Day 19 Fish: Agnatha & Chondrichthyes
Fish
Fish is an informal name for three classes of vertebrates
The three classes of fish are
-Agnatha (Jawless Fish)
-Chondrichthyes (Cartilaginous Fish)
-Osteichthyes (Bony Fish)
Class Agnatha
-Have no Jaw
-The Jawless fish are of the most primitive fish living today
-Because they have no jaw they feed by suction
-They have a round mouth with rows of teeth
Hagfish (this is the only agnatha animal you need to know)
-They mostly eat dead or dying fish but some times they will bore into a fish and eat it from the inside out
-Have slime glands
Hag Fish Teeth
Hag Fish Slime
Watch this video on the hagfish. Create a box or separate section in your sketchbook and title it "Hagfish". Write down anything you might find interesting.
Watch this video on hagfish slime.
Class Chondrichthyes
-Cartilaginous fishes
-Includes the sharks, rays, skates, and ratfishes
-Have a cartilage skeleton
-Placoid scales- rough sand paper like skin because placoid scales are similar to teeth.
-The scales point backwards. This means shark skin is smooth one way and rough the other way
-They have Paired lateral fins
Order of Sharks
-Caudal fin- pointing up and down
-Heterocercal- Upper lobe of the tail fin is longer than the lower lobe
-They have two dorsal fins
-Paired pectoral fins
-All sharks have five to seven gill slits
-They can replace teeth that are lost
-Can sense electricity
-Can sense vibrations in the water
Watch this short Johnathan Bird video on Shark Senses. Create a box or separate section in your sketchbook and title it "Shark Electrosensory System". Take notes, write down anything you might find interesting and include a picture.
The worlds largest fish is a whale shark (It is not a whale, it is a type of shark)
-A whale shark can grow up to 50ft. It has no teeth and eats plankton
-Sharks are not very dangerous to humans
-Only about 5 deaths world wide happen because of sharks
-In comparison, almost 500,000 people in the United States a year go to the emergency room because of dog bites
The shark that is the most dangerous to humans is the great white shark. The great white has a very fast metabolism and needs to constantly eat. It is an aggressive eater and will eat what it can.
Male and Female Sharks
Males have claspers on their pelvic fin
Watch this short Johnathan Bird video on how to tell the difference between a male and female shark. Create a box or separate section in your sketchbook and title it "Shark Claspers". Take notes, write down anything you might find interesting and include a picture. Make sure that you can tell the difference between a male and female shark.
Watch this short Johnathan Bird video on shark hearing. Create a box or separate section in your sketchbook and title it "How Sharks Hear". Take notes, write down anything you might find interesting and include a picture.
Watch this short Johnathan Bird video on shark anatomy. Create a box or separate section in your sketchbook and title it "Shark Anatomy". Take notes, write down anything you might find interesting.
Watch and enjoy this Johnathan Bird video.
Watch this SciShow video about 7 weird sharks. Create a box or separate section in your sketchbook and title it "7 Unique Sharks" write down interesting things you learn. Include a picture if you want to.
Watch and enjoy the first 2:50 minutes of this Jonathan Bird shark video. You can continue watching the rest if you like.
Watch and enjoy this Jonathan Bird shark video. Feel free to add some notes to your book about the spiny dogfish shark and add a picture but it is optional.
Watch and enjoy this Jonathan Bird shark video. Feel free to add some notes to your book about the megalodon shark and add a picture but it is optional.
This is an optional but great video on Basking sharks
Watch and enjoy this Jonathan Bird shark video. Feel free to add some notes to your book about the basking shark and add a picture but it is optional.
Enjoy
Order Batoidea (Rays and Skates)
-Rays and skates are dorsally and ventrally flattened
-Rays have live birth
-Skates lay eggs
-Skates have more of a triangle shaped front end
Watch this Jonathan Bird video on Skates and Rays. Create a box in your sketchbook, title it "Skates and Rays" and take notes, write down interesting things that you learn from the video. Write down the differences in skates and rays and include an image in your sketchbook.
Bat Rays
Manta Rays
-Have Cephalic Horns
The saw fish is an interesting type of ray
Skates
Order Ratfish
Optional Jonathan Bird Videos.
Optional Jonathan Bird shark video.
This is an optional video. Watch and enjoy if you are interested.