Chapter 41 Reptiles - PowerPoint PPT Presentation

Chapter 41 reptiles
1 / 37

  • Uploaded on
  • Presentation posted in: General

Chapter 41 Reptiles. Section 1 Origin & Evolution of Reptiles. History of Reptiles. Fossils & comparative anatomy suggest that reptiles arose from amphibians Earliest reptiles date 359-299 million years ago Many insects during this time period which served as food. History of Reptiles.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Download Presentation

Chapter 41 Reptiles

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

Chapter 41 reptiles

Chapter 41Reptiles

Section 1

Origin & Evolution of Reptiles

History of reptiles

History of Reptiles

  • Fossils & comparative anatomy suggest that reptiles arose from amphibians

  • Earliest reptiles date 359-299 million years ago

  • Many insects during this time period which served as food

History of reptiles1

History of Reptiles

  • Around 299 to 251 million years ago- reptiles dominant land vertebrates

  • Pangaea- super continent

  • Interior of Pangaea was dry- suitable for reptiles- why?

  • End of Permian Period (299 MYA)- mass extinction

History of reptiles2

History of Reptiles

  • Mesozoic era (251-66 MYA)- Age of the Reptiles

  • Nearly all large vertebrates were reptiles

Evolution of dinosaurs

Evolution of Dinosaurs

  • 235 MYA- dinosaurs- group of extinct reptiles

  • Evolved from thecodonts- extinct group of crocodile-like reptiles

  • Evolution was affected by the break-up of Pangaea

  • Climates changed- some died, some flourished



Triassic dinosaurs

Triassic Dinosaurs

  • 235 MYA- oldest dinosaur fossils- Triassic Period

  • Successful because-

  • 1. legs positioned under body provided support

  • 2. well-adapted to dry conditions

  • 3. Last mass extinction wiped out other animals

Triassic dinosaurs1

Triassic Dinosaurs

  • Evidence suggests asteroid impacts contributed to mass extinction

  • Canada, France, Ukraine, and Minnesota have evidence to support this theory

Jurassic cretaceous dino

Jurassic & Cretaceous Dino

  • Jurassic- golden age of dinosaurs- variety and abundance

  • Sauropods- largest land animals of all time

  • Theropods- powerful legs and short arms (T. Rex)

Dinosaur diversity

Dinosaur Diversity

  • Land dinosaurs

  • Mesozoic reptiles- pterosaurs- evolved the ability to fly

  • Ichthyosaurs & plesiosaurs- lived in the oceans- resembled bottle-nose dolphins

Chapter 41 reptiles



Extinction of dinosaurs

Extinction of Dinosaurs

  • Scientists still have many questions, but they have some ideas and evidence as to why the dinosaurs are extinct

Asteroid impact hypothesis

Asteroid Impact Hypothesis

  • Asteroid impact hypothesis- suggests huge asteroid hit Earth and formed a crater on the Yucatan Peninsula in southern Mexico

Asteroid impact hypothesis1

Asteroid Impact Hypothesis

  • Caused much dust that covered Earth and changed climate

  • Sediments during Cretaceous time- high iridium- very rare metal (abundant in asteroids)

Multiple impact hypothesis

Multiple Impact Hypothesis

  • Proposes multiple asteroids hit Earth

  • Unfavorable environmental conditions because of this event

  • Paleontologist- Gerta Keller- provided evidence to support this hypothesis

Success of reptiles

Success of Reptiles

  • Order Chelonia- turtles & tortoises

  • Order Squamata- lizards & snakes

  • Order Crocodilia- alligators & crocodiles

  • Order Rhynchocephalia- tuataras

  • Found on every continent except Antarctica

Modern reptiles

Modern Reptiles

  • Turtles have changed very little in structure

  • Tuataras- lizard-like reptiles

  • Snakes & lizards- majority of reptiles

  • Crocodiles & alligators changed very little- decedents of thecodonts

Modern reptiles1

Modern Reptiles

  • Crocodiles resemble birds especially by looking at the structure of their heart (four-chambered)

  • Crocodiles take care of young

  • Scientists suggest birds are direct decedents of reptiles

Amniotic egg

Amniotic Egg

  • Amniotic egg- encase embryo in a secure, self-contained aquatic environment

  • More secure than jelly-like amphibian eggs

Amniotic egg1

Amniotic Egg

  • Amnion- thin membrane enclosing the fluid in which the embryo floats

  • Yolk sac- encloses the yolk, fat-rich food supply for developing embryo

  • Allantois- stores nitrogenous wastes produced by embryo

  • Chorion- surrounds all other membranes and protects embryo

Amniotic egg2

Amniotic Egg

  • First occurred in reptiles, but also is found in birds and mammals

  • Strong evidence suggests that reptiles, birds, and mammals evolved from a common ancestor

  • The eggs of some reptiles & nearly all mammals lack shells & embryo develops in mother’s body

Water tight skin

Water-tight skin

  • What type of skin do amphibians have? Why do they have this type?

  • Reptiles have thick, dry, scaly skin that prevents water loss

  • Keratin- same protein that forms your fingernails & hair

  • Lipids & proteins in the skin help make it water-tight

Respiration excretion

Respiration & Excretion

  • All reptiles have lungs for gas exchange

  • All reptiles have bodies adapted to conserve water

  • Tissues for gas exchange located in body- kept moist

  • Reptiles lose small amounts of water in urine (uric acid)



  • Explain the importance of iridium found in sediments from the end of the Cretaceous period.

  • Summarize the two asteroid impact hypotheses.

  • Describe three characteristics that contribute to the success of reptiles on land.

  • Login