Zoology from lecture 10/5 chordata and fishes

Chordata/ fishes

What are features of chordata

-notochord

-dorsal, hollow nerve cord

-pharyngeal slits or cleft

-muscular post anal tail

What is a Notochord

-flexible, rod-shaped structure that provides skeletal support; “hydrostatic organ”

-can bend back and forth

-myomere segments

-cannot be compressed

What is a myomere segment

a repeating block of skeletal muscle found along the sides of fish and other aquatic chordate , cone shaped

What is a hydrostatic organ

fluid/gas fluid structure that helps control buoyancy, maintain body shape, or assist in movement using pressure, “ water—under pressure”

humans are ____

Chordates

What is a dorsal hollow nerve cord

a fluid-filled central nervous system structure found on the back (dorsal side)

What is a pharyngeal nerve slits or cleft

-opening or grooves along the side of the pharynx

-used as filter feeders (about constant trading of food)od)

What is a muscular post anal tail used for

used for movement, balance, communication, defense, hunting

“Acorn worms”

under phylum Hemichordata, filter feeders

Urochrodata

-all chordata features in larvae, in adulthood it losses some chordata features (tail, notochord, and most of the nerve cord)

Cephalochordata

has all chordata features through adulthood

All vertebrata are chordates, but not all chordates are vertebrata

true

Agnatha

vertebrate without jaw

what are Hox genes

group of specialized control genes that act as master blueprints to determine the basic body plan and segment identity of an animal from head to tail along the anterior-posterior axis

What is the word for multiple fish from 1 species

fish

what is the word for multiple species of fish

fishes

What means without jaw

Anathans

Which layer of the skin does mucus lie

epidermis

What are the characteristics of a hagfish

-no mandable/ cant bite anything

-can suction on with dental elements

-produced mucus

What is mucus made of

mucin and water

mucin has…

goblet cells “slime glands”

what are the layers of skin

epidermis, dermis, hypodermis, and muscle

what is the epithelial tissue made of

epidermis and dermis

What is the connective tissue

hypodermis

What are the characteristics of lamprey

-no mandable

-most are ectoparasites

-are oviparous

-larvae in sediment of lakes

what does oviparous mean

“lay eggs” to larvae to adults / “egg reproducing”

What are the characteristics of Gnathostomes

-has jaws

-jaws come from supporting cartilage from pharyngeal slits

-jaw bits can be modified

what are Chondrichthyes

-The skeleton is primarily made of cartilage

-Jaw is made of bone

-Has placoid scales

-do serial replacement of teeth

ex: sharks, skates, and rays

what are placoid scales

-starts in the dermis w/ bone, then pierces and extends over the epidermis(dentine and enamel) and covers epidermis

what are the three different types sharks reproduce

oviparous, ovovivparous, viviparous

Oviparous

means egg laying, laid in an egg case, outside body

Ovoviviparous

eggs formed inside mother, then hatched “mermaid purse”

Viviparous

Shark pups are born live after developing in the mother

What is Osteidthymes

- skeleton: mostly bone

-boney fish