VERTEBRATESVERTEBRATES

Ch. 25 & 26Ch. 25 & 26

LifeLife

BirdsBirds MammalsMammals

What are vertebrates?What are vertebrates?

Animals with a backboneAnimals with a backbone Examples: fishes, frogs, turtles, Examples: fishes, frogs, turtles,

snakes, birds, alligators, mammals, snakes, birds, alligators, mammals, etc.etc.

Vetebra comes from the Latin word vertere, meaning “to turn”

Phylum ChordataPhylum Chordata

Chordates are named for an Chordates are named for an embryonic structureembryonic structure

– The The notochordnotochord is a flexible rod that extends is a flexible rod that extends through much of the length of the bodythrough much of the length of the body

Most chordates are vertebrates, Most chordates are vertebrates, butbut

There are two groups of There are two groups of invertebrates that are chordates invertebrates that are chordates (tunicates & lancelets)(tunicates & lancelets)

Vertebrates are ChordatesVertebrates are Chordates

Vertebrates are animals with Vertebrates are animals with a skull and a a skull and a backbonebackbone– An endoskeletonAn endoskeleton

In vertebrates, only remnants of the notochord In vertebrates, only remnants of the notochord remainremain

Example: the cartilage discs in your Example: the cartilage discs in your backbonebackbone

Most vertebrates have paired limbsMost vertebrates have paired limbs

Hinged JawsHinged Jaws– Importance?Importance?

Other important featuresOther important features

VertebratesVertebrates

Hagfish and lampreysHagfish and lampreys Do not have hinged jaws or paired limbsDo not have hinged jaws or paired limbs

VertebratesVertebrates

FishesFishes– Have hinged jawsHave hinged jaws– aquaticaquatic

Tetrapods:Tetrapods:

Amphibians, reptiles, birds, Amphibians, reptiles, birds, mammalsmammals

Tetrapods (“four footed”) have 2 sets Tetrapods (“four footed”) have 2 sets of paired limbsof paired limbs

This allowed them to??This allowed them to??

Snakes are tetrapods!Snakes are tetrapods! They evolved to become leglessThey evolved to become legless

ActivitiesActivities

1) Finish grasshopper dissection & 1) Finish grasshopper dissection & turn in.turn in.

2) pHSuccessnet.com2) pHSuccessnet.com– Ch. 25 webquestCh. 25 webquest– Activity 25.1Activity 25.1

FISHESFISHES

2 Categories:2 Categories:

Cartilaginous fishesCartilaginous fishes – Chondrichthyes – Chondrichthyes Skeletons are flexible and made entirely of Skeletons are flexible and made entirely of

cartilagecartilage Sharks and raysSharks and rays

Bony fishesBony fishes Skeletons contain bone hardened by calcium Skeletons contain bone hardened by calcium

depositsdeposits

The 1st jawed vertebrates.

Bony FishesBony Fishes

Stiff skeleton made of calciumStiff skeleton made of calcium Gills to extract OGills to extract O2 2 from waterfrom water

– Operculum- flap that covers the gillsOperculum- flap that covers the gills

- - pumps water over the gillspumps water over the gills Lateral line systemLateral line system

Bony FishesBony Fishes

Stiff scales made of boneStiff scales made of bone

The outer mucus allows fish to glide The outer mucus allows fish to glide more easily through the watermore easily through the water

Most are carnivoresMost are carnivores Some feed upon plankton or algae (seaweed)Some feed upon plankton or algae (seaweed)

Bony FishesBony Fishes

Air SacAir Sac– ““swim bladder”swim bladder” makes fish more buoyant makes fish more buoyant– Also aids in hearing by transmitting vibrationsAlso aids in hearing by transmitting vibrations

Heart ---> 2 ChambersHeart ---> 2 Chambers The ventricle (1) pumps blood to the gillsThe ventricle (1) pumps blood to the gills The atrium (2) receives blood returning from the bodyThe atrium (2) receives blood returning from the body

2 Chamber Heart2 Chamber Heart

One way circuitOne way circuit

Very basicVery basic

Much slower than Much slower than

land vertebratesland vertebrates

VideoVideo

Life Science: Fish and Amphibians Life Science: Fish and Amphibians

ReviewReview

1) What is the major difference 1) What is the major difference between cartilaginous and bony between cartilaginous and bony fishes?fishes?

2) Describe the function of the lateral 2) Describe the function of the lateral line system.line system.

3) List the general characteristics of 3) List the general characteristics of bony fishes.bony fishes.

4) List and contrast the 3 classes of 4) List and contrast the 3 classes of bony fishes.bony fishes.

Perch DissectionPerch Dissection

Perch DissectionPerch Dissection

The First TetrapodsThe First Tetrapods AmphibiansAmphibians are are

descendants of four descendants of four limbed ancestors that limbed ancestors that were fully aquatic 400 were fully aquatic 400 myamya– Limbs and legs evolved in Limbs and legs evolved in

fishes– moved to land (50 fishes– moved to land (50 million years)million years)

Leg-like limbs allowed for Leg-like limbs allowed for movement through dense movement through dense marine vegetationmarine vegetation

The First TetrapodsThe First Tetrapods

AcanthostegaAcanthostega have gill structures, have gill structures, but amphibian-like limbsbut amphibian-like limbs

AmphibiansAmphibians

AmphibiosAmphibios= “living a double life” in Greek= “living a double life” in Greek Many live in their larval stage in water and Many live in their larval stage in water and

adult stage on landadult stage on land Eggs do not have shells so are easily dried outEggs do not have shells so are easily dried out Water is often necessary for laying eggsWater is often necessary for laying eggs

Adults generally:Adults generally: Have LungsHave Lungs Have moist skin without Have moist skin without

scalesscales

Stage of DevelopmentStage of Development Tadpoles --> the larvae of amphibiansTadpoles --> the larvae of amphibians

Legless aquatic plant-eaters with:Legless aquatic plant-eaters with: Gills, lateral line system, long tailGills, lateral line system, long tail

Metamorphosis into adult form leads to:Metamorphosis into adult form leads to: Lungs in place of gillsLungs in place of gills EardrumsEardrums No lateral line systemNo lateral line system 4 legs4 legs

***Some amphibians do not have a ***Some amphibians do not have a terrestrial stage, some amphibians do not terrestrial stage, some amphibians do not have an aquatic stagehave an aquatic stage

Other characteristicsOther characteristics

Moist skin often assists lungs with Moist skin often assists lungs with gas exchangegas exchange

May also contain poison glandsMay also contain poison glands

Amphibians have a 3-chambered Amphibians have a 3-chambered heartheart

Remember fish have 2 chambered heartRemember fish have 2 chambered heart

Allows for Allows for 2 pathways2 pathways of blood flowof blood flow

One to the lungs and One to the lungs and skin for gas exchangeskin for gas exchange

One to the other One to the other tissuestissues

Advantage??Advantage??

The Atria collect blood The Atria collect blood returning to heartreturning to heart

Ventricle pumps blood Ventricle pumps blood outout

Amphibian DiversityAmphibian Diversity

about 8% of vertebratesabout 8% of vertebrates

Frogs Frogs – insect eatersinsect eaters– Toads are terrestrial frogsToads are terrestrial frogs

Salamanders Salamanders – insect eatersinsect eaters

Caecilians Caecilians Legless & blind; burrow in soilLegless & blind; burrow in soil

VideoVideo

Life Science: Fish and Amphibians Life Science: Fish and Amphibians

General Characteristics of General Characteristics of Amphibians?Amphibians?

1)1) 2)2) 3)3) 4)4) 5)5)

What if they were forced to live on What if they were forced to live on land and have no access to water? land and have no access to water?

AMNIOTESAMNIOTES

Amniotes- reptiles, birds, mammalsAmniotes- reptiles, birds, mammals

General Characteristics:General Characteristics:– Live on land (do not need water)Live on land (do not need water)– Amniotic eggAmniotic egg– Internal fertilizationInternal fertilization– Water-tight skin Water-tight skin

Amniotic EggAmniotic Egg

Waterproof egg with a shellWaterproof egg with a shell Amnion- protects embryo from drying Amnion- protects embryo from drying

outout

Water-tight SkinWater-tight Skin

Enriched with keratinEnriched with keratin– Prevents dehydrationPrevents dehydration

Reptiles- scalesReptiles- scales Birds- feathersBirds- feathers Mammals- nails, hair, hornsMammals- nails, hair, horns

ReptilesReptiles

Reptile CharacteristicsReptile Characteristics

Water-tight, scaly skin that Water-tight, scaly skin that moltsmolts LungsLungs Lay eggsLay eggs Cold-blooded Cold-blooded

(ectotherms)(ectotherms)

Komodo Dragon Hunting a Komodo Dragon Hunting a Water BuffaloWater Buffalo

http://dsc.discovery.com/tv/life/http://dsc.discovery.com/tv/life/episodes.html episodes.html

BIRDSBIRDS

Ancestor- dinosaurAncestor- dinosaur Endothermic amniotesEndothermic amniotes Adaptations for flight: Adaptations for flight:

– Wing shapeWing shape– Feathers (also for insulation) Feathers (also for insulation) – Several weight-reducing featuresSeveral weight-reducing features

Review of Frog DissectionReview of Frog Dissection

Where is the tympanic membrane?Where is the tympanic membrane? How can you tell a male from a How can you tell a male from a

female?female? What is the cloaca?What is the cloaca? What is the purpose of the fat What is the purpose of the fat

bodies?bodies? What are 3 differences between What are 3 differences between

reptiles and amphibians?reptiles and amphibians?

Wing ShapeWing Shape

Airfoil-shaped wingsAirfoil-shaped wings

Air-sac SystemAir-sac System

Function with lungs for respirationFunction with lungs for respiration Helps supply high level of O2 that Helps supply high level of O2 that

supports a high metabolism. supports a high metabolism. Also reduces density of birdAlso reduces density of bird

Weight-Reducing FeaturesWeight-Reducing Features

Air-sacs Air-sacs Honey-combed bonesHoney-combed bones Absence of some internal organsAbsence of some internal organs

Circulatory SystemCirculatory System

Efficient oxygen deliveryEfficient oxygen delivery 4-chambered heart4-chambered heart

– Adaptation for active, endothermic Adaptation for active, endothermic lifestylelifestyle

MAMMALSMAMMALS

Mesozoic era- evolved from mammal-Mesozoic era- evolved from mammal-like reptiles, therapsids like reptiles, therapsids

Mammal CharacteristicsMammal Characteristics

EndothermicEndothermic Mammary glands- milkMammary glands- milk Hair- insulationHair- insulation Lungs with diaphragmLungs with diaphragm 4-chambered heart4-chambered heart Internal fertilization Internal fertilization

Mammal DiversityMammal Diversity

Monotremes- lay eggs, cloacaMonotremes- lay eggs, cloaca

Mammal DiversityMammal Diversity

Marsupials- “pouched mammals”Marsupials- “pouched mammals”

Mammal DiversityMammal Diversity

Placental Mammals- Embryo Placental Mammals- Embryo completes development within the completes development within the uterus; placenta forms & feeds uterus; placenta forms & feeds embryo embryo