(Chordates, Subphylyum Vertebrata)

Group of jawed fishes, characterized by large spines in their fins from Lower Silurian to Lower Permian

Chordates, Class Petromyzontida

Filter feeding larval stage of lampreys

produce a feeding current by muscular pumping action

well developed brain, paired eyes, pronephic kidneys

representative of the vertebrate body plan

Annelida, Class Oligochaeta

excreted by aquatic oligochaeta

Annelida

Body segmentation

division of the body into a series of segments, each of which contains similar components of all major organ systems

delimited internally by septa

Annelida (except leeches)

tiny chitinous bristles

short, needle-like - anchoring

long, hairlike - swimming

stiff- prevent from being pulled out of home

Annelida

Oligochaetes (earth/fresh worms)

leeches(only during rep. season)

reproductive structure of secretory cells

fat band @ midbody segment

produces the cocoon in which eggs are deposited during sexual reproduction

Phylum Annelida

ONLY MARINE (aquatic & fresh) WORMS

Largest class of annelids

well differentiated head w/specialized sense organs

paired appendages ; parapodia

Many Setae on parapodia

NO Clitellum

most pronounced differentiation of body segments and specialization of sensory organs found in annelids

Annelida

one of the segmentally arranged, paired excretory tubules of many invertebrates, notably the annelids.

with an external opening and with or without an internal opening

Annelida, Polychaeta (marine worms)

Free swimming, ciliated larval stage

Annelida, Class Oligochaeta

along the esophagus secrete calcium ions into gut to reduce the calcium ion concentration of their blood. Also regulate acid-base balance of body fluids.

Annelida, Class Oligochaeta

longitudinal fold in intestine

increases absorbtive and digestive surface

Annelida, Class Hirundina Leeches

system of spaces in coelemic cavity

serves as an auxiliary circulatory system (some)

Arthopoda

crustacea

two branched appendages

Arthopoda

Myriapods, Hexapods, Crustacea

head appendage; mouthpiece

in crustacea - multijointed

in myriapods & hexapods - single joint

Arthopoda

Chelicerata; Spiders

Structure of crustacean and insect cuticles

tough, nitrogenous polysaccharide that is insoluble in water, alkalis, and weak acids.

protects against dehydration

Arthopoda

actual shedding of the skin

Arthopoda

when segments combine or fuse into funtional groups which have specialized purposes

ex: spider body - 2 tagmata

horseshoe crabs, spiders, ticks, mites, scorpions, sea spiders

two tagmata: a cephalothorax & abdomen

6 prs of chephalothoracic appendages

-pr of chelicerae (mouthparts)

-pr of pedipalps

-4 prs of walking legs

no antennae

Arthropoda - Crustacea

shieldlike plate covering the cephalothorax of certain crustaceans

Arthropoda, Chelicerata - aquatic only

respiratory structure of of terrestrial chelicerates where many thin, blood filled gills are layered like the pages of a book. Gas exchange occurs as sea water passes between each pair of gills

Arthropoda - Chelicerata- terrestrial

respiratory structure of terrestrial chelicerates where many thin-walled air pockets extend into a blood filled chamber in the abdomen

Second pair of appendages of arachnids

have sensory function

used by male to transfer sperm into female

Spiders

modified nephridia that open at the coxa, or base of the first and third walking legs.

spiders

Function- secrete scleroprotein from spinnerets

Spiders

two or three pairs

contain hundreds of microscopic tubes that run to silk glands

"many footed"

two tagmata - head and trunk

use trachae to carry respiratory gases directly to and from all body cells

I need to know

Class Chilopoda - centipedes

Class Diplopoda - millepedes

Centipedes

dorsoventrally flattened

variable # of segments, each with one pair of legs; one pair of long antennae; oviparious

Millipedes

Body almost cylindrical

head with short antennae and simple eyes;

body with variable number of segments;

short legs; usually two pairs of legs to segment; oviparious

Crustaceans

mostly aquatic, with gills

cephalothorax usually with dorsal carapace; biramous appendages; modified for various functions

head appendages consisting of two pairs of antennae, one pair of mandibles

two pairs of maxillae

development primitively with nauplius stage

crustaceans

food manipulating appendages (2prs)

primary body cavity in arthropods (rather than coelom)

persistant blastocoel that becomes blood filled

Crustaceans

A saclike statocyst, opening to the surface by a dorsal pore,occurs on the basal segment of each first antenna of crayfish.  Serves as a sensory organ when animal changes positions.

Crustaceans & insects

photoreceptor units in their compound eyes

arthropod, crustacean, insect

Change from larva to an adult

Ancestral and most widely occuring larva in Crustacea

only 3 pairs of appendages & simple eye

Crustaceans

1. tubular heart

2. may contain, hemolymph, hemocyanin, or hemoglobin

Ecdysone

inhibits y-organ

group of neurosecretory cells in the medulla terminalis of the brain

a. secrete molt inhibiting hormone

-changes in environmental factors

-and/or pressure sensors in animals body

b. lead to lower production of hormone

lie underneath muscles of mandibles

secrete molting hormone

spiders

modified nephridia at base of legs - function in excretion

(Insects)

plates that make up exoskeleton

(insects)

balancing wings

(insects)

dragonflies & butterflies- muscles move wings up and down

(insects)

bees & flies - both longitudinal and dorsoventral muscles

1. Ecdysiotropin (brain hormone) - fm neurosecretory cells in brain -> production of molt hormone

2. Ecdysone(molt hormone) fm prothoracic gland

-> sheeding of old cuticle

3. Neotenine (juvenile hormone)

a. fm corpora allata

b. controls type of molt

high levels = simple growth molt

low levels = metamorphic molts

Insects

Neotenine (juvenile hormone)

a. fm corpora allata

b. controls type of molt

high levels = simple growth molt

low levels = metamorphic molts

detect mechanical stimuli (touch, pressure, vibration)

may be a seta or hairlike process, connected with a nerve cell; a nerve ending just under the cuticle and lacking seta; or a more complex organ - scolophorous organ

insects

Mechanical Sensory organ in insects

consists of sensory cells with their endings attached to the body wall

Most adult insects, crustacea, hexapods

thousands of ommatidia

can see simultaneously in all directions

most insects go through this/these change(s) in form through a series of molts

more dramatic than any other group

associated with the evolution of wings

Incomplete metamorphosis of grasshoppers, cicadas, mantids and terrestrial bugs etc.

the young are called nymphs

Insects - hemimetabolous

young whose wings develop externally as budlike outgrowths in early instars and increase in size as the animal grows by successive molts.

Complete Metamorphosis

larvae, pupa, adult

Insecta

Dormancy in "anticipation" of stressful conditions

a. even if conditions never materialize

b. part of life cycle

Insecta

Communication - Chemical Signals - Pheromones

Insecta

Social Organization - queen, soldiers, etc

Insecta

communication - tactile signals - social insects

Chordata

flexible rod like structure - supports main body axis

Urochordata & Cephalochordata

replaced in vertebrates

Chordata

tubular nerve chord in uro&cephalochrodata

`Chordata

openings that lead from the pharyngeal cavity to the outside, evolved as a filter feeding apparatus (prochordates)

Chordata

protochordates form of a thyroid gland

also in lamprey larvae

regulate metabolism and calcium balance

Chordates

provides the motility that larval tunicates and amphioxus need for their free swimming excistence.

water propulsion

Annelida,cephalochordata

in closed circulatory system

evolutionary retention of juvenille or larval traits in the adult body

chordates, amphibians

Chordata- Superclass Agantha

no jaws

no paired fins

heavily armoured

first vertebrate???

cambrian period

Superclass Gnathostomata

extinct

first jawed fishes

paired fins

heavily armoured

did not give rise to any extant group
jaws evolved from gill arches

Class Chondrichthyes (sharks)

Class Actinopterygii (ray fish)

vertebral column turns upward and extends into the dorsal lobe of the caudal fin, provides thrust and some lift as it sweeps back and forth

Male Sharks

used in copulation, on the medial part of the pelvic fin

sharks

toothlike scales

reduce the turbulence of water flowing along body surface during swimming

sharks

sensing low frequency vibrations to find prey that are far away

chrondrichthyes - sharks

slows passage of food and increases absorbtive surface

in intesine

sharks

attached to rectum

secretes a colorless fluid containing a high concentration of sodium chloride

regulate salt concentration in heart

ray and lobe finned fishes(bony fishes)

gill cover

increases respiratory efficiency bc it creates a negative pressure pressure so water is drawn across the gills

earliest Actinopterygians (ray fin)

small

large eyes

heterocercal caudal fin

thick interlocking scales

present in early bony fishes

composed of layers of silvery enamel (ganoin) on the upper surface and bone on the lower

sturgeons, birchirs, and paddlefish

ganoid scales and heterocercal tail

simple lung  or air bladder connected to esophagus

appeared late permian

contemporary bowfins and gars

cycloid and ctenoid scales (lighter than ganoid scales)

gave rise to teleosts

clade of neopterygians

the modern bony fishes

high diversity

symmetrical tail

teleost

Class Sarcopterygii

thought extinct for 70 my

resdiscovered

only 2 species

class sacropterygii

possible link to tetrapod ancestral stock

bony elements in fleshy fins

Class Sarcopterygii

3 groups of lungfishes

primitive lung for 'air gulping'

part of bony fish respiratory system

counter current mechanism

blood and water flow in opp. directions

increases effic. of gas exchange

bony fishes

used for bouyancy

gas exchange

bony fish

muscles - body musculaure - zig zag bands

Bony Fishes

part of bouyancy system,

resorptive area by gas gland

Bouyancy mechanism

secretes lactic acid which enters the blood causing a localized high acidity in the rete mirable that forces hemoglobin to release its load of oxygen

also has counter current mechanism

possible vertebrate ancestor of Chordates

both vertebrate and protochordate characters

control body organization during development

chordates

part of genetic expansion hypothesis

hox genes

found in all animals

very similar in all animals

invertebrates - 1 group of hox genes

vertebrates - 4 groups on 4 diff chromosomes

Subphylym urochordata

notochord and nerve cord in free swimming larva (tadpole larva)

adults sessile filter feeders

evolution of vertebrates

tunicate larvae gave rise to vertebrates

larval forms developed mature fonads & ability to reproduce (paedomorphosis)

Tadpole larvae similar to ammocoetes larva of lampreys

recent molecular data do not support this

ANNELIDS

1. epitokes -free swimming reproductive segments break off adult (Atoke)

2. produce trochophore larva

3. samoan palolo worm

Annelids

dorsal heart

ventral vessel

aortic arches

also in sharks

arthopods

hemolymph

hemocyanin

hemoglobin

generally animals w/trachea-no transport pigments

truly social animals

insects esp.

green glands

function in excretion

crustaceans

crustaceans

digestive system

acts as a gizzard contains 1 dorsal and 2 lateral teeth = gastric mill

arachnids

chitinous parts on chelicerae

has all chordate characteristic

some vertebrate characters

but notochord over extended - for burrowing

kidney not same as vertebrate

related but not ancestral

Subphylum cephalochordata

lancelets - notochord and nerve cord for entire life cycle