Fish and Herps Amphibians and Reptiles

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Fish and Herps (Amphibians and Reptiles)
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FISH

• Complete their lifecycle in water
• Respiration by gills (mostly)
• Many desert fish endangered due to
• Habitat Loss (dams, diversions, groundwater
  pumping, grazing, etc.)
• Introduced Species

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AMPHIBIANS

• Have anamniotic eggs, permeable skin, and a
  larval stage
• Anamniotic eggs are jelly like and must be laid
  in water or moist area
• Respiration by skin augmented by gills or lungs
• Amphibians hatch as a larva and metamorphose to
  an adult form.
• Includes salamanders, frogs, toads, spadefoots,
  etc.

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ANAMNIOTIC EGG jelly-like, must stay moist (Fish
Amphibians)
egg membrane
Usually laid in water, and aquatic larva hatches
out
embryo
yolk sac
yolk
AMNIOTIC EGG shell, dry land (Reptiles, Birds,
Mammals)
allantois
amnion
chorion
Laid on land, and mini version of adult hatches
out.
yolk
yolk sac
http//www.umanitoba.ca/faculties/science/zoology/
faculty/horn/z232/overheads/265,10,Slide 10
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REPTILES

• Have scaled skin, amniotic eggs, and no larval
  stage
• Amniotic eggs have a shell and must be laid on
  dry land
• Respiration by well-developed lungs
• Includes turtles, lizards, snakes, crocodiles,
  etc.

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Reptile tail autotomy
Many lizards can break a piece of their tail off
when attacked by a predator. This often allows
the lizard to escape while the predator is
distracted by the wriggling tail. The tail then
grows back, but never looks the same.
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Reptile Birth

• Oviparous egg-laying
• Advantages/disadvantages? See self quiz
• Ovoviviparous live birth after retaining egg
  within body
• Advantages/disadvantages? See self quiz
• Viviparous live birth after fetus develops
  within mother while drawing nutrients from her
  all along

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Rattlesnakes are ovoviviparous
http//www.herpnet.net/Iowa-Herpetology/images/sna
kes/prairie_rattlesnake_babies.jpg
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Reptile Parthenogenesis

• Every member of species is female (e.g., sonoran
  spotted whiptail).

Left to right Little striped New Mexico
(hybrid) Tiger
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Reptile Parthenogenesis

• Reproduce by cloning (without sex young hatch
  from unfertilized eggs)

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Reptile Parthenogenesis

• Advantages
• Population potentially increases twice as fast
  because every member produces offspring
• No time, energy, risk with finding mate
• Dont mess with success (genes worked for mother)

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Reptile Parthenogenesis

• Disadvantages
• Little genetic variability means less
  adaptability
• No two-parent care

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Reptile Territoriality

• Geographical Range everywhere species lives.
• Home Range everywhere individual lives.
• Territory everywhere individual defends.

Click on picture to see him do pushups to
defend territory