Post on 19-Dec-2015
What is a chordate?
•Members of the ANIMAL KINGDOM and the PHYLUM CHORDATA
•They have a dorsal, hollow nerve cord and a notocord
Most chordates are vertebrates (SUBPHYLUM VERTEBRATA)
A few Chordates that are NOT vertebrates include a group know as protochordates. These include: Sea Squirts or Tunicates
What is a vertebrate?
---Animals with a backbone or vertebral column (endoskeleton)----Have spinal cord - dorsal, hollow nerve cord ----Front end of spinal cord develops a brain
Vertebrate Classes
• Jawless Fish (lamprey, hagfish)
• Cartilage Fish (sharks, rays…)
• Bony Fish (salmon, catfish,
goldfish…)
• Amphibians (frogs, salamanders…)
• Reptiles (lizards, turtles…)
• Birds (sparrows, hawks…)
• Mammals (humans, whales, cats..)
Fish Classification
•Kingdom- Animalia•Phylum- Chordata•Sub Phylum- Vertebrata•Classes- Agnatha, Chondrichthyes, Osteichthyes
Fish have a two chambered heart – and single loop circulation:blood is passed over the gills where it picks up oxygen, goes to the body and returns to the heart
Fish Respiration•Water flows over Gills
as fish opens mouth and swims.
•Water flows opposite direction of blood flow.
Fish Respiration•O2 diffuses from the water into the
blood.•Gills are made of thousands of gill
filaments.•Gills are covered by the Operculum.
The Nervous System
- Cerebrum - thinking, voluntary activities- Cerebellum - coordination- Medulla Oblongata - functions of internal organs- Lateral Line System - senses vibrations
Reproduction•Most fish lay eggs that are
fertilized externally - called spawning
•Some fish bear live young
Fish Adaptations• Lateral Line System- used to detect
vibrations, orient the fish in water, it is a line of cells running down the side of the fish.
• Operculum- gill cover, movement of operculum allows more water to be drawn in.
• Swim Bladder- a gas filled sac that helps the fish maintain buoyancy. Sharks don’t have a swim bladder!
• Fins- Dorsal, Caudal, Pectoral, Pelvic, Anal.
Types of Agnathans•Hagfish- Ocean
scavengers, not much is known about them.
•Lamprey- fresh and salt water, they are parasitic and prey on other fish.
* Both have cartilagenous skeletons and sucker-like mouths.
Class Chondrichthyes
• Cartilage skeletons, no bones• No operculum, must keep
moving to breathe.• Have live births.• Special scales feel like
sandpaper.
Sharks and Rays
Types of Chondrichthyes• Sharks
• Sharks are adapted for a predatory lifestyle.
• Cartilage skeletons, no bones stiff pectoral fins (speed).
Types of Chondrichthyes
• Rays
Manta, and Sting Rays- live in shallow water, have mouths located on the underside, are fairly docile, wide flat bodies and wing-like fins that are flexible.
Types of OsteichthyesRay Finned
– Most fish are this type– Fins are supported by bony
structures called Rays.