Vertebrate Animals

DOMAIN- Eukarya KINGDOM- Animalia

PHYLUM- Chordata•SUBPHYLUM- Vertebrata

CLASS- 7 differentORDERS- 10 Placental mammals

Phylum ChordataRecall that vertebrates are chordates.Phylum Chordata includes the lancelets and tunicates (invertebrate chordates) as well as the vertebratesAll chordates have:

Notochord• flexible rod-like structure • main longitudinal structural element of

chordates and of the early embryo of vertebrates

• plays an organizational role in nervous system development

• becomes part of the vertebral column.

Pharyngeal slitsGill-like slits on vertebrates in embryo stageDisappear in most adultsContinue on in some vertebrates

Characteristics of all Vertebrates

Endoskeleton with a backbone for support of a dorsal nerve cord & muscle attachmentDistinct skull/cephalization (head)Bilateral symmetry (like us!)2 pairs of jointed appendagesCoelom (cavity within between middle and inner tissue layer)Closed circulatory system & chambered heart

Vertebrate Evolution

Major Groups of Vertebrates• Fish – aquatic tetrapods with scales, gills, & 2 chambered hearts

• Agnathans – jawless fishes – hagfish and lampreys• Chondrichthyes – cartilagenous fish - sharks & rays• Osteichthyes – bony fish – mahi-mahi, tilapia, halibut, puffer

fish, tetras, guppies• Amphibians – semiaquatic tetrapods with split lives & 3-

chambered hearts• Anura – “tailless ones” – frogs & toads• Urodela – “tailed ones” – salamanders & newts• Apoda – “legless ones” - caecilians

• Reptiles – terrestrial amniote tetrapods with scales & lungs & 3-ish to 4 chambered hearts• Squamata – lizards and snakes• Testudines – turtles & tortoises• Crocodilia – alligators, crocodiles, and related species

• Birds – terrestrial amniote tetrapods with feathers & lungs & 4 chambered hearts• Ratites – ostriches, emus, kiwis• Passeriformes – perching birds – jays, sparrows, crows,

etc.• Aquatic birds – ducks, swans, geese• Raptors – eagles, falcolns, hawks• Penguins

• Mammals – terrestrial amniote tetrapods with lungs, hair and mammary glands & 4 chambered hearts• Monotremes – echidna and platypus• Marsupials – koala, kangaroo, opossom• Placentals – humans, bears, tigers, giraffes, deer, pigs,

dogs, cats, raccoons, squirrels, whales, walruses, manatees, etc

Fish Vocabulary• Gill – respiratory structure that uses countercurrent exchange to extract oxygen from

water• Operculum – gill covering in bony fish• Lateral line - a row of microscopic organs sensitive to pressure changes, can detect low

frequency vibrations.• Swim bladder – internal, air-filled sac that acts as an organ for buoyancy in bony fish;

sharks have oils in their livers to help them remain buoyant • Scale – small, platelike structure covering an organism (or parts of an organism); sharks,

fish, reptiles, and birds all have different types of scales• Fin – paired appendage found on fish used for locomotion and steering• Reproduction

• External fertilization – release of gametes to the environment where fertilization takes place; bony fish

• Internal fertilization – deposition of sperm in the female reproductive tract where fertilization takes place; sharks

• Hermaphrodite – some organisms are capable of producing both male and female gametes; few are capable of self-fertilization; most exchange sperm; evolutionary adaptation for solitary and slow-moving or sessile organisms

• Ovoviviparous = eggs are fertilized inside the parent and hatch inside the parent and are born liveOviparous = eggs are laid in a nest or in the ground and hatchViviparous = internal fertilization with live born young (as soon as the egg is fertilized, it becomes an embryo and develops as a fetus).

Class AgnathaHagfish and lampreys

- Jawless & finless- Skeleton of

cartilage- Reproduce sexually- Gills- 2 Chambered Heart- Oviparous

Hagfish – a detritivore

Lamprey – an ectoparasite

Evolution of Gnathostomes – the

jawed fishes

Gills are supported by cartilage or bone. Some of these gill supports became other structures, including the jaws and inner ear bones of other vertebrates.

Class Chondrichthyes – sharks and rays

- Endoskeleton made of cartilage- Paired fins- Jaws- 2 chambered heart- Well-developed sense of sight and

smell- Lateral line system (for sensing

pressure changes – vibrations - in water); whole body acts as an “ear”

- unique scales; teeth may be modified scales

- Oviparous, ovoviviparous, and a few are viviparous

- Internal fertilization using claspers to deposit sperm in female reproductive tract

Sharks have a unique digestive structure called spiral valve that increases surface area

Sharks & some rays are carnivoresRays (and the largest sharks) are suspension feeders

Can detect electrical fields of living organisms with special pores in their skin (not the same as the lateral line system which they also have)

Class OsteichthyesTuna, perch, bass, clown fish, eels, seahorses, goldfish, catfish,

etc….* One of the most successful groups on Earth – ever!

- Endoskeleton made of bones- Swim bladder- Usually, external fertilization & oviparous (think caviar)- Lateral line system- Scales different from those in sharks - 2 chambered heart (all fish!)- Water balance important; some fish excrete salt through

their gills, others very watery nitrogenous waste using kidneys

Above: internal anatomy of a ray-finned fish left - photo of a lobe-finned fish; right – photo of a lungfish

Three main groups of Osteichthyes – bony fish

Summing up FISH

FEEDING – herbivores, carnivores, filter feeders, etc.RESPIRATION – Most have gills that absorb oxygen by diffusion from water to blood. A few also have lungs.CIRCULATION – two-chambered heart that pumps blood in loop around body.

EXCRETION – Kidneys expel waste as ammonia. Salt water fish must retain water that leaks out of them, so they have very concentrated urine. Fresh water fish have water leak into them, so must constantly expel very d________ urine.

Solid waste is expelled from stomach.

SENSES AND RESPONSE – brain at end of spine. Very good senses of

sightsmellpressure/movement (lateral line)

hearing less goodPain? Evidence is inconclusive…

MOVEMENT– muscles move finsScales reduce resistanceswim bladder filled with air/gas to adjust buoyancyREPRODUCTION – most have external fertilization. Eggs hatch outside body (oviparous)Some fertilize eggs in body and keep eggs until hatched inside (ovoviviparous) Sharks etc. viviparous embryo gets nourishment from mother.

Aquatic tetrapods gave rise to the first amphibians, who probably came on land in search of food (abundant plant and arthropod species in Devonian)

Amphibian VocabularyEctotherm – organism that must gain (or lose) heat from the environment to maintain body temperature; metabolism is NOT sufficient to heat the body; most invertebrates, fish, amphibians, & reptilesEndotherm – organism that maintains a stable body temperature through metabolism; few reptiles, most birds and mammals, insectsMetamorphosis – change from a sexually immature stage to a sexually mature stage in the life cycle; involves change in body structure and niche; ex) tadpoles are herbivorous, aquatic larvae with gills and no limbs that change into carnivorous, terrestrial adult frogs with lungs and 4 limbsTetrapod – vertebrate with 4 limbs located in pectoral and pelvic girdlesLungs – internal respiratory organs that exchange gases across a membrane surface, usually in conjunction with the circulatory systemCloaca – common opening to the outside of the body through which fecal material, nitrogenous waste and gametes pass; common to amphibians, reptiles, and birds

Class Amphibia: live in water and on land, breathe with lungs and through skin,

moist skin, no scales

More…Frogs, toads, salamanders, and newts

- Ectotherms - Need H2O for breeding- Metamorphosis (tadpole frog)- Gas exchange through moist skin & mouth; primitive

balloon-like lungs- Goos eyes, tympanic membrane- External fertilization- Oviparous- 3-chambered heart- Many have chromatophores in the skin for coloration,

as well as poison glands for defense- Nitrogenous waste varies – aquatic habitat – dilute

urine; terrestrial, concentrated urine

3 major groups of amphibians:

Apoda – caecilians; legless

Anura – frogs & toads; tailless

Urodela – salamanders & newts

Summing up AMPHIBIANSFEEDING – tadpoles filter feeders/herbivores. Adults carnivores. Many have long sticky tonguesRESPIRATION – tadpoles through skin and gills, adults have lungs and breathe through skinCIRCULATION – three-chambered heart that pumps blood in double loop around body.

EXCRETION – Kidneys expel waste through cloaca. Solid waste is expelled from stomach.SENSES AND RESPONSE – brain at end of spine. Very good senses of

sight (big eyes, covered with nictitating membrane to protect eye.)

hearing (tympanic membrane behind eye acts as ear)

MOVEMENT– tadpoles swim like fishFrogs strong hind legs to jump.Salamanders walk or run.REPRODUCTION – external fertilization. Eggs hatch outside body (oviparous) in water.

REPTILESTerrestrialWell-developed lungsDry scales and waterproof skin, amniotic

eggs with shells allow for living on land without drying out

Control body temperature by moving into/out of sunlight

Reptile VocabularyAmniotic egg – adaptation to terrestrial life that

results in a water-proof egg with extra-embryonic membranes that aid in the vital functions of a

living organismExtinct – all members of a species have died; ex) pterosaursExtant – members of a species are still aliveBask – behavioral adaptation of ectotherms to increase body heat; involves moving to locations where more radiant energy (such as from the sun or warm rocks) is available for absorption

Amniotic egg in reptiles - note leathery shell characteristic of reptilian eggs

Class Reptilia turtles, snakes & lizards, crocodiles

- Ectotherms – bask and hide to regulate temperature*- Scaly, waterproof skin- Respire through lungs only**- Internal fertilization- Oviparous, ovoviviparous, viviparous (depending on

species)- 3 or 4 chambered heart- Nitrogenous waste is a paste rather than a liquid for

water conservation; uric acid

- Extinct reptiles include dinosaurs and pterosaurs, which dominated the Earth during the Triassic period

Major extant groups of reptiles:

Squamata – snakes & lizards• both snakes and lizards shed their skin as they grow• Loss of legs is unique to snakes within the reptiles; remnants of pelvic girdles

present in boas, as are external claws on the abdomen• many have unique adaptations for life as predators

• Jacobson’s organ – when a snake flicks its tongue it is collecting molecules that are then brought in to Jacobson’s organ for “processing”; kind of a combined sense of taste and smell

• Pits – many snakes have heat sensory organs on their head that gives an IR picture of an organism, decreasing dependency on vision

• Hollow fangs – with or without poison glands for capturing, holding, and killing prey

• Muscles the length of the body allow it to move quickly and many use those muscles for immobilizing and strangling prey

Major extant groups of reptiles: (cont’d)

Testudines – turtles and tortoises * Some are herbivorous, but most are carnivorous• Lay eggs on land (oviparous)• Cloaca is secondary respiratory surface in aquatic species **• Shell is part of the body, connected to muscle and intimately

intertwined with the skeleton

Crocodilia – alligators and crocodiles (caiman, and other related species)• Adapted for aquatic life with upturned nostrils and eyes

on top of head• endothermic*• 4-chambered heart• Related to feathered reptiles

Major extant groups of reptiles: (cont’d)

crocodiles

American alligator

gharial

Summing up REPTILESFEEDING – Some lizards and turtles are herbivores; snakes and crocodiles are carnivores

http://www.youtube.com/watch?v=p-nj_iOBDqA

RESPIRATION – well-developed lungs CIRCULATION – double loop blood flow to heart with two atria and one or two ventricles

EXCRETION – Kidneys expel waste as ammonia through cloaca. Solid waste is expelled from stomach.SENSES AND RESPONSE – brain at end of spine. Very good senses of

sightsmelltaste – tongue and organ in mouthsense vibrations with skullbody heat – rattle snakes

MOVEMENT– Strong legs and body muscles allow rapid movement

REPRODUCTION – eggs laid on land after internal fertilization; leathery, waterproof shellMales have penises (snakes have two) that penetrate female body.

BIRDS – flying reptiles?

Bird VocabularyFeather – modified scale used for flight and insulation (contour and down)Keel – sternum modified for flight muscle attachmentRatite – flightless birdsBeak – adaptation to the diet of a bird; cranial structure used for feeding and defenseAir sac – pocket attached to the lungs that aid the bird in maintaining constant air flow into the lungs, allowing for flight at high altitudes and greater muscle usePreen gland - gland located on the base of the tail, especially in aquatic birds, that produces oil for waterproofing the feathersCrop – portion of esophagus used for temporary storage of foodGizzard – chamber of the stomach for grinding food

Class AvesBirds

- Endothermic - 4 chambered heart- Internal fertilization- Oviparous- Amniotic eggs with calcerous, hard shells- Cloaca- Nitrogenous waste paste-like for water

conservation; uric acid- Beaks and claws modified for specific niche- Classified as reptiles by many taxonomists- Digestive system modified for diet, including

crop & gizzard

- Many modifications for flight:- Only organism with feathers (modified scales) for

flight and insulation- Evolutionarily may have began as courtship or

defensive displays (behavioral adaptation, rather than for flight)

- Hollow bones - make bird lightweight- Front limbs modified into wings- Air sacs to aid in breathing at high altitudes- Unique muscle tissue for sustained, intense use- Keel – modified breastbone for muscle attachment

Birds migrate – move long distances on a seasonal cycle to reach mating and/or feeding grounds

8600 species of birds in 28 orders• Flightless birds called ratites – emu, ostrich, kiwi• Penguins have wings modified for swimming• Aquatic birds have preen gland to keep their feathers

from becoming saturated, impeding flight• Most birds are passeriformes – perching birds, including

jays, swallows, sparrows, and warblers (see pp. 790 & 91 in your text for more groups of birds)

Bird courtship and mating behaviors are an evolutionary adaptation unique to each speciesMany other groups of birds, including birds of prey, marine birds, seed eaters, woodpeckers, hummingbirds, etc

Summing up BIRDSFEEDING - birds generate own body heat- need large amounts of food - beaks adapted for specialized feeding- no teeth- food stored in crop, then moves to one/two part stomach (gizzard) for grinding up (by stones!) and to intestines

RESPIRATION – well-developed lungs and air sacs to ensure one-way flow of air through lungs. Why important?

http://www.youtube.com/watch?v=iigxJXFJF4U

CIRCULATION – double loop blood flow through heart and lungs and body, like humans

EXCRETION – Kidneys expel waste as uric acid through cloaca. Semi-solid waste (white) is expelled from stomach.

SENSES AND RESPONSE - well-developed brain- very good colour eyesight- good hearing- taste, smell not too good

- migrate using sun, magnetic field, visual markers, smell combination

MOVEMENT- hollow bones with strengthening struts make birds light for flying- strong chest muscles attached to sternum enable flight- feathers provide aerodynamic shape

REPRODUCTION- Mating is seasonal- male bird usually mounts female to allow cloacas to touch and transfer sperm; some male birds have a penis - fertilized eggs are enveloped with shell and laid through cloaca- incubation can take from 11-90 days- chick breaks open shell with an egg tooth

Bird linksEgg hatchinghttp://www.youtube.com/watch?v=0Z87u9t6Nww Bird migrationhttp://www.birds.cornell.edu/allaboutbirds/studying/migration/

http://www.youtube.com/watch?v=bte7MCSBZvo Arctic Terns

Mammal VocabularyMammary gland – gland adapted to produce protein and fat rich nutrition for offspring during early development Hair – keratinous growth for insulation, camouflage, and display; made of same material as reptilian scales and bird feathersFat – layer of connective tissue for insulation and padding; energy reserveDiaphragm – sheet of muscle separating thoracic and abdominal cavities used in respirationMonotreme – mammal that lays eggsMarsupial – mammal with young that finish developing in a pouchMarsupium – pouch in a marsupialPlacental – mammal whose young develop in a uterus attached to a placentaUterus – muscular organ that houses the fetus until birthPlacenta – extraembryonic tissues that develop as a connection between the circulatory system of the mother and that of the developing fetusDentition – tooth pattern; varies with diet; ex) reptilian dentition is characteristically uniform conical teeth for capturing prey, mammalian dentition varies significantly (carnivores, herbivores, insectivores, baleen, omnivores)

Class MammaliaHumans, bears, pigs, horses, dogs, cats, whales, elephants,

mice, koalas, platypus- Endothermic – hair and layer of fat aid in conserving

heat - Hair – keratinous protein that aids in insulation - Mammary glands – produce milk to feed offspring- Internal fertilization

- 2 species of monotreme; oviparous- Marsupials and placentals are viviparous

- Diaphragm for increased respiration & spongy lungs for increased surface area

- 4-chambered heart- Dentition & jaw structure reflect diet- Inner ear contains 3 bones for improved hearing- Large brain; learn; Extended parental care- Most effective kidney for water conservation; urea

Evolutionary advances in jaw structure, dentition, and inner ear structure from reptile to mammal

3 categories of mammals1. Monotremes

- mammals that lay eggs, have hair, and produce milk with mammary glands

- mother produces milk which is excreted from glands on the abdomen and the babies lap up the milk or suck it off the fur of the mother

Echidna and platypus

Platypus has a cartilaginous bill used to find food on the bottom of a pond or river.Males have poisonous spurs on their hind feet for defensePlatypi store fat in their beaver-like tails

2. Marsupials - embryo develops in a uterus with a

placenta Immature fetus is born into a pouch called a

marsupium.Young develop in marsupium, attached to a

teat, until much more mature. All marsupials live in Australia with the

exception of the opossum, which can be found in the Americas.

Interesting Evolutionary NoteMarsupials and placentals show parallel evolution

3. Placentals

Placental mammals develop in a uterus attached to a placenta until at a comparably advanced stage of development

Widespread on earth – found in every major biome, including marine, arctic, and tundra.

Many orders of placental mammals. 10 discussed as follows:

Orders of Placental MammalsRodentia- razor sharp teeth (rats, squirrels)Lagomorpha- fused hind leg bones (rabbits)Chiroptera- flying mammals (bats)Carnivora- eat meat (lions, tigers, wolves)Cetacea- Blow holes to breathe (dolphins, whales)Insectivora- eat insects (moles, shrews, hedgehog)Artiodactyla- even # of toes (cows, sheep, goat,

pigs, hippos, camels)Perissodactyla- odd # of toes (horse, zebra, rhino)Proboscidea- trunks (elephants)Primates- opposable thumbs (apes, monkeys,

humans)

Order PrimatesProsimians – lorises, lemurs, tarsiers

Monkeys – New World Old World

Prehensile tails

Apes Humans

Gibbon OrangutanGorilla Chimpanzee