Take a guess… Which type of animal are most vertebrates?

Chordates Chordate Example: Mrs. Holden’s 17 year old childhood pet cat “Mookie” (class Mammalia) after a trip to the groomer for a “lion cut”…

Trends in animal evolution- as animals get more advanced they have more features than the prior phylum

PHYLUM CHORDATA 4 characteristics present AT SOME TIME during life cycle 1. Dorsal, hollow nerve cord 2. Notochord – long, supportive rod, below nerve cord* 3. Pharyngeal gill slits – in neck or throat region 4. Post-anal tail – extends beyond anus

Nonvertebrate Chordates Two groups do NOT have backbones: 1. Tunicates: filter feeders, larval form has chordate characteristics, adults do not 2. Lancelets: small, fish-like, live on sandy ocean bottom

Chordate Origins Many studies suggest that the most ancient chordates were closely related to echinoderms

Most Chordates are Vertebrates… Vertebrate: a chordate that has a strong supporting structure called the vertebral column or backbone which is made up of bony or cartilaginous vertebrae In vertebrates, the dorsal, hollow nerve cord is the spinal cord Vertebrates have an endoskeleton which grows as the org grows, and is made up of living cells which produce non-living material

Chordate Diversity

CLASSES PHYLUM CHORDATA – 7 CLASSES CLASS AGNATHA – jawless fish CLASS CHONDRICHTHYES – cartilaginous fish CLASS OSTEICHTHYES – bony fish CLASS AMPHIBIA - amphibians CLASS REPTILIA - reptiles CLASS AVES - birds CLASS MAMMALIA - mammals

Figure 34.8 A hagfish Agnatha

Figure Cartilaginous fishes (class Chondrichthyes): Great white shark (top left), silky shark (top right), southern stingray (bottom left), blue spotted stingray (bottom right) Chondrichthyes

Figure Anatomy of a trout, a representative ray-finned fish Osteichthyes

Figure “Dual life” of a frog (Rana temporaria) Amphibia

Figure Extant reptiles: Desert tortoise (top left), lizard (top right), king snake (bottom left), alligators (bottom right) Reptilia

Section 31-2 Esophagus Crop Liver First chamber of stomach Gizzard Small intestine Cloaca Pancreas Air sac Kidney Heart Lung Brain When a bird eats, food moves down the esophagus and is stored in the crop. 1 As digestion continues, the food moves through the intestines. 4 Undigested food is excreted through the cloaca. 5 Large intestine The muscular walls of the gizzard squeeze the contents, while small stones grind the food. 3 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. Figure 31–14 The Anatomy of a Pigeon 2 Aves

Figure Apes: Gibbon (top left), orangutan (top right), gorilla (bottom left), chimpanzee (bottom right) Mammalia

Evolutionary Trends in Vertebrates From Water to Land  Land specific adaptations  Overcome problems posed by living on land From Simple to Complex  More organized systems  More efficient systems  Increase in size of systems  Appearance of successful adaptations – such as jaws and paired appendages – has launched adaptive radiations in chordate groups

Temperature Control in Chordates Notice as the environment temperature changes, so does the temperature for certain ectotherms Fish, Amphibians

The Digestive System of Chordates Note differences between carnivores and herbivores! Which has a straighter track? Which has a larger liver? Which has a longer intestine?

Chordate Respiration Aquatic chordates – gills Land vertebrates - lungs

Chordate Circulation Those that use gills for respiration have a single- loop circulatory system  Blood travels from the heart to the gills, then to the rest of the body, and back to the heart in one circuit Those that use lungs for respiration have a double-loop circulatory system  1 st loop carries blood between the heart and lungs, oxygen poor blood from the heart is pumped to the lungs, while oxygen rich blood from the lungs returns to the heart  2 nd loop carries blood between the heart and the body – oxygen rich blood from the heart is pumped to the body, while oxygen poor blood from the body returns to the heart

Double-Loop Circulatory SystemSingle-Loop Circulatory System FISHESMOST REPTILESCROCODILIANS, BIRDS, AND MAMMALS Circulatory Systems of Vertebrates Which type of heart prevents oxygen poor blood from mixing with oxygen rich blood?

Chordate Hearts Chambers and partitions that help separate oxygenated and deoxygenated blood traveling in the circulatory system  Gilled vertebrates: 2 chambered hearts  Amphibians: 3 chambered hearts  Reptiles: 3 chambered hearts with partitions  Birds, mammals, crocodiles: 4 chambered hearts that are completely partitioned

Chordate Excretion How to get rid of wastes without losing too much water? Fishes and aquatic amphibians:  Excrete ammonia directly from gills, skin via diffusion Mammals, land amphibians, and cartilaginous fishes:  Ammonia is changed into urea before excreted using kidneys Reptiles and birds:* saves most water  Ammonia is changed into uric acid before excretion through kidneys

Chordate Response Nonvertebrate chordates have a relatively simple nervous system with a mass of nerve cells that form a brain Vertebrates have a more complex brain with distinct regions, each with a different function

Chordate Movement Nonvertebrate chordates lack bones but have muscles for movement The skeletal and muscular systems support a vertebrate’s body and make it possible to control movement

Chordate Reproduction Oviparous (eggs develop outside mother’s body) Unprotected egg  Most fishes and amphibians Amniotic egg  Some reptiles, birds Ovoviviparous (eggs develop within the mother’s body)  Sharks, some reptiles Viviparous (born alive)* most advanced  Most mammals

AKS Log Book Use the notes and CP Ch 33 Answer question 6 Some of the Vocab will NOT be in the back of the book!