Key concept all vertebrates are chordates not all chordates are vertebrates Sea squirts Subphylum. Urochordata Subphylum. Vertebrata Subphylum. Cephalochordata Phylum. Chordata Chordata Lancelet

Phylum Chordata contains all vertebrates Chordates share common features or structures at some stage of development at some point in their life cycle. Notochord Long, firm rod that extends along the back of the animal becomes the vertebral column Hollow nerve cord Hollow tube that in chordates that becomes the brain and spinal cord pharyngeal slits Gills in the throat region Postanal tail

Chordate Characteristics Bilateral symmetry Two pairs of appendages Cephalization Closed circulatory system Coelom – body cavity that contains vital organs Internal skeleton deudostromes

An endoskeleton allows vertebrates to grow to large sizes. internal made of bone or cartilage An endoskeleton can be divided into two parts. Axial skeleton Appendicular skeleton braincase braincase (cranium) vertebrae Pectoral girdle vertebrae Pelvic girdle Pectoral girdle Pelvic girdle

Evolutionary Adaptations of Chordates From filter feeding ancestors to active predators Skeletal respiration Digestion Circulation Nervous system

Skeleton becomes stronger to work with bigger muscles More complex for better motor control Sensory detection of the animals environment (brain) Skeleton becomes stronger to work with bigger muscles Allows more rapid movement nervous skeletal Stronger heart to circulate blood faster Adaptations circulation respiration Digest more food Muscularized gut parastalsis Digestive glands Liver Pancreas digestive Gill slit and muscular pharynx will move more water over gills More oxygen is extracted from water

Subphylum Urochordata Sea squirt Gill slits (pharyngeal slits) Notochord Only in larva Adult has tunic

Subphylum Cephalochordata Lancelet Amphioxus Notochord length of body Dorsal hollow nerve cord Gill slits Segmented muscles

There are seven classes of vertebrates. 1. Agnatha 2. Chondrichthyes 3. Osteichthes 4. Amphibians 5. Reptilia 6. Aves 7. Mammalia

Main Characteristic 4 reptiles scales Agnatha Chondrichthyes Osteichthyes Amphibia Aves Mammalia 2 JAWS Jaws 1 Agnatha Jaw is missing. 3. amphibia Four limbs 5 aves Feathers 6 mammals Hair jawless cartilaginous fish bony fish amphibians birds mammals 4 reptiles scales

There are 30,000 species of Fish – 20,000 are Marine. The dominant aquatic vertebrates are the fish. 97% of fish are bony fishes. They belong to Phylum Chordata. Most fish use counter shading as a means of camouflage

Characteristics of All Fish They are aquatic They are cold blooded They have a backbone They have paired fins They breath with gills Lateral line system Developed brain

Fish are vertebrates with gills and paired fins. Fish use specialized organs called gills to breathe underwater. sheets of thick, frilly tissue filled with capillaries take in dissolved oxygen from water, release carbon dioxide Have countercurrent flow

Fins are appendages that project from a fish’s body. keep fish stable redirect water around fish as it swims help fish maneuver in water

Fins are appendages that project from a fish’s body. keep fish stable redirect water around fish as it swims help fish maneuver in water

All fish have a lateral line system. sensory system sensitive to small changes in water movement lateral line

Parts of the fish brain Olfactory lobe cerebrum Optic lobe cerebellum Medulla

body regions of a fish thorax tail . head

Class Agnatha Tunicates (worms) may be the closest relatives to vertebrates. The first recognizable vertebrates were jawless fish. Two groups of jawless fish still exist today. hagfish lampreys

Feeding reproduction Reproduction Fasten to the side of a fish Flip their body scrap a hole in the side Suck out the blood & tissues Reproduction reproduction Freshwater lakes and streams Lay eggs in hollows made in gravel Eggs are fertilized externally Worm like larvae hatch and burrow into the gravel They remain there for 3 years

Hagfish Bottom dwellers Cold ocean waters 5 – 15 pairs of gills Mucus-secreting glands all over their bodies Sometimes called slime eels Poorly developed eyesight Slit-like toothed mouths Scavengers Hermaphrodites Produce sperm one year and eggs the next Internal fertilization Young hatch and look like the adult

Only two groups of jawed fish still exist. Cartilaginous fish and bony fish are still in existence.

Jaws evolved from gill supports. Jaws developed from gill arches located around the pharynx. cranium mouth gill arches Jaws gave vertebrates a huge advantage as predators.

Class Chondrichthyes Cartilaginous fish have skeletons made of cartilage orders Holocephali include ratfish, a small group of deep-sea fish. Elasmobranchs include sharks, rays, and skates. Rat fish

characteristics There are 300 species of cartilaginous fish Jaws lined with rows of teeth that are constantly replaced Skin is covered with small pointed teeth – placoid scales 5 – 7 pairs of gills Two chambered heart Separate sexes Fertilization is internal Marine Carnivorous Detect prey with lateral lines system

Sharks Liver controls their buoyancy Dermal denticles teeth like scales allow them to taste with their skin Ampulae of Lorenzini in their jaws allow them to sense electrical impulses They are all muscles and skin and can’t take much abuse

Skates/Rays More than 200 species have been described, in 27 genera slow growth rates and, since they mature late, low reproductive rates Among the best know rays are stingrays, which have long, slim, whiplike tails armed with serrated, venomous spines. A stingray lashes its tail only as a defensive measure when it is caught, stepped on, or otherwise disturbed.

Skates/Rays Have gills on their ventral side use spiracles to breath on top of their head primarily feed on mollusks, crustaceans, worms, and occasionally smaller fishes. Some rays crush their prey between their blunt teeth, sometimes referred to as bony plates Often completely burying themselves in the sand or soft sediment camouflaged by a grayish-brown, often mottled coloration

The major difference between rays and skates is in their reproductive strategies. Rays are live bearing (viviparous) while skates are egg laying (oviparous), releasing their eggs in hard rectangular cases sometimes called "mermaid´s purses". Also, skates typically have a prominent dorsal fin while the dorsal fin is absent or greatly reduced in rays.

Most rays are kite-shaped with whip-like tails possessing one or two stinging spines while skates have fleshier tails and lack spines. Rays protect themselves with these stinging spines or barbs while skates rely on thorny projections on their backs and tails to for protection from predators. rays are generally much larger than skates.