Chordates Phylum Chordata Chordates What is a chordate

Chordates

Phylum Chordata

Chordates • What is a chordate? – 1. Has either a backbone or a notochord (vertebrate) – 2. Can either be an ectotherm or an endotherm – 3. Only 4 -5% of animals are chordates

What is a vertebrate? • Animals with a backbone or vertebral column (notochord) • Have spinal cord- dorsal, hollow nerve cord • Front end of spinal cord develops a brain Sea Squirt or Tunicate Lancelet http: //www. diverosa. com/categories/Ascidians. htm

Chordates • Endotherm (warmblooded) –Has a stable body temperature • Ectotherm (coldblooded) –Can change body temperature due to the environment

Section 30 -1 Chordate Cladogram Birds Amphibians Fishes Nonvertebrate chordates Invertebrate ancestor Reptiles Mammals

Chordates • Vertebrate Classes – Jawless Fish (lamprey, hagfish) – Cartilage Fish (sharks, rays…) – Bony Fish (salmon, catfish, goldfish. . ) – Amphibians (frogs, toads…) – Reptiles (lizards, turtles…) – Birds (sparrows, hawks) – Mammals (humans, whales, dogs…)

What are Fish? • Anything with gills, scales and fins… • 1 st fish were jawless • Devonian Period - “Age of Fish” • Fossil of a devonian fish • With jaws and armored plates http: //www. fossilmuseum. net/Ed. Resources/Fish. Images. htm

• Fish have a two chambered heartblood is passed over the gills where it picks up oxygen

Respiration • Water passes over GILLS, oxygen is added • Some fish have gill covers OPERCULUM • (Some fish have special organs to serve as lungs; lungfish)

Excretion • Homeostasis: maintaining balance, internal conditions (in the case of fish, water balance) • Salt water fish tend to lose water • Fresh water fish tend to gain water • *This is why you can’t put a salt water fish in a fresh water tank.

Other Fish Adaptations • Fish fins help stabilize the fish and propel it forward • Swim Bladder - maintains buoyancy (like a balloon)

Reproduction • Spawning- fish lay eggs that are fertilized externally

Warm Up • 1. What are the steps of complete metamorphosis? • 2. What are the stages of incomplete metamorphosis? • 3. What is an open circulatory system? • 4. How do bivalves move and feed?

Class - Amphibians

Amphibians • Amphibian- means “double life” – Why? • After beginning their lives in water, most amphibians spend their adulthood on land, returning to water to reproduce. (Lose gills and acquire lungs)

• http: //video. nationalgeographic. com /video/player/animals/amphibiansanimals/frogs-andtoads/frog_greentree_lifecycle. html

Amphibians • 3 types/orders: – Anura (frogs and toads), – Caudata (salamanders and newts), and – Gymnophiona (caecilians, limbless amphibians that resemble snakes)

• What’s the difference between a frog and a toad? – 1. Many toads have lumps behind their eyes that contain poison that oozes out when they are attacked. – 2. Skin • Frogs are moist and smooth • Toads are dry and bumpy

Frog Dissection • What are the rules of lab? • How should we behave? • http: //www. mhhe. com/biosci/genbio /virtual_labs/BL_16. html

Frog Dissection- Mouth

Reptiles

Reptiles • An ectothermic vertebrate that has lungs and scaly skin. • Major Groups: – Lizards – Snakes – Turtles – Alligators – Crocodiles

4 living orders are typically recognized: • Crocodilia (crocodiles, gavials, caimans, and alligators): 23 species • Sphenodontia (tuataras from New Zealand): 2 species • Squamata (lizards, snakes, and worm lizards): approximately 9, 150 species • Testudines (turtles, terrapins and tortoises): over 300 species

Reptiles • Unlike amphibians, which have a thin, moist skin, reptiles have dry, tough skin covered with scales. – Skin protects and helps keep water in their bodies.

Reptiles • Lizards and snakes shed their skin. • All snakes are carnivores but not all lizards are. • Turtles have a shell made from their ribs and backbone.

Reptiles • What is the difference between an alligator and a croc? – Alligators have broad, rounded snouts, with only a few teeth visible. – Crocodiles have pointed snouts, and you can see most of their teeth.

Birds • Bird: an endothermic vertebrate that has feathers and a fourchambered heart, and lays eggs. • The rule is: – If it has feathers, it’s a bird.

Birds • Feathers: – Contour: one of the large feathers that give shape to a bird’s body. – Flight: long contour feathers that extend beyond the body on the wings and tail. – Down: short, fluffy that are specialized to trap heat and keep a bird warm.

Birds • Feed – Capture, grip and handle food, birds use their bills. – Bills specify per species – Internal storage tank called a crop – Birds do not have teeth, a gizzard performs the grinding function

Birds • Adaptations for Flight – 4 chambered heart – Highly efficient respiratory system – Lightweight bones with air spaces

Evolution of Birds… • Create a Venn Diagramcharacteristics of reptiles, similarities, characteristics of birds. Then come up with your own explanation of the evolution of birds.

The evolutionary origin of birds has always been a subject of considerable debate. Birds and flying reptiles have delicate, lightweight skeletons which do not fossilize well - hindering studies on how the birds evolved. The first bird fossil to be found was a feather, which was discovered in 1860 in a limestone quarry in Bavaria. The feather was given the name Archaeopteryx, which is Greek for 'ancient feather'. A year later an almost complete skeleton of Archaeopteryx was discovered in the same quarry, with the feathers and other fine structures preserved in minute detail.

The skeleton showed several features which are intermediate between reptiles and birds, suggesting that Archaeopteryx and the other birds evolved from a dinosaur similar to the Velociraptor featured in the film 'Jurassic Park'. Seven partial or complete Archaeopteryx skeletons have now been found, and they are still among the most famous, and scientifically valuable, fossils.

Mammals • All mammals are endothermic vertebrates with a 4 chambered heart and skin covered with fur or hair.

Mammals • • • All mammals have…. 1. Hair or fur 2. Mammary glands (feed with milk) 3. Distinctive teeth 4. Highly developed brain 5. Extended care for the young

Mammals • Three groups of mammals – Monotremes – Marsupials – Placental mammals

Mammals • Monotremes – Mammals that lay eggs – Two species: • Spiny anteaters • Duck-billed platypuses

Mammals • Marsupials – Young born alive at an early stage, but continue to develop in a pouch – Examples: • Kangaroos • Koalas • Wallabies • opossums

Mammals • Placental Mammals – Develop inside a mother’s body until its body system can function independently. – Examples: • Insect-eaters • Flying mammals • Primates • Rodents • Rabbits/hares • Marine mammals • Hoofed mammals