Comparative Anatomy Lecture exam 1

Natural selection

environment put selective pressure on an organism

selective pressure

when a advantageous trait is favored in an environment

Alfred R. Wallace

Survival of the fittest

Mendel

Support Darwins natural selection, characteristics are inherited

Punctuated equilibrium

rapid change in species followed by stasis 

Three tiers of evolution

Microevolution, macroevolution, mass extinction

homologous

features that share common ancestry regardless of function

Analogous

Features with similar function but different ancestry

Homoplastic

features with similar appearance but not function or ancestry (mimicry)

Vestigial organ

non-functioning structure (tailbone, wisdom teeth) NOT APENDIX

Two types of symmetry

Radial and bilateral

Radial symmetry

invertebrates have central axis

bilateral symmetry

vertebrates have midsagittal plane

Segmentation

repeating sections within an organism (vertebral column, tape worm)

Allometry

unequal growth rate in different body parts

Isometry

equal growth rate of all body parts

Increase size increases

stress on skeletal elements and oxygen/nutritiondemands

more surface area is typically ——-

better

hypertrophy

increase mass of a cell

atrophy

loss of tissue substance

Chordate characteristics

Notochord, pharyngeal slits, endostyle, dorsal nerve cord, postanal tail

Where does notochord develop from?

mesoderm

Pharyngeal slits

facilitate feeding/digestion

When does differentiation happen?

Gastrulation and Neurulation

Endostyle

accumulate food and move to GIT, becomes thyroid

ontogeny

embryonic development

Gastrulation

formation of gut, and germ layers

Neurulation

formation of neural tube

organogenesis

formation of organs

tissue

group of cells that perform a function

organ

a group of tissues that perform a function

order of zygote development

zygote —> morula —> blastula with blastoderm

Three germ cell layers

Ectoderm, mesoderm, endoderm

What is in ectoderm?

Skin, central and peripheral nervous system, adrenal medulla 

what is in mesoderm?

Kidneys, repro system, bone/cartilage, muscles,lymph, splean

What is in the endoderm?

GIT, Liver, endocrine system, bladder, respiratory tract

Types of tissue in body

Epithelium, connective tissue (bone), muscle, nervous

Squamous epithelium

flat

cuboidal epithelium

cube

columnar epithelium

tall, specialized

transitional epithelium

between squamous and cuboidal

What type of epithelial cells?

Squamous, cuboidal, columnar, transitional 

Exocrine gland

product secreted into duct

endocrine gland

products secrete into blood

Three types of cartilage

hyaline, elastic, and fibrocartilage

Reproductive toxicology research is done on —- bc——

Mice, rabbits, and zebra fish bc clear embryo and rapid reproduction

New in vertebrate after chordates

vertebral column replace notochord, cranium

Agnathans

without jaw (lampray)

Gnathostomes

jaw, make preditor prey relationship/change in diet, everything beyond agnathas

Placoderms

boney armor on external body

placode

embryonic structure that gives rise to other structures (hair follicle, feather, teeth)

Chondrichthyes

cartilagenous skeleton

chondro-

cartilage

Actinopterygii

endoskeleton ossification, otoliths (hearing)

Sarcopterygians 

give rise to tetrapods

Amniotes

all terrestrial vertebrates except amphibia

Amnion

innermost embryonic membrane of reptile, bird, mammal

Aves

outnumber all other vertebrate besides fish

Mammalian characteristics

hair, mammary gland

Metatheria

early live birth

Eutheria

placental animals

Skull function

protect brain and sensory organs, support jaw

Chondocranium

Basal plate, ethmoid, optic, otic, occipital, cartilagenous

Splanchnocranium

arise from brachial arches, ancient skill, develop mandibular

Dermatochranium

predominate part of skull

Cranial bones

all bones in skull

Skull phylogeny

trend is to reduce number of bones and adapt to feeding style

Chondrichthyes

chondrocranium dominant

Snake

dislocation of mandible

avian sclerotic bones

hardened around eye

turbinates

filter and warm air in nasal cavity

Notochord/vertebral column function

locomotion, prevents compression, long axis, support head

ribs function 

protect viscera, respiration 

notochord in vertebrates

only present in embryo

vertebral column regions

cervical, thoracic, lambar, sacrum, caudal

processes

projections for muscle/tendon insertion

zygapophyses

pre and post, prevent twisting

diapophyses and parapophyses

rib articulation only in thoracic

cervical

transverse foramen

acoelous

flat end vertebrae

amphicoelous

limit motion, shark

heterocoelous

saddle joints allow flexibility (birds)

Annulus fibrosus

fibrocartilage ring in intervertebral disk

nucleus pulposus

gel-like notochord remnant center of intervertebral disk

two parts of intervertebral disk

annulus fibrosus and nucleus pulposus

IVDD

B. lack nucleus pulpous

Sternum origin

endochonrium

true ribs

meet at sternum

gastrila vs thoracic

dermal and abdominal ribs vs upper ribs endo

Atlas

nodding

axis

twisting

pectoral girdle evolution

separate skill from limbs

adipose fin

small fin dorsal near caudal fin

pelvic vs anal fin

pelvic more cranial ventral 

clavicle in amphibians

may be present

no clavicle in mammals

dog, horse, cattle, sheep

yes clavicle in mammals

primates, cats, mouse, rabbit, bullfrog

furcula

wishbone/clavicle in bird

pectoral girdle in mammals

scapula and clavicle