|Sonoran Spotted Whiptail (Cnemidophorus sonorae)|
DESCRIPTION: L=up to 3.5" (9cm) not including tail which can be longer than the body. Overall dark with 6 white to yellow stripes running down back. Very faint spots appear between stripes. Like all whiptails, has a pointed snout and moves in a jerky fashion. Notice in picture to left how Western Whiptail actually appears more "spotted" than Sonoran Spotted Whiptail.
NATURAL HISTORY: Carnivorous, feeding on arthropods and other lizards. Diurnal. Lays eggs. Parthenogenic (see below).
have sex? To increase genetic variability (offspring get mix of parents'
genes) which confers greater adaptability. To potentially provide two
parents to raise offspring.
the option? Parthenogenesis -- producing
eggs asexually, without sex, through mitosis instead of meiosis. Instead
of putting only half the chromosomes into the egg (and getting the other
half from the sperm), duplicate them all! This results in a clone of the
female (genetically the same except for copying errors). No longer is
time and energy wasted looking for, fighting for, courting, and copulating
with another, you haven't messed with success, and now everyone is producing
offspring so you can recover from heavy mortality due to predation, weather,
Solution. We see both strategies used in nature. During relatively stable times, parthenogenesis works, but sexual reproduction eventually prevails when environmental conditions change. Some species (e.g. aphids) produce both sexually-reproducing and parthenogenic offspring at different times of the year.