Final Zoology

What are three major mammalian groups and their primary reproductive distinctions?

Monotremes - lay/incubate eggs

Metatherians (marsupials)- short gestation, long lactation

Eutherians - Lengthy gestation, short lactation

What structures are involved in sperm transport from the testes?

Seminiferous tubules (spermatogenesis) → epididymis → ductus deferens → urethra

What is capacitation?

Sperm becomes mature in female reproductive tract

Describe characteristics of Class Aves:

• Epidermis - feathers, leg scales

• Skeleton - fully ossified (pneumatized bone)

• 12 pairs of cranial nerves

• head, neck, trunk, tail

• Front limbs - flight

• Rear limbs - walking, swimming, perching

• 4 chambered heart

• Metabolism used to maintain body temp.

• Lungs, air sacs

• Paired kidneys

• Ureters empty into cloaca

• Dioecious - external fertilization

• Oviparous

• No urinary bladder

How are bodies of flightless birds redesigned to remove the restrictions of flight?

Keel is absent

Flight muscles absent

Define the major feather types:

• Contour feathers - cover/stream line body

• Flight

• Down - thermoregulation

• Powder down - water proofing

• Filoplume - sensory

Describe molting:

Replace old feathers

Seasonal

What is the uropygial gland?

(Preen gland)

Produce secretions → condition + protect feathers

What are skeletal modifications for flight?

Pneumatized bone

Light skull

Vertebrae fused (except cervicals)

Unicate processes - braces between braces

What is the function of the keel?

Extension of sternum for flight muscle attachment

What is the function of the furcula?

Fused clavicles

Strengthen thoracic girdle

Define the two primary flight muscles:

Pectoralis - depresses wings

Supracoracoideus - elevates wing

Where are the leg muscles concentrated?

Thigh

Allowed greater agility for feet and muscle mass near center of gravity

What prevents a bird form falling off its perch when it is sleeping?

Perching tendons - toe locking mechanism

Function of the crop:

Dilation at distal esophagus

Function of the gizzard:

Food grinding

Function of the proventriculus:

Chemical digestion

Function of the ceca:

Paired extensions of intestine → processing plants (cellulose)

Function of bursa of fabricius:

Maturation of B-cells

What do some birds do with indigestible materials?

Forms pellet that’s regurgitated

What do some birds swallow to assist in the grinding process?

Grit (small, rocky material)

Describe heart anatomy in birds:

Right - pulmonary pump

Left - systemic pump

4 cambers

What are the functions of phagocytes in bird blood?

Phagocytize microbes and cell debris

Describe unidirectional air flow through the respiratory system:

Inhalation → posterior air sacs → lungs → anterior air sacs → exhalation

What is the other function of the air sacs?

Cool the bird during vigorous activity

Birds have no diaphragm. How is inhalation initiated?

Lowering of sternum = expansion of ribcage

What is the function of the syrix?

Make sounds

What are the costs of endothermy?

Increase calorie intake

What are methods of heat conservation?

Grow winter feathers, aggregations, shivering, wind sheltered sites, microhabitat selection, countercurrent heat exchange

What are heat dissipation strategies in birds?

Spread wings, tuck legs and beak, gaping, salivation, bathing, soaring

Why do some birds practice daily torpor?

Response to lower night temperature and low food supplies

Preparation for migration (store fat reserves)

How do birds excrete nitrogenous wastes?

Uric acid

How do marine birds get rid of excess salts?

Drip salt solution from beak

What are sources of water gains in birds?

Food, drinking free water, and metabolic water

How is eye placement in the head correlated with life habitats?

Lateral eye placement in omnivores - see “sideways” for predators

Forward eye placement in carnivores - depth perception and binocular vision

Which bird species has the longest migration?

Arctic tern

What are stimuli for migration onset?

Daylength and temperature

What are physiological and behavioral changes associated with migration?

Gonadal development

Fat deposition

Courtship/mating behavior

What sense do most birds use in navigation?

Visual (landmarks)

Magnetic fields

Most male birds lack a penis. How is sperm transferred?

Cloacal eversion and opposition

What type of mating system is most common in birds?

Seasonal monogamy, male participates in care of chicks

What is the most common form of polygamy in birds?

Male mates with multiple females

What are the two primary factors involved in mate selection by female birds?

Plumage and body size

What is a brood patch?

Area of increased vascularization + feather loss → incubation of eggs

What are precocial hatchlings?

Feather, eyes open

What are altricial hatchlings?

Born blind and naked

What are nest parasites?

Bird that lays their eggs in the nest of another bird tricking them into raising their young

Describe mammary glands:

Provide nourishment to young and create maternal bond

Describe sweat glands:

Thermoregulation

Describe sebaceous glands:

Produce sebum to condition hair and skin

Describe scent/musk glands:

Pheromone production

Territory marking

Special orientation

What is the function of hair (pelage)?

Insulation

How does the environment help to determine coloration?

Camouflage in substrate and thermoregulation

What are the functions of color patterns in mammals?

Camouflage, communication, physiological (thermoregulation)

What is countershading?

Organism in lighter ventrally and darker dorsally

What are the functions of adipose tissue?

Thermoregulation/insulation

Energy

Heat/water source

Describe heart anatomy in mammals:

4 chambered heart

Right - pulmonary

Left - systemic circuit

How do the red blood cells differ than those of other vertebrates?

Non-nucleated red blood are “sacs of hemoglobin”

What are the primary components of the respiratory system?

Trachea → bronchi → bronchioles → alveoli

What are nasal conchae?

Scrolls of bone that provide turbulence for nasal function

What is an important defense mechanism in the respiratory tract?

Ciliated epithelium covered in mucus that traps debris and pathogens

What muscles are used in respiration?

Diaphragm and intercostal muscles

What is the neopallium?

Increased cerebral cortex (grey matter) that allows for increased intellectual capacity

How is surface area increased in order to maintain cranial size relative to body size?

Gyri - folds in the cerebrum that increase surface area

What is the corpus callosum?

Area of white matter that allows for communication between hemispheres

What is the vomeronasal organ?

Organ that detects pheromones

What are pheromones?

Chemical signals that cause a behavioral or physiological change in conspecifics (same species)

How is the importance of olfaction dependent on habitat and life style?

Some senses (like olfaction) will be prioritized more than other depending on habitat and life style

What are functions of hearing?

Communication, prey detection, predator avoidance

What is infrasound hearing? Examples:

Hearing below human range

Examples: Giraffes, rhinos, elephants

What is ultrasound hearing? Examples:

Hearing above human range

Examples: Bats, cetaceans

Describe the auditory pathway:

Pinna → external auditory canal → tympanic membrane → auditory ossicles and cochlea (receptors)

Describe the visual pathway:

Cornea → aqueous humor → lens → vitreous humor → retina (receptors: cones and rods)

What is the tapetum lucidum?

Reflective structure - posterior to retina → enhance night vision

What are the two types of photoreceptors? In which mammals are each relatively more important?

Rods - noctural and aquatic - vision in dim light

Cones - diurnal - provide color vision

What are vibrissae?

Longer, coarse hairs → tactile receptors

What are functions of mammalian salivary glands?

Neutralize plant toxins

Digestion

Lubrication

Defense - antibodies and antibacterial

How do herbivore digestive systems differ from carnivores?

More surface area on large intestine and cecum

Describe copaphagy in rodents and lagomorphs (rabbits, hares)

High fiber - hard pellets

Soft feces - spend time in cecum

What muscles in the head region are unique to mammals?

Orbicularis oris - suckling

Facial expression muscles

Why is the mammalian skull termed akinetic?

Tempromandibular joint

What are the two functions of the large braincase?

Muscle attachment and protect brain

What is heterodont dentition? Define the tooth types:

Different tooth types/ functions

What is diphyodont dentition?

Deciduous teeth → replaced by permanent teeth

What is homodont dentition?

All teeth have same form/function

What are sectorial teeth?

Interdental shearing

Define axial and appendicular:

Axial - bones that protect organs, skull, vertebral, ribs, sternum

Appendicular - forelimbs and pectoral girdle, hindlimbs, and pelvic girdle

What are the 5 sections of the mammalian vertebral column?

• Column

• Thoracic

• Lumbar

• Sacral

• Caudal (coccygeal)

What are general mammalian strategies for survival in cold environment?

• Larger body size

• Increase insulation - subcutaneous fat and pelage thickness

• Increase metabolic heat production

• Allowing for hypothermia

What is regional heterothermia?

Temperature in extremities is lower than core temperature

What are the two primary mechanisms for regional heterothermia?

Vasoconstriction

Countercurrent exchange

What is temporal hypothermia?

Body temperature change on a daily or seasonal cycle

What is daily torpor?

Body temperature, metabolic rate, heart rate are decreased for some part of a 24 hr. period

Define estivation:

Seasonal torpor in hot, dry conditions

Define shallow hibernation:

Winter lethargy - body temp. maintained within 10 celsius of normal

Define profound hibernation:

Body temperature maintained with 1 celsius of environment temperature

Compare alarm arousal and final arousal:

Alarm - shivering in response to dangerous temperature

• Due to loud noises or mechanical stimuli

Final - coming out of hibernation for the season

What is non-shivering thermogenesis?

Oxidation of brown adipose tissue for heat production

What are the primary mechanisms for mammalian thermoregulation in hot environments?

Radiation across skin

Evaporative cooling

Avoidance of heat

How do many desert mammals use behavioral thermoregulation?

Burrowing

Avoiding daytime heat

Basking on rocks