Comaparative Anamotmy Lec (LE1

Comparative anatomy

Studies the descriptive and functional morphology of vertebrates

descriptive

pertains to the structure of vertebrates

functional

pertains to the sigificance of the structure

evolution and phylogeny

Comaparative anatomy is a study of…

vertebrate evolution

Comparative anatomy can be considered as

morphology is the structural evolution while anatomy is the description of structures

difference between morphology and anatomy

morphology

structural evolution

anatomy

description of structures

zoology, physiology, histology, genetics, embryology, evolution, paleontology, ecology, and physics

Comparative anatomy incorporates different disciplines like (9)

comprehend the structural basis of biology, probe ancient past and study evolution, develop appreciation of vertebrates, develop dissection skills, understand man’s place in the vertebrate world

main significance of comparative anatomy

fish, reptiles, amphibians, birds, mammals

big five groups of vertebrates

protochordates and hemichordates

belongs to the lowest class of vertebrates

notochord

common characteristic of chordates is having a notochord

postanal tail, notochord, pharynx, dorsal hollow nerve cord, endostyle

common characteristics found in vertebrates (5)

dorsal hollow nerve cord

eventually will develop into brain and spinal cord. 

True

No vertebrate will proceed without passing through these five characteristics

nerve cord

During embryology the first organ formed is the…

notochord

supports the dorsal hollow nerve cord

Centrum

Is the remnant of the notochord

notochord

rod of living cells ventral to the CNS and dorsal to the alimentary canal.

skeletal support

notochord provides ___ throughout most of the length of the chordate

is incorporated to the skull floor

fate of notochord in head region during deveelopment

surrounded by cartilaginous or bony vertebrate

fate of notochord in trunk and tail region during deveelopment

axial skeleton surrounded by notochord sheatg

fate of notochord in adulthood (protochordates)

has lateral neural cartilages

fate of notochord in adulthood (aganathas)

persist the length of the trunk and tail within the centrum

fate of notochord in adulthood (fishes and amphibians)

disappears and becomes pulpy nucleus in vertebrate

fate of notochord in adulthood (reptiles, birds, and mammals

vertebrae

chordate adults will have a ___ that replaces the notochord

centrum

is deposited around the notochord

neural arch

will form over and encases the spinal cord

nerve cord

develops from a plate of ectoderm that rolls into a tube dorsal to the notochord.

invagination

the dorsal hollow nerve cord is formed through the process of ____

Central nervous system: brain and spinal cord

the nerve cord develops into the ____

pharynx

Can be perforated by openings (slits) to either the exterior or an atrium (reflecting common ancestry)

pharynx

Membranous, digestive, and respiratory organ located at the back of the mouth that serves as passageways of food and air.

gills (permanent slits)

pharynx is a vital part of craniate embryo that produces the ___ of fishes

lungs (temporary slits)

pharynx is a vital part of craniate embryo that produces the ___ of tetrapods

skeleton and musculature

pharynx is a vital part of craniate embryo that produces the ___ and ___ of jaws

endocrine glands

pharynx is a vital part of craniate embryo that produces the ___ glands

parafollicular cells and parathyroid glands

Endocrine glands that regulate metabolic rates in all body cells & maintain appropriate calcium levels in bones, other tissues and circulating blood. Will eventually form:

middle ear cavity (auditory and tympanic cavity

pharynx is a vital part of craniate embryo that gives rise to the _____ of tetrapods

immune system, fetal life

pharynx is a vital part of craniate embryo that provides initial cells of _____ during _____ life and shortyly after

Pharyngeal arches

Column of tissue which separates each embryonic pharyngeal pouch or slit from the next.

skeleton, blood vessels, muslces, and nerves

pharyngeal arches has 4 blastemas in which they develop from:

6 pairs

total pair of pharyngeal arches that develop in cranio-caudal sequence

pharyngeal cleft

Ectodermally-lined grooves on the outside of the embryonic pharynx.

1st cleft

Most important pharyngeal cleft

Yes

Are pharyngeal clefts lost in development

Pharyngeal pouches

Arises as diverticula of endoderm or foregut and grows towards the surface of the animal

8

maximum number of pouches in basal sharks

15

maximum number of pouches in living agnathas

Pharyngeal cleft

_____ will grow towards each pouch

pharyngeal plate

What separates the pharyngeal cleft and pouch

pharyngeal slits

Are formed between the pharynx and exterior when the pharyngeal plate ruptures

permanent slits

adults that live in water and breathe via gills has

temporary slits

 adults that live on land has

spiracles

the first pharyngeal slit that are seen in sharks are___

endostyle

glandular groove in the floor of the pharynx and is involved in filter feeding.

thyroid gland

endostyle develops into the ___

posterior

the tail is ___ to the anus

Chordates

animals that have a notochord in the embryo stage at least

neurocranium

cranaiteas are chordates with ___

vertebrates

vertebrates are chordates with ___

embryonic development, notochord

vertebrates appear during ____ after the ____ has been formed

head, trunk, postanal tail

typical craniate body consists of three components namely

Head

Contains the sense organs (eyes, ears, and nose)

cephalization

centralization or localization of nervous structures and functions in the head with accompanying dominance of the head

is more marked/ high degree of cephalization

the higher the kingdom of the organism or animal, their cephalization

trunk

contains the coelom which houses most of the visceral organs

body wall

surrounds the coelom and consists chiefly of muscle, vertebral column, and the ribs

pectoral, pelvic

the trunk is associated with paired ___ and ___ appendages

neck

narrow extension in the trunks that connects the trunk with the head

postanal tail

commences at the anus or vent

Metamerism or segmentation

Regular repetition of body parts along the cranio-caudal axis

Myosepta

Separates myotomes

Metamere, segment, somite

Series of divisions of the body of segmented animals

Homonous segmentation

Segmentation of the animal body into nearly alike segments

Heteronomous segmentation

Various segments differ from each other

Internally

Are the segmentation in most adult reptiles, birds, and mammals seen externally or internally?

Hindbrain, midbrain, forebrain

Three part brain consists of

Cranium, three part brain, neural crest and its derivatives.

Craniate characteristics (3)

Vertebral column, two semicircular canals, electroreception, lateral line system, soft tissue specialization

Vertebrate characteristics

Integument, respiratory mechanism, coelom, digestive system, urogenital organs, circulatory system, skeleton, muscles, sense organs

Other craniate characteristics

Ernst Haeckel

Proposed a taxonomic classification of deuterosto es

Eneterocoelomates

Deuterostomes are also known as ____

Xenoturbellida, echinodermata, hemichordata, chordata

Four extant phyla

Anus

In deuterostomes, what develops from the blastopore

Protochordates

Are the closest relatives of vertebrates along with the hagfish

Hemichordata, urochordata, cephalochordata

Protochordates are composed of (4)

Echinodermata

Phylum that has a unique calcium skeleton

Bilateral then radial

Echinodermata’s symmetry in early life vs adults

Hemichordata

Phylum that is commonly known as acorn worms. They are veriform bottom dwellers found in shallow mud water

Proboscis

Part of acorn worms body for burrowing into mud

Dorsally

Batesons considerations for placing phylum hemichordata under phylum chordata

1. collar nerve cord is ____ located with lumen

Slits

Batesons considerations for placing phylum hemichordata under phylum chordata

2. have ___ that open to the exterior in lateral walls of the forgut

Stomochord

Batesons considerations for placing phylum hemichordata under phylum chordata

3. Have a ____. A short diverticulum of the foregut

Yes

Is stomochord not homologous to the chordate notochord?

Enteropneusta

Class under hemischordata of worm like acorn worms

Active proboscis

Collects food in mucous strands