Day 18 Reptiles
Class Reptilia
Reptile Characteristics
-All reptiles have lungs and are born with lungs
-Are ectothermic (cold blooded)
-Reptiles have amniotic eggs
-The evolution of the land egg led to reptiles and eventually dinosaurs taking over the land
-All reptile eggs need to be laid on land
Some reptiles have a defined parietal eye. The parietal eye is a scale on top of their head that is used to sense sunlight. It helps with the hormones involved in thermoregulation. It is attached to the pineal Gland.
Even some amphibians and fish have parietal eyes.
Watch this video on the class Reptilia. Create a box in your sketchbook, title it "The Class Reptilia" and take notes, write down interesting things that you learn from the video and include an image in your sketchbook. Make sure you understand the characteristics of Reptiles and can tell the differences between their orders.
Orders of the Class Reptilia
Order Testudines (300 species)
-The turtles and tortoises
-Teeth absent in adults and replaced by a horny beak
-Short broad body
-Shell consisting of a dorsal carapace
-Tortoises are terrestrial
-Turtles are aquatic
Tortoise
Turtle
This is an optional video
This is an optional video
Order Crocodylia (21 Species)
-The crocodiles, alligators, caimans, gavials (gharials)
-Tongue not protrusible
-Complete ventricular septum
Crocodile and Alligators
Gharial
Order Sphenodontida
-The Tuataras
-Well developed parietal eye
-Lizard like
-Are different than other reptiles because of their teeth
-There are two rows of teeth on the top and one row on the bottom
-This creates a sawing action as they bite
-Only two species in New Zealand
Order Squamata
-Snakes and Lizards
-Characterized by skull and jaw
Suborder Sauria (Lizards, 4,500 species)
There are two venomous lizards with venom glands
The Gila Monster
The Beaded Lizard
The Komodo Dragons do have venom in their saliva
Monitors are a group of large lizards that use their tongue to sense their environment like a nose
Geckos are soft bodied lizards
-Most can climb walls
-There are two groups
-With eyelids
-Without eyelids
Iguanas are herbivorous lizards
Skinks are short legged lizards that have long tails. They have no pronounced neck which makes them look like a transition between snakes and lizards. There are even some skinks that are legless.
California Blue Tail Skink
California Alligator Lizard
This is an optional and interesting video on how lizards breath
Here is a great link if you want to identify any California lizards you might have seen
This is an optional and very interesting video
If you are interested in Chameleons or how they change color, this is a great optional video
Sub order Serpentes (Snakes, 2,900 species)
Pythons
-usually large
-Constrictors
-Have heat vents along their mouth
Boas
-Also large constrictors but have no heat vents
Some California snakes
King Snake
Gopher Snake
Rattle Snake
This is an interesting and optional video on how snakes drink
The following information does not have to be in your notes. We are going to talk about the evolution of reptiles and their transition into dinosaur, mammals, and Birds.
Phylogeny of Reptiles and Dinosaurs
Phylogeny is the study of acquired characteristics. These characteristics help determine evolutionary history. Animals can be placed in groups called Clades based on their acquired characteristics.
Phylogenetic Tree for zoology
Phylogenetic tree for Reptiles
In the tree above, the Therapsids are a group of reptiles that evolved to have fur. This group would eventually lead to the order of mammals.
Phylogenetic Tree of Amniotes
Dinosaurs and modern reptiles evolved from a group of animals known as the diapsids. The diapsids have two holes in their skull behind each eye socket.
Mammals evolved from a group known as the synapsids. The synapsids only have one hole in their skull behind each eye socket.
Early reptilian synapsid (this is not a dinosaur)
Later the synapsids evolved fur between their scales. The mutation of fur helped with thermoregulation.
The saurischians evolved feathers. The mutation of feathers, like fur helped with thermoregulation. Later, feathers had an advantage for flight. The surviving saurischians became modern day birds.
