1. BIOL 3300 Vertebrate Zoology: Ectotherms - Herpetology

2. How do amphibians reproduce?
Or Not…

3. How is gender determined?
Bipotential gonads
GSD or ESD?
Heterogametic
Homogametic
XY, XX
ZW, ZZ
XO,
XXY
ZZW
ZWW
Pristimantis crepitans

4. How is gender determined? Atrazine feminized exposed males.
Atrazine feminized exposed males. Cloaca (A–C) and gonads (D–F) for control male (A and D), atrazine-exposed male (B and E), and atrazine-exposed female (C and F) ZZ animals (genetic males). (G) Atrazine-induced female (genetic male, ZZ) copulating with an unexposed male sibling. (H) Same pair as in G, producing eggs. Eggs (H) were viable and produced larvae that survived to metamorphosis and adulthood. Yellow coloration (F) is the result of fixation in Bouin’s solution. Brackets (B and C) indicate protruding cloacal labia. (Scale bar in A applies to A–C; in D applies to D and E.)‏
Hayes T B et al. PNAS 2010;107:
©2010 by National Academy of Sciences

5. What regulates reproductive cycles?
Environmental Stimuli
Brain (hypothalamus)
Reproductive behaviors
GnRH
Gamete production
Pituitary
LH & FSH
Gonads
2nd Sex characters
Androgens & Estrogens

6. What regulates reproductive cycles?
Isthmohyla pseudopuma
Smilisca sila

7. How are eggs fertilized?
What is trying to be accomplished?
Considerations?
Modes of fertilization:

8. How are eggs fertilized?
Modes of fertilization:

9. What is in a frog egg?
Yolk membrane
Yolk (?)
Vitellogenesis
Embryo

10. What modes of reproduction are there?
Reproductive Mode =
Oviparous =
Ovoviviparous =
Viviparous =

11. What modes of reproduction are there?
Caecilians
Exhibit 2 modes of embryonic development
Oviparous (80%)
Viviparous (20%)

12. What modes of reproduction are there?
Urodelans
Exhibit 3 modes of embryonic development
Oviparous (>90%)
Where do they lay their eggs?
Plethodon cinereus
Ambystoma maculatum

13. What modes of reproduction are there?
Urodelans
Ovoviviparous/Viviparousin Salamandridae
Salamandra salamandra
Salamandra atra

14. What modes of reproduction are there?
Anurans
Exhibit 3 modes of embryonic development
Oviparous = most/many
Where do they lay their eggs?

15. What modes of reproduction are there?
Anurans
Exhibit 3 modes of embryonic development
Ovoviviparous/viviparous
Nimbaphrynoides occidentalis
Eleutherodactylus jasperi

16. What variables are important?
Type of parity
Egg size
Clutch size
Clutch shape
Clutch deposition site
Parental care

17. What variables are important?
Pseudotriton ruber
(~80 eggs)
Anaxyrus boreas
(5,000 – 12,000 eggs)

18. What variables are important?
Lithobates catesbianus
(11,000 – 20,000 eggs)
Rana luteiventris
(~600 eggs)

19. What variables are important?
Agalychnis callidryas

20. What variables are important?

21. What variables are important?
Physalaemus pustulosus (Tungara Frog)

22. What modes of reproduction are there?
Parental care…
Pipa pipa

23. What types of larval development are there?
Caecilians
Urodelans
Anurans

24. What happens during metamorphosis?
Caecilians
Urodelans
Anurans

25. What happens during metamorphosis?
Caecilians
Urodelans
Anurans