LIFE 103- Vertebrates

Chordate Subphyla

urochordata (tunicates), cephalochordata (lancelets), vertebrata (fish, amphibians, mammals, etc)

Tunicates

• see squirts

• only kept trait is slits

• all 4 characteristics as larvae, lost with age

• salps (free floating, colonial)

Separation from other chordates

• vertebral column replaces notochord

• endoskeleton to provide support and muscle attachment points

• head w/ skull

Fish

• vertebral column w/ skull

• jaws and paired appendages

• internal gills

• single-loop blood circulation

• nutritional deficiencies- certain amino acids

Jawless Fish

hagfish and lampreys

Hagfish

• predators and scavengers that emit slime when bothered

• cartilage but no paired appendages

• jaws evolved from anterior gill arches

Lampreys

• Parasites that suck on fish flesh or blood

• cartilage but no paired appendages

• jaws evolved from anterior gill arches

Chondrichthyes

• skin made of cartilage and calcium carbonate granules

• became dominant predators during carboniferous period

• sharks, skates, rays

• teeth not embedded in jaw, easily lost/replaced

• lateral line system to detect water movement/pressure

Bony Fishes

• evolved around same time as chondrichthyes

• bony skeleton instead of cartilage

Ray-finned fish

fins have rigid struts (prototype fish)

Lobe-finned fish

muscular tail, thought were extinct, but 2 species still exist

Lungfish

developed lungs, paired appendages to help move

Swim bladders

regulate buoyancy, fish gulp air to fill bladder, air is secreted to/from blood

Operculum

flap that allows most bony fishes to move water over the gills while stationary

Amphibians

• first vertebrates to walk on land

• main features include legs, lungs and cutaneous respiration, pulmonary veins, 3 chamber heart

• deuterostomes

Atrium

blood goes into the heart

ventricle

blood exits the heart

Anura

• frogs and toads

• no tails; modified for jumping

• some produce interesting defense compounds

• lay eggs; external fertilization

• tadpole form- gradual metamorphosis

Caudata

• salamanders

• lay eggs near H2O

• aquatic larvae, terrestrial adult

• most have lungs

• predators, but developmentally flexible

Apoda

• aka caecilians

• tropical, burrowing

• legless w/ tiny eyes and jaws w/ teeth

• internal fertilization

Amniotes

• waterproof amniotic egg

• dry skin

• thoracic breathing (expands ribcage for air intake)

• endothermic

Amniotic Egg

4 membranes, outer later is H2O proof; internal fertilization

Synapsid

1 hole behind eyes; mammals

diapsid

2 holes behind eyes; reptiles and birds

anapsid

no holes behind eyes; turtles

Reptiles

• ectothermic

• double-loop circulation, 3 chamber heart w/ septum

Chelonia

• turtles and tortoises

• shell attached to skeleton

• turtles are mostly aquatic predators

• tortoises are terrestrial herbivores

• teethless

Squamata

lizards and snakes

Rhynchocephalia

tuartaras

Crocodilians

• complete 4 chamber heart

• nocturnal

• tropical and subtropical

• ambushes predators; eyes and nostrils high on head

• 2 species of gators

Aves

• most diverse terrestrial vertebrate

• amniotic egg and scales on legs

• feathers evolved for insulation

• no urinary bladder

• thin, hollow bones

• efficient respiration and circulation

Mammals

• endothermic

• hair and milk

• efficient respiratory and circulatory systems

• 4 chamber heart and diaphragm for respiration

• derived milk, hair, differentiated teeth

• not complete amniotic egg

Monotremes

• egg laying mammals

• 5 species total

• shelled egg and cloaca (opening for waste)

• lack well-developed nipples

Marsupials

babies in pouches; differentiated nipples for different life stages in pouch

Placental Mammals

babies in placenta

Marsupial and Placental characteristics

• nipples, live birth, placenta all derived

• longer development in uterus

Primates

• binocular vision and grasping hands

• arboreal insectivore ancestor

• lemurs, lorises, tarsiers

Anthropoids

monkeys, apes, humans

hominids

apes and humans