Vertebrate Evolution

The “Big 5” of Kingdom Animalia

Multicellular Eukaryotic Heterotrophic

Motile No cell walls

What taxonomic groups will vertebrates have?

Kingdom Animalia

Phylum Chordata

Subphylum Vertebrata

Class… we will study 7 classes…

Phylum Chordata Subphylum Urochordata

Ex. Sea squirt (tunicate)

Subphylum Cephalochordata Ex. Lancelet

Subphylum Vertebrata Bilateral sym; coelomate; endoskeleton;

closed circ. Sys. Ex. Fish, amphibians, reptiles, birds and

mammals

Phylum Chordata- chordates share 4 traits:

Most chordates have a backbone – called vertebrates

Integuments – Body Coverings

Adapted for varied habitats and temperature control

•Fish scales

•Soft, moist skin

•Scaly dry skin

•Feathers

•Fur/hair

Temperature Regulation

Ectotherms

~ “cold-blooded”

~ regulate body heat using their surroundings

~ limited habitats

*more efficient because do not have to make body heat

Endotherms

~ “warm-blooded”

~make own body heat

~ costs more food (energy)

~ can live in really hot/cold places

Heart Chambers

2 chambers is less efficient than 4

4 chambers allows maximum oxygen to be carried in the blood

Reproduction

Fertilization can be…

External Internal

- usually in water - usually fewer made

- usually very large #s - usually higher parental care

- usually very low parental care

Class AgnathaJawless FishesEx: lampreys & hagfish

Most primitive fish

Class ChondrichthyesCartilaginous Fishes

Sharks & Rays

Class OsteichthyesBony Fishes

“common” fish!

Types of Respiratory Organs

Gills – fishes

Skin – amphibians

Lungs – most higher

vertebrates

Water Land

Must develop way to move…way to breathe…and way to not dry out!

Class Amphibia

Frogs, Newts, Salamanders

Class Amphibia Habitat

Land; but must be near water for reproduction & to stay moist

Integument Moist, thin skin

Skeleton/Appendages Bones, 4 limbs, often

webbed Temperature

Regulation ectothermic

Respiration Skin; primitive lungs

Circulation/Heart 3 chamber heart

Reproduction/Fertilization External/internal

fertilization; sexual/parthenogenesis; oviparous

Nutrition carnivore

Amphibian Reproduction

Amniotic Egg

• Invented by the reptiles

• Allows for fully living on land

• Embryo protected w/I membranes & a shell

• Mammals take this a step further by keeping embryo inside

Amniotic Eggs- have shell and membranes so they don’t dry out

Class Reptilia

Turtles, Snakes, Lizards, Alligators, Crocodiles

Class Reptilia Habitat

Full land (though some are aquatic)

Integument Dry, scaly skin resists

drying out Skeleton/Appendages

Bones, claws; (snakes none)

Temperature Regulation ectothermic

Respiration lungs

Circulation/Heart 3 chamber heart for

most 4 chamber heart in

crocs Reproduction/

Fertilization Amniotic eggs; leathery

shells Internal fertilization;

sexual; all three methods of birth

Nutrition Carnivore/herbivore

Class Aves

Birds!

Birds make changes to enable flight

Hollow bones, Feathers, Beaks

Birds evolved from reptiles

Class Aves

Habitat land

Integument Skin with feathers

Skeleton/Appendages Bones hollow for flight Beaks instead of teeth Wings & reptile-like claws

Temperature Regulation endothermic

Respiration lungs

Circulation/Heart 4 chamber heart

Reproduction/Fertilization Internal fertilization;

harder shells; sexual; oviparous

Nutrition Herbivore/omnivore

Class Mammalia – Placentals

Monotremes – odd mammals!

Duckbill Platypus

Marsupials have pouches in which offspring develop

Kangaroo & Opossum

Class Mammalia

Habitat land

Integument Skin with hair or fur

Skeleton/Appendages Bones; 4 limbs; wide

variations in appendages

Temperature Regulation endothermic

Respiration lungs

Circulation/Heart 4 chamber heart

Reproduction/Fertilization Internal fertilization;

live birth: viviparous (except monotremes)

Sexual reproduction Other

Mammary glands to nurse young

Marsupials = pouch

Mammalian Reproduction

Meiosis produces gametes with haploid # of chromosomes Haploid = 23 for humans

Males start producing sperm at puberty

Females are born with all of their eggs At puberty one per month matures

The End

Vertebrate Ontogeny

Class Agnatha

Habitat

- aquatic Integument

- skin Skeleton

- cartilage Nutrition

- parasite/carnivore

Respiration

- gills Circulation/Heart

- 2 chambered heart Reproduction/Fertilization

- external fertilization; sexual reproduction; oviparous

Temperature Regulation

- ectothermic

Class Chondrichthyes

Habitat aquatic

Integument Scales/ denticles

Skeleton/Appendages - cartilage; fins

Nutrition- carnivore

Temperature Regulation Ectothermic

Respiration gills

Circulation/Heart 2 chamber heart

Reproduction/Fertilization internal fertilization;

sexual; all 3 birthing methods

Other Swim bladder to

maintain position

Class Osteichthyes

Habitat aquatic

Integument scales

Skeleton/Appendages bone; fins

Nutrition - detrivore, herbivore, carnivore, omnivore

Temperature Regulation Ectothermic

Respiration gills

Circulation/Heart 2 chamber heart

Reproduction/Fertilization Internal & external

fertilization; sexual reproduction; all 3 birthing methods

Other Swim bladder to

maintain position

Methods of Birth

Oviparous – egg-laying animals Ovoviviparous – egg is inside parent w/ no placental connection, fed by egg yolk; hatches inside; live birth

Viviparous – baby in uterus w/ placental connection; live birth

Gills in Fish

Which is the __?

1. Heart

2. Lung

3. liver

4. Intestines

5. Stomach

Reptiles are first to develop amniotic egg

Quiz #1

1. List 3 traits that vertebrates/chordates have that distinguish them from invertebrates.

2. What is the advantage of being ectothermic?

3. What is the disadvantage of being ectothermic?

4. Why was the amniotic egg such a big deal in terms of evolution of animals?

Quiz #1

5. Which vertebrate group was the first to develop the amniotic egg?

6. Excluding “general animal/vertebrate traits”, what is ONE similarity between: A. Osteichthyes and Amphibia B. Amphibia and Reptilia

7. Although amphibians were the first land animals, they are still tied to the water. Describe TWO reasons why they are still tied to the water.

Quiz #1

Which is the… 8. heart? 9. liver? 10. lung? 11. stomach? 12.

intestines?

4 heart chambers > 3 > 2

Oxygenated & Non-oxygenated blood kept completely separate in 4 chamber heart…

they mix in others (not as efficient!)