DIGESTIVE SYSTEM-BIRD-MAMMAL-REPTILE-COMPARISON

TOPICS LIST

Amphibians - PowerPoint PPT Presentation
Thank you for your feedback. You can use PowerShow. Mouth is terminal, slitlike aperture bounded by horny Jaws. Long-toed Salamander Thurston Road, ponds at W. Previous page Circulatory system. At the end of pyloric stomach a small constriction is present. The tongue of the amphibians is provided with a viscosity that makes it very sticky.

Downloading prezi...

How is the Amphibian Digestive System?

Prior to the evolution of the metanephric kidney, the products of the male gonad , the testis, traveled through the same duct with the nitrogenous wastes from the kidney. But with the appearance of the metanephros , the two systems became separated.

The female reproductive system never shared a common tube with the kidney. Oviducts in all female vertebrates arise as separate tubes with openings usually near, but not connected to, the ovaries.

The oviducts, like the Wolffian ducts of the testes , open to the cloaca. Both ovaries and testes lie in the body cavity near the kidneys. With the evolution of the reptilian egg , internal fertilization became necessary. The males of all modern reptiles, with the exception of tuatara , have functional copulatory organs.

Unlike the penis of turtles and crocodiles, the copulatory organ of lizards and snakes is paired, with each unit being called a hemipenis. The hemipenes of lizards and snakes are elongated tubular structures lying in the tail. Completion of the erection is brought about by blood filling the sinuses in the erectile tissue.

Only one hemipenis is inserted into a female, but which one is a matter of chance. Unlike the penis of mammals, the copulatory organs of reptiles do not transport sperm through a tube. The ducts from the testes, as already mentioned, empty into the cloaca, and the sperm flow along a groove on the surface of the penis or hemipenis. In general construction the eyes of reptiles are like those of other vertebrates.

Accommodation for near vision in all living reptiles except snakes is accomplished by pressure being exerted on the lens by the surrounding muscular ring ciliary body , which thus makes the lens more spherical. In snakes the same end is achieved by the lens being brought forward.

The lens moves as a result of the pressure built up on the vitreous humour by contractions of muscles located at the base of the iris. The pupil shape varies remarkably among living reptiles, from the round opening characteristic of all turtles and many diurnal lizards and snakes to the vertical slit of crocodiles and nocturnal snakes and the horizontal slits of a few tree snakes.

Undoubtedly the most bizarre pupil shape is that of some geckos , in which the pupil contracts to form a series of pinholes, one above the other. The lower eyelid has the greater range of movement in most reptiles. In crocodiles the upper lid is more mobile. Snakes have no movable eyelids, their eyes being covered by a fixed transparent scale.

Visual acuity varies greatly among living reptiles, being poorest in the burrowing lizards and snakes which often have very small eyes and greatest in active diurnal species which usually have large eyes.

Judging by the size of the skull opening in which the eye is situated, similar variation existed among the extinct reptiles. Extinct forms, such as the ichthyosaurs, that hunted active prey had large eyes and presumably excellent vision; many herbivorous types, such as the horned dinosaur Triceratops , had relatively small eyes and weak vision. Colour vision has been demonstrated in few living reptiles. We welcome suggested improvements to any of our articles.

You can make it easier for us to review and, hopefully, publish your contribution by keeping a few points in mind. Your contribution may be further edited by our staff, and its publication is subject to our final approval. Unfortunately, our editorial approach may not be able to accommodate all contributions.

Our editors will review what you've submitted, and if it meets our criteria, we'll add it to the article. Present to your audience. Invited audience members will follow you as you navigate and present People invited to a presentation do not need a Prezi account This link expires 10 minutes after you close the presentation A maximum of 30 users can follow your presentation Learn more about this feature in our knowledge base article.

Please log in to add your comment. See more popular or the latest prezis. Constrain to simple back and forward steps. Copy code to clipboard. Add a personal note: Houston, we have a problem! Send the link below via email or IM Copy.

Present to your audience Start remote presentation. Do you really want to delete this prezi? Neither you, nor the coeditors you shared it with will be able to recover it again. Oregon Habitat forest Life cycle 26 NewtPoisonous!! Defense mechanisms Color Poison glands Posturing Evolutionary arms race with garter snake. Long-toed Salamander Thurston Road, ponds at W.

Whether your application is business, how-to, education, medicine, school, church, sales, marketing, online training or just for fun, PowerShow. And, best of all, most of its cool features are free and easy to use. You can use PowerShow. Or use it to find and download high-quality how-to PowerPoint ppt presentations with illustrated or animated slides that will teach you how to do something new, also for free. Or use it to upload your own PowerPoint slides so you can share them with your teachers, class, students, bosses, employees, customers, potential investors or the world.

That's all free as well! For a small fee you can get the industry's best online privacy or publicly promote your presentations and slide shows with top rankings. But aside from that it's free. We'll even convert your presentations and slide shows into the universal Flash format with all their original multimedia glory, including animation, 2D and 3D transition effects, embedded music or other audio, or even video embedded in slides.

Most of the presentations and slideshows on PowerShow. You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all. There is truly something for everyone! Related More from user. PowerPoint Templates - Are you a PowerPoint presenter looking to impress your audience with professional layouts?

With over 30, presentation design templates to choose from, CrystalGraphics offers more professionally-designed s and templates with stylish backgrounds and designer layouts than anyone else in the world. And their quality is top notch. Chart and Diagram Slides for PowerPoint - Beautifully designed chart and diagram s for PowerPoint with visually stunning graphics and animation effects.

Our new CrystalGraphics Chart and Diagram Slides for PowerPoint is a collection of over impressively designed data-driven chart and editable diagram s guaranteed to impress any audience. They are all artistically enhanced with visually stunning color, shadow and lighting effects.

How Do Amphibians Digest Their Food?