PostLab 1 - Introduction Flashcards
study of the structure of vertebrates and of the functional significance of the structure
comparative vertebrate anatomy
Two categories of animals
- invertebrates
- vertebrates
no vertebral column
invertebrates
with vertebral column
vertebrates
transitional between invertebrates and vertebrates
protochordates
back or upper side (posterior - human)
dorsal
underside (anterior - human)
ventral
sides, right and left
lateral
dorsal side of humans
posterior
ventral side of humans
anterior
head end, superior - human
- anterior
- cephalic
- cranial
anterior, cephalic, or cranial in humans
superior
tail end (inferior - humans)
- posterior
- caudad
posterior or caudad in human
inferior
middle
median
nearest the middle of the animal
central
nearest the surface
peripheral
near the main mass of the body
proximal
away from the main mass of the body
distal
on or near the surface
superficial
some distance below the surface
deep
above
superior
below
inferior
Three principal body axes
- longitudinal axis (anterioposterior)
- dorsoventral axis
- left-right axis
Three principal anatomic planes
- transverse plane
- frontal plane
- sagittal plane
- divides the body into upper (superior) and lower (inferior) halves
- cross section
transverse plane
anatomical plane that divides the body into dorsal and ventral sections
frontal plane
Any plane that divides the body into right and left parts
sagittal plane
regular repetition of body parts along the anteroposterior axis
metamerism or segmentation
each division of the body
- metamere
- segment
- somite
types of segmentation
external and internal
centralization or localization of nervous structures and functions in the head with accompanying dominance of the head
cephalization
manifestation of homologous structures in different species
homology
- structures that had been inherited from a common ancestor
- may be similar or broadly dissimilar morphologically and functionally
homologous structures
- coincidental resemblance
- two structures that have the same function
analogy
example of analogous structures
horns of cattle (epidermal) and rhinoceros (dermal)
analogous structure evolution
convergent evolution
homologous structure evolution
divergent evolution
example of homologous structures
pentadactyl limb in vertebrates
The Big Four in Phylum Chordata
- pharyngeal slits
- dorsal nerve cord
- notochord
- post-anal tail
openings that connect the inside of the throat to the outside of the neck
pharyngeal slits
bundle of nerve fibers which runs down the “back”, connects the brain with the lateral muscles and other organs
dorsal nerve cord
cartilaginous rod running underneath, and supporting, the nerve cord
notochord
extension of the body past the anal opening
post-anal tail
- characterisitc believed to have evolved within a family tree
- can be used to separate one group from the other
- possession of feathers is unique to birds and defines all members of the class Aves
apomorphy
- trait shared by two or more taxa and their most recent common ancestor
- derived/specialized or modified
synapomorphy
similarity in the features of structures in a series within the same individual
serial homology
example of serial homology
- vertebral column
- limbs
- hands
characteritic shared by two or more taxa also found in their earliest common ancestor; primitive; generalized
symplesiomorphy
divergences or speciation events
nodes
common ancestor shared by all organisms on the cladogram
roots
most recent common ancestor of the group and all of its descendants
monophyletic
most recent common ancestor of the group but not all of its descendants
paraphyletic
does not include the most recent common ancestor of all members of the group
polyphyletic
study of the organization and relationships of different clades of organisms
cladistics
animals that have notochord at least in the embryo stage
Phylum Chordata
Subphyla of Phlym Chordata
- Urochordata
- Cephalochordata
- Craniata
- sometimes known as the Tunicata, are commonly known as “sea squirts.”
- The body of an adult is quite simple, being essentially a sack with two siphons through which water enters and exits. Water is filtered inside the sack-shaped body
Subphylum Urochordata
consists of notochord extended to the head region
Subphylum Cephalochordata
chordates with a neurocranium (braincase)
Subphylum Craniata
craniates without vertebrae
hagfish
craniates with vertebrae
vertebrata