Lect 9

Question 1

Amniota within tetrapoda

Answer 1

• Includes Synapsida, Testudines (turtles), Lepidosauromorpha, and Archosauria

• United by skeletal, soft tissue, and developmental characters
- These combine to make amniotes less dependent on bodies of water for survival and reproduction.

Amino egg structuremuchless dependent on water —> better for terrestrial lifestyle
Diff than lifestyle of amphibians

Question 2

Amniote skeletal characters

• Vertebral characters

Answer 2

• Axis in addition to atlas cervical vertebrae
• Two or more sacral vertebrae (connected to spinal column, for support)

Unlike fish amps haves necks, atlas —> vertebrae that holds head, connects to op condole
Get additional bone for support

Question 3

Amniote skeletal characters

• Skull

Answer 3

• Lateral flange of pterygoid (bone in palate, or roof of mouth) (extra surface area for muscle attachment to connect to temper oral fenestrae)
• Allows for more complex muscles for closing mouth
• Attachment point for muscles associated with temporal fenestrae (contribute to movement of jaws)

Still chonna but not as large as in amps

Question 4

Amniote skeletal characters

• Ankle

Answer 4

• Astragalus and calcaneus in ankle
• Make mesotarsal joint
• Allows for more dexterous foot
• Phalangeal formula: number of elements in each digit
(Bones that make up the finger digits)
Hindlimb —> joint we’re limb and foot is between bones within ankle
Contributes to flexibility, more dexterity

Aminotes get more variation in foot therefore diff ways of moving

Question 5

Skull fenestration

Answer 5

on;y applied to amniotes

• Temporal fenestrae – openings in skull behind orbits
- Excludes any openings for sensory organs (gives more space)

• Surrounded by four skull bones:
• Postorbital (behind eye), squamosal behind post), jugal(below post), and quadratojugal(below jugal and under squamosal)
• Anapsid – no temporal fenestrae (turtles)
• Synapsid – one temporal fenestra (mammals)
• Diapsid – two temporal fenestrae (birds and reptiles)
• Provide more locations for jaw muscle attachment

Question 6

Amniote soft tissue characters

Answer 6

Keratinized skin (protein of epidermis)
• Relatively waterproof
• Many varieties of elaborations (fur,feathers,scales. Most come back to keratin in 1 way or another)

Metanephric kidney
• Compact, discrete organ
• Drained by ureter
(In fish and amp kide\hey diff compared to aminotes. Tissue make a band along spine instead of a whole ball, this involves aquatic lifestyle, able to get water is not a problem—> land life struggle to get water more so kidney becomes more important)

Question 7

Amniotic egg

Answer 7

• Embryo surrounded by extraembryonic membranes and shell
• No larval stage (no metamorphoses)
• No gills (at any point, if do have gills, have gill slits in early development, gills one of those things that doesn’t evolve back)
• Internal fertilization necessary (b/c egg can’t be fertilized outside of body)

• Shell leathery or calcified
• Pores in shell for gas exchange (b.c embryo would suffocate)
• Albumen (egg white) for protection and source of water and protein
• Yolk sac for nutrients
( provided by mothers body, may be sole source of nutrients. None of these things are the extra embryonic membranes)

Question 8

Amniotic egg – extraembryonic membranes

Answer 8

Came from development of embryo —> germ layers

Amnion (closest to embryo)
• Functions for direct protection
• Derives from ectoderm and mesoderm (includes amniotic cavity)

Allantois
• Functions for waste storage and gas exchange (b/c it’s undergoing metabolism)
• Derives from mesoderm and endoderm (only one that has developed from endoderm —> digestive tract)

Chorion
• Functions for protection and gas
exchange
• Derives from ectoderm and mesoderm

Chorion and amnion most similar to each other

Question 9

Different physical forces

Answer 9

• Density and viscosity of air minimal in comparison to water
• Gravity a significant constraint in comparison to water
• Vertebral column with four regions: cervical, trunk/thoracic, sacral, and caudal (diff in these contributes to how they deal with differences in physical forces)

Trunk supports body and ribs
Sacral supports hip
Cuadul support deals on group

Question 10

Axial musculature

Answer 10

• Support the body
• Change volume of thoracic cavity to ventilate lungs
• Epaxial muscles elongated (rung along entire body, bend front and back and side to side)
• Hypaxial muscles layered
(Ex: abdomenial muscle provide additional support, b/c not as may bones around this area or keep in place, changes in how body can move)

May be more muscle but may not be more volume of muscle, they divide —> pull in diff ways

Ones around lungs can contribute to breathing

Question 11

Trunk flexion

Answer 11

• Ancestral condition: lateral undulations

• Derived condition: dorso-ventral flexion during bounding
( flex/bend front and back as well, result in diff types of gaits, limbs structure adjusts to this)

Question 12

Limb posture

Answer 12

Out from side
• Humerus/femur extend laterally from limb girdles
• Ventral muscles larger

Underneath body
• Humerus/femur extend ventrally from limb girdles
• Dorsal muscles larger
(Muscle start from trunk region. Seems more efficient for locomotion as uses less energy)

Question 13

Amniote respiration

Answer 13

Muscles between ribs expand thorax volume (run opposite to each other)
• Air drawn in passively
(Get extra support but differ from each group)

Trachea
• Elongated tube to lungs
• Supported by cartilaginous rings
(Cartilaginous windpipe, opening to lungs always open —> amps can collapse on them if don’t breath. Passively allow for air flow. Also have lower metabolism—> less respiration)

Question 14

Circulation

Answer 14

• Ventricle divided
• Double circulation: pulmonary and systemic circuits
• Oxygenated and deoxygenated blood fully separated

Fish = 2
Sarco = 3
Amp = atrium divided
Complete separation allows —> double circulation, more efficient for diff tissue in body.
Right atrium —> right ventricle to lungs then back to heart —> left atrium to left ventricle to rest of body

Question 15

Water retention

Answer 15

In nasel cavity
• Less water lost through skin due to keratinization (additional protein)
• Less water lost through respiration due to nasoturbinates (thin curly layers of bone, so small impossible to cast)
• Consolidated kidneys resorb water from filtered waste
(Beneath Boone Air Forced over nasoturinates it absorbs moisture which prevents water loss.)
Dessert or cold environment organisms likely will have more

Question 16

Senses

• Olfaction

Answer 16

• Odor molecules travel better in air than water
• Odor molecules can also be deposited on stationary substrate
• Turbinates also increase surface area for scent receptors

2ndarly more surface area —> better smell

Question 17

Senses

Sound and light

Answer 17

• Sound and light move differently in air than in water (sound travels worse in air than water)

• Eye structures shaped differently (lens in aquatic = round, in terrestrial = flat)

• Middle ear bones transmit vibrations from air to inner ear
• Eg. Columella/stapes

• Different regions of inner ear elaborated for sensitivity to different sound frequencies

Question 18

Senses

Equilibrium

Answer 18

• Different modes of locomotion associated with differences in semicircular canals

Vestibular system = balance, position in 3D world
Size in hit relates to lifestyle/locomotion
Birds have a lot of elaborations

Question 19

Key Concepts

Answer 19

• Amniotes united by having atlas and axis, two or more sacral vertebrae, lateral flange of pterygoid, and astragalus and calcaneus in ankle.

• Different groups of amniotes have different patterns of fenestrae posterior to orbits.

• The amniotic egg is characterized by three extraembryonic membranes: chorion, allantois, amnion.

• Locomotion on land involves adaptations of skeletomuscular system.

• Light, sound, scent molecules move differently in air than in water.