336 Final =)

What is the function of the endostyle?

Assists in filter-feeding, secretes a mucus to accumulate food particles and pass them along to the digestive tract

Study a female specimen closely. What is strange about the female reproductive system? Propose a reason for this novelty.

Asymmetric reproductive system. The right half is greatly reduced and nonfunctional. Reason: Reduce redundancy (you only need eggs from one side to reproduce) and weight control.

Does bone continue to change throughout the life of an organism? If so, how? If not, why not?

Bones grow in length at the epiphyseal plate by a process that is similar to endochondral ossification. The cartilage in the region of the epiphyseal plate next to the epiphysis continues to grow by mitosis. Osteoblasts move in and ossify the matrix to form bone. This process continues throughout childhood and the adolescent years until the cartilage growth slows and finally stops. When cartilage growth ceases, usually in the early twenties, the epiphyseal plate completely ossifies so that only a thin epiphyseal line remains and the bones can no longer grow in length

Gently rub the skin of the frog. How does this texture compare to that of the iguana and the snake and why might this be?

Both the iguana and the snake have keratinous scales covering their entire bodies. The bullfrog, on the other hand has a smoother skin and lacks the scales seen in reptiles. This lack of scales is due to the amphibious nature of the bullfrog. The frog does not need to devote the energy to structures that retain moisture because of the semi-aquatic nature, in which the frog can freely move into the water and restore its moisture balance.

Observe the ventral side of your ray. Comment on the position of the mouth. How can we link its position to the animal's behavior?

Bottom-feeder, they can rest mouth flat against floor to feed.

BOWFIN CRANIAL ANATOMY Take a look at Figures 5 and 6 above. Which skull is more robust? Link this fact to the Takecology/behavior of the two organisms.

Bowfin skull more robust; perch skull is thin and transparent. Bowfin uses its skull to ram into objects, so it must be built to withstand more force than the perch skull.

How does the external anatomy of the bowfin compare to that of the perch?

Bowfin: 1 dorsal fin, gular plate, bony head. Fins lack spine. Also a more primitive heterocercal tail. Perch: 2 dorsal fins, no gular plate, no bony head. Has spiny fins. Homocercal tail.

Give two reasons why robust musculature is important for adult lampreys.

Breathing: muscle around gill slits actively move water in/out. Swims upstream to lay eggs; more power per stroke to go against current. Efficient predation.

Does your specimen have eyelids or a nictitating membrane? Why is this not surprising?

Snakes do not have eyelids and nictitating membranes. Their cornea is covered by a transparent spectacle called brille. Not surprising because they do not transition between land and water.

Knowing that the gallbladder stores bile, why is it not surprising that a snake has a large gallbladder, while cows, for example, do not possess a gall bladder at all? How do you think a cat's gallbladder would compare in relative size to that of the snake?

Snakes eats its prey whole so a lot of bile needed at one time. It is also carnivorous so requires bile to digest the fats in its prey. Cows eat grass (no fats) and they graze so they eat constantly. Cats have a relatively small gallbladder.

Which musculature do you think has undergone more dramatic changes from the fish to the cat - axial musculature or appendicular musculature? Why

-appendicular because its associated with the limbs and terrestrial life

What structure in humans is equivalent to the cecum in cats(and other species we looked at this semester)?

-appendix

Intestinal wall of colon and intestine, compare to stomach wall texture?

-I thought the walls of the colon and intestine were more smooth than the stomach. Not sure what other people thought

In general, would you consider domesticated cats to exhibit a high degree of sexual dimorphism? Why or why not? How does this compare to wild cats such as the lion? What is one reason for this difference?

-Male and female domestic cats do not appear that different from each other, so they do not appear to have a high degree of sexual dimorphism. Wild cats have a higher degree of sexual dimorphism, stemming from male-male competition in the wild. Domestic cats do not have this selection pressure.

What is the function of villi? Where are they found?

-They are fingerlike projections that increase surface area absorption in the intestine

The gallbladder and liver are sometimes referred to as accessory organs of the digestive system. What is meant by this? How does the function of the gallbladder and liver make this nomenclature valid?

-They are organs that do not participate directly in digestive, but assist in digestion by providing bile for digestion. The gallbladder stores bile, the liver produces bile.

Morphological differences between the arteries and veins present on the esophagus versus those on the stomach. What is the significance of these differences?

-based on diameter stomach has bigger blood vessels. Lots of interconnectivity that goes on. Not as much going on in esophagus

- Name the five types of vertebrae in order from most cranial to most caudal.

-cervical, thoracic, lumbar, sacral, caudal

Name the three components of the kidney

-cortex, medulla, capsule, sinus

Cat Part II: Internal Anatomy Part I Digestive anatomy of Cat Name three sections of small intestine in order from most cranial to most caudal

-duodenum, jejunum, and ileum

What is the function of arterial loops?

-loops provide alternative routes for blood to flow through a particular region.

Part III. Urogenital Anatomy What sex is your cat? How can you tell?

-male because of testes and penis

For is the technical term used for internal walls (of stomach)?

-rugae

Part II Cat Respiratory/Circulatory Anatomy How do we link form with function when discussing arteries and veins of the circulatory system?

-the branching patterns can vary even within a species. The vessel is identified with the area is supplies or it drains. Arteries have thick, elastic, muscular walls whereas veins have thin walls with few elastic fibers. Veins need valves as the blood flowing through them is at such a low pressure that they need something to prevent it going backwards. Diameter is differential based on flow rate to a particular area (slower flow rate to areas that don't require as much blood or oxygen supply).

In what way does the esophagus differ from the trachea? How is this anatomical difference linked to the function of each structure?

-the trachea, not the esophagus has cartilaginous rings. Food is propelled down the esophagus by rhythmic muscular contractions that force the esophagus open as necessary. Air is drawn through the trachea by negative pressure, resulting from a lowering of the diaphragm and an expansion of the chest. The negative pressure in the trachea needs the support of the stiff rings to allow it flexibility to bend and support to keep from collapsing.

Why would certain muscles be downsized in some organisms, such as birds? Give two reasons]

-use it or lose it mentality (think about people with weak muscles) -reduce body weight be more compact?

Packet 8: PIGEON Key Bird Characteristics:

1) 4-part body: head, neck (disproportionately long), tail, trunk 2) paired limbs, forelimb modified for flight 3) epidermal feather covering and leg scales 4) fully ossified skeleton with pneumatization 5) well-developed nervous system + 12 pairs of cranial nerves and brain with large cerebellum and optic lobes 6) 4-chambered heart 7) endothermic 8) unique, one-way, 2 stage flow of respiration with lung and air-sac utilization 9) derived kidneys (uric acid as waste product) 10) internal fertilization, oviparous

What are the key chordate characteristics?

1) DTNC 2) Notochord 2) Post-anal tail 3) Pharyngeal slits 4) Endostyle

Packet 4: PERCH Key Actinopterygii Characteristics:

1) Fins supported by rays 2) homocercal tail 3) rigid skeleton 4) operculum pumps water through gills 5) has swim bladder

Packet 3: STINGRAY EXTERNAL ANATOMY Key stingray characteristics:

1) Flattened body 2) Enlarged pectoral fin fused to head 3) Ventral gill slits 4) Dorsally located eyes 5) No anal fin 6) Venomous tail spines 7) Mostly bottom feeders

Background:

1) In lakes, rivers, ponds of eastern North America 2) Size of external gills depend on oxygen availability in water (larger gills for water with less oxygen) 3) Modified limbs for swimming and walking on bottom of streams and ponds 4) Mucous glands for slimy protective coating 5) Glandular glands for poison as defense against predators 6) Carnivorous; prey on insects, mollusks, annelids, small fish, amphibians, earthworms, spiders 7) Predators: crayfish, turtles, water snakes and humans

Key agnathan characteristics?

1) Jawless 2) No paired fins 3) Cartilaginous skeletons 4) soft skin/ no scales

Shark Background:

1) L Ordovician 2) Earliest adaptive immune system

Key Mudpuppy Characteristics:

1) Large feathery external gills 2) Flat head with minimal movement 3) Four well-developed limbs 4) Neotenic 5) Delayed fertilization 6) Completely aquatic 7) Nocturnal 8) Carnivorous 9) Solitary

Packet 7: SNAKE Key Snake Characteristic:

1) Limbless 2) Ectothermic 3) Carnivorous 4) Thin, elongate internal organs 5) Unpaired/non-identical lungs 6) Staggering of paired organs 7) Scaly skin 8) High flexibility 9) Teeth Curved Backwards 10) Forked tongue 11) Flexible ribs 12) Variable locomotory patterns: slithering, side-winding, accordion (for climbing trees)

BOWFIN EXTERNAL AND INTERNAL Background:

1) Retain ancestral traits: modified heterocercal caudal fin, vascularized gas bladder lung, vestiges of spiral valve, bony gular plate 2) non-specific, ambush predators 3) lives in North America freshwater 4) during winter: seek deeper water, pack in large groups and become inactive

Packet 6: IGUANA Key Iguana Characteristics:

1) Unique male sex organs (hemipenes) 2) social behavior 3) salt gland/unique nasal configuration 4) striking sexual dimorphism 5) ectothermic 6) acute vision and hearing 7) colic caecum (specialized digestion) 8) highly territorial

Snake Background:

1) dark crossbands on neck and foreparts 2) alternating dorsal and lateral blotches on rest of body 3) adults tend to darken in color 4) nocturnal forager, spends daytime in sun 5) inhabits aquatic habits

Perch Background:

1) fins have spiny cartilage and/or bone rays for protection and support 2) streamlined body plan for efficient movement 3) strong teeth and powerful jaw for prey 4) mostly bottom feeders, prefer minnows, insect larvae, plankton, worms 5) move in schools of several hundred other perches

Background

1) herbivorous: leaves, flower, fruit 2) live in tropical areas of Mexico, Central America, Caribbean 3) live in canopy, only comes down to mate, lay eggs or change trees 4) ectotherms 5) active during day 6) live near water, good swimmers 7) fast, agile on land 8) strong jaws, razor-sharp teeth 9) strong, long tail 10) tails can detach and regenerate 11) 20 years lifespan

Stingray Background

1) large pectoral fins fused to head 2) slender tail with spines 3) live in warm water near coastal environments 4) bottom-dwellers, hiding in sand 5) nocturnal 6) feed on shellfish and other benthic fishes 7) has shark characteristics: cartilaginous skeleton, 5 pairs of gills with no operculum, no swim bladder, same internal anatomy plan but space-optimized

Key Shark Characteristics:

1) pelvic clasper (male) 2) heterocercal tail 3) cartilaginous skeleton 4) teeth unattached to jaw 5) No swim bladder

Skates vs Rays:

1) pelvic fin: 2 lobes in ray vs 1 lobe in skate 2) tail: skates have stocky tail, no spines vs whip-like tail in rays with spines 3) scales: bucklers along midline of back and tail vs no bucklers in skate 3) ray males have spine near eyes vs no spines in skate

Key Chondrosteans Characteristics:

1) secondary loss of bony skeletal elements 2) shark-like jaw structure 3) mostly no scales 4) has spiracles 5) heterocercal tail (some)

Which aspect(s) of the shark's digestive system is an indication that it is a carnivore? Why?

1) sharp, hooked teeth 2) short digestive tract (herbivores have longer intestine length) 3) spiral valve to increase food absorption 4) contents found in stomach

Packet 5: MUDPUPPY Key Amphibia Characteristics:

1) tetrapods 2) ectothermic 3) both gill and lung breathers 4) three-chambered heart 5) thin, soft, glandular skin 6) oviparous 7) distinct larval and adult ecologies

How many chambers does the perch heart have?

2

How many chambers does the stingray heart possess?

2

SHARK CIRCULATORY/RESPIRATORY SYSTEM How many chambers does the shark heart possess? Name them.

2, ventricle and atrium.

How many lobes does the liver have? Which lobe communicates directly with the duodenum? How can you tell?

2; right and left lobes of liver. Right lobe communicates directly with duodenum because of proximity to the gallbladder. Gallbladder then releases bile into duodenum.

How many chambers does the heart possess?

3

How many lobes does the liver possess?

3

SHARK DIGESTIVE SYSTEM How many lobes does the liver have?

3

MUDPUPPY RESPIRATORY & CIRCULATORY ANATOMY How many chambers does the mudpuppy heart possess? How does it compare to the perch and shark?

3; ventricle, partially divided atrium. Perch's and shark's atria are not divide

- How many sternebrae comprise the sternum? What is the name for the first sternebrae? What is the name of the last sternebrae?

8 sternebrae 1st=manubrium last=xiphisternum

Observe the heart. How many chambers does it have? How does it differ from the iguana? What about the perch? What does this say about the efficiency of the circulatory and respiratory systems compared with those of the perch and iguana?

4 with complete interventricular septum. Also relatively larger. Iguana has 3 chambered heart, perch has 2. Birds have more efficient oxygen transport from complete separation of oxygenated and deoxygenated blood due to energy demands of flight.

How many afferent branchial arteries are there?

5

How many pairs of gill slits are present? How does this compare with the shark?

5 pairs, same as shark.

What is the function of the tunic?

Acts as an anchor to the sea floor. Holds the inner cavity together.

SHARK MUSCULATURE You will notice that the first constrictor muscle is highly modified. This isn't altogether surprising considering that the first gill arch is also modified. What three muscles comprise this modified constrictor muscle?

Adductor mandibulae (quadratomandibularis), Spiracularis, Levator palatoquadrati

Complete the following table by listing the relevant muscles for each of the following functional categories.

Adducts and rotates forelimb: 1 pectoantebrachialis 2 pectoralis major 3 pectoralis minor 4 xiphihumeralis Elevates lower jaw: 1 temporalis 2 masseter Adducts thigh: 1 adductor femoris 2 adductor longus 3 gracilis 4 pectineus 5 sartorius Flexes Forearm 1 biceps brachii 2 branchialis Extends foot 1 gastrocnemius 2 soleus 3 tibialis posterior Extends lower leg 1 vastus intermedius 2 vastus lateralis 3 vastus medialis 4 rectus femoris Compresses abdominal viscera 1 external oblique 2 rectus abdominis 3 internal oblique Flexes the shank 1 tenuissimus Rotates head 1 cleidomastoid 2 sternomastoid

Based on your answer to the first part of question 15 (above), how is the behavior of the shark affected?

Affects hunting/feeding behavior.

Distinguish between the terms 'afferent' and 'efferent'.

Afferent describes sensory signals that are carried from the peripheral nervous system to the central nervous system. Efferent describes motor signals that are carried from the central nervous system to the peripheral nervous system

Which mode of respiration do you think plays the most minor role in the lifestyle of the mudpuppy? What sort of anatomical modifications would permit this mode to be more effective? Name two.

Air breathing (lungs) plays a minor role of respiration for mudpuppy. Anatomical modification 1: having a nasopharynx would allow them to eat and breathe at the same time. Anatomical modification 2: They must also rely on the glottis for air to get out of the pharynx.

- What is different about the jaw joint in birds when compared with alligators? How does this affect cranial kinesis in both of these species? (Not sure)

Alligators: Rigid skull with little cranial kinesis, but has max bite force; skull is flatter to allow the bite force to spread throughout the skull instead of concentrated in one area; Occipital opening in the middle of the back of the skull, limits movement of the head Birds: A lot more cranial kinesis for eating (ex: nuts) or for absorbing shock to beak; have pivoting quadrates (when quadrate is pushed forward, motion transmitted to upper beak via movable palate and movable zygomatic arch); occipital opening more inferior on the skull to allow for a great range of motion for the head.

Sharks have a modified section of the lateral line. What is it called and how does it function?

Ampullae of Lorenzini, sensory/movement detection

- Lizards, snakes, turtles, and birds are considered diapsids despite the fact that they lack two fenestra on both sides of their skulls. Why would this be the case?

Anapsid skull is secondarily derived from diapsids

List the types of fins. How many of each is present on the perch?

Anterior dorsal x 1, posterior dorsal x 1, caudal x 1, anal x 1, pelvic x 2, pectoral x 2.

There are two major regions of the kidney (anterior and posterior), which is dedicated to genital function? Why does this make sense?

Anterior region (the epididymis) is involved in sperm transport. The posterior end produces urine. This makes sense because the testes are adjacent to the anterior end of the kidneys

The mudpuppy has well developed axial musculature. Why would this be advantageous?

Axial muscle forms skeletal muscles of the trunk and tail. They swim with side to side undulations so they needed the axial muscles.These muscles are important for locomotion in water.

What is meant by the terms axial and appendicular?

Axial: consists of the bones along the axis (head, torso, etc.) Appendicular: consists of the bones of the appendages

Lamprey background

Background: 1) L Cambrian 2) Jawless, eel-like, aquatic 3) marine and freshwater 4) distinctive circular mouth with keratinous teeth 5) Adults are herbivorous, only small subset are parasitic

Ammocoete background

Background: 1) filter feeder larva (duration of larval stage depend on species)

Protochordate background

Background: 1) protochordate: informal taxonomic umbrella group 2) includes hemichordata, cephalochordata, urochordata 2) all are marine with distinct larval and adult stages 3) ecology + behavior vary among groups and throughout lifetime

There are anatomical aspects of the lamprey that are bilaterally symmetric and those that are not. Name one unique feature of the lamprey that is bilaterally symmetric, and name one feature of the lamprey that is not bilaterally symmetric despite being so in more derived fishes.

Bilaterally Symmetric: Gill slits Not Bilaterally Symmetric: Nose/nostrils, dorsal fins

The beak is covered with a horny sheath and grows continuously throughout life. Why is continuous growth of the beak necessary?

Birds are constantly pecking so continuous replacement is necessary (like rat teeth).

Compare the teeth of the stingray to that of the shark. Very generally, how are they morphologically different? How are stingray teeth adapted to their diet?

Blunt teeth (more like plates). For crushing/ grinding shellfish instead of tearing apart prey.

- What is the nucleus pulposus? From which basal structure is it derived?

Intervertebral disk that arises from notochord cells

Notice a coloration difference between the dorsal and ventral surfaces of your specimen. What do you suppose is the adaptive significance of this contrast?

Camouflage: From bottom: blends in with light coming in from above From top: blends in with darkness of water below

- List and define the three categories of ribs.

Category 1: true rib Definition: costal cartilage articulates separately within sternum Category 2: false rib Definition: costal cartilage united with adjacent costal cartilage before finally articulating with sternum Category 3: free rib Definition: false rib whose distal end has no attachment to the sternum

The cere is a waxy structure that covers the base of the beak and so is the junction of the beak with the head. In all bird species, the cere is a proxy for the "quality" of the bird in some capacity. What is meant by "quality"? Give a possible example as to how the cere can reflect "quality."

Cere is a phenotypic proxy for individual fitness in male-male competition. The bigger the cere, the more likely the bird is to be healthy and so better quality mate.

Name the five types of vertebrae in order from most cranial to most caudal.

Cervical, thoracic, lumbar, sacral, caudal

Packet 9: ALLIGATOR AND PIGEON SKELETAL What Bones Tell Us 1) External anatomy 2) Organ size + position 3) Evolutionary relatedness 4) Use/disuse 5) Sex/dimorphism 6) Age 7) Diet + nutrition 8) Pathology/Disease/Trauma 9) Behavior 10) Locomotion/Gait 11) Physical Living Environment 12) Depositional Environment 13) Predator/Prey dynamics 14) Geological dating 15) Ancestry (humans)

Challenges of study bone: 1) Taphonomic degradation: missing elements, structural erosion 2) variations in population 3) inconsistent rubrics 4) sample size 5) incipience of species 6) behavioral correlations 7) inter/intra observer error

What two components of the vertebrate skull are present in the cartilaginous mounts?

Chondrocranium, splanchnocranium

What is the fundamental cell of cartilage?

Chondrocytes

What structure functions as the common exit duct for both the digestive and urogenital systems?

Cloaca

- Which openings on the vertebrae serve as an exit for the spinal nerves?

Intervertebral foramen

Cut open the gizzard. Does it contain anything peculiar? What is the purpose of these contents?

Contains rocks to grind up food

What is the function of the semicircular canals? Where are they located?

Convey movement of self in relation other object, located vestibular apparatus and in three different planes.

How is the cloaca divided? Name the structures and their function.

Coprodeum- intestinal receiver of contents Urodeum- urogenital receiver of contents

The arrangement of cranial musculature is highly conserved across vertebrates. For each of the following shark muscles, state the feline equivalent(s):

Coracomandibularis = Rectus cervicis, sternohyoid, omohyoid, thyrohyoid Intermandibularis = Mylohyoid, anterior digastric Cucullaris = trapezius

GENERAL VERTEBRATE SKELETON Define cortical and medullary bone. Sketch a cross section of a long bone and label (i) compact bone and (ii) cancellous bone. Discuss how the anatomy of each supports their unique function.

Cortical (AKA compact bone): dense outer surface that is a protective layer for the internal cavity. Nearly 80% of skeletal mass. Important for body structure and weight bearing. High resistance to bending and torsion. Medullary (AKA cancellous bone AKA marrow cavity): central cavity of bone shaft where bone marrow is stored.

Which type of bone do you think preserves more often in the fossil record, cortical or medullary bone? Why?

Cortical bone because it is dense and more resistant to breaking down than medullary. Medullary also contains red and yellow bone marrow that breaks down more readily.

Stingrays possess a poisonous barb. Do you think this structure serves as an offensive or defensive function? Why?

Defensive. They are benthic and the barb is on their tail (likely grows on head if offensive). Barb to fend off predators that startle them.

What is paedomorphosis? Why would paedomorphosis be adaptive? Give two reasons.

Definition: Retention of juvenile or larval traits into later life. Reason 1: When environment is favorable for growth, paedomorphosis help mudpuppies prioritize energy and resources for reproduction (so offspring can have the good growth environment) before their own somatic development. Reason 2: When environment is unfavorable for growth, paedomorphosis is still beneficial because mudpuppies can bypass the energetic costs of metamorphosis so that they can reproduce.

Name the three dermal bones of the lower jaw.

Dentary, angular, surangular.

The iguana is an ectotherm. Propose another function for the transparent scale.

Detect areas of light/heat. They rely on sunlight to regulate body temperature, so it also functions in thermoregulation.

The pineal gland is often referred to as the "third eye" in the lamprey. Based on this, what role do you think the pineal gland has? That is, in what manner do you think it aids in the perception of visual stimuli?

Detection of intensity of light Predation protection: Predator fish over top block out light and stimulate response Larvae: use it to change color Light rhythms: for seasonal activities (metamorphosis + reproductive cycles)

What feature indicated in Figure 3 do you think is the most sexually dimorphic? Based on this inferred dimorphism, propose a function for this structure.

Dewlap is sexually dimorphic. Used in terms of male-male competition. Sexual display in male-male competition reduces physical fighting and injury. Physical contact is a last resort because it lowers both winner's and loser's fitness.

ALLIGATOR SKULL - An anapsid is an amniote reptile lacking two temporal fenestra on either side of the skull, while a diapsid is an amniote reptile with two temporal fenestra on either side of the skull. Is an alligator an anapsid or diapsid reptile?

Diapsid

The urogenital system of the mudpuppy is very similar to that of chondrichthyan fishes. However, there are some key differences. Name two.

Difference 1: Female mudpuppies don't have shell gland. They don't lay eggs with shells. Difference 2: Male mudpuppies don't have claspers. Difference 3: Mudpuppies are only oviparous. Sharks can be all three (depend on species). Difference 4: Urinary collecting tubules transport urine to the caudal end of ductus deferens, thus part of the ductus deferens transport both urine and sperm. Sharks' ductus deferens transport only sperm.

MUDPUPPY DIGESTIVE ANATOMY Name three significant differences in the digestive tract of Necturus compared to the shark.

Difference 1: Mudpuppy has small and large intestine. Shark has one spiral valvular intestine. Difference 2: No rectal gland. Difference 3: Straight (not as much bend) stomach. Sharks have J-shaped stomach with bend in pyloric region.

Compare the eyes to that of Necturus. Name a difference and give a reason for this difference.

Difference: mudpuppies lack eyelids Reason: Iguanas live on land more than mudpuppies. Need eyelids for moisture retention.

Make a note of both the differences and similarities between the bowfin and what you have seen with the perch. What sort of ecological and behavioral pressure could explain these differences?

Differences: Bowfin only has 1 dorsal fin (not separated into anterior and posterior), gular plate, dense bony head. Bowfin charges at prey so they are more aggressive predators than the perch. They are also territorial and go after things their size or smaller. Similarities: The rest of the body (general body plan).

Unlike their adult counterparts, tunicate larvae are planktonic or free-swimming. Knowing that these organisms are filter feeders, what is the utility of this free-swimming modality in early life?

Dispersion - helps larvae pick a location far enough away from one another to maximize food abundance.

Do the gills of the dogfish shark have the capability to draw water over themselves? Do you think this is something that is consistent across all species of sharks? If no, what sort of niches (generally) would you predict of sharks that (a) have this capability and (b) do not have this capability? If yes, what sort of selective pressure would drive this physiological ubiquity?

Dogfish shark cannot draw water over themselves. This is not consistent across all species of sharks. Those who have this capability are sharks that use ambush strategies to capture prey and thus need to remain still in the water but maintaining oxygen exchange at the same time. Sharks that do not ambush prey do not need this capability.

How do the fins compare to those of the shark? For each fin type on the stingray (of which there are four), comment on morphological differences between those of the stingray and those of the shark. Which fin type has undergone the most changes in morphology?

Dorsal fin (small on the tail), caudal fin (very end of tail), pelvic fin (flaps merged with body) Pelvic fin had the most change

Compare the dorsal and ventral scales of your specimen. How are they different? What is the significance of this/these difference(s)?

Dorsal: darker in color, rougher, smaller, thicker (for protection and camouflage) Ventral: lighter in color, bigger, thinner (for movement)

Observe the numerous tiny pores on the at the top and bottom of the head. These pores open into special sensory structures called ampullae of Lorenzini. These ampullae are used to detect which two environmental stimuli?

Electrosensitive: for minute electrical fields, temperature gradients

Given the general anatomy of the snake that you have observed, how do you think the internal anatomy will differ from other reptiles? Use previous specimens we have observed to support your hypothesis.

Elongated internal organs that exemplify spatial optimization

Based on your answer to question 5, what is the functional significance of these examples?

Example 1: Offset - spatial constraints Example 2: If gallbladder was attached to liver (adjacent to stomach), ingestion of large prey will press on the gallbladder and cause premature release of bile into the small intestine Long - maximize absorption, spatial constraint Stomach and skin very elastic for large meals

How is the snake jaw adapted to ingest large prey? Give three examples.

Example 1: glottis - lets them breathe while mouth full Example 2: extra bone in jaw allows unhinging Example 3: jaw solely attached to skull via ligaments

Provide three anatomical examples which support the lancelet lifestyle of filter feeding. Briefly support your examples with the function of these structures.

Example 1: midgut cecum Function: long midgut allows for filtering/absorption Example 2: buccal cirri Function: filtering; sorts large particles Example 3: wheel organ (with ciliated tracts) Function: 2nd filtering; sweep food into mouth

SNAKE INTERNAL ANATOMY What is striking about the organs present in the snake, especially when compared with other vertebrates? Give two examples.

Example 1: paired organs are offset Example 2: gallbladder not attached to the elongated liver

What two body systems comprise the functional significance of the cloaca?

Excretory and digestive systems

The function of the cloaca as a "common chamber" has remained unchanged from that of the mudpuppy. What two body systems does it serve?

Excretory and reproductive.

PIGEON EXTERNAL Feathers, while largely assisting in the functionality of flight, were not originally adaptive for this reason. Recent studies have shown that many species of theropod dinosaurs possessed feathers. Propose two alternative explanations as to the initial adaptive significance of plumage in the reptilian lineage

Explanation 1: heat insulation (thermoregulation) Explanation 2: sexual display

How would you characterize the reproductive mode of the bowfin? Is fertilization internal or external?

External fertilization.

Stingrays are primarily nocturnal. With this fact in mind (coupled with their location on the body), comment on the utility of their eyes in prey detection and predator detection.

Eyes are for crude overhead predator detection because preys are mostly in sand. Do not have well-developed eyes and vision.

Observe the positioning of the eyes. From this, comment on the extent of their field of vision as well as the degree of depth perception they possess

Eyes are positioned laterally so they have poor depth perception because not much field of vision overlap.

Given what you now know about bird respiration, comment on the heart beat rate between a bird and an iguana.

Faster. Lub-dub of heart is 2 heart beats. First beat is from blood entering right ventricle through tricuspid valve. Second beat is from blood exiting right ventricle through pulmonary valve. Because there is interventricular septum now, right ventricle fills faster and valves open and close faster (more efficient).

MUDPUPPY EXTERNAL ANATOMY What feature of its external anatomy is most striking?

Feathery external gills.

What distinguishes cartilage from bone? Name three features.

Feature 1: cartilage doesn't have blood supply Feature 2: cartilage has no innervation Feature 3: cartilage has unorganized calcium deposits

Based on the position of the velum, what is its function?

Feeding; to help direct food down the pharynx

Is your perch a male or a female? How can you tell?

Female; can tell because eggs. Females are also much bigger.

Other than for respiration, why might a frog have lungs and want to fill them with air?

Filling the lungs with air adds buoyancy to the frog, and prevents the organism from sinking in water.

What are plicae? Based on their location, what is their function?

Folds in small intestine. Increase surface area for nutrient absorption.

Birds possess a modified posterior region of the trachea called the syrinx. This structure is unique to birds. Based on position, infer its function.

For singing, can modify how quickly air moves through when exhaled.

- Which skeletal element do you think articulates with the foramen magnum? How do you think this articulation varies between an alligator and a human? How does the natural of this articulation influence the overall behavior of the organism?

Foramen magnum is attachment point for skull and spine through which the spinal cord passes to the brain. Differs in location for human and alligator. Opening in humans is more central and indicates bipedal locomotion. Opening near rear of skull in alligator and indicates quadrupedal locomotion.

Define the terms in question 7.

Foramen: a perforation or hole through a tissue wall Transverse Process:a general term for a lateral process from a vertebra Tuberosity: a large, roughened projection Condyle: a smooth articular end of a long bone

On average, the tail of the iguana comprises about 60 to 67 percent of the total length of the body.Keeping in mind that iguanas are known to spend time both on land and in the water, propose three functions for having a robust tail.

Function 1: Defense Function 2: Propulsion in water Function 3: Balance in trees so they don't fall off

Inside of the iguana's thighs is a row of about 12 to 20 large pores known as femoral pores. Males in breeding season often develop spine-like 'spurs' that protrude and exude a soft waxy substance. This substance carries a pheromone produced by glands under the skin. Given this fact, propose two functions for the femoral pores in males.

Function 1: Female-male attraction Function 2: Marking territory (like dogs peeing)

Based on the position and structure, what do you think is the function of the gill rakers? Name two.

Function 1: Prevent debris from entering. Function 2: Provide structure for the gills.

The subtympanic shield is a conspicuous and rather enigmatic anatomical novelty. Biologists are unsure as to the exact function of this structure; however, there is a prevailing hypothesis. Given its relative position to other features, propose two possible functions.

Function 1: predation intimidation by mimicking an eye/ male-male competition Function 2: sexy son hypothesis: indicative of fitness thus it is used as a phenotypic proxy in sexual selection; higher fitness if shield has more sheen and is bigger

The anterior dorsal fin and anal fin have sharp spines. Propose two functions for these spines.

Function 1: protection from predation Function 2: fin structure (may help them from rolling in the water column)

Propose two functions for the vertebral column.

Function 1: protection of the spinal cord Function 2: stiffening of the body, and attachment for bodily muscles

PIGEON CIRCULATORY/RESPIRATORY SYSTEM Air sacs represent some of the most complex respiratory machinery available to vertebrates. For birds, the efficiency afforded by these air sacs is intimately tied to flight capabilities. However, these air sacs serve other functions. Name two plausible functions unrelated to flight.

Function 1: reducing body weight because they are just filled with air Function 2: reduce heat production during flight

What is the function of the nidamental gland? What is another name for this structure?

Function is to produce shell membrane around eggs. Also referred to as the shell gland.

What is the function of the notochord? What structure is analogous to the notochord in vertebrates?

Function: support nerve cord Analog: intervertebral disks

- What is the difference between the urostyle and the coccyx?

Fused vertebrae (urostyle) vs. unfused vertebrae

STINGRAY INTERNAL ANATOMY Describe the inner wall of the esophagus.

Has esophagus papillae.

You will notice that the bird does not have any teeth. How does it grind up its food? Is it possible for a bird to have teeth? Why or why not?

Gizzard of the bird contains stones and is used to "chew food". Birds can have teeth because they lost it secondarily but it is impractical to have teeth because they need to be as light as possible.

SHARK MUSCULATURE Group the following list of muscles by general function (e.g., moves pectoral fin, moves pelvic fin, etc). For each group, state the function. (i) Adductor mandibulae, (ii) Coracohyoid, (iii) Superior Oblique, (iv) Coracomandibularis, (v) Medial Rectus, (vi) Interhyoideus, (vii) Inferior Oblique, (viii) Preorbitalis, (ix) Levator Hyomandibulae, (x) Ventral Constrictors

Group 1: Closes mouth Adductor mandibulae Preorbitals Group 2: opens the mouth Coracohyoid Coracomandibularis Group 3: Rotates eye Superior Oblique Medial Rectus Inferior Oblique Group 4: Compress gill pouches Interhyoideus Levator Hyomandibulae Ventral Constrictors

Given the position of this bone, what is its function?

Gular plate allows for muscle attachment for chewing and strengthening biting force.

What cranial element is unique to the bowfin among other extant bony fishes?

Gular plate is unique to the bowfin, making it a living fossil.

Describe the inner wall of the stomach. What structures are present? How does this compare with the shark?

Has stomach rugae (folds) like shark.

If you have a male iguana, you may notice two organs on either side of the tail. These are a synapomorphic characteristic of squamates. What are these structures?

Hemipenes

Observe the digestive tract, would you say that the iguana is primarily herbivorous or carnivorous?

Herbivorous. Colic caecum (see above). The relative length of their digestive tract is also longer because plant matter is harder to digest and takes a longer time.

Based on what you know about the digestive system of other more "basal" forms, what is the function of the colic caecum (hindgut)?

Hindgut fermenter: Caecum has microflora that ferments and breaks down food (cellulose)

Distinguish between holobranch and hemibranch. Is the first gill holobranch or hemibranch? How about the fifth gill?

Holobranch: "a complete gill", has gill lamellae covering both sides (all the ones in between 1st and last) Hemibranch: "half gill", has lamille only on one side (1st and last gill in a shark)

The teeth of a shark are actually modified, enlarged placoid scales - scales characterized as spiny, bony projections with an enamel-like covering on the bodies of chondrichthyan fishes. The teeth themselves are continually replaced throughout the lifetime of a shark. Given the morphology of these teeth, how does this characteristic of continuous replacement "limit" the overall dental anatomy of the shark?

Homodont: all the same teeth; no specialized teeth

How are muscles similar to the skeleton in terms of how they evolve over vertebrate evolution? Why does this make sense?

Homology? Hox genes? Supporting musculature for branchial arch development? Muscles mirror the increasing complexity of skeletal plans. Form of bone changes as the associated muscles attach

Observe the mouth region of your lamprey. How is the mouth adapted to prey on other fish?

Hooked teeth to latch onto prey (made from keratin); suction cup of buccal cirri; anticoagulant glands

Propose a reason why this directionality would be advantageous to the perch?

Hydrodynamics for swimming.

What is particularly striking when you compare the intestinal tract of the iguana to that of the mudpuppy?

Iguana has colic cecum, mudpuppy does not. Length of relative intestinal tract.

The frog does not have a diaphragm to push and pull air directly into and out of the lungs. How does the frog move air through its respiratory system?

In order to gather and expel air, the frog creates a pressure difference in its mouth (buccal pump). The frog expands its throat and opens its external nares. Air then enters the nares due to the low pressure inside the mouth. The nostrils close, the mouth contracts, and the air is forced into the lungs. In order to expel carbon dioxide, the same steps occur in the reverse.

Think about what it means to be an ectotherm. Link the morphology of the dewlap to this physiological characteristic.

Increase surface area of dewlap, increase surface area for sunlight absorption, helps in thermoregulation.

What is the function of the spiral valve?

Increased surface area for nutrient absorption

Which bones form the middle ear? From where are they derived?

Incus-quadrate Malleus-articular Stapes-stapes (I think hyomandibular but have to double check)

Based on the following figure, describe how the lungs are constantly filled with air. Use the terms "anterior air sacs", "posterior air sacs", "lungs", "inhale", and "exhale", in your response.

Inhalation 1: air through nostrils -> trachea and mesobronchus -> posterior air sacs (abdominal + thoracic) Exhalation 1: air out of posterior air sacs -> lungs (gas exchange) Inhalation 2: air in lungs -> anterior air sacs (caudal, cervical, interclavicular); new air is going through steps under inhalation 1 Exhalation 2: air in anterior air sacs -> trachea and out; new air is going through steps under exhalation 1

How is the digestive tract of the bowfin similar to that of the shark?

J-shaped stomach (bends at pyloric region). Spleen hangs off body of stomach like in shark. Spiral valvular vestiges in intestine.

- A primary function of bone is to serve as a location for muscle attachment. Consider the location and dimensions of the keel. What do you think is the primary function of the keel? Why would some birds not have a keel?

Keel: ventral projection from sternum; for flight muscle attachment Some birds don't fly, no need for flight muscle or keel.

Leathery and scaly skin. Large keratinized scales act as barrier to prevent water loss.

Land iguanas: UV protection, but they are mostly on land, covered by canopy Marine iguanas: UV protection, must have darker skin to not get sunburned because they are directly under sun

The structures that comprise the digestive tract are elastic. How would this affect hunting behavior?

Large, elastic esophagus helps with swallowing prey whole. Elastic stomach means being able to eat more prey per hunt. They don't have to hunt as often so higher energetic efficiency.

Which chamber is largest? Which chamber is the main contracting chamber of the heart?

Largest and contracting chamber: ventricle

PIGEON UROGENITAL SYSTEM The urogenital system of birds changes size throughout the year. During what time of the year would you expect it to be largest? In general, what are two advantages of having a urogenital system that can modulate its size?

Largest during mating season due to hormonal differences, food availability, amount of light/temperature in environment. Advantage 1: Weight control. Only needs to be heavier when reproducing. Advantage 2: Maximize reproduction during mating season.

Given that stingrays are elasmobranchs, what other structure do they possess for detecting disturbances in the water?

Lateral line system

IGUANA EXTERNAL Feel the skin of the iguana. What about it makes it particularly efficient at retaining moisture?

Leathery and scaly skin. Large keratinized scales act as barrier to prevent water loss.

Describe the shape of rostrum. Notice the presence of cartilage along the medial line of this region. Propose a function for the shape and cartilaginous nature of the rostrum.

Like a stiff shovel for digging in sand.

Frog Dissection Background:

Lithobates catesbeianus, or the American Bullfrog, belongs to the order Anura of the Amphibia class. This organism also belongs to the Ranidae family, which is considered to be the family of "true frogs." The bullfrog often lives in stagnant water--swamps, ponds, lakes, etc.--close to the edge. Bullfrogs are voracious, ambush predators that use the cover of the water's edge to their advantage. It is not uncommon to find a rodent or small bird within the bullfrog's stomach. Their voracious appetites are possible in part because of their mouth. They have incredible jaw strength as well as a tongue that can extend outside the mouth and pull their prey into the mouth. Bullfrogs, like other amphibians, spend their larval stage submerged in water, and their adult stage moving between water and land. A male will grasp onto a female, who will lay her eggs in shallow water near vegetation, and will release his sperm. The eggs are then externally fertilized, and the resulting larvae will hatch in the shallow water and remain there until metamorphosis. This transition from larval to adult state can take anywhere from a few months to 3 years depending on the climate.

Which cranial element of the vertebrate skull do you think was lost in the snake to increase buccal flexibility? Why?

Lost the jugal/zygomatic, articular, squamosal bones. Can expand its mouth more when feeding.

The mudpuppy has three modes of respiration! One of these is via the skin (cutaneous respiration). What are the other two?v

Lungs and gills.

The lungs of birds are less flexible and generally smaller than other organisms we have looked at this semester. Why?

Lungs aren't muscularized because they don't move air in and out (they don't have diaphragm). Smaller due to weight restraint.

Think about sex differences in the shark. Is your stingray male or female? How can you tell?

Male, has claspers

Observe the external anatomy of your shark. Does your shark have claspers? What sex is your shark?

Males have claspers. Females don't.

Interestingly, iguana hearing is tied to body temperature. The morphology of the ears themselves is striking. How does the ear morphology differ from that of a mammal?

Mammal ear has incus, malleus, stapes. Tympanum (external eardrum) in iguana is morphologically distinct. We hear by air vibrations. Iguana hears by placing its head against the ground because tympanum cannot detect air vibrations.

The mudpuppy is proof that it is possible to live in water with fully functional lungs. But is it possible for an organism to live on land without lungs? If not, why? If so, how?

Many species in the salamander family Pethodontidae do by using their moist skin as the only respiratory surface. Increased vascularization of the skin and smaller body size helps make this possible.

You will notice that the pleuroperitoneal cavity is lined with thin, translucent membranes. What are these called? What is their function?

Mesenteries. Keeps organs suspended and in place; protects organs.

Name the mesenteries of the reproductive tract. What is the broad ligament?

Mesovarium where the ovary is suspended from. The oviduct is supported by mesosalpinx The ovarian ligament attaches the posterior end of the ovary to the oviduct. The uterine horn is supported by the mesometrium. Collectively, these structures form the broad ligament of the mammalian uterus

PIGEON DIGESTIVE SYSTEM Given its location, the crop is a swelling or modification of which structure?

Modification of esophagus

- Why are there more muscles located in the forelimb as compared with the upper arm or leg?

More fine movements and rotations perhaps?

- List three bones that are most likely to preserve in the fossil record. List three bones that are least likely to preserve in the fossil record. Support your choices with a brief statement.

Most likely: femur (large, dense), pelvis, cranium Least likely: clavicle (thin), scapula, sternebrae, hyoid

Trace the route food would travel through the digestive system by filling in the following pathway (does food go into pyloric caeca?):

Mouth -> Pharynx -> Esophagus -> Stomach -> Pyloric caeca -> Intestine -> Anus No food does not enter pyloric caeca, it acts as a digestive gland?

List major organs of the digestive tract (name four).

Mouth, esophagus, stomach, intestines, colon.

Briefly contrast the larval and adult environment of most salamanders. How is the mudpuppy different?

Mudpuppies are one of many species of salamanders that fail to undergo metamorphosis, so they retain larval traits like gills. Thus, mudpuppies tend to stay in water like larval salamanders, but fail to become terrestrial like adult salamanders.

The skull of the snake is characterized by the presence of several fenestrae, or holes. Following from question 10, how is this advantageous to diet?

Muscle attachment for jaw strength. Also helps to lighten bone while providing blood/nerve supply.

The iguana eyelids possess an additional layer known as the nictitating membrane. Given the environment of the iguana, why is this layer useful?

Nictitating membrane prevent debris entry.

Do the pharyngeal slits in the lamprey behave in the same fashion as gill ventilation in most fishes? If yes, explain the behavior. If no, state the discrepancy and propose a reason why an alternative physiology would be necessary.

No, lamprey are parasitic; mouth is occupied from latching onto host; uses only gills for ventilation

Are birds ovoviviparous?

No, they are oviparous.

Do birds have a urinary bladder? What is the advantage of this?

No, they produce uric acid (water retention in body). Also reduction in weight.

Based on your observations, comment on how common you think lampreys would be in the fossil record. Substantiate your hypothesis.

Not common; no bones or bony structures.

Is the Leydig's gland found in female sharks? What is its function?

Not found in females. To transport sperm.

Why is it not surprising that the stingray and the shark have a highly similar digestive tract? What is the only major difference between the stingray and shark digestive system?

Not surprising because they are both Chondrichthyes. Difference: spleen is in a different place. Organs are generally more winded and tightly packed due to space constraints in body (spatial optimization).

SHARK UROGENITAL SYSTEM What is the technical term for the shark kidney?

Opisthonephric kidney

What is the fundamental unit of compact bone? What two structures comprise this unit

Osteon units - osteocytes and canaliculi

SHARK MUSCULATURE Define origin and insertion as it relates to muscle attachment.

Origin: site of muscle attachment that doesn't move during contraction Insertion: site of attachment that moves with muscle contraction

Which structure do you hypothesize to be the evolutionary precursor to the swim bladder? Why?

Outpocketing of the digestive tube that became primitive lungs because it was a vascularized sac for gas exchange. The primitive lungs then became the swim bladder.

Trace the movement of an ovum through the female reproductive tract of the cat by filling in the following:

Ovary -> Oviduct -> ostium -> uterine horn -> Uterus -> vagina

The northern water snake is ovoviviparous. However, there are a vast majority of snakes that are oviparous. Where would you expect oviparous snakes to live? Why? Based on this, why is it not surprising that northern water snakes are ovoviviparous?

Oviparous snakes live in dry, warm climates. Ovoviviparous in northern water snake so its eggs can be kept warm enough to hatch. A latitude (climate temperature) issue, not dehydration.

Which mode of reproduction best describes the life cycle of the mudpuppy (viviparous, oviparous, or ovoviviparous)?

Oviparous.

Are stingrays oviparous or ovoviviparous? If you had a female specimen, how might you be able to tell?

Ovoviviparous. Can tell if female had eggs and her young attached to yolk in uterus.

On the dorsal surface of the head, you may notice a tiny, transparent scale. This is known as the parietal eye. Think about its position on the body and hypothesize a function for this structure. Do you think the marine iguana possesses a parietal eye? Why or why not?

Parietal eye: contains pineal gland. For predation detection. Marine iguanas have it as well because they still come on land to mate and nest so they need protection from avian predators as well.

- What are the three parts of the pelvis? Contrast the Saurischian and the Ornithischian configuration of the pelvis. To which group do birds belong? What is the explanation for this?

Pelvis: Ilium, ischium, pubis Saurischian pelvis: pubis is not parallel to ischium Ornithischian pelvis: pubis is parallel to ischium Birds: have saurischian pelvis; ornithischian is named for similar appearance to bird hips but birds really evolved from saurischian radiation

We did not (and will not) study the musculature of the perch this semester; however, hypothesize in what general ways you expect shark musculature to differ from that of the perch.

Perch: not specialized for predation, less muscle mass. Shark: more robust musculature, specialized for predation (especially head region).

Is there anything that is particularly striking about the orientation of the pharynx, esophagus, and stomach? If so, how is it an advantage.

Pharynx, esophagus and stomach are all linearly oriented. Advantage: Can swallow prey whole.

Which structure undergoes the most dramatic changes from larva to adult? How is the structure changed?

Pharynx: turns into the branchial basket, flips directions and elongates

What is the function of the gill lamellae?

Place of oxygen exchange.

The liver, gonad, and intestine reside in what body cavity?

Pleuroperitoneal cavity

Which defining chordate characteristics are lost in the adult tunicate? Why do you think these traits are lost? Provide a reason for each characteristic.

Post-anal tail: Lost; adults don't need it cause no locomotion Notochord: Lost; no support for nerve cord needed cause no nerve cord Pharyngeal slits: Became stigmata DTNC: Became cerebral ganglion, in part

SNAKE EXTERNAL The scales of the snake are keratinous. Why would this be adaptive?

Predator protection, moisture retention

The nictitating membrane, as in the iguana, protects and hydrates the eyes. However, in diving birds, it serves an additional function. Think about what it means to be a diving bird and infer this function.

Prevents debris from entering eyes when diving.

The stomach has two parts. Name them. Which of these two parts do you think is primarily responsible for secreting digestive enzymes? Why?

Proventriculus: glandular portion, digestive enzymes mixed with food Gizzard: muscular portion, mechanically grinds up the food

The cartilaginous striations you observe are called fin rays. What do you think the functional significance would be for these structures?

Provides rigidity to support caudal/dorsal fins; locomotion; predator protection

- Which two bones seen in the pigeon skull (along with the stapes) become the incus and malleus in the mammalian inner ear? Why is this not altogether surprising?

Quadrate -> incus; Articular -> malleus Quadrate-articular jaw joint was slowly replaced by the dentary-squamosal jaw joint so the quadrate and articular bones moved inward and became part of the inner ear.

Describe the configuration of muscles. Provide two functional reasons for this configuration.

Reason 1: Constriction (strangling) Reason 2: Locomotion

Observe the dorsal side of your stingray. Locate the spiracle. Its position on the dorsal surface of the organism is crucial. Give two reasons why a dorsally located spiracle is important for this species.

Reason 1: allows them to breathe while laying on bottom (ventral surface is covered with sand and murkiness of sea floor) Reason 2: they hide in sand; can cover themselves without suffocating

Since the mudpuppy has gills and never transitions to life on land, what is the use for lungs in an aquatic medium? Give three reasons.

Reason 1:can supplement gill respiration in oxygen poor water Reason 2: lungs filled with air give a means to control buoyancy Reason 3: be able to relocate from their shallow ponds

- Birds possess skeletal pneumaticity, or the presence of air spaces within bones. Why is this adaptive?

Reduce overall body mass for flight; better distribution of weight within the body, better balance, agility and ease for flight

What is the function of the pyloric sphincter?

Regulates flow of food entering intestines from stomach

- What is the function of the palatine processes? How does the function relate to the biology of the alligator?

Ridge of bone that separate the oral cavity from the nasal cavity- it allows the animal to breath while they are subduing prey

Observe the trachea of your specimen. How is it morphologically distinct from the esophagus? How does this morphology reflect its function

Rings in trachea (ribbed), esophagus has no rings. Prevents trachea from collapsing from pressure.

Gently run your hand across the surface of the shark. Which way feels smooth and which way feels rough? What is the significance of this?

Rough from tail to head, makes them hydrodynamic.

The nostrils of the iguana have a unique function. The nasal chambers store accumulated liquid from the iguana's salt glands. These glands act as a secondary kidney in that they are specialized to remove excess amounts of sodium, potassium, bicarbonate, and chloride from the body. Why would this function be especially critical for an iguana?

Salt glands help them get rid of excess salt without peeing (losing water). Water retention is important when they live in dry hot climates.

Examine a dorsal scale under the dissecting scope. Draw and measure what you see. Compare the body:scale measurements of other specimens. What do you notice?

Scales have medial lines, attached to body by fibers

Carefully remove the skin to uncover the underlying musculature. Draw what you observe below.

Segmented muscles with different portions: lateral, ventral, dorsal

What can be said about the arrangement of the branchial musculature in relation to the gill arches? How does this fact aid in our understanding of the evolution of the jaws from a comparative anatomical perspective?

Segmented, each bundle associated with a particular gill arch. Became muscles that became associated with jaws.

Do you have a male or a female? How can you tell? Give two reasons.

Sex: Female; Male Reason 1: Ovaries; testes Reason 2: Much larger in size than males; ductus deferens

What is the sex of your lamprey? Give a reason to support your claim.

Sex: male; female Reason: smooth gonad; bumpy (eggs) gonad

The rectal gland is responsible for regulating salt in the blood by removing excess salts from the blood and passing it off to the intestines for excretion. Why would a shark need to regulate its salt concentration?

Shark lives in seawater. Rectal gland is used to osmoregulate salt concentration.

How many pairs of gill (pharyngeal) slits does the dogfish shark possess? How does this compare with the lamprey?

Shark: 5 Lamprey: 6-7 Reduction in pairs of slits in evolutionary time

How does the stingray musculature compare to that of the shark? What is the significance of this difference?

Sharks have more complex musculature. Sharks actively hunt for prey, stingrays are more passive and are benthic feeders.

Make an incision and open up the stomach. Are there any contents? How would you describe the lining of the stomach?

Shrimps and small fishes. Lining is heavily folded and smooth.

Compare your specimen with what you know of the human respiratory system. What are the similarities and differences?

Similarities: the lungs are a major site for gas exchange. Differences: the frog lacks a diaphragm, frogs are unable to breathe through their mouth because they use muscles in the mouth to pull air through their external nares, and frogs have more than one site for gas exchange (mouth and skin).

Despite the highly adapted configuration of the avian skeleton, in what ways are bird skeletons similar to those of crocodilians? Name three.

Similarity 1: Single occipital condyle Crocodilians and birds can rotate their heads more than mammals (two occipital condyles) Similarity 2: Single middle ear bone Crocodilians and birds only have stapes. Mammals have incus, malleus and stapes. Similarity 3: lower jawbone made of fused bones Crocodilians and birds have articular, surangular, angular, coronoid and dentary bones in their lower jaw. Mammals only have dentary.

Aside from what was discussed in the previous questions, in what ways is the stingray digestive tract similar to that of the shark. Name three.

Similarity 1: Stomach rugae Similarity 2: Spiral intestine Similarity 3: Same number of lobes of liver Similarity 4: relative length of digestive tract

Feel the texture of the liver. How would you describe it? Link your description to a unique function of the shark liver. How is its function adaptive?

Slimy, soft, dense -> produces oil for buoyancy, no swim bladder

What do the striations you observe on striated muscle indicate?

Skeletal muscle

- Consider the influence of predators on skeletal remains. Which skeletal elements would be more likely recovered from the remains of the prey? Which ones would appear more rarely? Why? (Not sure)

Skeletal parts in the cranial region and appendages are most likely to survive. Skeletal parts in the abdominal region would appear more rarely.

The nerves in a lamprey are un-myelinated. Try to relate this fact to the overall body size and complexity of the lamprey in relation to other vertebrates. What is the significance of this?

Small body size. Action potentials cannot travel fast and far without myelination of nerves.

Gently run your hand along the body of the perch toward the anterior end then back toward the posterior end. Which way feels smooth and which way feels rough?

Smooth anterior to posterior. Rough opposite way.

- What is a diastema?

Space between teeth (usually between incisors and molars)

Sharks have a modified gill slit. What is it called? Given that spiracles are reduced or absent in pelagic species, what do you suppose is the utility of having a spiracle for sharks that are bottom-dwellers?

Spiracles on dorsal surface that allow sharks to breathe while on the bottom of the floor.

What structure in the list above (step 6) is not part of the digestive system? What is the function of this structure? To which system is this structure a part?

Spleen - immune system; produces lymphocytes and destroys old RBCs Accessory organs (pancreas, liver, gallbladder): - pancreas: digestive enzyme release into intestines + blood sugar regulation (endocrine system) - liver: bile production, detoxification, glycogen storage (digestive + immune system) - gallbladder: bile storage (digestive system)

How does the shape of the stingray stomach compare to that of the shark? What is the significance of this difference?

Stingray's stomach loops up in the body. Shark's stomach is straight. Significance: spatial optimization.

Based on your last answer, why is the adult configuration of the ductus deferens and the urinary collecting tubules necessary?

Storing sperm in a region of the ductus deferens that also must transport urine may harm the sperm or the sperm may interfere with passage of urine. Thus, by shifting connections between the ductus deferens and urinary collecting tubules more caudally, additional space is available in the ductus deferens to store sperm.

What is the mesotubarium? What is its function? In what other organ system have you seen a similar structure?

Subdivision of ventral mesentery. Attaches oviduct to dorsal body wall-- urogenital system. The dorsal mesentery holds the intestines to the dorsal wall; it is called the mesocolon at the large intestine-- digestive system.

PIGEON SKELETON - Based on their location, what is the function of the sclerotic rings?

Support eye shape and tissues. Close-range focusing [debated].

- What is the function of the hyoid?

Supports the tongue; anchor and allow extension of tongue.

- What is striking about the skeleton of a bird? As an example, what are the components of the synsacrum? Give two more examples of this novelty and list the components.

Synsacrum: fusion of last thoracic, lumbar, sacral + first few caudal vertebrae into a single piece Innominate bone: fusion of ilium, ischium, pubis Tibiotarsus: fusion of distal tibia + proximal tarsal Tarsometatarsus: fusion of tarsal + metatarsal

Locate the lateral line. To what system does this structure belong? What is the function of the lateral line?

System: Nervous/sensory system. Function: Detects movement in the water.

Contrast the role of the ductus deferens and the urinary collecting tubules in the larval and adult salamanders. What is paedomorphic about the mudpuppy in this regard?

The caudal region of the ductus deferens of mudpuppy and larval salamanders can conduct both urine and sperm. However, this dual role is typically not found in adult salamanders. Mudpuppy males retain this juvenile trait and this is an example of paedomorphic morphology.

What is the structural difference between the ductus deferens and the seminal vesicle?

The ductus deferens is highly folded and the seminal vesicle is not (just a straight tube).

Compared with the previous dissections that involve the caeca structures, why might the frog lack the caeca?

The frog most likely lacks the structure of the caeca because the frog can maximize its absorption without the need of any additional structures. It is possible that evolution drove the frog to have stronger enzymes that break down food more efficiently. The small intestine was also longer compared with previous specimens, meaning the small intestine had more surface area to absorb the necessary nutrients. The frog may have evolved this efficient digestive system due to a physical constraint. As observed in our specimen, the female bullfrog, though larger in size than the males, was dominated by her ovaries so much so that her oviduct was pushed upwards towards the respiratory and circulatory system.

Frogs have a unique way of pushing their food from their mouth and into the esophagus. How is this done?

The frog will blink in order to push food from the mouth down the throat. The frog's blinking pushes the eyes back into the sockets and press down on the food, pushing it back into the throat.

IGUANA INTERNAL ANATOMY How many chambers does the iguana heart possess?

The iguana has 1 ventricle and 2 atria.

The oviduct is responsible for transporting eggs from the ovary to the cloaca. As it does so, it deposits a jelly coat around the eggs. What is the function of this jelly coat?

The jelly coat allows the eggs to be attached to hard surfaces (usually underside of rocks). It might also prevent them from drying out.

The frog is a voracious eater and can eat large quantities of food at a time. What adaptive features of the digestive tract allow this dietary behavior?

The main adaptive feature to allow this behavior is the elasticity of the esophagus and stomach. These two organs are capable of stretching to accommodate the swallowing of rodents and small birds. Once the food makes it to the stomach, digestive enzymes are secreted to break down the food and allow for easier passage through the rest of the digestive tract. Only once the food is digested will the pyloric sphincter be capable of pushing the food into the small intestine

What is primitive about the structure of the male shark urogenital system?

The male shark has an integrated urinary and reproductive tract. There is only one tube with specialized regions for the ureter, seminal vesicle and vas deferens. There are no separate structures.

Look at the spines of your specimen. Which region of the body has the most elaborate spines? What is the utility of this?

The nuchal region. Stops avian predators from picking grabbing the iguana up from its back.

Both the pancreas and the gallbladder release fluid to aid in digestion. What macromolecules do these specific fluids break down?

The pancreatic fluids break down carbohydrates and proteins. The bile breaks down the lipids.

The skin is an important part of the respiratory system in terms of gas exchange. How does the skin function in relation to the respiratory system? What other sites of gas exchange does the frog have?

The skin of the frog is filled with a vast network of blood vessels. When the frog is completely submerged in the water, the skin allows the frog to perform gas exchange directly with the circulatory system through the skin. When on land, glands keep the skin moist to allow for the skin to continue making this direct gas exchange with the air. The other sites of gas exchange occur in the lungs.

What is the spermatic cord? Name its components.

The spermatic cord is the cord-like structure in males formed by the vas deferens (ductus deferens) and surrounding tissue that runs from the deep inguinal ring down to each testicle.

How does the internal anatomy of the bowfin compare to that of the perch?

Their digestive tract are very similar. Bowfin's caeca is more parallel/rounded and next to the stomach than perch's.

Comment on the stature of the mudpuppy. That is, how would you best describe the position of the limbs relative to the body? In what ways are they adapted for swimming? In what ways are they adapted for land?

Their limbs are close and parallel to their bodies. For swimming: they hold their limbs close to their torso and swim with their tails. For land: they have digits in their limbs for easier climbing/walking.

The fish does not have any eyelids. Why are they not necessary?

There is a mucosal layer over the eye to prevent debris from getting into the eye. Also do not need to moisturize eyes in aquatic environment.

Iguanas (like the mudpuppy) have one ventricle. What sort of physiological constraint does this place on the organism? Relate this to their behavior in the natural environment.

There is mixing of oxygenated and deoxygenated blood. Not the most amount of possible oxygen brought to the muscles. Can only have short bursts of energy, cannot have sustained periods of high energy.

What is the function of the pulmonary veins?

These blood vessels carry oxygenated blood from the lungs to the left atrium.

- Do you think a chicken skeleton preserves well in the fossil record? Why or why not?

They might not preserve well in fossil record because they are light and mostly hollow. But they preserve better than cartilage.

What is unique about the vertebrate urogenital system in terms of development?

They must produce gametes prior to mating Gender neutral (up until specific differentiation)

Why are the urinary and reproductive systems of vertebrates oftentimes treated as one 'urogenital' system?

They share many of the same ducts

The crop is elastic in nature. What is the adaptive significance of this?

They store food in the crop (can remain there up to 12 hrs). Adults also produce "crop milk" for young in the crop.

- Considering the natural environment of the alligator, what is the function of the palpebral bone?

This bone sits in front of the orbits to keep debris from entering into the eye when the alligator is swimming just below surface of the water. Acts as a physical barrier to divert the debris.

Although the frog exhibits similar dietary behavior to snakes, why is the gallbladder smaller in the frog?

Though the frog is eating whole prey like the snake, the frog does not require a larger gallbladder. This is most likely because the frog is still limited to a certain size of prey. The frog is not able to expand its jaw like the snake in order to devour prey and thus limits the prey size to as large as the frog can open its mouth. So by the time the frog's prey reaches the pyloric sphincter, the food has been mostly digested and can more easily be moved into the small intestine. While bile is still needed to help the digestive tract move the food through, the frog does not require as much bile as the snake would.

What is the modern analog to the endostyle?

Thyroid

What function do you suppose the teeth have in this configuration?

To hook onto prey; prevent them from escaping mouth.

Which technical term is used to collectively refer to the prosencephalon, mesencephalon, and rhombencephalon?

Tripartite brain

How would you characterize the flow of air through the respiratory system?

Unidirectional airflow. Constant supply of air for gas exchange in the lungs so more oxygen obtained than mammals.

MUDPUPPY UROGENITAL ANATOMY What is curious about the configuration of the bladder in the mudpuppy?

Urine: from urinary bladder -> terminus of large intestine -> cloaca (usually urinary bladder -> urethra)

- Name the muscles that comprise the quadriceps. They all have a similar insertion. Name it.

Vastus medialis Vastus lateralis Vastus intermedius and rectus femuris

The typical amphibian heart ventricle does not possess an internal septum. What is the consequence of this? Does the bowfin or stingray possess an internal ventricular septum?

Ventricles without septum cause mixing of deoxygenated and oxygenated blood (less efficient oxygen transport). Bowfin and stingray do not have interventricular septum.

Open and close the mouth to observe the action of the mandible and maxilla. Take note of appearance of the teeth as well as the direction that they point.

Very hard mandible. Small, strong teeth organized in rows. Also has two large specialized teeth pointed inwards.

What is the difference between viviparous and oviparous species? From this, what is meant by ovoviviparous? Which of these three terms best describes the dogfish shark's reproductive cycle?

Viviparous: live-bearing Oviparous: egg-laying Ovoviviparous: has eggs but gives live birth Dogfish shark is ovoviviparous

Some species of stingrays are known to spray water from their mouths while foraging for food. What is the function of this? Given its anatomy, provide another means by which rays can accomplish this function.

Water spraying can uncover shellfish in the sand. They also flap their pectoral fins to remove sand.

Does the pigeon possess caeca? If so, how many? What is their function?

Yes, 2 at large intestines. Function: reabsorption of water from digested material, food fermentation.

- Do you think alligator skulls typically preserve well in the fossil record? Why or why not?

Yes, incredibly dense bone with little cartilage.

Does the mudpuppy possess a lateral line? What does this tell us about its ecology?

Yes, their lateral line system has pressure, motion, electroreceptor sensory cells. The cells trigger fast escape by rapid fishlike swimming.

Name the three components of the skull. Circle which components are endochondral in origin.

[Chondrocranium, Splanchnocranium] dermatocranium

Summarize the pathway of water through the lamprey by listing (in order) the structures involved in this pathway. (Hint: You will use structures more than once.)

_gill slits_ → __gill pouch__ → __gills__ → __gill pouch__ → _gill slits__

- The femur possesses a hemispheric head. To which skeletal element does this head articulate?

acetabulum

Name the three muscles that comprise the hamstrings.

biceps formis, semimembranous, semitendinous

SHARK MUSCULATURE Determine the major group of muscles (Axial, Branchial, Fin) to which the following belong. For Axial and Branchial, also state the series (Epaxial, Hypaxial, Constrictor, Levator, Interarcual, Hypobranchial): Cucullaris Coracomandibularis Ventral Longitudinal Bundle Spiracularis Interarcuals Extensors Lateral Longitudinal Bundle Intermandibularis Flexors Common Coracoarcuals

cucullaris (muscle); branchial (group); levator (series) corcacomandibularis (muscle); branchial (group); hyobranchial (series) ventral longitudinal bundle (muscle); branchial (group); hypaxial (series) spiracularis (muscle); branchial (group); constrictor (series) interarcuals (muscle); branchial (group); interarcual (series) extensors (muscle); fin (group) lateral longitudinal bundle (muscle); axial (group); hypaxial (series) intermandibularis (muscle); branchial (group); constrictor (series) flexors (muscle); fin (group) common coracoarcuals (muscle); branchial (group); hyobranchial (series)

- Name the three bones that comprise the hindlimb.

femur, tibia, fibula

CAT SKELETAL ANATOMY - What three elements comprise the innominate bone?

ischium, pubis, ilium

- What is the technical term for the elbow?

olecranon process

Name the three bones that comprise the forelimb

ulna, radius, humerus