UNIT 11ANIMAL

EVOLUTON

CHAPTER 32:INTRODUCTION TO ANIMAL EVOLUTION

Archenteron

Grade Phylogeny

Molecular Phylogeny

CHAPTER 33: INVERTEBRATES

PARAZOA Phylum Porifera

SessilePorous Bodies

Filter/ Suspension Feeders (pump water) Color - symbiotic algaeHermaphrodites Regeneration

RADIATA Phylum CnidariaSac with a central digestive compartmentSessile polyp and the floating medusa

Tentacles (capture prey)Stinging capsules

Muscles and nerves (simple)No brainNoncentralized nerve net

Acoelemates Phylum Platyhelminthes (flatworms)

BILATERIA

Free-living formsSome parasites (tapeworm/fluke)Flattened dorsoventrally

Mesoderm (triploblastic)True muscle tissueLack a digestive tract

Lack organs specialized for gas exchange and circulation

Osmoregulatory (pharynx opening)

Head (cephalized)Pair of eyespotsSmellLearn to modify their responses to stimuliHermaphrodites, copulating

BILATERIA Pseudocoelemates Phylum Rotifera

JawsCrowns of ciliaComplete digestive tractMouth and anus

Some Parthenogenesis (all females)Some degenerate males (sperm donors)

YouTube - Sponge Feeding.movYouTube - Sponge Reproduction.movYouTube - Sea Sponges Under The Sea

YouTube - Cnidarian Eating.movYouTube - Cnidaria Ability To Move.mov

YouTube - Planarian Regeneration Part 1.movYouTube - Planarian Regeneration Part 2.mov

Phylum MolluscaPROTOSTOMIASnails and slugs (land), oysters, clams, octopuses and squids

Most have hard shell made of calcium carbonateMuscular footVisceral massMantle

GillsRadula to scrape up food

Open circulatory system Dorsal heart Circulatory fluid (hemolymph) Arteries

Excretory organs (nephridia)

Nerve cords

Most separate sexes, with gonads (ovaries or testes)

closed circulatory systemcomplex brain

Phylum Annelida (segmented worms)PROTOSTOMIA

Digestive system with specialized regions

Closed circulatory system

Blood pumping vessels

Brainlike pair of cerebral ganglia

Pair of nerve cords

Hermaphrodites, but they cross-fertilize

Regeneration (asexual)

Earthworm, leachesCoelom Segmentation

PROTOSTOMIA: ECDYSOZOA (molecular)Phylum Nematoda (round worms)

Nonsegmented pseudocoelomatesTough cuticle covering (exoskeleton)Molting, or ecdysisComplete digestive tractNo circulatory system

Separate sexesInternal fertilization

Pinworm, hookworm

YouTube - Wow! Giant octopus - extreme animals - BBC wildlifeYouTube - Cuttlefish: Chameleons of the Sea

YouTube - Roundworm inside cat's intestineYouTube - Parasites Eating Us Alive - Part 2YouTube - Parasite Monsters Inside Me - Part 1YouTube - Monsters Inside Me: Toddler Under AttackYouTube - Monsters Inside Me- Pork TapewormYouTube - Removing Intestinal Worms and Parasites from a 3 Year Old

Phylum: ArthropodaPROTOSTOMIA: ECDYSOZOA (molecular)

Segmented coelomatesExoskeletons (cuticle/chiton)Jointed appendages

Two out of every three organisms known are arthropodsNearly all habitats

modified for walking, feeding, sensory reception, copulation, and defense

Molting (ecdysis) Well-developed sensory organs (sight, smell, touch)Cephalization is extensive

Open circulatory systems (hemolymph) Heart (arteries and spaces called sinuses)Specialized gas exchange (gills/ trachea)

DEUTEROSTOMIA Phylum Echinodermata

Water vascular system and secondary Radial anatomy

Sessile or slow-moving animalsEndoskeletonWater vascular system

Tube feetMetamorphosis from bilateral larvae

Sea Stars, Sea Urchins, Sand Dollars

Regeneration

Phylum ChordataDEUTEROSTOMIA Two subphyla of invertebrate animals plus the subphylum Vertebrata, the animals with backbones

Summary the animal phyla we have discussed in this chapter.

Choanocytes (collar cells--unique flagellated cells that ingest bacteria and tiny food particles); cells tend to be totipotent (retain zygote’s potential to form the whole animal)

Unique stinging structures (cnidae), each housed in a specialized cell (cnidocyte); gastrovascular cavity (incomplete digestive tract with a mouth but no anus)

Colloblasts (adhesive structures) for prey capture; eight rows of comblike ciliary plates; gastrovascular cavity

Dorsoventrally flattened, unsegmented acoelomates; gastrovascular cavity or no disgestive tract

Pseudocoelomates with complete digestive tracts; jaws in pharynx structures (trophi); head with a cilated crown (corona); no circulatory system

Coelomates with lophophore (feeding structure bearing cilated tentacles)

Unique anterior proboscis surrounded by fluid-filled cavity (rhynchocoel); complete digestive tract (mouth and anus); circulatory system with closed vessels

Coelomates with three main body parts (muscular foot, visceral mass, mantle); coelom reduced; main body cavity is a hemocoel

Coelomates with body wall and internal organs (except digestive tract) segmented

Cylindrical, unsegmented pseudocoelomates with tapered ends; no circulatory system

Coelomates with segmented body, jointed appendages, exoskeleton from ectoderm

Coelomates with secondary radial anatomy (larvae bilateral; adults radial); unique water vascular system; endoskeleton

Coelomates with notochord; dorsal hollow nerve cord; pharyngeal slits; muscular postanal tail

CHAPTER 34VERTEBRATE EVOLUTION

AND DIVERSITY

1. Notochord (disks)2. Dorsal, Hollow Nerve Cord

phylum Chordata Deuterostomes

Central nervous system: the brain and spinal cord

3. Pharyngeal Slitsmodified for gas exchange (in aquatic vertebrates), jaw support, hearing, and other functions

4. Muscular, Postanal Tail

Subphylum Urochordata (Tunicates/ Sea Squirt) Sessile or Planktonic

Tunic (celluloselike carbohydrate)

Larva

Subphylum Cephalochordata (Lancelet)SmallLive in the sand Suspension feeders

Swim like fish

Some Invertebrates

Both areInvertebrates

Subphylum VertebrataLarger sizeActive lifestyleNeural crest (form skeletal elements/braincase)Pronounced cephalizationVertebral columnClosed circulatory system

Endoskeleton Axial skeleton (cranium, vertebrae, ribs) Appendicular skeleton (support appendages) Grows

Ventral, chambered heart (blood, arteries, capillaries)Gills or lungs*Adaptations for feeding, digestion, and nutrient absorption

Jaws/ 2 sets of paired appendages4 footed

shelled, water-retaining eggAgnathansJawless vertebrateseel-like in shape

predate the origin of paired fins, teeth, and bones hardened by mineralization (ossification)

Class Myxini: HagfishesMost primitive living "vertebrates"Bottom-dwelling scavengersSlime producing glandsCartilage (connective tissue)Serpentine swimming

Class Cephalaspidomorphi:Lampreys

larvae for years in freshwater streams migrate to the sea/lakes streamsCartilaginous pipe surrounding the rodlike notochord

Toothlike structures (keratin)

Chondrichthyes (the cartilaginous fishes: sharks and rays) Osteichthyes (the bony fishes: ray-finned fishes, lobe-finned fishes, and lungfishes)JawsPaired finsTailActive predators

Gnathostomes Jaws evolved by modification of the skeletal rods that had previously supported the anterior pharyngeal (gill) slits

remaining gill slits = respiratory gas exchange

Class Chondrichthyes: Sharks and raysCartilaginous skeletons Sharp Bony teethStreamlined bodiesPowerful swimming musclesBuoyancy by storing a large amount of oil in its huge liver Animal is still denser than water, and it sinks if it stops swimming

Use muscles of the jaws and pharynx to pump water over the gillsSuspension feeders and CarnivoresShort digestive tract (spiral valve)Acute senses (predation)Sight good (no color)Smell (nostrils)Lateral line system (detect water pressure changesDetect electrical fields generated by muscle contractions of animalsEntire body transmits sound to hearing organs of inner ear (no eardrum)Internal fertilization (cloaca/ male claspers near pelvic fin)Oviparous; they lay eggs that hatch outside the mother’s body. Ovoviviparous; they retain the fertilized eggs in the oviduct. Viviparous; the young develop within the uterus, nourished by placenta

Class Osteichthyes: The bony fishesRay-finned fishes, lobe-finned fishes, and the lungfishes

Most numerous vertebratesOssified endoskeleton (calcium phosphate)Flattened, bony scalesMucous glandsLateral line systemFour or five pairs of gillsOperculum (muscle movement)Swim bladderFlexible finsMost oviparous

Ray-finned fishes Bass, trout, perch, tuna, herring, etc. Fins supported by long flexible rays

Lobe-finned fishes Coelacanth Muscular pectoral and pelvic fins supported by extensions of the bony skeleton

Lungfishes Lungs connected to the pharynx of the digestive tract Gills (main organs for gas exchange) Aestivate (state of torpor).

Adaptations to shallow waterBuccal pumping/ mouth breathing (lungfishes and frogs)Leglike appendagesAcanthostega

Tetrapods

Class AmphibiaSalamanders, frogs, and caecilians

Order Urodela "tailed ones"

Aquatic and Terrestrial (as adults)Walk with a side-to-side bending swagger (resembling early tetrapods)

Moist skin to carry out gas exchangeEggs lack a shell (dehydrate)External fertilization (most)Complex and diverse social behaviorRapid and alarming population decline (worldwide)

Order Anura "tail-less ones"Powerful hind legsLong sticky tongueCamouflageSkin glands (distasteful/poison mucus) Brightly colored (poisonous)Metamorphosis

Order Apoda, meaning "legless ones,"

CaeciliansLegless and nearly blindSuperficially resemble earthwormsBurrow in damp soil

Salamanders

Amniotes reptiles, birds, and mammalsAdaptations to land (terrestrial)Amniotic egg (shell)Extra embryonic membranesWaterproof skinIncreasing use of the rib cage to ventilate the lungs

key differences between the three groups in their skull anatomy

Scales (protein keratin)LungsShelled amniotic eggs (land/ leather)Internal fertilizationViviparous (some lizards and snakes)“Cold blooded”Ectothermic (basking)Dominant terrestrial vertebrates for +200 million yearsDinosaurs and Pterosaurs Social behavior and parental care Endothermic?

Class: Reptilia (lizards, snakes, turtles, crocodiles)

Order Testudines (turtles)

Order Sphenodontia (tuataras);

Order Squamata (lizards and snakes)

Order Crocodilia (alligators and crocodiles)

Hard shellLay eggs on land

LizardsMost numerous and diverse reptilesRelatively small

SnakesDescendants of lizards that adapted to a burrowing lifestyle (vestigial limbs)LimblessCarnivorousAcute chemical sensorsLack eardrums but sensitive to ground vibrationsHeat-detecting organs between the eyes and nostrils of pit vipersToxin through a pair of sharp hollow or grooved teethTongue (olfactory organs on the roof of the mouth)Loosely articulated jaws

Among the largest living reptilesUpturned nostrils

Two species of New Zealand animals

Class: Aves (birds)

Amniotic eggs and scales on the legs (reptilian features)Flight Bones are honeycombed (light) Absence of some organs (one ovary) Toothless Gizzard grinds food (crocodiles/dinosaurs) Beak of keratin (adaptations)Active metabolism Endothermic Feathers (retain heat) Advanced circulatory (4 chambered heart) Advanced respiratoryAcute senses Sight (possibly the best) Motor skills/ coordinationSocial behaviorInternal fertilization

Large pectoral (breast) muscles anchored to a keel on the sternum (breastbone)Feathers (endothermy and flight)

Archaeopteryx

Ratites (no keel)Carinates (keels)

Passeriformes“perching”

Class: MammaliaMammary glandsHair (keratin)EndothermicCirculatory-4 chambered heartRespiratory-diaphragmFat (retain heat)

Internal fertilizationBirth (some placenta)Large brainsCognitive abilitiesExtended parental care

Differentiation of dentition (teeth)Inner ear (from jaw bones)

Therapsids

Monotremes (platypuses spiny anteaters) Egg laying (reptilian like) Milk and hair No nipples (just glands)

Marsupials (Opossums, kangaroos, koalas) Early birth Pouch (marsupium) Austraila

Eutherians (Placental) Longer gestation (pregnancy)

PrimatesGrasping handsOpposable thumb (big toe)Larger brainFlattened faceStereoscopic visionNailsFinger skin ridges (prints)Extended parental careComplex social behaviorCoordinationFlexible joints

Great Apes/ HumansHominoids

Bonobo chimpanzee

Australopithecines

Homo habilis Homo erectus Homo sapiens

~5 – 2 mya

~2 – 1.5 mya ~1.6 mya ~400,000 – 100,000 ya

Hominids

BipedalismLarger brain (~400 cm3 1300 cm3)Shorter jawsDentitionSexual dimorphism (male size to female)Extended parental careFamily structureLearning

~5 million years of Evolution

Human