Bio 3 exam 3

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Urodela

Salamanders

Amphibians with tails

Anura

Frogs and toads

Amphibians without tails

Apoda

Caecilians

Amphibians without legs

Amphibians

Aquatic larva/terrestrial adult

• Metamorphosis

• Paedomorphosis

external

Amphibian fertilization is typically _____, with eggs deposited in water or other moist environments

Amniotes

Tetrapods with a terrestrially adapted egg

• Includes reptiles and mammals

Amnion

encloses a compartment of fluid that bathes the embryo and acts like a hydraulic shock absorber

Chorion

exchanges gases between embryo and air. O2 and CO2 diffuse freely though the egg shell

Allantois

In the chorion, acts as a disposal sac for certain metabolic wastes

Yolk sac

Contains a nutrient rich liquid that is used by the embryo for energetic needs. Has blood vessels that deliver nutrients to the embryo

resistant to desiccation

Amniotic egg was a major advancement in the evolution of vertebrates because it is _______ _ ________.

Sarcopterygii (lobed-finned fishes)

Includes coelacanth, lungfish, tetrapod lineages

• Thick muscles of pectoral and pelvic fins surround rod-shaped bones

Lungfishes (Dipnoi)

Sarcopterygii with a true lung

• Can estivate for several months during the dry season

Tetrapods

Gnathostomes that have limbs

Tetrapod adaptations

• Four limbs and feet with digits

• A neck

• Ribs

• Absence of gills

• Ears/sensory organs for air

Tiktaalik

‘Fishapod’ that had:

• Fins, gills, lungs, scales

• A neck and rubs

• Fins with the bone pattern of a tetrapod limb

Osteichthyes (bony fishes)

Fishes with a mostly bony skeleton

• Gills covered by operculum

• Technically includes tetrapods

Actinopterygii (ray-finned fishes)

Fishes with flexible rays to support their fins

• Operculum flap over gills

• Swim bladder

• Lateral line pits

Gnathostomes

Jawed vertebrates

• Mineralized hinged jaws and teeth

• Evolved from pharyngeal slit skeletal supports

Condricthyes (sharks)

Bony skeleton replaced with flexible cartilage

• no swim bladder (fatty livers aid with buoyancy)

• exposed gill slits

• well developed sensory organs

Oviparous

eggs hatch outside mother

Ovoviviparous

Embryo fed by yolk in uterus

Viviparous

Embryo fed by placenta in uterus

Osmoconformers

Animals that maintain a similar osmolarity to their environment

• Cnidaria

• Hagfish

Osmoregulators

Animals that maintain a blood salinity different from their environment

• Terrestrial/freshwater animals

• Bony fish

• Lamprey

Ionoregulators

Animals that regulate the types of ions they put in their blood different from seawater

• Elasmobranch (sharks)

• Bivalves