Vertebrates Fishes Amphibians Birds Reptiles Mammals Chordate Cladogram

Vertebrates Fishes, Amphibians, Birds, Reptiles, Mammals

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

Nonvertebrate Chorodate • Choradate – Dorsal hollow nerve cord – Notochord – Pharyngeal pouches – Tail that extend beyond anus • Nonvertebrate Chorodates – Tunicates and Lancelets

The Generalized Structure of a Chordate Section 30 -1 Notochord Muscle segments Tail Anus Hollow nerve cord Mouth Pharyngeal pouches

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3 Characteristics of all Vertebrates 1. Endoskeleton. l Supports larger animal size. l Grows with animal (No molting!) 2. Backbone and cephalization. l Well-developed brain with sensory organs. l Earliest vertebrates were called ostracoderms. 3. Closed circulatory system with multi-chambered heart. l 3 - or 4 -chambered heart allows blood to be separated into oxygenated or deoxygenated. l More efficient delivery of oxygen to the body.

Endotherms and Ectotherms • Ectotherm: Temperature is regulated by external environment. – Fish, amphibians, reptiles • Endotherm: Body temperature is regulated by internal processes. – Mammals, birds

Temperature Control in Chordates Body Temperature (°C) Section 33 -2 Environmental Temperature (°C)

Diversity of Chordates Section 33 -1

Characteristics of Fishes • Agnatha (Jawless Fish) • Chondrichthyes (Cartlagenous Fish) • Endoskeleton: Cartilage (no jaw) • Respiratory: Multiple Gill Openings • Circulatory: 2 chambered heart • Reproduction: External Fertilization and development • Examples: Lamprey, Hagfish • Endoskeleton: Cartilage • Respiratory: Multiple Gill Openings • Circulatory: 2 chambered heart • Reproduction: External Fertilization (internal for sharks) and development • Examples: Sharks, Skates, Rays

Circulation in a Fish Section 30 -2 Gills Body muscle circulation Digestive system circulation Heart Oxygen-rich blood Oxygen-poor blood Brain and head circulation Sinus Venosus Oxygen-poor blood from the veins collects in the sinus venosus. Ventricle The ventricle pumps blood into the bulbus arteriosus. Atrium Blood enters the atrium and flows to the ventricle. Bulbus Arteriosus The bulbus arteriosus moves blood into the ventral aorta and toward the gills.

• Agnatha: • Chondrichthyes:

Osteichthyes (Bony Fish) • Endoskeleton: Cartilage and Bone • Respiratory: One Gill Openings • Circulatory: 2 chambered heart • Reproduction: External Fertilization and development • Examples: Trout, Cod, Salmon

Characteristics of Amphibians • • Endoskeleton: Cartilage and Bone Respiratory: Gills, Skin, Lungs Circulatory: 3 chambered heart Reproduction: External Fertilization and development • Examples: Frogs, Salamanders

Amphibians: Energy and Wastes • A frog’s skin “breathes” – it must be kept moist. • 3 -Chambered Heart, Double-looped circulatory system. – What is that? Why is that a good thing? • Metamorphisis: teeth/jaws, gills turn into lungs, circulatory system changes • Kidneys regulate the amount of water in the frog. – In water excrete, on land retain.

The Life Cycle of a Frog Section 30 -3 Adult Frog Young Frog Adults are typically ready to breed in about one to two years. Frog eggs are laid in water and undergo external fertilization. Fertilized Eggs The eggs hatch into tadpoles a few days to several weeks later. Tadpoles gradually grow limbs, lose their tails and gills, and become meat-eaters as they develop into terrestrial adults.

Characteristics of Reptiles • • Endoskeleton: Cartilage and Bone Respiratory: Lungs Circulatory: 3 chambered heart Reproduction: Internal and External Fertilization and development • Examples: Snakes, Turtles • Ectotherms. – How does a reptile regulate its body temperature?

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The Amniotic Egg (Figure 26. 4) • • • Embryo: connected to Yolk by a stalk. Yolk: food source. Amnion: fluid that protects the embryo. Chorion: regulates gas exchange. Shell: Waterproofs, protects. The shell is porous (gas can exchange through it). • Allantois: stores wastes.

The Amniotic Egg Section 31 -1 Amnion The amnion is a fluid-filled sac that surrounds and cushions the developing embryo. It produces a protected, watery environment. Allantois The allantois stores the waste produced by the embryo. It also serves as a respiratory organ. Embryo Chorion The chorion regulates the transport of oxygen from the surface of the egg to the embryo and the transport of carbon dioxide, one product of respiration, in the opposite direction. Yolk sac This baglike structure contains a yolk that serves as a nutrient-rich food supply for the embryo. Shell

Characteristics of Birds (Aves) • The one reptilian characteristic of birds is their scale-covered legs. • • Endoskeleton: Cartilage and Bone Respiratory: Lungs Circulatory: 4 chambered heart Reproduction: Internal Fertilization and External development • Examples: Birds

The Digestive System of a Pigeon Section 31 -2 Brain Esophagus 1 When a bird eats, food moves down the esophagus and is stored in the crop. Lung Heart Crop Kidney Air sac 2 Moistened food passes to the stomach, a two-part chamber. The first chamber secretes acid and enzymes. The partially digested food moves to the second chamber, the gizzard. Liver First chamber of stomach Gizzard Small intestine 3 The muscular walls of the gizzard squeeze the contents, while small stones grind the food. Pancreas Large intestine Cloaca 5 Undigested food is excreted through the cloaca. 4 As digestion continues, the food moves through the intestines.

You Eat Like A Bird… • Endotherms – requires a lot of energy to maintain their high metabolism. • Feathers – trap body heat. • Unique respiratory system – air flows one-way. • Crop Gizzard Intestines. – Figure 26. 18.

Characteristics of Mammals • • • Endoskeleton: Cartilage and Bone Respiratory: Lungs Circulatory: 4 chambered heart Reproduction: Internal Fertilization and development Examples: Humans, Whales. . . SPECIAL CHARACTERISTICS: – – – Endotherms – hair. Mammary glands – produce milk. Large, well-developed brains.

Variety of Mammals • Size – Smallest: shrew (weighs less than a dime) – Largest: whale (100, 000 kg; 32 elephants) • Speed – Slowest: Two-toed sloth (1 meter/15 seconds) – Fastest: Cheetah (400 meters/15 seconds) – Humans (150 meters/15 seconds) • Environments

Mammals: Movement and Energy • High-speed running: long bones and flexible hip and shoulder joints. • Eat a variety of foods: different teeth structures. • Diaphram: More gas exchange. • Air sacs: increased surface area for gas exchange.

The Jaws and Teeth of Mammals Section 32 -1 CARNIVORE Canines are pointed teeth. Carnivores use them for piercing, gripping, and tearing. In herbivores, they are reduced or absent. HERBIVORE Jaw joint Wolf Horse Chisel-like incisors are used for cutting, gnawing, and grooming. Molars crush and grind food. The ridged shape of the wolf’s molars and premolars allows them to interlock during chewing, like the blades of scissors. The broad, flattened molars and premolars of horses are adapted for grinding tough plants.

Mammals: Types of Life Cycles • Monotremes: Reproduce by laying eggs (duck-billed playtpus). • Marsupials: Give birth to small, immature young that then further develop inside the mother’s external pouch (kangaroo). • Placental mammals: Babies develop inside the mother’s body (95% of all mammals).

Section 39 -4 The Placenta

The Success of Mammals • Well-developed cerebrum: The largest part of the brain; makes processing information and learning possible. • Care of the Young: Development inside the mother; care of the young for the first year(s) of their life.

The Circulatory Systems of Vertebrates Section 33 -3 Single-Loop Circulatory System FISHES Double-Loop Circulatory System MOST REPTILES CROCODILIANS, BIRDS, AND MAMMALS

The Digestive Systems of Vertebrates Section 33 -3 Esophagus Stomach Intestine Liver Gallbladder Pancreas Cloaca Crop Gizzard Cecum Rectum Shark Salamander Lizard Pigeon Cow