FISH, AMPHIBIANS and REPTILES

The first steps up the vertebrate ladder!
Aquatic vertebrates (fish) and the first to
transition from water to land (amphibians
and reptiles), able to free themselves from
water by developing amniotic eggs.

SALAMANDERS
North America has more species of sala- manders than the rest of the world. Often confused with lizards, salamanders are amphibians not reptiles.2 pgms.44 pictures.
EP #432X SLIDES
$72.50

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SAVE OVER $15.00 ON 2 SLIDE SET BUNDLE ORDER EP #432X........$72.50
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SALAMANDERS Order #432........$42.50

Salamanders are amphibians but differ from frogs and toads in that they
possess tails throughout their lifetimes. The U.S. has more different species of
salamanders than the rest of the world combined. People tend to confuse them with
lizards, even though they are quite different. This program surveys 16 species of these
little known creatures and, in addition, describes and illustrates spermatophore,
salamander eggs and defense postures. 20 slides and guide.

CONTENT SAMPLE: 660 The majority of our salamanders, like the frogs and toads,
must lay their eggs in water. These eggs eventually hatch into gilled larvae, which resemble the
adults in general body form but which breathe by means of gills. This is a larva of a Kentucky
spring salamander (Gyrinophilus porhyriticus duryi). Like adult salamanders, larvae feed on
various smaller creatures which they find in the water. After a period of development which may
last anywhere from a few months to several years, the larvae of most salamanders lose their gills
and take on adult habits and colors.

Spring salamanders of one kind or another are found throughout the northeastern part of
the U.S. They are very sensitive to pollutants, and seem to be most common in the purest
streams and springs and rare or absent in the dirty ones. Spring salamanders are unsatisfactory
as pets; they often die soon after capture, and if they survive they will eat any small amphibians
(including other spring salamanders) which are housed with them. Adults may exceed 8 inches
in length.

REVIEWS: “The slides are very good!” W.D.W., Dept. of Biology, Pomona College.
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SPECIATION: A CASE STUDY Order #SS-0290S ........$44.95

An interesting look at the well-documented speciation of the California
salamander Ensatina eschscholtzi, showing the interplay of heredity and environment.
24 frames and guide. (Filmstrip order SS-0290F ...........$15.00.)

CONTENT SAMPLE: 24. The deciding factor for speciation among Ensatina
eschscholtzi was geographic reproductive isolation. If individuals become geographically isolated
from members of their populations, any mutations occurring in these isolated individuals will
further remove them genetically from the original population. With sufficient divergent evolution,
the groups, if brought into physical contact, may not be able to produce offspring--and if they are
able to reproduce, the offspring may be sterile.

Some other changes that might accomplish this are seasonal incompatibility (different
breeding seasons preclude cross-copulation), behavioral incompatibility (nonmeshing courtship
rituals), gamete incompatibility (sperm and eggs from different groups cannot form a zygote), and
embryo mortality (the zygote cannot develop past a premature stage).
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~0214-29~ Arboreal salamander (Aneides lugubris). photo by John R. MacGregor.

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