Download Vertebrates!

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.