BIOL2712 Study Guide - Final Guide: Neoteny, New Zealand, Viviparity
25 Jun 2018
School
Department
Course
Professor
The Herpetofauna – Amphibians &
Reptiles
Outline
Conquest of the land
Primitive amphibians
Key adaptions of amphibians
Why life on land?
Modern amphibians
Evolution of the amniotic egg
Reptile characteristics
Mesozoic – age of reptile
Dinosaurs and pterosaurs
Cretaceous extinctions
Modern retile
Conquest of the Land
Depended on lobe-finned fish adaptions:
oEvolution of jaws
oPaired fins as appendages to the skeleton
oLungs for breathing air
oBony skeleton
Vital preadaptations:
o1. Jaws and fins – predation off the bottom
o2. Lungs – an adaption to Devonian droughts, were a vital precursor to
leaving the water
o3. Bony skeleton can support body out of water
find more resources at oneclass.com
find more resources at oneclass.com
Primitive Amphibians
Oldest tetrapods
Oldest fossils are Devonian
o365 mya
Prominent and variable
oSome 4m long
Carboniferous = “Age of Amphibians”
oMany resemble reptiles
Decline in late Carboniferous and by late Mesozoic – left with mainly modern forms
Differed from lobe-finned fish in limbs
Why Life on Land?
Early amphibians lived alongside lobe-finned fish in Devonian and Carboiferous
freshwater ecosystems
Why did amphibians leave the water?
oTo breathe air? Gain food? Escape predators?
oParadoxically, may have developed limbs to each water not to leave it
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Depended on lobe-finned fish adaptions: evolution of jaws, paired fins as appendages to the skeleton, lungs for breathing air, bony skeleton. Jaws and fins predation off the bottom: 2. Lungs an adaption to devonian droughts, were a vital precursor to leaving the water: 3. Bony skeleton can support body out of water. Oldest fossils are devonian: 365 mya. Carboniferous = age of amphibians : many resemble reptiles. Decline in late carboniferous and by late mesozoic left with mainly modern forms. Early amphibians lived alongside lobe-finned fish in devonian and carboiferous freshwater ecosystems. Escape predators: paradoxically, may have developed limbs to each water not to leave it. Once evolved limbs can exploit new niche: linger around pools and devour stranded fish. Three orders: urodela = tailed ones, salamanders and newts, 400 species, some terrestrial, some aquatic, neoteny is common e. g. axolotl, anura = tail-less ones , frogs and toads, 3500 species, very diverse and widespread, highly adapted c. i.
