![Page 1: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/1.jpg)
26.2 Reptiles
Reptiles are a diverse group.
• Reptiles share several characteristics.– ectotherms– covered with dry scales– reproduce by laying or retaining amniotic eggs– three-chambered heart (most)– cloaca
Evolutionarily, what problem did reptiles have to overcome?
![Page 2: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/2.jpg)
26.2 Reptiles
KEY CONCEPT Reptiles were the first amniotes.
![Page 3: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/3.jpg)
26.2 Reptiles
• Reptiles have two reproductive strategies.– Oviparous reptiles deposit eggs into an external nest.– Viviparous reptiles retain eggs and give birth to live
offspring.
![Page 4: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/4.jpg)
26.2 Reptiles
Reptiles have been evolving for millions of years.
• Over time, amniotes evolved into three different groups. – synapsids– anapsids – diapsids
![Page 5: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/5.jpg)
26.2 Reptiles
• The diversity of ancient reptiles led to the evolution of modern reptiles, birds, and mammals.
![Page 6: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/6.jpg)
26.2 Reptiles
There are four modern groups of reptiles.
• Turtles and tortoises• Lizards, worm lizards and snakes• Crocodilians• tuatara
![Page 7: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/7.jpg)
26.2 Reptiles
There are four modern groups of reptiles.
• Turtles, tortoises, and terrapins are the remaining anapsids.– Unique characteristic: bony shell encases body– 200 species
![Page 8: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/8.jpg)
26.2 Reptiles
The Turtle Shell
• Carapace: top• Plastron: bottom• 59-61 fused bones
connected by bony bridges on the sides and fused to the vertebrate and ribs on the inside
• So successful an adaptation that everything else evolved around it– No running or jumping or
flying turtles!– Opportunistic eaters
• Lures, ambush
![Page 9: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/9.jpg)
26.2 Reptiles
The type of limbs tells a lot about the habitat of a turtle
![Page 10: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/10.jpg)
26.2 Reptiles
• Snakes and lizards are very closelyrelated and share a number of features.– diapsids– shed skin at regular intervals– flexible skull– Jacobson’s organ
brain
tongue
Jacobson’sorgan
![Page 11: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/11.jpg)
26.2 Reptiles
Survival Adaptations
• Freezing• Losing tail• Changing color• Threat displays
Lizards can run but snakes….
![Page 12: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/12.jpg)
26.2 Reptiles
video
![Page 13: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/13.jpg)
26.2 Reptiles
• Instantly recognizable by outer appearance• Large toothy snout• Compressed tail
• Important characteristics are internal!• Heart & brain more
advanced• Crocodilians are more
closely related to birds..
– diapsids– semi-aquatic predators– 23 species
![Page 14: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/14.jpg)
26.2 Reptiles
Adaptations as an aquatic predator?
• Eyes, nostrils and ears high on head in same plane• 3rd eyelid (nictitating membrane)• Nostrils and ears can close when dive• Valve at the back of the mouth closes (glottis) for
catching prey w/o drowning• Muscular compressed tail• Webbed feet• Four chambered heart
![Page 15: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/15.jpg)
26.2 Reptiles
Crocodilian locomotion
• Belly crawl• High walk• Gallop• Swimming• Jumping
![Page 16: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/16.jpg)
26.2 Reptiles
Alligators versus crocodiles?
Alligator
• Rounded snout (u shaped)
• Upper teeth overlap and hide bottom teeth
• Lack modified salivary glands into functional salt glands
• Pressure sensory organs only around jaws
Crocodile
• Pointy V shaped snout• Teeth interlock• Salt glands for living in
brackish and salty water• Pressure sensory organs
on virtually every scale
![Page 17: 26.2 Reptiles Reptiles are a diverse group. Reptiles share several characteristics. –ectotherms –covered with dry scales –reproduce by laying or retaining](https://reader036.vdocuments.mx/reader036/viewer/2022062422/56649ecf5503460f94bdc218/html5/thumbnails/17.jpg)
26.2 Reptiles
Threats to Reptiles (Conservation)
• H• I• P• P• O
Habitat LossIntroduced SpeciesPollutionPopulation (people)Overconsumption of resources
Dilemma
Don’t buy wild caught reptiles for petsDon’t buy products from reptiles – turtle soup, items made from turtle shells, reptile skin boots/beltsAppreciating reptiles