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The
Diversity of The World of Life
Vertebrates
(Vertebrata)
Turtles, Tortoises, Terrapins, etc.
(Anapsida)
Representatives
(Extinct)
Cotylosaurs
Turtles,
Tortoises, etc.
Biology
See
also Higher Reptiles, with
which turtles have been traditionally grouped.
ENVIRONMENTS
Turtles are marine, freshwater, or terrestrial species
(Terrestrial turtles are typically called tortoises).
DESCRIPTION
Turtles are covered by a protective shell, composed of bony
plates (derived from the skin and fused to the skeleton) lying under horny
scales. The top section of the shell is the "carapace";
the bottom section, the "plastron". The head and neck as
well as the legs and tail can typically be safely withdrawn
into the shell.
Turtles have a horny beak but no bony teeth.
Prehistoric
cotylosaurs had a skull similar to that of turtles (that is, having holes
in the sides only for the eyes, not for jaw muscles, as in higher
reptiles).
Tortoises
typically have stout, scaly legs and a high, domed carapace.
FEEDING HABITS
Various turtles are scavenging, herbivorous, and/or carnivorous.
MOTION
Sea turtles have legs modified as flippers.
REPRODUCTION
Reptiles reproduce sexually, with the sexes
"separate" (an individual is either male or female).
Terrestrial reptiles were the first vertebrates to
"copulate" (mate with physical contact) -- the sperms of the
male cannot otherwise swim to the eggs of the female.
The typically hard-shelled fertilized eggs of reptiles are
typically laid in terrestrial environments -- the developing
"embryo" within is bathed and cushioned by an "amniotic
sac", fed from a "yolk sac", and "oxygenated" by
an "allantois" membrane.
Vertebrates
(Vertebrata)
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