Copy of Copy of Vertebrate Zoology

Brachiopoda

Bryozoa

Vertebrate Zoology

Mollusca

Annelida

Odocoileus virginianus

Hominidae

Gibbons

Great Apes

White-tail deer

Poecile atricapillus

Sirenia

Proboscidea

Ardea herodias

Black capped chickadee

Dryocopus pileatus

Great blue heron

Pileated woodpecker

Buteo jamaicensis

Bubo virginanus

Red-tailed Hawk

Great-horned owl

Hirundo rustica

Barn swallow

Passer domesticus

Pelicaniformes

House sparrow

Sphenisciformes

Boobies, herons, pelicans, cormorants, frigate birds

Piciformes

Strigiformes

Accipitriiformes

Passeriformes

Penguins

Hominoidea

Vultures and Hawks

Old World Monkeys

Owls

Songbirds

Toucans, woodpeckers, honeyguides

Cardinalis cardinalis

Northern Cardinal

Flightless

Wing-propelled divers

Well developed Syrinx

Altricial young

Webbed feet

Some - expandable throat pouches

Some - nostrils absent

Altricial young

Splayed, grasping toes

Zygodactyl

Modified hyoid in woodpeckers

Carnivores/Scavengers

Hooked bill

Sharp talons

Keen vision

Altricial young

Larus delawarensis

Gaviiformes

Binocular vision

Asymmetric ears

Facial disks

Hooked bills

Sharp talons

Altricial young

Lack feather barbules

Ringed-bill gull

Cyanocitta cristata

Hyoid and tongue wrap around the head in order to reduce force while hammering a tree trunk.

Blue jay

Branta canadensis

Turus migratorius

Canada goose

American Robin

Larus argentatus

Herring gull

Hyracoidea

Platyrrhini

New World Monkeys

Artiodeactyla

"Water birds"

Charadriiformes

Bonasa umbellus

Ruffed Grouse

Catarrhini

Shorebirds

Zenaida macroura

Mourning dove

Webbed feet

Eat invertebrates or

marine vertebrates

Anseriformes

Ducks, Geese, Swans

Tarsiers

"Land Birds"

Galliformes

Keratinized ridges on bills

Webbed feet

Flat, broad bills

Precocial

Archilochus colubris

Ruby throated hummingbird

Columbiformes

"Fowl" - Chickens, turkeys, pheasants, ect.

Cetacea

Apodiformes

Doves, pigeons, dodo

Swifts and Hummingbirds

Sceloporus undulatus

Most ground dwelling

Precocial

Small heads

Anthropoidea

Fleshy bump at base of bill

Small heads, short necks and legs

Altricial young feed "pigeon milk)

Sickle-shaped wings

Torpor used to conserve energy

Altricial young

Northern Fence lizard

Galloanserae

Stoeria dekayi

Strepsirrhini

Brown snake

Lemurs

Haplorhini

Paleognathae

Neognathae

Most flightless birds - Ostriches, Emus, Kiwi

Loss of keel on sternum

Perissodactyla

Sciurus carolinensis

Chamaeleonidae

Eastern gray squirrel

Horses, tapirs, rhinoceroses

Aves

Chamaeleons

Sylviiagus floridanus

Nerodia sipedon

Ichthyornis

Northern water snake

Eastern cottontail

Primates

Hesperornis

Scincidae

Paleocene - Present

Viperidae

Colubridae

Confusiusornis

Single toe

Feathers

Keratinized bill (beak)

Keeled sternum

Furculum (Fused clavicles)

Fusion of vertebrae to pelvic girdle - synsacum

Fusion of tarsals to tibia - tibiotarsus

Fusion of metatarsals - tasometarsus

Pygostyle

Skinks

Thamnophis sirtalis

Common garter snake

Archaeopteryx

Peromyscus maniculatus

Tongue projection

Prehensile tails

Zygodactylous feet

Ability to change color

Eyes can rotate independently

Castor canadensis

Flat nails with pads on fingers and toes

Opposable thumb / big toe with grasping hands

Forward directed binocular vision

Deer mouse

Beaver

Elongate fusiform body

Rectangular scales

Phrynosomatidae

Dromeosauridae

Crotalus horridus

Timber rattlesnake

Mephitis mephitis

Horned/spiny/fence lizards

Striped skunk

Amphisbaenia

Tyrannosauridae

Eptescicus fuscus

Big brown bat

Serpentes

Iguanidae

Lagomorpha

Rodentia

Rabbits, pikas, hares

Avialae

Compsagnathidae

Myotis lucifugus

Flight & Asymmetric feathers

Procyon lotor

Vulpes vulpes

Little brown bat

Elongate

Mostly limbless

Fossorial

Highly fused skull and reduced eyes

Raccoon

Red fox

Limbless

Increased cranial kinesis

Dermoptera

Maniraptora

Chiroptera

Allosauridae

Bats

Elongate feathers

Ever-growing incisors

Mosasaurs

Varanidae

Mustela frenata

Typically herbivorous

Septa in the colon

Two pairs of upper incisors

Long-tailed weasel

Cetariodactyla

Ceratosauria

Filamentous feathers

Gekkota

Carnivora

Geckos

Glires

Rows of lamellae on feet

No eyelids

Tubulidentata

Scandentia

Macroscelidea

Pholidota

Theropoda

Sauropodomorpha

Ungulata

Hollow bones

Furcula

Reduced digits

Archonta

Anagalida

Anguimorpha

Scincomorpha

Iguania

Ornithischia

"bird-hipped"

Scleroglossa

Use jaws, not tongue, for prey capture

Scaled tongue is used for chemoreception

Insectivora

Saurischia

"Lizard-hipped"

Squamata

Tomistoma

Crocodylus

Rhyncocephalia

Tuatara

Pterosaurs

Hemipenes

Tail autotomy

Hinged quadrate

Loss of lower temporal bar

Xenerthra

Armadillos, sloths, anteaters

Dinosauria

Crocodylidae

Caiman

Alligator

Lepidosauria

Gavlalidae

Xenarthroles

Osteoderms

Phytosauria

Alligatoridae

Didelphis virginiana

Springer et al., Molecular data-based

Virginia opposum

Shed skin as a unit

Scales overlap

Notched tongue

Transverse cloacal slit

Determinate growth

Placentalia

Ornithodira

Crocodylia

Marsupialia

(Becker et al., 2011 & Lyson et al. 2011)

Webbed feet

Laterally compressed tail

Secondary palate (convergent with mammals)

Placenta

Corpus callosum

Crurotarsi

Theria

Multituberculata

Monotremata

Archosauria

Plesiosaurs

Icthyosaurs

Antorbital fenestra

Mandibular fenestra

Serrated teeth

Four chambered heart

Gizzard

Parental Care

Muscular diaphragm

4th trochanter on the femur (muscle attachment)

Trend toward bipedialism

Sauria

Mammalia

Hadrocodium

Morganucodon

Pseudacris crucifer

Spring peeper

Desmognathus fuscus

Dusky Salamander

Petrolacosaurus

Thrinaxodon

Eurycea bislineata

Northern Two-lined Salamander

Bufo americanus

Plethodontidae

Hyla versicolor

Grey tree frog

Ambystoma maculatum

Bufonidae

Hylidae

Dendrobatidae

Spotted Salamander

Toads

Tree frogs

Poison dart frogs

Lack lungs

Nasolabial grooves

Modified hyoid skeleton

Dicamptodontidae

Ambystomatidae

Connect the upper lip to the nostrils, for chemoreception

Mole Salamanders

Notophthalmus viridescens

Allowing tongue projection to capture prey.

Eastern Newt

Toe pads

Costal grooves

Amphiumidae

Largest of terrestrial alamanders

Include Japanese/Chinese giant salamanders

Salamandridae

Congo eels

Newts

Anapsida

Mammaliaformes

Reduced number of digits on some species

Triphasic life cycle

• Gilled larvae
• Terrestrial juveniles - Efts
• Most adults aquatic w/ caudal fins

Warning colors for poison glands

Thick, warty skin

Terrestrial

Lack teeth as adults

Large paratoid glands behind the eyes

Proteidae

Mudpuppies

Rhyacotritonidae

Torrent / Olympic Salamanders

Rana catesbeiana

Dimetrodon

Bullfrog

Secrete toxic, smelly substances

Supratemporal fenestra

Permian

Cynodontia

Entirely aquatic

Paedomorphic

Diapsida

Hyloidea

Infratemporal fenestra

With more sophisticated jaw movements, there is increased stress on skull bones. So, part of the skull are left open to relieve that stress (muscle bulge)

Ranidae

Microhylidae

Pond frogs

Tadpoles lack tooth plates and have closed nostrils until metamorphosis.

Scaphiopodidae

Spadefoot Toads

Ranoidea

Sirenidea

Keratinized digging structure

Cryptobranchidea

Hynobiidae

Neobatrachia

Lack pelvic girdles/hindlimbs

Tiny front limbs

Pipidae

Salamandroidea

Reptilia

Cryptobranchoidea

Acosmanura

Fully aquatic

Lateral lines

No Eyelids

No tongue

Permian

Synapsida

Internal fertilization (exchange of spermatophores)

External fertilization (Plesiomorphy)

Pipanura

Ascaphidae

Leiopelmatidae

Males have "tail" which is a copulatory organ

Vocal sacs in males

Complete absence of free-ribs

Loss of the tail-wagging muscle

Fulcrum system for feeding

Caudata

Retention of extra vertebrae, free ribs and "tail wagging muscle"

Salamanders

Tongue is attached to the anterior part of the jaw, and flips out of the mouth forward with a sticky pad on the end to capture prey.

Ford and Cannatella (1993)

Uric acid as a wasteproduct

Color vision

Temperature dependent sex determination

Anura

Frogs

Lateral line

Sometimes paedomorphic (Adults retain juvenile features)

Retain true tail from ancestor

Caudal vertebrae fused into urostyle

Illia elongated into rods

Fused tibia/fibula and radius/ulna

Elongated femur, tarsals and toes

Robust forelimbs and shoulder girdles, designed to take impact of jumping.

Gymnophiona

Caecilians

Loss of limbs (no digits, limbs or girdles)

Protrusible copulatory organ in males

Protrusible sensory tentacle (Chemoreception)

Reduced eyes, some with covered orbit with skin/bone.

Batrachia

Look segmented like an annelid worm.

These segments are called annuli, which sometimes contain dermal bony scales embedded in the skin.

Amniota

Amphibia

Circulatory / Respiratory Systems

Pulminary Vein

Skin

(Cutaneous respiration)

Right Atrium

Left Atrium

Waterproof skin (keratin)

True Claws

Mobile Ribs - used in ventilation (aspiration pump)

Laryngeal/Tracheal apparatuses

Axis in addition to atlas

Internal fertilization

Amniotic Egg

Glandular skin (sometimes with poison glands) with cutaneous respiration.

Pedicellate teeth

Papilla amphibiorum

Green rods in the retina of the eye

Levator bulbi

Operculum-columella complex (For sound transmission)

Hyomandibular bone has now become the stapes - used for hearing.

Body

Lungs

Ventricle

Conus Arteriosus

Pulminary Artery

Egg can now be laid away from water.

Developing embryo is protected by a shell which also prevents it from drying out.

Yolk is a source of food

Allantois disposes of waste

Temnospondyl hypothesis

Tetrapoda

Acanthostega

Circulatory / Respiratory Systems

Pulminary Vein

(Ahlberg et al. 2005)

Eyelids and Lips

Loss of internal gills

Tongue skeleton (Hyoid) for feeding and buccal pumping

Epaxial muscles used for bending and posture, Hypaxial muscles used for respiration. (Movement of the ribs)

Tear ducts

Muscular tongue supported by a hyoid skeleton

Five digits

Double blood circulation (Pumping out oxygenated blood to body as well as deoxygenated blood to lungs)

Midline interclavice bone (joins the clavicles)

Occipital condyles

"Labyrinthodont" teeth

Broad, fish-like tail with fin rays

8 toes on each foot with no real wrist/ankle

Zygapophyses

Pelvic girdle attached to vertebrae

Well ossified gill bars

Right Atrium

Left Atrium

Body

Lungs

Ventricle

Slight mixing in ventricle, but oxegynated and deoxygenated blood stay in relative channels from flow and pressure.

Ichthyostega

Conus Arteriosus

Pulminary Artery

Vertebral column differentiated into separate regions

Stem-tetrapods

Lamniformes

Goblin, mako, megamouth and great white sharks

Ventastega

Pelvic girdle likely attached to vertebral column

more tetrapod like than Tiktaalik

Mouth and jaw extend behind the eyes

(Gergus and Schuett, 2000)

Tiktaalik

Tetrapodamorpha

Shoulder not connected to head - neck

Ear notch - ear drum

Elpistostege

Esox niger

Squaliformes

Esociformes

Salmoniformes

Dogfish, sleeper, cookie-cutter and bramble sharks

Perca flavescens

Orectolobiformes

Pandenrichthys

Micropterus salmoides

Wobbegons, carpet, nurse, zebra and giant whale sharks

Lepomis gibbosus

Shark Internal Anatomy

Perciformes

Protacanthopterygii

Colon

Nostrils with nasoral grooves and barbels

Small intestine

Eustnenopteron

Liver

Spiral valve located inside

Squatiniformes

Flattened head & humerus

Angel sharks

Stomach

Euteleostei

Ostariophysi

Clupeomorpha

Kidneys

Spleen

Osteolepis

Along the inner wall of the skin

Differentiation of limb bones

Anguilla rostrata

Dorsoventrally flattened

Terminal mouth

Lack anal fins

Osteoglossomorpha

Elopomorpha

Dipnoi

Acipenseriformes

Sturgeon (Acipenseridae) and Paddlefish (Polyodontidae)

Carcharhiniformes

Osteolepiforms

Hammerheads, bonnet heads, bull and leopard sharks

Teleostei

Amia calva

Amiiformes

Diphycercal tail

Palatoquadrate fused to skull (autostyly)

Estivation

Homocercal tail

Mobile premaxilla

Symmetrical: horizontal swimming without use of paired fins

Frees fins for other functions

Eyes with a nictating membrane

Retain ganoid scales (but armor reduced)

No endochondral bone (unique)

No centra (unique)

Strongly heterocercal tail

Extreme jaw protrusion

Allows new feeding specializations

Pristiophoriformes

Heterodontiformes

Saw sharks

Pectoral fins move to dorsal end of body

Pelvic fins move to anterior part of body

Lepisostiformes

Gars

Halecostomi

Choanata

Heavy armor of ganoid scales

Ambush predators

Chondrostei

Single pair of barbels in front of the eyes

Lack anal fins and dorsal fin spines

Crests dorsal to the eyes

Nostrils connected to the mouth by a deep groove.

Cycloid scales

Mobile maxilla

Polypteriformes

Bichirs and reedfish

Neopterygii

Batoidea

Actinistia

Coelacanths

Abbreviated heterocercal tail

Skates, rays, guitar fishes, sawfishes, torpedoes

Three-lobed tail

Heavily ossified (inside and out)

Retain many ancestral actinopterygian features

• Ganoid scales
• Lung
• Heterocercal tail

Dorsal finlets (unique)

Actinopteri

Benthic adaptations

Many durophageous, large ones planktonic

Highly protrusable jaws - suction feeding.

Sarcopterygii

Lung becomes swim bladder

Silurian - Recent

Circulatory / Respiratory System

Holocephali

Ratfish, Rabbitfish, Chimaeras

Conus

Arteriosus

Gills

Actinopterygii

Ray-finned fishes

Ventricle

Muscular lobed fin, with bony central axis

Cosmoid scales

Pulmonary vein and divided atria

Right Atrium

Left Atrium

Lung

Body

Trends

Sinus Venosus

Acanthodii

Pulmonary Vein

Ordovician - Permian

Scales with ganoine

Fins supported by lepidotrichia only

Everted brain

Claeson and Hilger (2011) Molecular Hypothesis

Locomotion:

Reduction of dermal skeleton.

Increasing ossification of vertebral column and internal skeleton.

Heterocercal to homocercal tail

Swim bladder (respiration -> buoyancy)

Feeding

Increased mobility of jaws

Elasmobranchii

Spine with venom gland

Deep water - feed on shrimp, mollusks, sea urchins

Tooth plates that grow throughout life

Male has two pelvic claspers and a cephalic clasper

No stomach

Operculum with single opening

Separate urogenital and anal openings

Two basal elements in fin

Osteichthyes

Ampullae of Lorenzini

Three basal elements in pectoral fin

Covers 4 gill slits

Stout spines anterior to fins

Multiple pairs of ventrolateral fins

Heterocercal tail

Fusiform shape

Operculum

Branchiostegal rays

Tooth whorl

Circulatory / Respiratory System

Gills

Conus

Arteriosus

Lung derived from gut

Adenticulate scales

Lepidotrichia

Endochondral bone

Ventricle

Atrium

Lung

Body

Sinus Venosus

Mixture of Oxygenated and Deoxygenated blood.

Chondrichthyes

Silurian - Recent

Calcified, "tessellated" cartilage may be present.

Teleostomi

Placodermii

Silurian - Devonian

Cartilaginous endoskeleton

Pelvic claspers

Rectal Gland

These claspers are used by the male to grasp the female during intercourse, allowing internal fertilization

Arthrodires have special joint, where jaw opens heads up rather than bottom down.

Cartilaginous jaw supported by muscles inside.

Armored fish with mobile heads and jaws

Global distribution in marine and freshwater

Bony plates attached to jaw margin

Cephalochordata

Anderson and Westneat, 2007

Amphioxus (lancelet)

Example fossils:

• Coccosteus
• Bothriolepis

First known jawed vertebrates

Gnathostomata

Circulatory / Respiratory System

Allow for rapid adjustment of body movements (In response to increasingly active predators)

Both sets of paired fins only in living gnathostomes

Likely acquired step-wise within Ostracodermi

Deoxygenated

Blood

For lens focusing

Ribs within connective tissue between muscle segments: provide anchor point.

• Second hox gene duplication

• Intrinsic eye muscles

• Hypobranchial muscles

• Two olfactory tracks lead to two nostrils

• Myelin sheathes on nerve fibers

Conus Arteriosus

Gills

Movement and balance within a 3D medium.

Rapid adjustment of body movements.

(Suction)

Ventricle

• Jaws

• Paired pectoral/pelvic fins

• Vertebrae with centra and ribs

• Three semicircular canals

• Spiracle

• Conus arteriosus (elastic reservoir) in heart

• Myomeres divided into epacial (dorsal) and hypaxial (ventral) portions

Oxygenated blood

Atrium

From the first gill slit

Sinus Venosus

Body

Deoxygenated

Myxinidae

• Pectoral fin folds with pectoral skeleton

Petromyzontiformes

Hagfish

Lamprey

1 Semicircular Canal

Sedentary creatures that live in burrows, feeding using suspension feeding with their pharyngeal slits.

Have serially arranged gonads.

2 Semicircular canals

Lateral Line system

Pineal Organ

Calcium Phosphate skeleton

True Dorsal/Anal Fins

Hypoglossal nerve

System of taste reception

Spleen

• Pectoral fin folds

- Possible fossil record -

Conodonata

Ostracodermi

Richard Fox - Lander University

Bone

Cyclostomata

Single nostril

Tongue-like apparatus with horny teeth

Pouch-shaped gills

Cartilaginous Skeleton

Lack paired fins and jaws

Pikaia - Burgess shale

Mid-Cambrian (530 MYA)

• Straight Myomeres
• Notochord
• Pharyngeal slits?

Yunnanozoans - Chengiang Fauna

Mid-Cambrian (520 MYA)

• Myomeres
• Notochord
• Pharynx
• Large brain?
• Eyes?
• Thick Branchial bars?

Advanced nervous system

Dorsal/ventral aorta

No heart

Photosensitive pigment spot ("eye")

Cirri (tentacles)

Hatshek's pit

Endostyle

Hepatic diverticulum

Atrium

Vertebrata

• Neurocranium (braincase) deepest lying
• Encases and protects the brain, nose, and inner ear (sensory capsules).
• Formed from cartilage and through the endochondral ossification of the neural cells.
• Remains cartilage in jawless fish and Chondrichthyes
• Replaced by bone in Osteichthyes.

• Chondrocranium (Phylogenetically the oldest)

• Dermatocranium

• Splanchnocranium

3 Basic Components

• Dermal elements that surround the chondrocranium and splanchnocranium.
• Skull roof, area around orbits, gill covers, roof of mouth, jaws.
• Makes up most of cranial structure in bony fish and tetrapods.
• Formed from cells of neural crest and skin cells.

• Visceral or branchial skeleton (mandibular arch, hyoid arch, gill arches).
• Supports gill arches for respiration and feeding
• Formed from cartilage and through the endochondral ossification of the neural crest cells
• In vertebrates without gills, becomes the larynx and trachea.

Life: The Science of Biology, Seventh Edition, Figure 34.1: The Ancestral Deuterostomes Had External Gills

Cranium

Vertebrae

W-shaped Myomeres

Liver

Kidney

Tripartite brain

Sense organs

Two chambered heart, plus Sinus Vinosus

Neural Crest Cells

Hox gene complex

41 microRNAs

• Hearing
• Vision
• Chemoreception

• Embryology

Neural crest

Tissue mineralization:

Source for many unique vertebrate characters:

• dermal skeleton and branchial skeleton, and plays a major role in the development of the skull.

Teeth

• Enamaloid (from mesoderm)
• Enamel (from ectoderm)
• Dentine (from neural crest)
• Cementum (bone-like substance)
• Cartilage (collagen-based in vertebrates; from mesoderm)
• Bone (From mesoderm and neural crest, made of CaPO4)

Epidermal placodes

Involved in the formation of major vertebrate sensory organs (olfactory, optic and otic capsules), and the lateral line system.

Three germ cell layers form during embryogenesis:

• Ectoderm - skin, nervous system, sense organs, lining of the anterior/posterior digestive track.
• Mesoderm - muscles, skeleton (notochord), connective tissue, circulatory system, urogenital system.
• Endoderm - lining of digestive track, glands for gut, respiratory surfaces.

In vertebrates, development is flexible.

Inductive interactions among structures determines the formation

of different cell types and tissues.

• Original mineralized tissue was skin
• Dermal bone - developes within the skin (membranous)
• Mineralization moved inside the body
• Endochondral bone - pre-formatino of bone within cartilage.
• External layers = lamellar bone (compact)
• Internal layers = cancellous bone (spongy)

We cannot observe these traits directly in fossils;

Adult derivatives are evidence for their presence

Dermal bone fagments from Ordovician may display dentinous tubercles

(evidence for neural crest cells)

and lateral line grooves

(evidence for placodes)

Urochordata

Tunnicates - Sea squirts, salps, sea porks

Euchordata

Lophotrochozoa

Most are sedentary adults, with some colonial species.

Filter feed using a basket-like pharynx

Free-living larvae possess derived chordate features

Adult

Larvae

Excurrent siphon

Arthropoda

Tunic

Incurrent & Excurrent Siphons

Tunic

Ocellus

Otolith

Heart and "Brain"

Dramatic metamorphosis

Light-detecting organ

Adhesive papillae

Pharynx

with pharyngeal slits

Intestine

Incurrent siphon

Gravity-sensing organ

Endostyle

Dorsal hollow nerve cord

Notochord

*Photos by Joshua Clark - 2012

Echinodermata

Hemichordata

Starfish

• Contact substrate with adhesive papillae.
• Within minutes, the notochord degenerates.
• Notochord, dorsal hollow nerve cord and tail resorbed.
• Pharynx enlarges, and gill slits increase.

Acorn Worms

Pharyngeal slits

muscular, fluid filled for locomotion and suspension feeding.

Anus

(no post-anal tail)

Tripartite body:

• Proboscis

• Collar

• Trunk

Ventral blood vessel

Pharyngeal slits

Dorsal hollow nerve cord

Stomochord

Proboscis

Chordata

Collar

Flexible carilage rod

V-shaped muscles

Xenoturbellida

Notochord

Myomeres - V shaped muscles

Anterior sense organs

Muscular pharynx

Posterior post-anal tail

Endostyle

Proterostomata

Loss of pharyngeal slits and dorsal hollow nerve cord

Used for filter feeding

Ambulacaria

Possible origin of the thyroid

Schubert et al. 2006

Supported by similarities in adult morphology, mitrochondrial and ribosomal data.

Deuterostomata

Alternative Hypothesis:

Supported by genomic data

Vertebrata

Urochordata

Cephalochordata

Olfatores

Radial egg cleavage after fertilization.

Indeterminate cleavage.

Transformation of the blastopore into the anus rather than the mouth.

Unique larval stage.

Pharyngeal slits

Dorsal hollow nerve cord

Ambulacaria

Chordata

CLADISTICS

Bilateria

Traditional Classification

Placozoa

Cnidaria

Ctenophora

Bilateral symmetry

Kingdom

Phylum

Class

Order

Family

Genus

Species

The initial form of classification - the linnaean method - grouped organisms together into ranks based on morphological data, using overall similarity to each other.

Under this system, organisms' classification did not reflect their evolutionary relation to others. Ranks are inconsistant and arbitrary.

Time

Phylogenetic Systematics

Metazoa

"Animals"

Introduced by Willi Hennig (German 1950; English 1966)

Groups organisms based on their shared ancestry, nesting instead of ranking, in order to recognize only natural groups that include an ancestor and all of its descendants.

Uses branching diagrams - cladograms (trees / phylogeny) - to visualize hypotheses of taxon relationships. They are open to tests, changes and falsification, with focus on genealogy.

Monophyletic Group

Paraphyletic Group

Polyphyletic Group

Porifera

Terminal Taxa - tip of a branch and represents a taxa of interest.

Branch - represents a lineage of interbreeding organisms.

Node - Divergence or speciation event (Split in the tree branches) Represents a hypothetical Most Recent Common Ancestor (MRCA)

Sister taxa - taxa that share a MRCA: Their order can be reversed, as long as their branching pattern remains the same.

Plesiomorphy - ancestral character inherited from a distant ancestor, not the most recent.

Apomorphy - A derived, new, character in a taxon inherited from the most recent ancestor.

Synapomorphy - A shared derived character found in more than one taxon.

Autapomorphy - A derived character found in only one taxon. (Unique trait)

Homology - Similarity between groups due to inheritance from a common ancestor. (Such as arm/hand bones)

Homoplasy - (analogy / convergence) similarities that evolved independently in different groups. (Such as wings in bats vs. birds)

Polytomy:

An unresolved relationship, due to lack of evidence, especially with the fossil record.

Is a group which includes an ancestor and all of its descendants.

Is a group consisting of taxa without any reference to their common ancestor.

(Ex: Grouping whales with fish)

Is a group consisting of an ancestor and some, but not all of its descendants.

Ex: Reptiles w/o birds (Descendants of reptiles)

Here, arm lengths are not indicative to amount of time or how derived a group is but merely meant to make reading easier.

Eukaryote

Fungi