Final Examination Wednesday, June 10 th, from 8:00 A.M. – 9:50 A.M. Laboratory Examination Tuesday...

Final Examination

Wednesday, June 10th, from 8:00 A.M. – 9:50 A.M.

Laboratory Examination

Tuesday and Thursday, covering Birds and “some” Mammals

Reproduction:Birds

• Clutch size variable (2 – 16 eggs); (1 to 3 clutches/year); single v. multiple nesters:

1) Trade-off Hypotheses: Driving force is maximization of lifetime reproductive success

• Physical strain on females / exposure to predation during food collection

2) Predation Hypotheses: Driving force is minimization of nest detection by predators

• More eggs / young = detection (sound / smell / trips to nest / etc.)

3) Seasonality Hypotheses: Driving force is food availability during breeding season

• More eggs / young = food reserves / competition

• Young at differing levels of development at hatching:

Infanticide

Precocial Semiprecocial Altricial

High yolk Moderate yolk Low yolk

Down present Down present Down Absent

Eyes open Eyes open Eyes closed

Mobile Semi-mobile Not mobile

Self-feeding Not self-feeding Not self-feeding

Ducks Hawks Passerines

Incubation may lastfrom 10 – 80 days

Altricial < Precocial

Growth Rates:

Altricial > Precocial

Ducks: (~ 35 species in North America) Shared Characteristics:

1) 3 front toes completely webbed

2) Penis present in males

3) Bill typically flattened / blunt-tipped

Birds

Characteristic

Legs

Feet

Feeding

Diet

Wings

Flight

Habitat

Examples

Dabbling Ducks

Northern ShovelerAmerican Widgeon

Cinnamon Teal

Diving Ducks

RedheadCanvasback

Lesser Scaup

Sea Ducks

BuffleheadEider

Merganser

Relatively long;centered under body

Short but strong;set far back on body

Short but strong;set far back on body

Smaller Larger; long outer toes Larger; long outer toes

Dip head underwater;skim surface with bill

Dive from surface;wings pressed to body

Dive from surface;wings open (steer / paddle)

Invertebrates;aquatic vegetation

Invertebrates Invertebrates;fish (rare)

Big, broad wings;lower wing loading

Smaller wings;higher wing load

Smaller wings;higher wing load

More maneuverable;can fly slow

Less maneuverable;need room to take off

Less maneuverable;need room to take off

Shallow edges of lake;surface in deeper areas

Center of lake;deeper water

Marine coastlines;fast, clear streams

Duck Life Histories:

Mating Behavior:

• Initiated late fall / early winter (wintering grounds / migration)

• Skewed sex ratio – many ♂; fewer ♀

• Form monogamous pair bond (seasonal)

• Males attract females via:

1) Visual Displays:

• Coloration (♂s more colorful than ♀s)

• Most elaborate in dabblers

Tufted Duck – head raise

Ruddy Duck – tail raise

Dabbler Specialty:

Iridescent speculum on wing

Lift wing to display speculum

2) Vocal Displays (primarily dabblers)

• Dabblers have louder, deeper voices

Birds

Ducks: (~ 35 species in North America)

Nesting Characteristics:

• Location of Nest:

• Dabblers = Ground

Merganser

Mallard

Scaup

• Age at 1st reproduction:

• Dabblers / Divers = 1 year

• Sea = 2-3 years

• # of Eggs in Nest:

• Dabblers / Divers = 8 – 12 eggs

• Sea = < 8 eggs (space issues in cavity)

• Sea = Tree cavities

• Divers = Emergent / Floating vegetation

Incubation:

• Females only (20 – 30 days)

• Pair bond only lasts until eggs are laid

Parental Care:

• Females: 2 – 6 weeks; guard from predators



Birds

Brood parasitismdoes occur…


Seasonal Migration Patterns:

• Benefit = Net increase in lifetime reproductive output

• Spring – Summer:

• Breed at high latitudes (e.g., Canada / Alaska; long days = increased foraging)

• insect population for young

• Fall – Winter:

• Fly south to avoid physical stresses of extreme cold / lack of food

• Costs = 1) death rate for young

2) food acquisition for energy to travel

3) Restricted stops (fewer wetlands to choose from)

Reduce Cost…

4 major N-S flyways in North America(Ducks heading to Alaska…)

50%10%25%

10%• Fly at night; usually < 1000 ft.

• Variety of orientation methods:

• Sun / star compasses

• Magnetic field

Birds


Mammals

Chapter #19 – “Geography and Ecology of the Cenozoic”

Pg. 509 – 518.

Cladogram of Tetrapods:Am

phib

ians

Syna

psid

s

Turt

les

Sphe

nodo

nLi

zard

s

Snak

es

Cro

codi

les

Bird

s

Diapsids (“two arches” - Greek)

Sauropsids (“reptile-like appearance” - Greek)

Amniotes

Mammals

Squamates

Lepidosaurs Archosaurs

Cladogram of Synapsids:Pe

lyco

saur

s

Mon

otre

mes

Mar

supi

als

Plac

enta

ls

MammalsMammal-like Reptiles

Non

-cyn

odon

ts

Cyn

odon

ts

Pelycosaurs (“sailbacks”)Late Carboniferous - Permian

Temperature-regulatingdevice

Mammals


lyco

saur

s

Mon

otre

mes

Mar

supi

als

Plac

enta

ls

MammalsMammal-like Reptiles

Non

-cyn

odon

ts

Cyn

odon

ts

Derived Features:• Increased metabolic rate

Therapsids

Cynodonts = Multi-cusped cheek teeth

Primitive turbinates (warm / humidify air)

Reduced size (~ size = dog or smaller)

Evidence:Radiation into colder climates

• Enlarged temporal fenestra • Large canine present (maxilla)

• Dentition differentiation• Upright posture

TherapsidsMid Permian – Early Cretaceous

“too ugly to survive” - Larry Gonick

Mammals

1) Lactation:

Features Shared by Mammals:

• Mammary glands milk for feeding the young

• Facial muscles (later = facial expressions…)

• Benefits = Production of offspring dissociated from seasonal food supply

Females need not rely on paternal care (Males - who needs them…)

Viviparity less strenuous (young born underdeveloped…)

• Evolution of Lactation:• Mammary glands anatomically similar to sebaceous glands (hair follicles)

1) Glands secreted pheromones – offspring mother recognition

2) Glands secreted anti-microbial proteins; protected eggs in nest• Similar to current milk proteins; later more copious / nutritional

Suckling = unique mammalian feature

Allow for breathing while suckling

• Fleshy seal (tongue / epiglottis)

Mammals

2) Hair (Fur = hairy covering):

B) Apocrine Glands – Scent; pheromonal signals

1) Panting (> 250 breaths / minute)

How Do Birds Cool Off?

2) Regulating blood flow to feet

3) Behavioral modifications

• Composed of keratin; functions in insulation, communication, and sensation


• Color = quality / quantity of melanin placed in developing hair• Replacement = continued growth / molting (loss & replacement of hairs)

• Hypothesized origin of fur:• Sensory bristles between “reptilian” scales

•Bristles increased in size; scales decreased in size• Guard hairs (protective – longer / stronger); underfur (insulation)

3) Specialized Glands in Skin:

A) Sweat Glands – release water on skin for cooling (evaporation)

C) Sebaceous Glands – lubricate fur / hairs & protect skin

Mammals

4) Teeth Features:• Heterodonts: Elaborate shapes / functions within single species

• Diphyodonts: 2 sets of teeth; no continuous replacement• Allows for continual occlusion (contact between upper / lower teeth)

• Allows for crushing / grinding food (mastication = chewing)

5) Turbinates (Nasal Conchae) in Nasal Cavity:• Whorls of bone covered with mucous epithelium

1) Adds moisture to air (prevents desiccation of lungs)

2) Warms air (prevents loss of body heat)

3) Improves filtering of air to keep airways clean (mucus)

4) Increases sense of smell ( surface area)


• Increased dietary specializations• Multicuspid – broader / flatter


lyco

saur

s

Mon

otre

mes

Mar

supi

als

Plac

enta

ls

Therians

Mammals

Therapsids

Mammal-like Reptiles

Non

-cyn

odon

ts

Cyn

odon

ts

“One Hole”

Reproductive / urinary / digestivesystems all exit via single opening

(cloaca)

Mammals

Mammals

Retain Various Reptilian Features:

1) Oviparous – lay eggs• Small; rubbery (nutrient material absorbed through egg)

Other Features:

Monotremes:

1) Females lactate

10 day incubation period

Mammalian Features:

2) Retain reptile-like gait (legs on side rather than underneath)

3) Reduced operational body temperature (Mean body temp ~ 32 ºC (~ 89.5 ºF))

• Endothermic (homeotherms)

• May enter periods of hibernation (cool weather)

• Testes located abdominally (unusual for mammals)

(do not have nipples)

1) Lack teeth as adults

2) Spurs present on ankle

Contain venom (Platypus)

• Milk secreted onto skin; lapped up by young

2) Fur present

Intraspecific fighting / predator defense

http://upload.wikimedia.org/wikipedia/en/3/3d/Platypus_spur.JPG

Mammals

• Diet / Foraging:

Ornithorhynchidae (“bird beak”)

Duck-billed platypus

• Habitat / Description:

• Primarily aquatic (freshwater – Australia)

• Stream-lined body; webbed feet• Horizontally flattened tail• Dense fur (inner insulation layer)

• Benthic invertebrates; frogs (1/2 BW / night)

• Rubbery bill (grind food via gum plates)• Electrosensitive pores present

• Reproduction:

• Seasonal breeder (Mature = 2 years of age)

• Incubate eggs (1 – 3) between tail / body• Young suckle ~ 4 months (fur = 6 weeks)

Geographically restrictedto Australia / New Guinea

Fossil evidence fromSouth America

Tachyglossidae (“rapid tongue”)

Spiny Anteaters (2 species)

• Diet / Foraging:

• Habitat / Description:

• Primarily terrestrial (Australia / New Guinea)

• Coat = course hair w/ spines (modified hairs)

• Termites / ants / earthworms• Strong diggers / sticky tongue

• Reproduction:

• Seasonal breeder (Mature = 1 year of age)

• Incubate egg (1) in pouch• Young suckle ~ 2 months (lifespan = 40 yrs)

Defensive BehaviorCurl into ball with spines extended

Dig vertically; cover body with loose soil


lyco

saur

s

Mon

otre

mes

Mar

supi

als

Plac

enta

ls

Therians

Mammals

Therapsids

Mammal-like Reptiles

Non

-cyn

odon

ts

Cyn

odon

ts

Mammals

Placenta:Complex of embryonic and maternal tissues

1) Anchors fetus to uterus

2) Transports nutrients from mother to fetus

3) Excretes metabolites from fetus to mother

4) Produces hormones (regulate reproduction)

Mammals

Placental Development:

Marsupials – Limited Placenta:

• Developing embryo forms shallow depression in endometrium of uterus• Surface area for adhesion / absorption limited (slight wrinkling)

• Primary nutrient source = yolk sac• Short gestation (Bandicoot = 12.5 days); long lactation

Placentals – Advanced Placenta:

• Developing embryo embeds deeply into endometrium• Chorionic villi (finger-like projections) enhance adhesion / absorption• Primary nutrient source = Maternal blood (does not mix with fetus)

• Long gestation (African elephant = 22 months); short lactation• At birth: 5% - 50% maternal body mass

Opossum newborn (~ 0.13 g)

At birth: < 1%maternal body mass

Precocial comparedto marsupials…

• Finish development in pouch / skin fold• Nipples utilized for lactation (swell to hold young)

By the time young are weaned, the parental investment between marsupicals and placentals is similar

Reproductive Variations:

Mammals

1) Delayed Fertilization:• Copulation (fall) dissociated from fertilization of egg (spring)

• Sperm stored in uterus / vagina New / Old world bats• Benefit = Efficient use of seasonal resources

2) Delayed Development:• Embryo implants in endometrium; development continues very slowly• Benefit = Synchronize young with unpredictable food resources

3) Delayed Implantation:• Development of embryo arrested following early cleavage

• Embryo free-floating in reproductive tract• Obligate (build into system) or facultative (environmentally induced)

• Benefit = ??? (Dissimilarity in closely related species in same area…)

Armadillo(obligate)

Roe Deer(facultative)

4) Embryonic Diapause:• Development of embryo arrested following late cleavage

Joey #1 – Lactation (outside pouch; ~ 1.5 years)

Joey #2 – Lactation (inside pouch; ~ 9 months)

Joey #3 – Held in embryonic diapause

♀ often supporting young of 3 litters (uterus / pouch / outside pouch)

Red Kangaroo(embryonic diapause)

Mammals

• Arrested due to Joey #2 suckling

Benefit:

Opportunistic reproduction in harshenvironments (Australian Outback…)

• Lost / abandoned offspring can be quickly replaced

“Box” with hind limbs (can be fatal)

Mammals

Marsupials (“little bag” – BUT only ~ 50% have permanent pouch):

1) Ameridelphians (New World Marsupials)

• Neotropical region / temperate North America

• Didelphimorphia (Opossums; ~ 77 species)

“Play Dead”• “…the opossum will fall on its side, curl its body, open its drooling mouth, and excrete droppings…”

• Nervous “shock”

Mammals

2) Australidelphians (Australian Marsupials)




• Neotropical region

• Paucituberculata (Rat Opossums; ~ 5 species)

Dasyuromorphia(Carnivorous Marsupials)

e.g., Tasmanian Devil

Tasmanian Wolf – 1930’s


Paired sperm:

Sperm coupled atthe head region…

Mammals

2) Australidelphians (Australian Marsupials)



• Neotropical region

Dasyuromorphia(Carnivorous Marsupials)

e.g., Tasmanian Devil

PeramelemorphiaInsectivores

Syndactyly (hindfeet)e.g., Bilby

DiprotodontiaRodent-like incisors

herbivores / omnivoresSyndactyly (hindfeet)e.g., Koala / Kangaroo



• Paucituberculata (Rat Opossums; ~ 5 species)Paired sperm:

Sperm coupled atthe head region…

Mammals

Placentals:

Insectivora• Primitive characteristics• Morphologically diverse

(e.g., mole, shrew, colugo)

Chiroptera• Only flying mammals

• Echolocation(bats)

Primates• Elaborate brain

• Refined hands / digits(e.g., look in a mirror)

Xenarthra• Low metabolic rates(e.g., armadillo, anteater)

Pholidota• Overlapping scales

(scaly anteaters)

Mammals

Placentals:

Carnivora• Mammalian predators

• Carnassial teeth(e.g., wolf, lion, weasel)

Cetacea• Modified for aquatic lifestyle• Largest mammals on record

(e.g., whales, dolphins)

Rodentia• Largest mammalian order

• Enlarged incisors(e.g., capybara, squirrel, mouse)

Tubulindentata• Smallest mammalian order

(aardvark)

Hyracoidea• closest relative = elephant

(Hyrax)

Mammals

Placentals:

Lagomorpha• Herbivorous

• Saltatory locomotion(e.g., rabbits, hares, pikas)

Perissodactyla• “odd-toed”

• Hindgut fermenters(e.g., horses, tapirs, rhinoceroses)

Artiodactyla• “even-toed”

• Ruminating stomachs(e.g., pigs, deer, hippopotamuses)

Proboscidea• Largest terrestrial mammals

(elephants)

Sirenia• Only marine herbivore

(e.g., manatee, dugong)

Final Examination Wednesday, June 10 th, from 8:00 A.M. – 9:50 A.M. Laboratory Examination Tuesday...

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