Today’s Plan: 4/20/10

Bellwork: Test Q&A (15 mins) Animals and Behavior test (the rest of

class) If you finish early, work on labs or

animal summary chart

Today’s Plan: 11/13/09

Continue with animals (15 mins) AP Lab 11 (45 mins) Finish Animals notes (the rest of

class)

Animal Development and Phylogeny

Animals: Are multicellular Are consumers Are eukaryotic Are motile at some point in their

development Reproduce sexually (some are

parthenogenic) Develop from embryos Have a variety of evolutionary advances

Symmetry and Body Plans 2 main body plans: invertebrate and vertebrate

Of the 2, invertebrate has the most variation Some are asymmetric Those which have symmetry, exhibit 1 of2 types :

Radial-may have top and bottom (oral and aboral sides), but can pass a plane through the body in any direction and make 2 equal, identical parts

Bilateral-have dorsal and ventral as well as posterior and anterior ends. May exhibit cephalization. Can pass a plane through the body in only one place to make 2 equal, identical parts

Figure 32-5 Asymmetry

Sponge

No plane ofsymmetry

Radial symmetry

Jellyfish

Multipleplanes ofsymmetry

Bilateral symmetry

Lizard

Single planeof symmetry

Posterior Anterior

Why Symmetry? In general, the most primitive

organisms are asymmetric, slightly more advanced are radially symmetric, and the most advanced are bilaterally symmetric

What’s the significance of symmetry? Indicator of health Serves the organism’s function Sometimes redundancy of parts Sometimes directed nervous

response

The Animal Family Tree The most primitive animals are conglomerations of cells

with little specialization and no true tissues Slightly more advanced animals have cells organized

into distinct tissues, but no organ systems or body cavity Diploblastic organisms have only 2 tissue layers (cnidarians

and ctenophorans) Triploblastic organisms have 3 tissue layers (bilaterally

symmetric organisms) The next group has organ systems, but still no body

cavity (acoelomates) Still more advanced organisms develop a body cavity

which is unlined (pseudocoelomates) The most advanced organisms develop a body cavity

lined in mesoderm (coelomates) In protostomes, coelom forms in mesoderm at the sides of

the archenteron (primordial digestive tube) In deuterostomes, coelom forms in the archenteron wall

Figure 32-6

Pseudocoelomates have an enclosed body cavity partiallylined with mesoderm.

No coelom

Acoelomates have no enclosed body cavity.

Coelomates have an enclosed body cavity completely linedwith mesoderm.

Muscles, organs(from mesoderm)

Skin(from ectoderm)

Gut(from endoderm)

Skin(from ectoderm)Pseudocoelom

Coelom

Muscles, organs(from mesoderm)

Gut(from endoderm)

Skin(from ectoderm)

Muscles, organs(from mesoderm)

Gut(from endoderm)

Family Tree Continued The coelomates are further divided

into two groups: Protostomes-”proto”=first,

“stome”=mouth, form from spiral cleavage

Deuterostomes-”deutero”=second, “stome”=mouth, form from radial cleavage

Groups are based on the fate of the Blastopore during gastrulation

Figure 32-10

Animalia

Segmentation

Anim

Choan

oflag

ella

tes

Fung

i als

Amoe

bozo

a

Protostoma

Bilateria

Lophotrochozoa

Deuterostoma

Ecdysozoa

Cho

rdat

a

Ech

inod

erm

ata

Art

hrop

oda

Nem

atod

a

Ann

elid

a

Mol

lusc

a

Rot

ifera

Pla

tyhe

lmin

thes

Aco

elom

orph

a

Cte

noph

ora

Por

ifera

Cni

dari

a

Cho

anof

lage

llate

s

Pseudocoelom

Acoelom

Protostome development

Growth by molting

PseudocoelomSegmen-tation

Radialsymmetry(in adults)

Deuterostomedevelopment

Segmen-tation

CoelomTriploblasty (origin of mesoderm)

Bilateral symmetry and cephalizationRadial symmetry

Diploblasty (ectoderm and endoderm)Epithelial tissue

Multicellularity

(com

b je

llies

)

(spo

nges

)

(jelly

fish,

sea

ane

meo

nes)

(aco

els)

(rot

ifers

)

(fla

twor

ms)

(seg

men

ed w

orm

s)(s

nails

, cla

ms,

squ

id)

(inse

cts,

spi

ders

,

cr

usta

cean

s)

(rou

ndw

orm

s)

(sea

sta

rs, s

and

dolla

rs)

(ver

tebr

ates

,

asc

idia

ns)

Phylogenetic tree based on similarities anddifferences in the DNA sequences ofseveral genes from various animal phyla.The bars along the branches indicate whencertain morphological traits originated

Figure 32-1-Table 32-1a

Figure 32-1-Table 32-1b

Figure 22-11

Cross section

Whole embryo

Blastocoel

Blastopore

Blastopore

Start of gut

EndodermEctoderm MesodermDURING GASTRULATION, EMBRYONIC TISSUES FORM DISTINCT LAYERS.

1. Different regions of the frog blastula containcytoplasmic determinants(signals or transcriptionfactors) that determinetheir fate during gastrulation.

2. Gastrulation begins with the formation of an opening—theblastopore—that extends intothe embryo. Cells from thesurface move into the interiorthrough the blastopore.

3. The blastocoel shrinks as the surface cellscontinue to move inward,forming the threeembryonic tissue layers.

4. The three embryonic tissue layers are formed,ready for organogenesis.The blastopore (futureanus in frogs) surroundsa plug of yolk cells.

Figure 22-12

Figure 32-8

2-cellstage

Porebecomesmouth

4-cellstage

PROTOSTOMES DEUTEROSTOMES

8-cellstage

Radialcleavage

Spiralcleavage

Porebecomesanus

Longitudinalsection

Anus

Mouth

Mesoderm Mesoderm

Coelom

Gut Gut

Coelom formation(body cavity linedwith mesodermdevelops)

Gastrulation(mass of cellsformed by cleavageis rearranged toform gut andembryonic tissuelayers)

Cleavage(zygote undergoesrapid divisions,eventually forminga mass of cells)

Cross section

Block of solidmesoderm splitsto form coelom

Mesoderm pockets pinch off of gutto form coelom

Figure 22-8-1

Radial cleavage: Cells divide at right angles to each other.

Spiral cleavage: Cells divide at oblique angles to each other.

A word about Germ layers “Germ” layers refers to the 3 layers of

tissues in most animals. The layers are present at gastrulation during embryonic development

Ectoderm is the outermost layer of cells. It gives rise to the nervous system, skin, hair and nails

Mesoderm is the middle layer of cells and is the most versitile. It becomes the skeleton, muscles, inner layer of skin, visceral lining, fatty tissues, and circulatory system

Endoderm is the innermost layer of cells. It gives rise to the gut and organs associated with digestion and excretion

Why a coelom? The most advanced group of

organisms have a coelom. What’s its significance?

In order for a body cavity to be considered a coelom, it must be lined in mesoderm. Mesoderm sections off parts of the body This leads to segmentation, a great

evolutionary advance. Why?

Figure 32-7 Hydrostatic skeleton of a nematode

Gut

Coordinated muscle contractions result in locomotion.

Muscles relaxed

Fluid-filled pseudocoelom(under pressure—createstension in body wall)

Body wall (in tension—creates pressure in fluid)

When the muscleson one side contract,the fluid-filled chamberchanges shape andthe animal bends.

Muscles (cause shape change)

Musclescontracted

Musclescontracted

Muscles relaxed

About Animal Classification As before, new molecular data continues to change

our views on how animals are grouped into phyla. The bilaterally symmetric animals are particularly messy to classify

Our understanding of Hox genes has changed our views on animal embryology

There are some points of agreement with respect to classification: All animals share a common ancestor Sponges are the base of the animals family tree Eumetazoa is a clade of animals with true tissues

(cnidaria and ctenophora, formerly coelenterata) Most animal phyla belong to the Bilateria clade Chordates and some other phyla belong to the clade

Deuterostomia

Major Invertebrate Phyla Sponges were formerly called “Porifera” and are

organisms that have the following characteristics: Suspension feeding (capturing food from the water as

it travels through the body Pores on the outer surface pull in water and send it

out through the spongocoel and it’s main opening, the osculum

All are hermaphroditic Have a few specialized cells but no tissues:

Choanocytes-collar cells that are flagellated for feeding Amoebocytes-mobile cells that have pseudopods and

carry nutrients around the body These are now split into 2 phyla:

Calcarea Silicea

Figure 32-26

Pseudoceratina crassa

Eumetazoans This is a clade, consisting of 2 major phyla of diploblastic

organisms: Cnidaria (Includes: jellyfish, hydra, sea anemones, etc)

Radially symmetrical Tissue layers (2 distinct-epidermis, gastrodermis)-mesoglea in

between (jelly) 2 forms-medusa (mouth down, free-swimming), and polyp (mouth

up, sessile) Stinging nematocysts for defense and predation (inside the

cnidocytes) 1st organisms with a nervous system (primitive-nerve net, no

central control) No matter which shape the organism takes, it’s internal cavity is

the gastrovascular cavity Food enters the mouth and broken down. Nutrients from the food

are absorbed by the surrounding cells and wastes are expelled from the mouth (2-way digestive tract)

Ctenophora (Comb Jellies) Look like jellyfish, but move via the 8 rows of cilia on their bodies No cnidocytes/nematocysts, instead use colloblast (specialized

mucous cells) secretions to catch and hold onto prey Actually have a nervous control structure called the Apical Organ

at one end of the body

Figure 32-27

Polyps attach to substrates. Medusae float near the water surface.Aurelia aurita Aurelia aurita

Figure 32-18

Sessile adult anemoneMotile larval anemone

Figure 32-3

Cnidarians and ctenophores arediploblastic.

Cnidaria include hydra, jellyfish, corals,and sea pens (shown).

Ctenophora are the comb jellies.

Ectoderm

Endoderm

This darkblue combjelly… …has just

swallowedthis whitecomb jelly

Figure 32-4

Captured prey will betransferred to mouth

Tentacles

Tubular body

Basal disk

Mouth

Figure 32-24

Reproductivepolyp

MITOSIS

Medusa(2n)

Zygote(2n)

Egg(n)

Sperm(n)

Feedingpolyps(2n)

MITOSIS

Colonies canget very large,with hundredsof polyps

Larva swims viacilia, then settles

Diploid

Haploid

FERTILIZ

ATION

MEIO

SIS

ME

IOS

IS

Figure 32-28

Pleurobrachia pileus

Rows of cilia

Sticky tentacles

Lophotrochozoans

Clade of organisms that have either/or both a crown of ciliated tentacles or a cilliated larvae called a trocophore

This includes the flatworms (Platyhelminthes), Rotifers, Molluscs, and annelids

Figure 33-11

Lophotrochozoa

EcdysozoaRotif

era

Platy

helm

inth

es

Annelid

a

Mollu

sca

Figure 33-4

Lophophores function in suspension feeding in adults.

Food particles

Trochophore larvae swim and feed.

Anus

Mouth

Watercurrent

Gut Anus

MouthCilia used inlocomotionand feeding

Acoelomates Also called the flatworms b/c they have no

body cavity and a flattened body First organisms with bilateral symmetry and

cephalization (anterior and posterior end) Organisms with a two-way digestive tract or

none at all No need for lungs or gills because of the

flat body plan (O2 exchange via diffusion) Water-living or parasitic Mostly vermiform (“vermi”=worm)

Figure 33-13

Pseudoceros ferrugineus

Turbellarians are free living.

Taenia species

Cestodes are endoparasitic.

Dicrocoelium dendriticum

Trematodes are endoparasitic.

Rotifers Small, freshwater organisms with a ciliated

crown Have an alimentary canal with 1-way

digestion Some species can reproduce via

parthenogenesis and are all female, others produce 2 types of eggs and are parthenogenesis, while others have males only for the purpose of reproduction

Figure 33-12 Rotaria rotatoria

Corona

Mollusca Bilaterally symmetric Muscular Foot (ventral) Mantle (dorsal)-secretes shell, forms mantle cavity Rasping organ called the Radula Coelomates Open circulatory system Primitive kidneys Gills or primitive lungs Eyes for seeing Several ganglia with a more complex nervous sys Examples include snails, slugs, chitons, limpets,

bivalves (clams, oysters, mussels, scallops), chambered nautilis, squid, octopus

Figure 33-7b

Muscular “foot”Mantle (secretes shell)

Visceral mass (internal organsand external gill)

Gill

Mollusc body plan (internal view)

Figure 33-15

Lima scabra Scallops live on the surface of the substrate andsuspension feed.

Most clams burrow into soft subtrates and suspension feed.

Gills are thin structures forgas exchange. They also trapfood particles as water passesthrough them. Cilia move theparticles to the mouth

Siphons

Foot

Gill

Water out Water in Foodparticles

Figure 33-16

Maxacteon flammeaSnails have a single shell, which they use for protection.

Land slugs and sea slugs (nudibranchs) lack shells.

Bright colors warnpotential predatorsof presence of toxins

Chromodoris geminus

Figure 33-17

Tonicella lineata

Figure 33-18

Octopus dofleini

Figure 33-4

Lophophores function in suspension feeding in adults.

Food particles

Trochophore larvae swim and feed.

Anus

Mouth

Watercurrent

Gut Anus

MouthCilia used inlocomotionand feeding

Annelids 1st organisms with segmentation (metamerism) Closed circulatory system (blood pigments), but gas

exchange occurs via osmosis 1-way digestive tract Double nerve cord, 2 ganglia, lateral nerves in each

segment (metamere), brain Taste, tactile, light sensation Vermiform Bilaterally symmetric Head (prostomium) and an anus-bearing terminal portion New segments form behind head and are pushed back (like

tapeworms) Circular and longitudnal muscles for complex movement

patterns-in each metamere Hydrostatic skeleton in each segment Septa cause internal segmentation, but are traversed by the

gut and nerves

Figure 33-14

Alvinella pompejana

Most polychaetes are marine.

Paranais litoralis

Most oligochaetes are terrestrial.

Hirudo medicinalis

Most leeched live in freshwater.

Chaetae

Ecdysozoans

Clade consisting of organisms that go through ecdysis (molting) b/c they have exoskeletons

Includes the Pseudocoelomates (Nematodes) and Arthropods

Figure 33-19

Lophotrochozoa

Ecdysozoa

Nemat

oda

Onychophora

Tardig

rada

Arthro

poda

Figure 33-5

Nematodes Have round bodies (pseudocoel) Organisms have sphincters to hold in

organs Both free-living and parasitic Ex: hook worm, Ascaris, pinworm, trichina

worm, dog heartworm Often have complex life styles

w/intermediate hosts Often have male and female forms with

dimorphism

Figure 33-21

Strongyloides species

Nematodes

Arthropods Arthro=jointed, pod=foot, all have jointed

appendages Exoskeleton made of chitin (a protein) and

sometimes calcium carbonate Have metamorphosis Bilateral symmetry, open circulation,

nervous system like that of annelids Have gills, air tubes, or book gills Have head, thorax, and abdomen

(sometimes head and thorax are fused into a cephalothorax

Figure 33-7a

Tagma

Jointed limbs Segmented bodyExoskeleton (covers body)

AbdomenThoraxHead

Arthropod body plan (external view)

Figure 33-23

Dermatophagoides speciesDolomedes fimbriatus

Spider, showing general chelicerate features Mites are ectoparasitic.

Posterior region

Anterior regionChelicerae

Figure 33-24

Enoplometopus occidentalisDeep-sea lobster

Fiddler crab

Carapace

Tetraclita speciesRed barnacle

Uca vocans

Compoundeyes onstalks

Barnaclessecrete theirown shells

Figure 33-23-Table 33-1-1

Figure 33-23-Table 33-1-2

Deuterostomia

This is a clade that includes all deuterostome animals

The major phyla within this clade are the Echinoderms and Chordates

Figure 34-1

Protostomes

Deuterostomes

Porifer

a

Cnidar

ia

Ctenophora

Acoel

omorp

haRotif

era

Platy

helm

inth

esAnnel

ida

Mollu

sca

Nemat

odaO

nychophora

Tardig

rada

Arthro

poda

Echin

oderm

ata

Hemic

hordat

aXen

oturb

ellid

aChord

ata

Deuterostomedevelopment

This phylum includesvertebrates: sharks,bony fishes, amphibians,reptiles (including birds),and mammals

CoelomTriploblasty

Bilateral symmetry

Animals that are notvertebrates are collectivelyknown as invertebrates. Over95% of the known animal speciesare invertebrates, including theechinoderms, hemichordates,and xenoturbellids.

Echinoderms Non-metameric adult with radial symmetry Larvae are bilaterally symmetric No head or brain, circular ring and radial nerves Skeleton of embedded ossicles (calcium carbonate)

within the dermis Pedicellariae for catching and moving food Water vascular system with tube feet for locomotion One-way digestive tract (sometimes with eversible

stomach) Dermal branchae also help with vascularization Usually separate sexes Ex: sea stars, sea lillies, sea urchins

Figure 34-2

Adult echinoderms areradially symmetric.

Echinoderm larvae arebilaterally symmetric.

Figure 34-3

Echinoderms have a water vascular system.

Opening to exterior

Podia

Tube foot

Podia

Podia project from the underside of the body.

Figure 34-21

Dendraster excentricusEchinus tylodesSand dollarSea urchin

Teeth at centerof underside

Invertebrate Chordates 2 major Phyla: Cephalochordata and Urochordata Widespread Marine Have a notochord at some point in their development Pharyngeal Gill slits Dorsal Nerve cord (tubular) Postanal tail Bilateral Symmetry Segmented muscles in an unsegmented trunk Ventral heart w/ closed circulation Complete digestive system

Figure 34-5a

Muscular,post-anal tail

Notochord

Dorsal hollow nerve cord

Pharyngeal gill slits

Urochordata (tunicates)

Water flow

Water flow

AdultPharyngeal gill slitsLarva

Figure 34-5b

Pharyngeal gill slitsWater flowMuscular,post-anal tail

NotochordDorsal hollow nerve cordAdult

Cephalochordata (lancelets)

Figure 34-23

Salpa fusiformisCiona intestinalisSalpSea squirt

Figure 34-24

Branchiostoma lanceolatum

Figure 34-7-1

LungfishCoelacanthsLampreysRay-finned

fishesSharks

rays, skatesLancelets HagfishTunicates

Loss ofpharyngealgill slits

AcornwormsEchinoderms Xenoturbella

Radial symmetry,water vascular system,loss of pharyngeal gillslits

Echin

oderm

ata

Hemic

hordat

a

Xenotu

rbel

lida

Uroch

ordat

a

Cephal

ochord

ata

Myx

inoid

ea

Actin

optery

gii

Petro

myz

ontoid

ea

Chondrichth

yes

Actin

istia

Dipnoi

Echinodermata

Deuterostromes

Hemichordata

Chordata

Xenoturbellida

Protostomes

Figure 34-7-2

Birds

Amniota

TurtlesAlligators,crocodiles

Lizards,snakesMammals

Tetrapoda

SalamandersFrogs,toads

AmphibiaAnura

Urodel

a

Mam

mal

ia

Testu

dinia

Lepid

osauria

Croco

dilia

Aves

Chordata

Vertebrata

Craniata

Sarcopterygii

Reptilia

Lactation

Fur

Amniotic egg

Limbs

Lungs

Bone

JawsVertebrae

Four distinguishingcharacteristics of chordates

Muscular, post-anal tail

Pharyngeal gill slits

Dorsal hollow nerve cordNotochord

Vertebrate Chordates Have all of the characteristics of invertebrate

chordates, but also have a vertebral column and spinal cord

These are also called the craniates-have a head Major Classes include:

Myxini-Hagfish Pterromyzontida-Lampreys Chondrichtheyes-Sharks, skates, and rays Osteictheyes (Actinopterygii, Actinistia, Dipnoi)-Bony

fish Amphibians-frogs, salamanders Reptiles-lizards, snakes, crocodillians Aves-Birds Mammalia-duh!

Figure 34-25

Eptatretus stoutii

Petromyzon marinus

Hagfish

Lampreys feeding on fish

Mouth

Lampreys

Figure 34-26

Prionace glaucaSharks are torpedo shaped.

Pectoral fin

Taeniura melanospilaSkates and rays are flat.

Pectoral fin

Dorsal fin

Asymmetrical tail

Figure 34-27

Bony rods in fin

Holocentrus rufus

Figure 34-28

Fleshy lobessupported by bones

Latimeria chalumnae

Figure 34-29

Eggs

Ichthyophis kohtaoensisBufo periglenes

Frogs and other amphibianslay their eggs in water.

Caecilians are leglessamphibians.

Figure 34-35

Testudo pardalis

Figure 34-37

Alligator mississippiensis

Figure 34-36

Morelia viridis

Figure 34-38

Diomedea melanophris

Figure 34-31

Tachyglossus aculeatusOrnithorhynchus anatinusPlatypus Echidna

Figure 34-32

Didelphis virginiana

Figure 34-33

Hylobates lar

Trends in Chordate Evolution From plain chordate characteristics to

having a cranium From cranium to jaw (made from gills of

fish) Tetrapodal body plan (made from fins of

fish) Amniotic (membranous) egg-waterproofing Feathers (from scales of reptiles) From oviparity (monotremes) to viviparity

(marsupials and eutherians)

Figure 34-10

Jawless vertebrate

Mouth

EVOLUTION OF THE JAW

Gill arches

Gill arches

Intermediate form (fossil acanthodian fish)

Gill arches

Fossil shark

Jaw

Jaw

Figure 34-12

Extinct lineage oflobe-finned fish(aquatic)382 mya

EVOLUTION OF THE LIMB

Early tetrapod(semiterrestrial)365 mya

Paleozoic tetrapod(terrestrial)350 mya

Limb

Fin

Figure 34-14

EVOLUTION OF THE FEATHER

3. Central shaft withpairs of branches

1. Simple projection 2. Tufts 4. Central shaft with pairsof branches bearing finerbranches

The feathers ofmodern birdslook like thisMicroraptor had

feathers like this

Figure 34-16

Albumenprovides water

Shell

Yolk saccontains nutrients

Allantois

wastecontains

Embryo

Figure 34-17

Yolk sac

Chorion

Amnion

Embryo

Allantois

Placenta

Mother’s uterus