Zool 110 Lec: Origins of Tetrapods + Amphibians plus some fossils

Sarcoptyergian fishes

tetrapod relatives are _____

Eusthenopteron

a choanate fish, best known form of sarcopterygian fishes

Ichthyostega and Acanthostega

what are the two known early tetrapods

temnospondyls and anthracosaurs

later fossil tetrapods include _____ and _____

not equal

the origin of tetrapods does ____ the origin of terrestriality

1. phenotypes that no longer exist in nature 2. when groups of organisms appeared and diversified 3. transitional features that help us understand evolution

what three things can fossils tell us

taphonomy

all of the things that happen between an organism's death and it being found as a fossil

1. old localities (looking in the literature and going there) 2. new localities (studying geologic maps)

what are the two ways we find fossils

Tiktaalik roseae

new "missing link" found in 2004, has a neck and wrist

99%

what percent of life that has existed on Earth is now extinct

Lissamphibia

modern amphibians, 3 living amphibian groups, form a monophyletic group

1. Order Anura (frogs and toads) 2. Order Urodela (salamanders) 3. Order Gymnophiona (caecilians)

what are the three orders of living amphibians

class amphibia

lissamphibians and fossil forms that aren't amniotes

Characteristics of Class Amphibia

cutaneous respiration, poison glands in skin for protection, reproduction often tied to water because of mesolecithal eggs, heart with two atria and one ventricle

Order Urodela (salamanders)

most generalized, over 600 species, reproduce with spermatophores, have aquatic larvae and semiterrestrial adult

neotenic (paedomorphic)

many species of salamanders are ____ which means they are sexually mature in larval form

direct-developing

salamanders can also be ____ meaning they lay eggs on land in moist places, includes some local plethodontid (lungless) salamanders

Newt life cycle

Order Gymnophiona (Caecilians)

wormlike (burrow and limbless), sensory tentacle in front of rudimentary eye, primitive species with aquation larvae, others direct-developing or live-bearing

to feed on uterine lining or skin of their mother

why do caecilian hatchlings have special teeth

Order Anura (frogs and toads)

found worldwide except artic/antarctic, tail-less as adults, hindlimbs elongated, typically a tadpole larva, well developed sense of hearing, males call (croak) to establish territories and attract females

metamorphosis

through what process do tadpoles become terrestrial juveniles

returns to the water and becomes aquatic

in the newt life cycle, the larva metamorphs to a terrestrial form that eventually does what

they have color vision which is rare in most vertebrates

what makes the eyes of frogs special

the stapes

frogs have a good sense of hearing because of what hearing bone

1. dorsal pouch 2. tadpoles adhere to back 3. dorsal brooding pouches 4. mouth brooding

what are the 4 different parental care types of eggs/larvae of anurans (frogs and toads)

frog life cycle

Amphibian metamorphosis

stimulated by thyroid and affects locomotion and all organ systems

they suction feed like fish

how do salamander larvae feed

they scrape algae with keratinized mouthparts

how do frog larvae feed

carnivorous

are adult salamanders and frogs carnivorous or herbivores

they have projectile tongues that can capture prey at a distance

how do adult frogs feed