Section 6.3: Kingdom Animalia pg Part 2: VERTEBRATES

Vertebrates (5% of Animal Kingdom) The Phylum Chordata is the phylum of vertebrates.

Phylum Chordata (Chordates) Most members of this phylum are vertebrates with bony skeletons and backbones. Most common on land & in water. Many fewer chordate species than invertebrate species.

Chordate Characteristics At some stage in their life cycle, Chordates have: 1.A dorsal nerve cord (nerves branch to all parts of the body) 2.A notocord (rod of cartilage that runs along the dorsal length of the body) 3.Gill slits in the pharynx (throat).

An Exception There are two groups of invertebrate animals that are part of the Phylum Chordata. 1.Tunicates 2.Lancelets They have the three characteristics of chordates.

Comparing Vertebrate Chordates The organisms within the Phylum Chordata are divided commonly by: 1. The presence of an amnion (fluid-filled sac around the embryo). 2.The development of the lung.

Chordate Respiration Fish are the only vertebrates adapted to live their lives entirely in water. They obtain oxygen from the water through their gills. Reptiles, birds & mammals have lung-base respiratory systems.

Chordate Circulation There are three types of circulatory pathways among vertebrates. 1.Mammals, birds, crocodiles 2.Amphibians & most reptiles 3.Fishes *** See and know Figure 6.25 on page 193.

Chordate Reproduction There are two main methods of fertilization in vertebrates: 1.External 2.Internal

External Fertilization The egg & sperm meet outside the body. Ex. Sharks, frogs

Internal Fertilization The egg & sperm meet inside the body Ex. Reptiles, birds, mammals Mammals are the only vertebrates in which the embryo develops internally! (Exceptions: Duckbill Platypus & Kangaroo)

Phylum Chordata Four Subphyla: 1.Urochordata (tunicates) 2.Cephalochordata (lancelets) 3.Agnatha (jawless fish, i.e. hagfish) 4.Gnathostomata (jawed chordates)

Subphylum Gnathostomata (jawed chordates) Divided into 6 classes: 1.Chondrichthyes (cartilaginous fish, i.e. sharks) 2.Osteichthyes (bony fish) 3.Amphibia (amphibians) 4.Reptilia (reptiles) 5.Aves (birds) 6.Mammalia (mammals) *** You should know the class (Table 6.3, page 190)

1. Chondrichthyes (Cartilaginous Fish) Skeleton is made of cartilage instead of bone Have 5-7 gill slits but lack gill covers Ex. Rays, skates, sharks

2. Osteichthyes (Bony Fish) Most numerous of the vertebrates. Skeletons are made of bone. Ex. Herring, trout, cod

3. Amphibia (Amphibians) In early stages are gill breathers in water, but live as air breathing adults on land. Have a heart with 3 chambers. Ex. Frogs, toads

4. Reptilia (Reptiles) Have better developed lungs than amphibians. Have a rib cage Skin is thick and scaly & is made from keratin (a protein) They shed their skin several times each year. Ex. Lizards & snakes

5. Aves (Birds) Have feathers Bones are hallow…..why?? Ex. Robins, Blue Jays, Swallows

6. Mammalia (Mammals) Have hair Have milk-producing mammary glands Give birth to live young Most live on land A small number are adapted to life in the water (i.e. whales, dolphins)

One Short Video Phylum Chordata “How Stuff Works”

Section 6.3 Review Questions Do question #’s 1-6 on page 196. Do “A Vertebrate Survey” Worksheet.

Section 6.3 Answers 1.On what basis do biologists distinguish animals from members of other kingdoms? They use characteristics such as: reproduction motility digestion cell type body form

2.Why is Phylum Arthropoda considered the most successful animal phylum? Arthropods have an exoskeleton, segmentation, a nervous system, and nutrition-related adaptations that have all helped them to be successful.

3.What characteristics distinguish chordates from other animals? Unlike other animals, chordates have a notochord.

4.How is the body of a flatworm similar to and different from the body of a sponge and a cnidarian? They are all multicellular. The flatworm has bilateral symmetry, and the sponge is asymmetrical while the cnidarian is radial. The flatworm has a simple nervous system like cnidarian but sponges do not have tissues or organs. All three lack a body cavity.

5.Sketch a diagram illustrating the difference between radial symmetry and bilateral symmetry in animal bodies. Ex. A starfish vs. a lobster

6.Construct a simple key that enables you to differentiate among any four animal phyla. Answers will vary!! Chordata = dorsal nerve cord Arthropoda = jointed appendages Platyhelminthes = three tissue layers Cnidaria = two tissue layers