vertebrates! fish & amphibians! created by: andrew alyssa robin
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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.
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