BIOL 3300 Vertebrate Zoology: Ectotherms - Herpetology http://www.amphibian.com.au/

How do amphibians reproduce? http://wanderingowloutside.wordpress.com/page/8/ Or Not…

How is gender determined? http://faculty.ksu.edu.sa/tatiah/Pictures%20Library/normal%20male%20karyotyping.jpg Bipotential gonads GSD or ESD? Heterogametic Homogametic XY, XX ZW, ZZ XO, XXY ZZW ZWW Pristimantis crepitans http://www.scielo.br/scielo.php?pid=S1415-47572009000300008&script=sci_arttext

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;107:4612-4617 http://www.savethefrogs.com/actions/pesticides/atrazine/index.html ©2010 by National Academy of Sciences

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

What regulates reproductive cycles? Isthmohyla pseudopuma Smilisca sila

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

How are eggs fertilized? Modes of fertilization:

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

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

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

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

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

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

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

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

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

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

What variables are important? Agalychnis callidryas

What variables are important?

What variables are important? Physalaemus pustulosus (Tungara Frog)

What modes of reproduction are there? Parental care… http://www.youtube.com/watch?v=aCayq56wHSA Pipa pipa

What types of larval development are there? Caecilians Urodelans Anurans

What happens during metamorphosis? Caecilians Urodelans Anurans

What happens during metamorphosis? Caecilians Urodelans Anurans