7. AMINOTES CHORDATES

Amniota (Reptiles & Mammals)

AMNIOTIC EGG

• Specialized shelled reproductive egg produced by reptiles, birds, and monotreme mammals

• Embryos develop on land rather than water

AMNIOTIC EGG ANATOMY (6+1) AACYAS

AACYAS

1. Amnion

2. Allantois

   • Placenta Formation

3. Chorion

   • Placenta Formation

4. Yolk Sac

5. Albumen

6. Shell

AMNION

Protects embryo in fluid-filled cavity
Cushions against mechanical shock

ALLANTOIS

Disposal sac for metabolic/nitrogenous wastes produced by embryo

• Allantois and Chorion = Placenta formation

CHORION

Exchanges gases between embryo and air, assisted by allantois

• Allantois and Chorion = Placenta formaton

YOLK SAC

Yolk, stockpile of nutrients

Reduced structure in mammals

• Embryo recieves nutrients from placenta

ALBUMEN

Provides additional nutrients, water, and protein

SHELL

Extra protection

SKULL TYPES (3)

Based on temporal fenestra (openings in skull BEHIND eye orbit)

1. Anapsid

2. Synapsid

3. Diapsid

ANAPSID

NO TEMPORAL FENESTRAE

• Extinct

SYNAPSID

ONE TEMPORAL FENESTRA behind eye

• Mammals evolved from

• Still retain ancestral skull characteristic, but it is highly modified

DIAPSIDS

TWO TEMPORAL FENESTRAE behind eye

• Reptiles, birds, dinosaurs

AMNIOTES DIVERSIONS

Amniotes —> Synapids & Sauropsids—> Aapsids (Extinct) + Diapsids—> Birds & Dinosaurs

EVOLUTION OF AMNIOTES

REPTILES (Non-Avian)

Tetrapods

Ectotherms (MOST)

• Cold-blooded

• Need heat from environment

Endotherms (REGIONAL, some crocodilian)

• Warm-blooded

• Internally regulate heat

• Need more energuy

Brumation

• Less active in lower temperatures

REPTILE CLADES (5, 4) CSSST

CSSST

1. CROCODILIA

2. SPHENODONTIA

3. SQUAMATA

4. TESTUDINES

5. Sphenodontia

CROCODILIA (“Small Lizard”)

Alligators, crocodiles, gharials, caimans

• Aquatic environments

• Able to walk and run (short distances), gallop (crocodiles), and lift bodies off ground

SPHENODONTIA (“Wedge Tooth”

Diapsid skull

Two rows of teeth (upper jaw)

Single row of teeth (lower jaw)

SQUAMATA (“Scaly or having scales” | Lizards and snakes)

• Largest Reptilia clade

• All continents except Antarctica

SQUAMATA Lizards

• 4 Limbs

• External Eyes

• Extravagant Ornamentation

  • Spines, crests, frills, bright colors

• Change skin color

  • Chromatophores

• Eyelids, good color vision

• Jacobson’s organ

  • Sensory structure to detect pheromones and chemical signals

• Carnivores

  • Except iguanas

• Long, sticky, fast tongue

• Venom glands

  • No constriction

SQUAMATA Snakes

• No limbs (except boa constrictors)

• May or may not have extravagant ornamentation

• Eyes protected by transparent scale

• Jacobson’s organ

• Carnivores

• Venom glands

  • Some immobilize or kill prey

  • Constriction

• Flexible skulls

• Infrared detection

• Jaws without a bony anterior attachment

TESTUDINES (“Having a shell”)

Turtles, terrapins, tortises

• Ectotherms

• Oviparous

  • Lay eggs on land

AVIAN REPTILES (BIRDS)

• Endothermic

• Feathers

  • Homologous to reptilian scales and mammalian hairs

    • Share common ancestry, different use

• Contour Feathers

  • Several parallel barbs bran from central shaft

  • Barbs interlocked by hooks in barbules

• Down Feathers

  • DO NOT interlock

  • Insulation

AVIAN REPTILES (BIRDS)

• Color vision

• Excellent eyesight

• 4-Chambered Heart

• Erythrocytes (red blood cells)

• Syrinx (voice box)

• Uropygial gland

  • Preening gland

  • Feathers, waterproofing

  • Flexibility to fly

AVIAN REPTILES (BIRDS) PRIMARY & SECONDARY FEATHERS

Primary Feathers:

• Move its wings downwards

Secondary Feathers:

• Provide lift

AVIAN REPTILES (BIRDS) ADAPTATIONS TO FLY (9)

PNEUMATIC BONES:

• Hollow, found in large birds

URINARY BLADDER:

• Absent

• N waste eliminated with feces through cloaca

SMALL GONADS:

• Male and female

ONE OVARY

CLOACA:

• Reabsorbs and redirects water to bloodstream

• Uric acid is eliminated and concentrated as urate salts

RESPIRATORY SYSTEM:

• Coelomic fluid REPLACED BY AIR SACS

AIRFLOW THROUGH:

• Lungs is undirectional

PARABRONCHI:

• Minimally expandible lungs

• Thin air sacs among visceral organs and skeleton

TOOTHLESS:

• Gizzard

MAMMALS EVOLUTION

MAMMALS OVERVIEW (3 Clades)

• Mammary glands

• Hairs

• Endothermic

• Sebaceous glands

  • Sebum (lipid mixture)

• Eccrine glands

  • Perspiration

3 CLADES:

1. MONOTREMEAS

2. MARSUPIALS

3. PLACENTAL

MAMMALS SKELETON FEATURES

• STAPES: Single bone that transmits vibrations to inner ear

• HETERODONT TEETH: Incisors, canines, premolars, molars

• DIPHYDONTS: Two sets of teeth in lifetime

• 4 Chambered heart

• ERYTHROCYTES: Red blood cells, not nucleated

• MOOVABLE EYELIDS

MONOTREMES CLADE (Egg Layers)

Echidnas and platypuses

• Lay eggs!

• Have hairs

• DO NOT HAVE TEETH

• Produce milk but lack nipples

• Mammary glands located on ventral body part

• After hatching, babies suck milk from mother’s skin/fur

MARSUPIALS CLADE (Pouch)

Opossum, kangaroo, koala, bilby

• Give birth to young

• Placenta

• Complete development in marsupium (pouch)

EUTHERIANS (Placentals)

• Adaptations for burrowing, flying, swimming, hunting, running, climbing

• Well-developed chorioallantoic placenta

  • Gas, fluid, nutrient exchange

• Longer pregnancy than marsupials

• Complete embryonic development within uterus

PRIMATES SYNAPOMORPHIES (6) Order

1. ROTATING Shoulder Joint

2. Hands/Feet GRASPING

   1. Big Toe

   2. Opposable Thumbs

      • Thumb can touch ventral surface (fingerprint side) of fingertip on all four fingers of the same hand with its own ventral surface

        • "Your brain is good if you can do this” BS

3. STEREOSCOPIC VISION

   • Two overlapping fields of vision from eyes

4. LARGER BRAINS, Shorter Jaws

5. MODIFIED CLAWS = Nails

6. (Usually) ONE OFFSPRING per pregnancy

PRIMATES GROUPS (2) SH

1. STREPSIRRHINES

2. HAPLORHINES

STREPSIRRHINES

• Nocturnal

• Larger olfactory centers in brain

• Smaller in size

• Smaller brain than anthropoids

• Enzymes for making vitamin C

HAPLORHINES

• Diurnal

• Depend more on vision

• Aquire vitamin C from food