Reptiles

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Reptiles

• Chapter 41

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Origin Evolution of Reptiles

• Section 41.1

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History of Reptiles

• 350 million years old
• Reptiles arose from amphibians
• Age of Reptiles Mesozoic era
• Reptile means to crawl
• Herpetology study of reptiles amphibians

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Evolution of Dinosaurs

• Dinosaurs group of extinct reptiles that
  dominated life 235 mya
• Triassic dinosaurs small, carnivorous
• Jurassic dinosaurs large, carnivorous
• Cretaceous dinosaurs large, herbivorous

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Extinction of Dinosaurs

• 66 million years ago
• Asteroid-impact hypothesis huge asteroid hit the
  earth, creating lots of dust that reduced the
  amount of sunlight causing massive climatic
  changes
• Multiple-impact hypothesis multiple asteroid
  impacts

Video
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Real reason
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Success of Reptiles

• Only 4 orders of reptiles survived the mass
  extinction
• Squamata, Chelonia, Crocodilia, Rhynchocephalia
• First totally terrestrial vertebrate

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Amniotic Egg

• Egg that encases the embryo in a secure,
  self-contained aquatic environment

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Draw this picture!
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Parts of the Egg

• Amnion membrane enclosing the fluid where the
  embryo floats
• Yolk sac encloses the yolk (fat-rich food
  supply)
• Allantois stores wastes produced by embryo
• Chorion protects the embryo
• Albumen stores protein water for embryo

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Characteristics of Reptiles

• Section 41.2

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Watertight Skin

• Thick, dry skin with keratin
• protein found in the outer surface cells
• Lipids protein barrier
• Protects from water loss, infections, injuries

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Excretion

• Efficient systems to help conserve water
• Little water loss in urine
• Lungs to breathe out CO2

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Circulatory System

• Composed of two loops
• Pulmonary loop deoxygenated blood from heart to
  lungs, oxygenated blood from lungs to heart
• Systemic loop oxygenated blood to body,
  deoxygenated blood to heart

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Heart Structure Function

• Most have a 3 chambered heart
• 2 atria 1 ventricle (partially divided)
• Crocodiles have a 4 chambered heart
• 2 atria 2 ventricles
• Ventricle divided by septum tissue
• Reptiles can reroute blood flow away from lungs
• Conserves energy
• Raises body temperature quickly

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Crocodile Heart
Septum
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Respiration

• Large, several chambered lungs with small sacs
  called alveoli
• Increases surface area for diffusion
• First vertebrae group to breath by expanding
  contracting their chest
• Air pressure gradient between outside and the
  thoracic cavity

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Nervous System

• Sight is very important thus big eyes
• Hearing is also important though snakes lack a
  tympanum
• Detect ground vibrations via jaw bones
• Jacobsons organ detects odor (smell), on roof
  of mouth
• Heat sensitive pits below eyes of some snakes

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Thermoregulation

• Definition control of body temperature
• Ectotherm warms body by absorbing heat from the
  surroundings
• Fish, reptiles, amphibians
• Endotherm generates heat from within
• Birds, mammals

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Advantages Limitations of Ectothermy

• Advantages
• Slow metabolism
• Less food needed
• Limitations
• Cannot live in cold climates (become dormant in
  winter)
• No sustained exertion

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Reproduction Parental Care

1. Oviparity egg surrounded by tough protective
   shell, no parental care
2. Ovoviviparity eggs stored within female until
   just before hatching, limited parental care
3. Viviparity eggs stored with female and receives
   nutrients from the placenta, most parental care

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Welcome to the world!
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Modern Reptiles

• Section 41.3

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Order Chelonia

• Examples turtles (water dwelling) tortoises
  (land dwelling)
• Body covered by a 2 part shell carapace (dorsal)
  plastron (ventral)
• Vertebrae ribs fused to carapace
• Cannot leave shell!
• Sharp beak with no teeth
• Lay eggs (oviparity)

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Two parts of the shell
Some Ohio turtles on the next few slides..
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Eastern Box Turtle
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Stinkpot Musk Turtle
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Soft-shelled Turtle
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Blandings Turtle
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Spotted Turtle
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Snapping Turtle
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Painted Turtles
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Tasha, Daisy, Bowser in the Maroons house!
Video
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Order Crocodilia

• Examples crocodiles alligators
• Closest relatives to dinosaurs
• All are carnivores
• Eat turtles, fish, etc.

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Order Squamata

• Examples lizards snakes
• Autotomy the ability to detach a body part often
  when a predatory is near
• Snakes swallow prey whole
• Detachable jaw

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Types of Snakes

• Constrictors wrap body around prey and suffocate
  by increasing pressure
• Boas, pythons, anacondas
• Elapsid inject venom through two small, fixed
  fangs in front of mouth
• Cobras, coral snakes
• Vipers inject venom through large, mobile fangs
  in the front of mouth
• Rattlesnakes, copperheads, water moccasins

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Order Rhynchoephalia

• Example tuatara
• Meaning spiny crest
• Only two modern species
• Live in New Zealand

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4 Order Note Cards

• Front Side
• Name of order
• Picture (in color) of animal
• Back Side
• Example organisms
• Where on Earth?/habitat
• Unique characteristics
• Feeding patterns
• Reproductive behavior