Comparative Lab

Taxonomy

The science of classifying organisms

Phylogeny

Graphic representation of evolutionary relationships among organisms where branches are proportional to amount of evolutionary time.

Cladogram

Graphic depiction of one ancestor and all of its descendants with branches of equal length that do no represent time.

radial symmetry

Symmetry about a central axis. (think of a circle)

bilateral symmetry

can be divided in two down the midsagittal plane producing a mirror image.

Anterior/Cranial

towards the head.

Posterior/Caudal

towards the tail.

Medial

towards the midsagittal plane or middle line of the body.

Lateral

Away from the midline of the body or toward the outside.

Dorsal

backside of the body.

Ventral

belly side of the body

Proximal

close to

Distal

away from

analogous traits

features that appear to have similar function but do not share common ancestry.

homologous traits

Similar features that can be traced back to a common ancestor.

Apomorphy

a trait that sets a further developed species apart from other clades generated from a common ancestor. (derived trait)

synamorphy

a trait shared by two or more species of shared ancestry. (recent ancestor)

monophyletic group

all the descendants of a particular ancestor.

polyphyletic group

species with multiple origins that do not share a common ancestor.

paraphyletic group

species that share a common ancestor but not ALL species descended from the common ancestor.

Phylum Cordata

makes up all vertebrates + two groups of invertebrates. (Chordata Vertebrata, Chordata Craniata, Chordata Urochordata, and Chordata Cephalochordata)

The Big 5

Traits required to be classified as a "Chordate".
(Post anal tail, notochord, endostyle/thyroid, dorsal hollow nerve cord, and pharyngeal gill slits)

Deuterostomes

Animals in which the blastopore becomes the anus during early embryonic development and the mouth forms second opposite of the anus.

Node

Point of connection on a phylogeny tree marking an ancestor.

Cephalochordata

lancelets
-notochord persists throughout life
-filter feeders
-external fertilization
-oviparous

Urochordata

tunicates,
-free living larvae with chordate features
-sessile adults
-asexual
-adults have two siphons

Craniata

class of. jawless fish that includes lamprey and hagfish.
-presence of cranium
-bone or cartilage protects organs of the head

Myxinoidea

hagfish,
-possess slime glands
-accessory hearts
-oral tentacles in place of teeth
-no vertebrae
-oviparous
-external fertilization

Petromyzontiformes

lampreys,
-rough tongue
-parasitic as adults
-oviparous
-external fertilization
-vertebrates

vertebrata

(vertebrates) organisms containing a vertebral column.

Gnathostomata

(jawed vertebrates)
-fish, tetrapods, amphibians, reptiles, birds and mammals.

Chondrichthyes

(sharks, rays, and skates)
-cartilage skeleton
-oviparous and viviparous
-mostly carnivores

Actinopterygii

(ray finned fishes)

Sarcopterygii

(lobe finned fishes)

Tetrapoda

four-limbed vertebrates
-limbs
-digits
-muscular tongue
-modified girdles

Amphibia

salamanders, frogs, caecilians,
-3 chamber heart
-can undergo metamorphosis
-permeable skin
-shell-less eggs or viviparous

Amniota

produce amniotic eggs (shelled),
-keratinized skin
-internal fertilization
-no larval stage

fenestra

small hole or opening behind the eye sockets of the skull.

Anapsid

no fenestra
-turtles

Diapsid

2 fenestra
-lizards, snakes and tuataras

Archosauria

4 fenestra,
-crocodiles and birds

Synapsid

1 fenestra,
-mammals

Squamate

snakes and lizards

Tuartara

lizards with peaks running down the back.

Testudines

turtles

crocodylia

crocodiles, alligators, caimans, and gharials

Aves

birds

Mammalia

mammals
-4 chambered heart developed here.

functional morphology

the study of organism structure and function.

saltatorial locomotion

hopping or jumping to move.

scansorial locomotion

climbing

fossorial locomotion

dig and live underground

volant locomotion

movement through the air

true flight

flying with the movement of wings

gliding

use of webbed extremities to float through the air

swimming locomotion

movement through water

brachiation locomotion

swinging from one hold to another

cursorial locomotion

high speed running

platigrade

palm on the ground

digitigrade

only digits on the ground

unguligrade

only hoof on the ground