Vertebrates Test Study Guide

Vertebrates

All groups share a backbone.

Jaws

Jawless fish branched off early; jawed vertebrates evolved later.

Bones vs. Cartilage

Chondrichthyes have cartilage, whereas bony fish and beyond have true bones.

Limbs

Tetrapods evolved limbs with digits.

Amniotic Egg

Amniotes evolved an egg adapted for land reproduction.

Endothermy (warmblooded)

Evolved separately in mammals and birds (a subset of reptiles).

Jawless Fish (Agnatha)

No jaw.

Cartilaginous Fish (Chondrichthyes)

Have a skeleton made of cartilage.

Bony Fish (Osteichthyes)

Have a skeleton made of bone.

Amniotic Membrane (Amnion)

A fluid-filled sac that surrounds and protects the embryo in amniotes.

Pouch (Marsupium)

An external skin fold or sac in marsupials where underdeveloped newborns continue to grow and nurse.

Placenta

A temporary organ that forms in the uterus during pregnancy in placental mammals.

r-selection (r-strategy)

Traits include many offspring, low parental care, short life span, early maturity, and high reproductive rate.

K-selection (K-strategy)

Traits include few offspring, high parental care, long life span, slower development, and higher survival rate per offspring.

Parthenogenesis

A type of asexual reproduction where an organism produces offspring without fertilization by a male.

Obligate Parthenogenesis

Species only reproduce this way.

Facultative Parthenogenesis

Species can switch between sexual and asexual reproduction.

Swim Bladder

An organ present in bony fish that helps maintain buoyancy.

Gills Covered

Bony fish have gills covered by an operculum.

Paired Fins

Bony and cartilaginous fish have paired fins, while jawless fish do not.

Examples of r-selected species

Insects, frogs, fish, bacteria.

Examples of K-selected species

Elephants, humans, whales, bears.

Egg

Gel-like, no shell

Larva

Gills, tail, no legs

Metamorphosis

Legs develop, lungs form, tail reduces

Adult

Lungs, legs, dry skin

Neoteny

Gills retained, stays in larval form

Upright posture

Legs under body, not sprawling

Hip structure

Saurischian vs Ornithischian pelvis

Skull openings (fenestrae)

Large openings to reduce skull weight

Teeth

Varied by diet: serrated (carnivores), flat (herbivores)

Digitigrade stance

Walking on toes

Growth/metabolism

Rapid growth, possibly warm-blooded

Reproduction

Egg-laying, some parental care

Feathers

Present in many theropods

Respiratory system

Air sacs + lungs

Digestive system

Beak + crop

Hunting strategy

Solitary stalking and ambush

Social structure

Solitary

Placental mammals

Live birth, long gestation

Marsupial mammals

Live birth, short gestation + pouch

Monotreme mammals

Egg laying

Ruminant digestion

Microbial fermentation