BIO 109 Home
Questions | Answers

1. Fish: gills (with countercurrent gas exchange)
Amphibians: skin, and by gills (when aquatic) or lungs (when in adult form breathing air on land)
Reptiles: well-developed lungs

2. Habitat Loss: groundwater removal lowers water table which dries up streams/springs; dams and diversions change the environment; grazing changes bank structure and water quality.
Introduced Species: In Arizona there are 3X more introduced species than native species, and the introduced species can compete with or prey on the native species.

3. Salamanders, frogs, toads, and spadefoots.

4. Anamniotic Eggs are jelly-like and must be laid in water (in most cases). This means that amphibians have an aquatic larval stage that may be susceptible to predation, drying up, etc.

5. Turtles/tortoises, snakes, lizards.

6. Amniotic Eggs have a shell and must be laid on dry land. This allowed reptiles to be free of an aquatic larval stage and to be the first totally terrestrial vertebrates.

7. Seen most commonly in lizards, this is when the tail can break off to fool a predator. The tail piece then regrows.

8. Oviparous: egg-laying. Embryo develops within an egg (feeding on yolk) laid outside the mother’s body. Mother provides food up front.
Pros: Mother doesn't have to carry around. Easier to lay eggs.
Cons: Can't control egg temperature as easily and susceptible to predation.
: live birth. Embryo develops within an egg (feeding on yolk) kept inside the mother until hatching time. Mother provides food up front.
Pros: Mother can thermoregulate the eggs; eggs probably safer in mother.
Cons: Mother has to carry them.
Viviparous: live birth. Embryo is attached to uterine wall inside mother, feeding from mother throughout gestation. Mother provides food throughout gestation.
Pros: Mother can thermoregulate the embryo/fetus; probably safer in mother; allows for longer gestation period.
Cons: Mother has to carry them; embryo/fetus takes nutrition from mother during whole time which can cause problems for mother; birth process may be difficult.

9. Asexual reproduction: producing offspring by cloning instead of sexual reproduction.

10. Parthenogenesis

  • Advantages:
    • Population potentially reproduces twice as fast (because every member is a female).
    • Keep successful gene combination of mother.
    • No time, energy, and risk associated with mating.
  • Disadvantages:
    • Less adaptable due to less genetic variability.
    • No two-parent care.

11. Geographic Range: everywhere the species occurs.
Home Range: everywhere an individual goes.
Territory: everywhere an individual defends. Lizard "pushups" often are to establish territories.