Bio 193 Ch 34. Chordata

phylum chordata

a diverse group of animals characterized by having a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail at some stage of development. This phylum includes vertebrates, tunicates, and lancelets.

chordata have a (closed/open) circulatory system

closed

phylum chordata

a diverse group of animals characterized by having a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail at some stage of development. This phylum includes vertebrates, tunicates, and lancelets.

chordata have a (closed/open) circulatory system

closed

dorsal nerve cord

hollow, nerve-filled structure runs along the back of the body and eventually forms the central nervous system (brain and spinal cord) in vertebrates

notochord

flexible, rod-like structure that provides support and structure during early development

in most species notochord remnants are surrouded by

vertebrae

post anal tail contains ____ muscles

somatic

post anal tail function in aquatic animals

to power movement

during development, the post anal tail may

become reduced or lost

what is unique to chordates

a notochord, a dorsal nerve cord, and pharyngeal slits.

anterior end of nerve chord in vertebrates is enlarged to form

the brain.

pharyngeal slits used for

suspension feeding

suspension feeding

a method of feeding where organisms filter small food particles from the water

pharyngeal slits form

gill slits for respiration

pharyngeal slits contribute to

development of ear, head, and neck in tetrapods

cephalochordata

a subphylum of chordates that includes lancelets

lancelets (adults/larvae) retain chordate features

adults

lancelets feed by

cilia draw water/food across the pharyngeal slits

urochordata

a subphylum of chordates that includes tunicates (sea squirts)

urochordata exhibit chordate traits during their ___ stage

larval

craniates

animals with a skill/cranium

craniates have Hox duplication which

allows for body plan diversification

double hox genes promoted the development of

true head, vertebrae, and other sense organs (more complex movement predation)

neural crest

feature unique to craniates

neural crest cells disperse thru the body and give rise to

specialized structures (teeth, dermis, neurons, etc)

mineralization began with

conodont (extinct species) mouth parts for protection

Myxini

jawless fish, commonly known as hagfish, that are characterized by their eel-like bodies and are mostly scavengers.

hagfish lack ___

jaws

hag fish have a ____ and primitive (not fully developed) _____

skull; vertebrae (made of cartilage)

the defense mechanism of hagfish

the secretion of mucus that can suffocate predators and aid in escape.

what allows for high disparity (diff looks) and low diversity

duplication of Hox gene

what enabled ancestors to move onto land

mineralized vertebrae and new limb evolution

adaptations support a ____ metabolic rate

higher (increased O2 intake, increased ATP, and increased nutrient intake)

actively pump water thru ___ for food/gas exchange

gill slits

muscles line alimentary canal which helps

more efficient processing

multichambered heart

allows for separation of oxygenated and deoxygenated blood, enhancing circulation efficiency in vertebrates.

hemoglobin

carries oxygen

multichambered heart, hemoglobin, and kidneys function

filter blood by removing toxic nitrogenous waste

petromyzontida

jawless vertebrates known as lampreys, characterized by their elongated bodies and circular mouths.

what are the oldest living vertebrate

Lampreys

what surrounds the notochord and nerve cord?

primitive cartilage vertebrae

Lampreys characteristics

no scales, no paired appendages (fins), adults are jawless with sucker like oral disk and well developed teeth

are lampreys parasitic

yes

gnathostomes

jawed vertebrates that include fish, amphibians, reptiles, birds, and mammals.

jaws evolved from

pharyngeal slit

mineralized jaws and teeth enable

firm grasping and slicing of food

gill slits that remain are major site of ___

gas exchange (O2 in, CO2 out)

second hox gene duplication supports

complexity

large forebrain enables

improved vision and smell

paired fins aid

maneuvering and predation

lateral line system

sensory system used to detect movement and vibration in the water.

360 degree sensing

can sense how far away someone is

chodricthyes

jawed fish that include sharks and rays, characterized by a cartilaginous skeleton and paired fins.

the bony skeleton in chondricthyes are replaced by

flexible cartilage

acute senses support

predation

sharks do not have a ___, so they rely on movement

swim bladder

swim bladder

gas filled organ to float

water flow over pelvic fins creates

lift

what aids in sharks buoyancy

cartilage skeleton, oily liver

when sharks stop swimming,

start to sink, do not oxygenate that well

rugae folds in stomach wall allow

for increased surface area and digestion.

spiral valve of the intestine

improves nutrient absorption by increasing surface area/time spent

modes of shark reproduction

oviparous, ovoviviparous, viviparous

oviparous

eggs hatch outside mother (feed on yolk)

ovoviviparous (live birth)

embryo fed by yolk in uterus

viviparous (live birth)

embryo fed by placenta in uterus

lateral line detect

pressure differences in water (mechanical vibrations)

ampullae

jelly filled structures that detect electrical signals

ampullae detect

electrical signals for long distance communication

octeichthyans

bony fish/tetrapods characterized by a skeleton made of bone, and which includes the majority of fish species.

bony fish have

mineralized endoskeleton

use gills or lungs for repsiration

bony fish

actinopterygii

ray finned fish

operculum flap

a bony flap that covers the gills of fish, aiding in respiration and protection.

air filled swim bladder regulates

buoyancy

ray finned fish skin contains

bony scales, LLS, and glands

ray finned fish mode of reproduction and fertilization site

oviparous w/ external fertilization

lobe finned fish include

coelacanths, lungfish, tetrapod lineage

thick pelvic fin muscles of lobe finned fish surround

rod shaped bones

tetrapods

Four-limbed (with digits) vertebrates that evolved from lobe-finned fish. They include amphibians, reptiles, birds, and mammals.

tetrapods evolved limbs with digits to

support weight on land

Pelvic girdle

becomes fused to spine to unite trunk and legs

fishy characteristics

gills, fins, and scales

transitions tetrapods still had

fishy characterstics

tetrapod adaptation:

4 limbs and feet with digits

tetrapod adaptation:

a neck (allows for separate movement of head)

1st neck vertebrae

allows for up/down

2nd neck vertebrae

allows for left/right movement

tetrapod adaptation:

fusions of pelvic girdle and ribs to backbone (trunk support and ventilation)

tetrapod adaptation:

absence of gills (mostly)

tetrapod adaptation:

genome changes in olfaction (smell/taste) and ears to detect airborne sounds

amphibians

“both ways of life” (aquatic larva and terrestrial adult)

amphibians need both

water (moist skin/egg protection) and air (ventilate lungs w/ mouth)

amphibians ventilate lungs using

mouth

positive pressure ventilation

amphibians actively push air into lungs with their mouth

amphibians external fertilization must be in

water (to keep eggs moist)

amphibians aquatic larvae

fins, gills, LLS

amphibians become terrestrial adults who have

lungs and skin w/ 4 limbs (no fins, no gills)

amniotes

entirely terrestrial life cycle

amniote embryos develop in

shelled eggs or uterus

negative pressure ventilation

breathing that uses the diaphragm to create a vacuum that pulls air into the lungs.