honors biology module 16

Honors BiologyModule 16

Reptiles

April 17, 2014

Our last day of Class

Thursday, May 8, 2014

Quiz 27

Label the parts of the flower

I.

Parts of the Flower

A. StigmaB. AntherC. PetalD. SepalE. OvaryF. ReceptacleG. OvulesH. FilamentI. Style

Class Reptilia

Turtles, snakes, lizards, alligators and crocodiles. Biologists also put dinosaurs in this class. See figure 16.2, page 498.

Members of class Reptilia have several characteristics in common:

1. Covered with tough, dry scales

2. Ectothermic

3. Breathe with lungs throughout their lives

4. Three-chambered heart with a ventricle that is partially divided

5. Produce amniotic eggs covered with a leathery shell, most oviparous, some ovoviviparous.

These characteristics serve

To distinguish reptiles from other creatures in creation, so they are worth discussing.

1. Reptiles are covered with scales that are tough, rough, and dry.

Are snakes slimy? Many people think so. A snake’s skin feels cool, dry and leathery. This is due to its scales to prevent water loss.

Many reptiles live where in regions where water is scarce. It is important that they do not lose water through evaporation.

The scales make sure this does not happen.

Reptiles are ectothermic

This means that they have no internal mechanisms to keep themselves warm.

This is why reptiles like to lie on warm rocks and sun themselves.

Scales are not living tissue, so they do not grow with the creature. Like arthropods, reptiles must periodically shed their old skin (molt) in order to continue to grow.

A reptile always has to have its scales, so new larger set of scales begins growing before the old scales are shed.

Reptiles breathe with lungs

A reptile’s lungs are very efficient and have more capacity than the lungs of a similarly sized amphibian.

Reptiles have a 3 chambered heart

With a ventricle that is partially divided.

Reptiles produce amniotic eggs

Aminiotic egg is a shelled, water-retaining egg that allows reptiles, bird, and certain mammals embryos to develop on land.

Fish and amphibians lay their eggs underwater…

These eggs are jelly like, with only a thin membrane covering them. That’s ok because they are covered in water.

If Reptile eggs were like that and laid on the ground they would dry out right away. The amniotic fluid prevents the egg from drying out. (see figure 16.1)

Reptile Reproduction

Fertilization occurs inside the female. Once this happens, the developing zygote is encased in a protective shell.

The shell is a remarkable engineered structure which is just porous enough to exchange gases with the environment but not porous enough for water to evaporate out of the embryo, forming a fluid-filled sac in which the embryo floats.

Order Rhynchocephalia: Tuataras

Page 499

Order Suamata: Snakes and Lizards

Differences between Snakes and Lizards:1. Lizards have two pairs of limbs, snakes none;2. Lizards have ears and can hear, snakes are

deaf;3. Lizards have the same type of scales all over

their bodies, while snakes have specialized scales on their bellies for locomotion.

4. Most lizards have eyelids and can therefore close their eyes. Snakes’ eyes are always open because they have no eyelids.

Order Testudines: Turtles and Tortoises

Turtles live in water and Tortoises live on land.

Most members of this order are distinguished by the large shells that they carry on their backs. Most can pull al of their appendages (legs, neck, and head) into the shell and close off the openings with little “trap doors.”

Marine Turtles

While most turtles and tortoises are small, marine turtles like the hawksbill typically reach the weight of 250 pounds.

The giant tortoise is larger than the hawksbill and can weigh up to 500 pounds.

The leatherback sea turtle can weigh up to 1,500 pounds.

A reptile has no eyelids and is deaf

Is it a lizard or a snake?

Order Crocodilia: Alligators and Crocodiles

How do you tell the difference?

Dinosaurs “Terrible Lizard”

The term dinosaur means terrible lizard, so we can conclude that dinosaurs are considered part of the class Reptilia.

Since we have never seen one, only their fossilized skeleton remains, it is a difficult task to actually classify them.

Fleshy tissue, organs, scales, hair, etc are rarely, if ever fossilized, so our knowledge of dinosaurs is rather limited.

Bill Nye The Science Guy - Reptiles (Full Episode)

http://youtu.be/-IAKz3sDmCY

Reptiles & Amphibians A Documentary Episode 1 Part 1

http://youtu.be/K-I34T3fGdY

Labs

Homework

1. Finish Module 15 reading, OYO and Study Guide.

2. Take the Module 15 Test;3. Next week we will be covering pages 507

– 518.4. Complete OYO question 16.1 – 16.195. Study Guide: define a-d; 2-8.6. Quiz: Difference between Reptiles and

Amphibians