unit 7

3 subphyla of chordata

cephalochordates, urochordates, vertebrates

4 defining characteristics of chordata

1. pharyngeal gill slits

2. dorsal hollow nerve cord

3. notochord

4. post anal tail

pharyngeal gill slits

openings into throat

nerve cord

nerve cord that run the length of body, comprised of projections from neurons

notochord

supportive & flexible rod, runs length of body

Cephalochordates

(lancelets) small, mobile suspension feeders, resemble fish, notochord functions as endoskeleton in adults, sexual external reproduction, separate sexes

Urochordata

(tunicates) tunic, U shaped gut, 2 siphons, consist of sea squirts, suspension feeders, sexual & asexual reproduction, internal or external

sea squirt

type of tunic, live on ocean floor, incurrent & excurrent siphon

salps

type of tunic, live in open ocean, moves via jet propulsion, internal feeding net that filters water inside , complex life cycle

2 distinguishing synapomorphies of vertebrates

1. vertebrae that form column along dorsal sides, protect spinal column

2. cranium is bony, cartilaginous or fibrous tha enclose and protects brain

vertebrae

column of cartilaginous or bony structures that form column along dorsal sides of most species, protect spinal cord

cranium

bony cartilaginous case that encloses and protects the brain

3 distinct regions of vertebrate brains

forebrain, cerebrum, midbrain, hindbrain

forebrain

houses sense smell in brain, part used to form cerebrum

midbrain

part of brain stem, associated with vision

hindbrain

part of brain responsible for balance and hearing

gnathostomes

jawed vertebrates

mesencephalon

part of brain stem, associated with vision, hearing motor control, sleep and wake cycles, arousal (alertness), and temperature regulation

cartilage

strong but flexible tissue

bony exoskeleton

series of scalelike plates, first fossils to contain bone

bony endoskeleton

function to support movement, evolved after bony exoskeleton

amniotic eggs

watertight eggs have membranes to nourish and protect embryos; all tetrapods, besides amphibians

series of key innovation in vertebrates

1. bony exoskeleton

2. jaws

3. bony endoskeleton

4. limbs capable of moving on land

5. amniotic egg

6. rib cage to support lung function

swim bladder

allows fish to alter their bouyancy

key vertebrate innovations

1. vertebrate jaw

2. bony endoskeleton

3. swim bladder

4. tetrapod limb

hagfish

really slimy creatures, not vertebrates, craniates, no vertebral column, scavengers

lamprey

vertebrates, no jaws, small pieces of cartilage slong dorsal hollow nerve cord, ectoparasites, metamorphosis

jaw evolution

4 arches fused to form

rays

have long elongated tail, flat, whip and venomous spine

skates

thicker tail, caudal fin, flatter

3 ways of shark reproduction

oviparous, viviparous, ovovivaparous

class actinoptergii

vertebrata, swim bladder, external fertilization, eggs require parental care

class osteichthyes

ray finned fishes?

class actinistia

coelacanths, lobe finned fishes, have muscles and bones similar to tetrapods in lobe fins, sexual & external, ovoviparous, closest living relative to amphibians and mammals

class dipnoi

lungfish, lobe finned fishes, have muscles and bones similar to tetrapods in lobe fins, sexual & external, ovoviparous, closest living relative to amphibians and mammals

tetrapod innovations

1. tetrapod limb

2. amniotic egg

3. rib cage and lungs

4. feathers and flight

5. placenta

6. parental care

pterosaurs, bats, birds

wings evolved independently in which 3 groups

amphibian 3 clades

anura, urodela, apoda

anura

frogs and toads (no tail), reproduction oviparous, external

urodela

salamanders (visible tail), reproduction oviparous, internal

apoda

caecilians (no legs), reproduction viviparous, internal

Class Amphibia (vertebrata)

carnivores, lay eggs in water, four limbs, sexual reproduction in water, dramatic metamorphosis to land dwelling adults,

Reptilia

monophyletic, openings in side of skull where jaw muscles pass, scales, well developed lungs, amniotic eggs

amniotic egg

4 membranes, 1 external, 3 internal, membranes provides mechanical support and surface area for gas exchange

watertight shell, food supply and water, waste repository

amniotic egg functions

amnion

protective inner membrane where embryo develops

yolk sac

internal membrane that contains nutrients for embryo

allantois

internal membrane that contains waste in amniotic egg

chorion

external membrane that allows gas exchange in egg

albumen

water with protein rich solution that provides water and mechanical support in amniotic eggs

Reptilia major lineages

Squamata, Testudines, Crocodilia, Aves

Squamata

lizards & snakes,

• well developed jointed legs, small reptiles with elongated bodies and scaly skin, smaller will be predators, larger will be herbivorous, lay eggs, many are ovoviparous

• limbless, carnivores, fangs to inject poison, lays eggs, many ovoviparous

Testudines

turtles, freshwater, marine, terrestrial environments, shell of bony plates, lack teeth, form beak from jawbone and lower skull, marine carnivorous, tortoises herbivores, all oviparous

Crocodilia

crocodiles & alligators, freshwater & marine, eyes on top of head, nostrils on snout, predators (can be semisubmerged), sex determined by what temperature egg is incubated, strong parental care

Aves

Birds, unique respiratory system, one way flow of air, 9 air sacs, oxygen flows opposite to blood, endotherms, omnivores and predators, oviparous with strong parental care, hollow bones, keel

ectothermic

do not use internally generated heat to regulate body temp (all reptiles except birds)

keel

projection from bird sternum, large surface area, for flight muscles to attach

hair/fur, mammary glands, endothermy, enlarged brains, specialized hearing

mammals distinguishing characteristics

3 lineages of mammals

monotremata, marsupialia, eutheria

synapsid

primitive reptile that a group of mammals evolved from

temporal fenestra

hole behind eye in skull

Monotremata

3 species, platypus & 2 echidna, oviparous, leathery beak/bill, milk patches

Marsupialia

have placenta, viviparous, young born underdeveloped w short embryonic period, develop while attached to mothers nipple until they grow large enough to move independently

Eutheria

placental mammals, larger placenta, viviparous, young better developed at birth

placenta

organ that is rich in blood vessels and facilitates flow of oxygen and nutrients from mother to embryo

gestation

development time of embryo in mothers body

1. better temperature to grow in

2. protection

3. portable

retaining embryo advantages

foramen ovule

hole b/w right & left atrium that allow blood to flow through atria

ductus arteriosis

connects pulmonary artery & aorta, and shunts blood away from lungs and into aorta

ductus venosus

shunts blood from liver to heart

4 majors groups of australopithecus, paranthropus, early homo, recent homo, bipedal,

hominins

foramen magnum

hole in back of skull, placements determines how animals walked

bipedalism

walking upright on two legs

FOXP2 gene

gene essential for human language