exam 1

species

groups of actually or potentially interbreeding natural populations which are reproductively isolated from other groups

ecotype

organisms that belong to the same species but possess different phenotype features as a result of environment factors

why is the identification of a species important?

classification and evolution: organizes life diversity and preserves/ prevents biodiversity loss

speciation

evolutionary process by which populations evolve to become distinct species through restricted gene flow and genetic differences

1st step of speciation

isolation of populations

2nd step of speciation

divergence in traits of separated populations ex: mating system

3rd step of speciation

reproductive isolation of populations that maintain isolation when pops come into contact again

allopatric speciation

most common, due to physical or geographic isolation. barrier divides 2 groups- cant interbreed

peripatric speciation

population size difference. founder population of large pop becomes isolated from large pop (niche exploitation) geographic separation and drift

parapatric speciation

individuals of a pop mate with neighboring individuals rather than those in distant range. continuous, but no random mating. results in genetic variation, and a new species may be formed

sympatric speciation

formation of a new species from an original population that are not geographically separated.

how do species come to occupy their present geographic ranges?

cosmopolitan and disjunct distribution

cosmopolitan distrubution

endemic/ circumpolar distribution, inhabit most of worlds oceans

disjunct distribution

occur in multiple regions separated by geographic barrier; different pops of same species separated by equator

biotic factors that affect distribution

spatial and temporal patterns of primary productivity leads to food sources. distribution of marine primary production: low, moderate, high

abiotic factors that affect distribution

geographic and seasonal surface water temp patterns. distribution of SSTs and marine climate zones

adaptive radiation

occurs when a small or single ancestral species rapidly diversifies into a large number of descendant species

metabolism

chemical reactions that occur in the body that convert nutrients to energy, repairs tissues and maintains vital functions

Basal metabolic rate (BMR)

minimum amount of energy needed to maintain essential functions like breathing. 1.5-3x higher in marine mammals

RMR

minimum energy REQUIREMENTS for an animal that is awake and alert but not engaged in strenuous activity

FMR

total energy expenditure of an animal in its natural environment; provides insight into energetic strategies. 1.3x higher than a similar sized carnivore

kleiber curve

compares BMR in terrestrial mammals; larger animal = lower metabolic rate per mass

kleiber curve mammals vs marine mammals

small mm = same size terr. mammal. large marine mammal= lower energy expenses

Cost of Transport

power required to move mass M at velocity V. COT = p/mv

behavioral strategies that reduce swimming and diving costs

echelon position, wave riding, porpoising, apneustic breathing

thermoregulation

maintenance of body temperature

methods to reduce heat loss

vascular countercurrent system, fur/blubber, streamlined body, huddling

vascular countercurrent system

peripheral blood circulation to appendages and vital areas. warm blood -> cold extremities, prevents reproductive overheating

blubber conductivity

function of thickness and lipid content, class, texture

metabolic water

obtaining water from food (water loss reduction)

how do marine mammals reduce heat loss?

osmoregulation, skin and respiration, urinary water loss

osmoregulation

process of maintaining the balance of salt and water in the body

skin and respiration water loss methods

waterproofing of the skin, no sweat glands, low breathing frequency

urinary water loss reduction methods

lobed (each lobe is basically a small kidney), glycogen stores, thick medulla

major components of mammalian heart

4 chambers: 2 ventricles, 2 atria. vena cava, aorta, pulmonary artery and pulmonary vein

how is the heart different in marine mammals?

larger, increased glycogen stores, expanded aortic bul/ arch that functions as elastic reservoir

retia mirabilia

complex network of interwoven veins and arteries that form tissue blocks on inner dorsal wall of thoracic cavity, extremities or periphery of body

pinniped cardiovascular adaptations

enlargement/ increased complexity of veins to enhance capacity. phocids have greatest # of venous adaptations. enlarged hepatic sinus, extra conduit for venous return

cetacean cardiovascular adaptations

no or nonfunctional caval sphincter or hepatic sinus; smaller veins, enlarged posterior vena cava

hemoglobin

02 binding molecule circulating in RBC

myoglobin

fixed o2 binding molecule in muscle cells

storage of o2 in mm blood

more blood overall, MB, Hb, and haematocrit, high o2 reserve in muscle

where do deep divers keep hgih oxygen storages?

muscle

where do pinnipeds/manatees store more O2?

blood

mammal respiratory tract

air through nasal cavity, pharynx, larynx, trachea, lungs

cetacean respiratory tract

short and broad trachea, oblong or pyramid shaped lungs, rapid breathing and dive with air filled lungs

pinniped respiratory tract

reduced tracheal rings, 3-lobed lungs, exhale prior to diving, frequent breaths

Sirenia tract

short trachea, long lungs, simple bronchi pattern, extend posteriorly to kidneys

dive response steps

bradycardia, vasoconstriction, drop in body temp, metabolism drop

what happens during a dive?

hypoxia, hypercapnia, asphyxia, lactate

mammalan skin

epidermis-dermis-hyperdermis

cetacean epidermis

thick, rapid regenration, high lipid content, minimal keratinization

cetacean dermis

thin, neuroplexies, hydrodynamic stimuli dense tissue, blood vessels and nerves

cetacean hypodermis

blubber; extensive, lipid content increases with age, mass, length

pinniped epidermis

stratum basale, stratum spinosum, stratum corneum. orthokeratotic cells, keratinized cells

pinniped dermis

hair follicles, thicker reticular zone, seb and sweat glands. arteriovenous astomoses: direct connection of arterioles and venules

pinniped hypodermis

blubber

sirenian epidermis

3 layers: stratum basale, stratum spinosum, stratum corneum, thickened corneum

sirenian dermis

thick with papillary layer, reticular layer, prominent dermal papillae, no sweat glands but seb glands in eyelid

sirenian hypodermis

very thin blubber layer

otter epidermis

thin, 1 oe 2 layers, keratinized stratum corneum

otter dermis

sebaceous and apocrine sweat glands, no true arrector pilli muscles, collagenous connective tissues

polar bear epidermis

densely pigmented, absorbs light and heat

polar bear dermis

same as otter but no squalene. hypodermis has no blubber, fat only

blubber

collagen and lipids- serves as insulation, buoyancy, low thermal conductivity, vasoconstriction

melanocytes

melanin forming cell in epidermis

hair

made of keratin, found as outer guard and inner fur

vibrissae

whickers; stiff hairs containing mechanoreceptors used for sensory roles

mammalian brain and spinal cord

cerebrum, cerebellum, brainstem

pinniped brain

larger, more spherical and convoluted, coronal gyrus facilitated transfer from land to water

cetacean brain

large with large hemispheres, thinner cortex, more convoluted.

sirenian brain

small, smooth, hemispheres have deep divide

marine fissiped brain

similar to terrestrial carnivores

pinniped spinal cord

short, phocids and walrus have large lumbosacral enlargement. otariids have small LE, forelimbs for locomotion

cetacean spinal cord

4:1 body length to spinal cord ratio, cervical enlargement, vestigial hindlimbs

sirenian spinal cord

ends at last lumbar vertebrae or 1st caudal vertebrae

sea otter spinal cord

larger after thoracis and lumbar region.

polar bear spinal cord

enlargements at forelimb and hindlimb regions, descends lower into lumbar

encephalization quotient EQ

relative brain size compared to body mass

EQ in pinnipeds and marine fissipeds

not significantly different than terrestrial carnivores

odontocete EQ

4-5 EQ, complex cognitive abilities

mysticete EQ

below average, disproportionate increase in body size associated with feeding modality

sirenian EQ

low EQ due to large size

endocrine organ and function

thyroid; breeding, molting, reproduction, metabolism

adrenal glands

on top of both kidneys; cortisol and aldosterone on outer, epinephrine and norepinephrine on inner

cetacean visual system

large flat eye, thick nonuniform cornea and sclera, bichromatic retina, tapetum lucidum and harderian glands present

cetacean taste system

present taste buds at base of tongue, may not be functional but may be able to taste salt

cetacean smell system

odontocetes have little to no smell

pinniped visual system

large thick cornea and sclera, monochromatic retina, tapetum lucidum and harderian glands present, TL well developed

pinniped smell

reduced in phocids and walrus compared to otariids

pinniped taste

taste buds present- some species can taste sour, bitter, salty

sirenian visual system

small eyes, nictitating membrane, dichromatic color vision, vascularized cornea

sirenian smell system

poorly developed structures

sirenian taste system

taste buds in row along pit on lateral side of tongue, present serous glands

sea otter visual system

rods and cones in retina, tupitum lucidum, round eye

polar bear visual

poorly developed rods and cones

polar bear smell

widest smell range

sea otter smell range

greatly developed