Exploring Vertebrates: Fish and Amphibians
Discover the fascinating world of vertebrates, focusing on key classes such as Fish and Amphibians. Learn about unique characteristics of these chordates, including structures like the notochord and specialized limbs for land and water. Understand the distinctions between bony fish and sharks, their skeletal systems, and adaptations like buoyancy and the lateral line system. Delve into amphibian life cycles, their skin adaptations, and breeding requirements. Explore the evolutionary journey from water to land through remarkable adaptations like amniotic eggs.
Exploring Vertebrates: Fish and Amphibians
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Presentation Transcript
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
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! • 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.
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.
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.