Vertebrates!Fish & Amphibians!

Created by: Andrew Alyssa Robin

Chordates

• All Chordates have:– A notochord– a hollow dorsal nerve cord– Pharyngeal Slits– Post-Anal Tail

Chordata

• Unlike echinoderms, the class Agnatha: – Hagfish and other chordate have bilateral body

symmetry.– Skeletons are NOT made of calcite, but cartilage.– They have evolved from craniates

This is a hagfish. Be scared.

Word of the Day

• Paedogenesis- the act of reproduction by an organism that has not achieved physical maturity.– http://en.wikipedia.org/wiki/Paedogenesis

Chondrichthyes: Bony Fishes!

• Jawed fishies obtained jaws when the two skeletal supporting rods in their gills modified to open and close their mouth

• This eventually strengthened to form jaws to capture food.

Sharks V. Bony Fish

• Bony Fish:

– Their skeleton is of bone, go figure. – Their upper jaw is attacthed to their skull.– It gets better, they sometimes have this 2nd set of jaws called

a pharyngeal. Don’t ask me.

• Sharks:– Shark’s skeletons are formed from cartilage, like your ear!– Shark’s have an upper jaw which is NOT attached to their

skull.

Chondrichthyes: Sharkies!

Chondrichthyes: Sharkies!

• To adapt to sea life, a shark has:– Gills• To extract the 02 from the H20

– Fins • dorsal, caudal, anal, pelvic, and pectoral. The latter two

of which are paired.

– Tail• Provides forward thrust, whereas fins direct water flow.

Buoyancy

• Sharks use a large liver filled with oil to stay buoyant.

• Sharks skeletal system is made of cartilage which is half as dense as bone.

• Whereas, bone fish use gas-filled bladders as their buoyancy system.

Lateral Line System

• Primary purpose of the LLS– Detection of vibrations cause by other organisms’

movement.– Can be use by ie., a shark to detect a wounded

fish.

Shark’s Skin!

• Layers of Flexible collagenous fibers called dermal denticles. – Acts like an outer skeleton– Reduces drag from water

• Bony Fishes use bony scales for skin– Layered with mucus to protect from infections and

reduce drag.

Amphibian(s)

Amphibia

• The Bare Facts of Amphibia:– THREE-Chamber heart

– Cold Blooded

– Derive Heat From Sunlight

– Produce Larvae

Amphibia v. Land

• To deal with the enviroment of land, amphibians developed:– Legs: Not only for swimming, but support them on

land.– Gills replaced with lungs– Skin excretes mucus to stay moist.

Breeding

• For amphibians to breed, they must return to water

• For those who don’t they need at least need a moist environment

• This is because the egg is jelly-like, without moisture the egg will dry out.

Amniote Examples

Vertebrata

• ALL VERTEBRATE HAVE:– A stiff rod running through the length of the

animal with a hollow tube of nervous tissue above it and the gastrointestinal tract below.

• Tetrapods were essentially the first land bound creatures, developing four (tetra) legs (pods).

More Evolution etc.

• Amniotic eggs are the next step in evolution, where eggs good be laid on land (ie., turtles)

• The Amniotes are the organisms that breed amniotic eggs.– In Humans, the amniotic sac is layers of a amniotic

membrane– The earliest amniotes were lizard like creatures

who laid their brood on land and returned to the sea.