth (like dinosaur) Long tail with many vertebrae Feathers (like dinosaur)
Mammals are endothermic amniotes with - Hair for temperature insulation - Internal fertilization - Mammary glands for milk production Two groups of mammals 1. Marsupials- Kangaroos 2. Eutherians, placental mammals
The embryos of marsupials are: - nurtured within the uterus - leave the uterus before completing development - complete development attached to the mother s nipple, usually inside a pouch Kangaroo Birth https://www.youtube.com/watch?v=pmjkn9djdq8
Eutherians, placental mammals, complete development before birth Birth of an elephant https://www.youtube.com/watch?v=1idride05ko