Tetrapods and Amphibians

Tetrapoda

Have 4 feet & are all non fish vertebrates

Ex: Amphibians, mammals, birds & reptiles

Where did Tetrapods evolve from?

Sacropterygii (lobed-finned fish)

Name the two major living groups of tetrapods.

Amniota

Lissamphibians

Amniota

Tetrapods consisting of reptiles, birds, & mammals that developed with an amniotic egg that has a shell and internal membranes

Lissamphibians

Tetrapods consisting of all amphibians who developed with an anamniotic egg with a jelly-like coating and lack of shell and internal membranes

What 2 qualities did tetrapod’s ancestors have before tetrapods evolved?

Nares

Air-filled Cavity

Nares

Nostriles

Air-filled Cavity

Swim Bladder that evolved into lungs

What 2 characteristics did tetrapods evolve with?

Limbs

Double Circulation (Bidirectional & Unidirectional Flow)

Double Circulation

Bidirectional Flow: blood flowing to the heart & lungs two ways

Unidirectional Flow: blood flowing to the heart & lungs one way

Limbs

Support the body

How long ago did the first fully terristerial animals evolve?

315 million years ago

How long did it take tetrapods to move to land from water?

80 million years

Amphibians

First tetrapod to evolve

Amphibia

Class amphibians belong to

What do most amphibians do?

Undergo metamorphosis where they start in water & move to land as adults

Ectothermics

Use the outside environment to regulate their body temperature

Ex: All amphibians

What kind of heart do amphibians have?

3 chambered

Name the 3 chambers of amphibians hearts

Left & Right Atrium

Ventricle

Left & Right Atrium

Receives blood

Ventricle

Pumps blood mixing both oxygenated and deoxygenated together

All amphibians are __________ as adults.

Carnivores

Where do and don’t amphibians live and why?

Amphibians live in all continents except Antarctica because it’s too cold for them to thermoregulate

How many orders of Amphibians are there?

3 orders

Name the 3 orders of Amphibians.

Gymnophiona

Urodela

Anura

Gymnophiona

214 species of worm-like caecilians that burrow, lay eggs in moist environments, sometimes metamorphose, provide parental care, and whose mothers secrete a milk-like substance through their pores to feed their babies.

Why aren’t Gymnophiona worms?

Unlike worms they have bones

Basal Caecillians

Earliest Gymnophiona who undergo metamorphosis

Urodela

771 species of salamanders and newts that lay jelly-like eggs in water, breathe through gills as larvae, sometimes reproduce in water, and may or may not have legs.

Spermatophores

Internal fertilization where male Salamanders release sperm packets for females to suck up using their Cloaca

Cloaca

One hole for pee, poop, & sex seen in Salamanders

How do gills in Urodela work?

Use diffusion to breathe in oxygen and release carbon dioxide

Describe the lifecycle of Urodela’s.

Most transition between aquatic and terrestrial environments

Which taxonomic ranks are we studying in class?

Domain: Eukarya

Kingdom: Animalia

Phylum: Chordata

Class: Amphibia

How do Urodela specifically Salamanders breathe?

Their gills as larvae and cutaneous breathing & lungs as adults

Cutaneous Breathing

Form of diffusion where amphibians breathe through their thin skin

Why are Salamander more susceptible to pollutants?

Their skin is very thin

Paedomorphosis

Retention of juvenile traits as an adult

Ex: Axolotl remaining in their juvenile form keeping their external gills and finned tails as mature adults

Amphiumas

Salamanders with reduced limbs

Which vertebrate regenerates the fastest? Why is regeneration rare in vertebrates?

Salamanders quickly regenerate the most body parts which is rare in vertebrates because they have to regrow bones.

Anura

Consist of frogs & toads, lack tails, and undergo metamorphosis

Describe the vertebrates in the order Anura.

Toads: lack teeth, have short legs, & thicker skin requiring less water

Frogs: have teeth, vary in size, tadpoles can be herbivores and carnivores, & have thinner skin requiring more water

Urostyle

Fused vertebrae in Anura that allows for shock absorption when hopping

Name and describe the 2 fused limb bones in Anura.

The tbiofibula & radioulna prevent bones from breaking when jumping

Amplexus

Form of external fertilization where a male gets on a female’s back embracing her to align their reproductive tracts releasing his sperm as she releases eggs

Plexus

Internal network of nerves & blood vessels in Anura that transmit nerve signals and blood

Describe Anura’s eggs.

Jelly-like eggs laid in water or wet environments

Why are female Anurans bigger than males?

Females are bigger to carry eggs

Suriname Toad

Females lay eggs on male’s backs for protection & to keep them wet

How do Anura breathe?

Gills as larvae, skin, & lungs

Buccal Breathing

Mouth cavity of Anura increasing & decreasing as they breathe in and out

Chytrid Fungus

A parasitic fungus that covers frogs, causing suffocation and affects most species resulting in it being their main cause of endangerment