Phylum Chordata - Amphibians & Reptiles
Transcript of Phylum Chordata - Amphibians & Reptiles
Phylum Chordata
Superclass VertebrataClass Amphibia
(salamanders, newts, frogs and toads)
Class Amphibia• These were first land vertebrate
• Endoskeleton (the rest being made of cartilage), complete gut, closed circulatory system.
• The skin is almost always moist and is water permeable. It lacks scales, and can be smooth (frogs) or bumpy (toads).
• Wide variety of shapes, sizes and colors, – some of the most poisonous vertebrates are amphibians
(arrow-point frogs).
There are approximately 3000 species in 3 orders:Gymnophiona (caecilians, legless amphibians) 160 spCaudata (salamanders, newts) 300 spAnura (frogs, toads) 2500 sp
Boophis viridis
• Viviparous – some give birth to live young• Oviparous (egg-laying) – some lay eggs
– will lay several hundred small, round eggs covered in a gelatinous mass.
• Eggs laid in water, either a pond or puddle or pool of water in a leaf.
• Some species carry the eggs in their belly, and hatch inside of the mother.
Life cycle
Metamorphosis!!!
• They all have three-chambered hearts
Respiratory System
Juvenile forms - gills, either internal or external, (for breathing underwater).
• Adult form - lungs. • + Water-permeable skin
which allows oxygen to diffuse through it, so they can "breathe" through their skin.
“Lungless” species found in a clear, cold-water stream on the island of Borneo in Indonesia
• There are separate sexes
• Some species can change gender depending on the circumstances.– Due to over farming and
pesticides, researchers are finding fewer males.
• Most vulnerable vertebrates due to reliance on the environment.
Caecilians• Inhabit the wet tropical regions of south
America, Africa and south east Asia.• Lack limbs but possess a retractable
sensory tentacle. • Have a burrowing lifestyle. • The skin of one African species is fat and
nutrient-rich, so the larvae peel this skin off the parent and eat it.
• Oviviparous
Salamanders
• Capable of regenerating lost limbs, as well as other body parts.
• Sticky tongue which adheres to the prey
• Defense– Tail autotomy to escape predators. The
tail will drop off and wriggle around for a little while.
– They can also produce a white milky substance that is poisonous
Texas Blind Salamander
Vestigial Eyes –
Left over, non-functional eyes
Axolotl
Mexican Walking Fish
Newts• Produce toxins in their skin as a
defense mechanism against predators.
• Taricha granulosa, “rough-skinned” newts of western North America are particularly toxic producing more than enough tetrodotoxin to kill an adult human.
• Some Native Americans of the Pacific Northwest used the toxin to poison their enemies.
However, the toxins are only dangerous if ingested.
Frogs
Poison dart frogs
Toads
Bufo Bufo –
the common toad
Phylum Chordata
Superclass Vertebrata
Class Reptilia
Crocodiles, alligators, lizards, snakes, turtles & tortoises
Class Reptilia• Air-breathing, ectothermic (cold-blooded) vertebrates• Having skin covered in scales, adaptation• Lay eggs with shells, adaptation
• Inhabit every continent with the exception of Antarctica. • Reptiles originated around 320-310 million years ago during
the Carboniferous period,
• Three main living orders:– Crocodilia (crocodiles, gavials, caimans, and alligators): 23 species– Squamata (lizards, snakes, and worm lizards): approximately 9,150
species– Testudines (turtles, terrapins and tortoises): over 300 species
• Species that lay eggs with shells.
• “Amniotes” – tetrapods that lay a terrestrially adapted egg.
Crocodilia
crocodiles
alligators
Squamata
http://www.youtube.com/watch?v=PCmqM3YP1-4
Infrared Sensing - Thermoreception
http://www.youtube.com/watch?v=lySW2-eYilg
Testudines
• http://www.youtube.com/watch?v=vfYSg2S5ljs