Download Frog Reproduction

Frog Reproduction
zoology
Objectives
 Explain how male frogs attracts females
of the same species.
 Discuss the reproductive system of a
frog.
 Describe the changes that occur during
metamorphosis.
 Identify two examples of parental care in
frogs.
Courtship
 Each species has a call that is specific to
that species.
 Males call to attract a mate.
 Air is driven back and forth from mouth to
lungs to vibrate vocal cords.
 Females respond only to males of the
same species.
Fertilization
 When female approaches, the male
climbs onto her back.
 He grasps her firmly. This embrace is
called an amplexus.
 The female releases her eggs and the
male deposits his sperm on top of them.
 Direct external fertilization is achieved.
Reproductive System
 Male has two bean shaped testes
located near the kidneys.
 Sperm is passed from the testes in a
tube and exits through the cloacal
opening.
 Female produces eggs in lobed ovaries
near the kidneys. Eggs leave through
the cloaca.
Life Cycle
 Eggs hatch into tadpoles within a few
days of fertilization.
 Tadpoles live off of the yolk of the egg for
a few days until the mouth opens and
gills are grown.
 Metamorphosis begins.
Metamorphosis
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Hatchling tadpoles
Hind legs appear
Front legs appear
Tale disappears
Young Frog grows to adult size.
Controlled by the hormone thyroxine.
Alternative methods
 Lay eggs on land
 Lay eggs in mucus
 Bypass larval stage
Parental Care
 Increase the likelihood that offspring
survive.
 Male often remains with eggs to guard
them.
 Some males hold eggs in their mouth
until they hatch.
 Females gastric brood eggs.