2. Anamniotic eggs – no shell, require moisture,
produce larval form – amphibians
Amniotic eggs – have shell and embryonic
membranes, resistant to drying out, protect
embryo, stores wastes, produce adult form -
reptiles
3. •
Reproductive System
Ovaries vs. testes:
Development affected by hormones
Development influenced by temperature
Potential to be male OR female present in most
amphibians
Fat bodies associated with gonads, supplies energy
4. Ovaries
Produce from 1 to thousands of ocytes at a time under
influence of pituitary, squeeze out into peritoneal
cavity.
Testes
Located near kidneys, produce sperm under pituitary
influence
Rudimentary ovary often nearby
5. Female ducts –
Oviduct covers egg with jellylike material
Oviduct and ureter may be united through much of
length
Male ducts
Mesonephric ducts carry both sperm and excretory
wastes
6. Amphibian Urogenital Tract
Mating / fertilization
Embryo development
Parental investment
Sexes of population
Breeding seasons and habitats
7. Amphibian Mating/Fertilization
External fertilization
Sperm fertilizes egg outside of female’s body
Eggs / sperm laid at same time
Amplexus used in anurans
Found in all anurans except tailed frog
Found in primitive salamander families
8. Amphibian Mating/Fertilization
Internal fertilization - Spermatophore = packet
with pedestal and sperm bubble deposited by male,
picked up by female – advanced salamanders
Cloacal kiss = press cloacas together for sperm
transfer – some salamanders
9. Egg laying
Oviparous species
1 to 25,000 laid – species dependent
Laid singly, in clusters, in strands –
species dependent
Laid in a variety of moist environments –
species dependent .
11. Gonads -
Paired, in abdominal cavity
Snakes/legless lizards: one gonad anterior,
one posterior
Snakes/lizards: gonads are sacs with lymph
cavities
Turtles/crocs/tuatara: gonads are solid structures
Fewer Graafian follicles at a time than in amphibians
13. Sexes of Population
Most are bisexual
2. A number of lizard species have parthenogenetic
populations or whole species.
Some parthonogenetic females mate with males of
related species, result is triploid sterile offspring
14. Embryo Development
Most reptiles are oviparous
Eggs larger and more easily hidden in
terrestrial environment so can have
fewer eggs than amphibians
Some lizards and snakes are ovoviviparous
or viviparous
15. Length varies by temperature
1. Sex of offspring dependent on incubation
temperature of clutch in many reptiles.
Pivotal temperature= produces 50% of each
sex
Turtles: males below the PT
Lizards: females below the PT
Crocodilians: two PTs, males in between the
two
17. The three living groups of
mammals vary in their methods of
reproduction
Placental Mammals, like the cat, are viviparous
Viviparity, or birth of live young, has independently evolved
more than one hundred times in vertebrates However,
many vertebrates retain the shelled egg laying method of
giving birth due to the nutrients provided by the shell and
passed to the embyo.
18. Monotremes –
are the most primitive living mammals.
They have retained the reptilian oviparous
method of reproduction and lay shelled
eggs.
19. Marsupials - undergo a distorted
version of viviparity. They give birth to
underdeveloped live young. When the
young are born, they make their own way
to the permanent brood pouch, or
marsupium .Development of the young is
completed in the pouch.