BIO-Vertebrates

Amniotes: Archosaurs Birds have

intelligence and the ability to learn and problem solve (including tool use)

Amniotes: Birds

Archosaurs, diverged from a group of bipedal feathered dinosaurs called theropods during late Mesozoic era

Bird Habitat Adaptations

emu and ostrich- strong legs for running, owls-silence for hunting at night, soaring, speed, and hovering for other birds

Birds- Sight

visual acuity in day or night for predation

Birds- Foot Adaptations

for perching and grasping, paddling, and wading

Birds- Beak Adaptations

prying out insects from bark, ripping flesh, probing for worms in mud, shoveling & sifting sediments, in-flight scooping fish

Mammalians Fossil History

descended from synapsid amniotes which had mammal traits

Mammal Fossil History Evidence

synapsis jaw-joint reduced to middle ear bones of modern animals

Mammals: Unique Traits

mammary glands secrete milk for feeding young (& extensive parental care, hair & fur (primarily for insulation, composed of alpha keratin, for camouflage, sensing, protection), teeth vary in size, shape, & number, adapted to many different food types, highly developed brain & complex behavior (the highly convoluted and folded cerebral cortex)

Mammals Unique Traits cont.

efficient respiratory and circulatory systems (ribcage breathing aided by muscular diaphragm & improves negative pressure breathing), digestive tract adaptations for food types (herbivores have longer tract than carnivores, cecum can hold mutualistic microbes that digest cellulose), sweat glands secrete 99% water for evaporative cooling, kidneys (conserve water from wastes)

Mammal Lungs

masses of alveoli (dead-end sacs), larger surface area than non-bird reptiles

Mammals Ruminants

mutualistic microbes digest cellulose in the rumen (cows, sheep, goats, deer, giraffes, antelope)

Mammals 4-chambered hearts

convergent trait with birds

Vertebrae

the series of bones that makeup the backbone

Three groups of terrestrial vertebrates

amphibians, reptiles (including birds), mammals

Subphylum of Phylum Chordata

Urochordata, Cephalochordate, Vertebrata

Characteristics of Chordata

notochord, dorsal hollow nerve chord, pharyngeal slits, post-anal tail, thyroid gland

Lancelets

key chordate features in adult, burrows tail in & filter feeds, cilia draw seawater into mouth, gas exchange occurs across external body surfaces

Urochordata: Tunicates (“sea squirts”)

larva has key chordate features, suspension feeds w/ pharyngeal slits, notochord, dorsal nerve chord, post-anal tail are absent in adults

axial skeleton

skull, vertebrae (backbone), ribs

appendicular skeleton

pectoral & pelvic area

Cyclostomes

jawless, reduced vertebrae, eel-like bodies, no lateral fins

Cyclostome: hagfishes

marine scavengers, cartilage skull, notochord, keratinous teeth(aid feeding), defensive slime, jawless

Cyclostome: lamprey

jawless parasite on fish, notochord, cartilogenous skeleton

Gnathostomes

vertebrates w/ hinged jaws, derived from skeletal rods which support gill slits, usually have bony teeth, large forebrain (for smell &sight)

Gnathostome fish lineages

cartilaginous, ray-finned, lobe-finned

Gnathostome Characteristics

vertebrates with hinged jaws, mineralized skeleton with 2 pairs lateral fins or limbs (pectoral & pelvic), lateral line system (aquatic species), gills are filamentous (gills are source of gas exchange w/ the environment)

countercurrent exchange

yields higher concentration of O2 in blood

Osmoregulation

maintain internal osmotic pressure at homeostasis when external environment changes, most vertebrae are Osmo conformers

Gnathostomes are osmo-

regulators, concentration of solutes in tissue constant even when environment salinity changes, marine&fresh water fish both maintain low levels in tissues

Marine bony fish osmoregulate by

drinking sea water & excreting salt but little urine

Freshwater bony fish osmoregulate by?

make lots of dilute urine & uptake salt ions

Chondrichthyes (cartiloginous)

cartilage skeleton, bone minerals lost to reduce density, buoyancy raised by liver oils & active swimming, with bony teeth, most are active predators, marine

Oviparous

eggs “laid” and hatch outside the mother’s body embryo develops within protective egg-case, fed by yolk

Viviparous

the young develop within the uterus, obtain nourishment prior to birth by nutrients from the mother’s blood through a yolk sac placenta, live birth

Ovoviviparous

fertilized egg retained within the mother, embryo fed by egg yolk, live birth

Characteristics of Gnathostome: Osteichthyes

bony, includes both ray-fin fish, lobe-fin fish, usually oviparous w/ external fertilization, skeletons remain mostly ossified, flat scales & slime protect & reduce drag, operculum (gill cover), lungs modified into swim-bladder for buoyancy

Operculum

gill cover that protects & helps pump water over gills

Ray-fin fish

Gnathostome: Osteichthyes, contains thin fins supported by long flexible rays modified for maneuvering, defense, etc. Most diverse group of all vertebrates (almost all living bony fish)

Lobe-finned fish

Gnathostome: Osteichthyes, pelvic & pectoral fins supported with bones & muscles, three lineages: coelacanths(actinistia), lungfishes(dipnoi), tetrapods

Gnathostomes: Osteichthyes-Actinistia

marine coelacanths, swim bladder full of lipids, ancient relic species once thought to be extinct

Gnathostome: Osteichthyes-Dipnoid

freshwater lungfishes, gulps air into lungs in stagnant ponds

Tetrapods

four limbs w/ wrist & digits, neck: head moves independent of body, pelvic girdle fused to backbone, lung breathing as adults (absense of gills: except in some aq. sp.), ears for detecting airborne sounds

Ancestors of Tetrapods

lobe-finned, lung-breathing fish, ex. Tiktaalik

Evolution of Tetrapods

diverse tetrapods of mid-Paleozoic all had close ties to freshwater, all extant tetrapods have 5 digits

Tetrapods: Amphibia

most basal extant tetrapod group, thin, moist skin, loses H2O easily, gas exchange w/ air across moist skin & lungs, gulps air like fish to fill lungs, larval stage common (aquatic w/ gills), metamorphosis into carnivorous adult, almost all are oviparous, reproduction is closely tied to freshwater, diverse mating behaviors, 3-chambered heart for better O2 supply, expanding mouth cavity “sucks” air into mouth

Amphibia examples

salamnder, newt, tree frog, caecilians, frog embryo, external fertilization, frog eggs, “marsupial” frog brooding eggs

Tetrapod: Class: Amphibia-Order Urodele

salamanders, 4 legs, tail as adult, “red-backed salamander, moist terrestrial”

Order Anura

amphibia, frogs, 4 legs but no tail as adult, moist terrestrial or freshwater

Order Apoda

amphibia, caecilians, snake-like, no legs as adult, evolutionary convergence with snakes, mostly terrestrial, burrowing

first amniotes evolved from tetrapod ancestors, include reptilia and mammalia

Amniotes

Anapsid skull has…Synapsid skull has…Diapsid skull has…

no opening, one opening, two openings, behind eye holes

reproduction freed from water, porous eggshell protects, reduces water loss but allows O2/CO2 exchange, fertilization must be internal, for mammals eggshell is absent but membranes still function

Amniote Characteristics

amnion

protects embryo w/in amniotic sac

extraembryonic membranes

sustain embryo w/ little water loss

Albumen

stores water

Amniote Characteristics: Mammals

eggshell is absent but membranes still function

Amniote Water Conservation

waterproof skin, little/no gas exchange across skin, water-conserving excretion of nitrogenous wastes, land amniotes convert NH3 to less toxic urea or uric acid (ex.bird droppings), negative pressure breathing by expanding ribcage

Amphibians & fish do _____ breathing

positive-pressure

Ammonia

most aquatic animals including bony fishes, highly toxic most lost through gills or skin

Urea

mammals, most amphibians, sharks, some bony fishes, concentrated by kidneys in urine

Uric Acid

many reptiles (including birds), insects, land snails, least toxic but most costly, saves the most water

Amniote circulation

improved dual blood circulation, septate or completely divided ventricle

Ectotherms

behavioral thermoregulation, use environment to warm body, low metabolic rates generate little heat, basking behavior, all non-bird reptiles

Endotherms

physiological thermoregulation, high metabolic rates warm body, requires insulation, birds & mammals (insulating feathers, fur, or fat)

Amniotes: Reptiles

tetrapods, snakes & legless lizards, scaly skin containing keratin and waxy lipids (key adaptations that helped reptiles live on land), cannot use their skin for respiration (breathe w/ lungs), negative pressure breathing by expanding rib cage

Non-bird reptiles ancestral features

scaly skin w/o feathers or fur, low prifle sprawling stance, low metabolic rates, ectothermic, eggs with leathery, less calcified egg shells

Amniotes: Turtles

upper & lower bony shells fused to ribs & vertebrae, beak made of keratin, keratinous scales, adapted to land, freshwater, marine, diverse foods: vegetation & animals, oviparous

Amniotes: Lepidosaurs: Tuataras

remnant, ancient lizard-like reptile, in lizard/snake clade but w unusual features

Amniotes: Squamates

class Lepidosauria, lizards & snakes, diverse in birth, some parthenogenesis, most are oviparous, snakes descended from lizards

Snake features

no legs, no external ear, no eyelid, broad ventral scales

Amniotes: Crocodilians

crocodiles, alligators & kin, semi-aquatic predators, both dinosaur and bird-like features, gizzard, 4-chambered heart, oviparous, teeth in sockets, extant from Triassic dinosaur age

Mammals: Marsupials

w/ maternal pouch, embryo starts growing in uterus w/ placenta, fetus is born at early stage, crawls to pouch, latches onto nipple to finish development

Example of Marsupials

kangaroo, wombats, koala, marsupial mouse, oppossum (only U.S. marsupial)

Mammals: Eutherians

“Placental mammals”, better placenta for longer gestation, young more developed at birth viviparous

Example of Eutherians

most diverse & widespread mammals, rodents, rabbits, primates

Characteristics of Mammals: Primates

related to arboreal life, hands & feet adapted for grasping, flat nails on digits, large brains, eyes forward, flat face

Primate groups

lemurs and relatives, tarsiers (arboreal, one of the smallest primates), anthropoids (monkeys, apes, and humans)

New world monkeys

prehensile tails (tails can grasp), arboreal, ex. spider monkeys, white-faced monkey, think Americas

Old world monkeys

tails cannot grasp, mostly ground-dwelling, ex. baboons, macaque, think Africa

Apes & humans

have no tail, ground-dwelling, lesser and greater apes

Hominid

family Hominidae, includes living and extinct great apes, modern humans, orangutans, gorillas, chimpanzees, and bonobos

Homo Sapiens Characterized by:

bipedal locomotion, ground-dwelling, much larger brain, language, complex tools, shorter digestive tract, reduced jaws, genetically 99% similarity

How long have humans been in North America?

at least 22,000 years ago, footprints were found on the shore of an ancient lakebed, dated using carbon dating of aquatic plant seeds found in the footprint

The evolution of skin color

largely reflects the amount of melanin

Melanin

a pigment produced by melanocytes (type of skin cells) in the epidermis, derivative of AA tyrosine

Skin tone

correlates with geography, relative position to earth’s poles, (northern climate—> lighter, white, closer to equator—>darker, black)

Constitutive skin color

genetically programmed and is based on the amount of pigment the skin contains without exposure to UVR

Facultative (inducible) skin color

increased pigmentation seen as tanning following exposure to UVR, immediate tanning—> hyperpigmentation, delayed tanning—> increase in melanocytes

Eumelanin

blackish brown pigment

Pheomelanin

reddish yellow pigment, fair skin freckling, carrot red hair

Folate

B vitamin, an essential nutrient, levels are influenced by UV light, intense sunlight halves amount of folate, affects light-skinned people more, dark-skinned people not affected

Vitamin D

a fat-soluble vitamin, maintains healthy immune system, and builds healthy bones and teeth

The production of Vitamin D requires…

UV light, dark skinned people are more vulnerable to Vitamin D deficiency, light-skinned people less affected

Light skin evolved-

helped the body produce vitamin D in sun-poor parts of the world

Dark skin evolved-

helped protect the body’s folate stores in people who lived in sunny climates

High-UV light environment

individuals with dark skin reproduce more successfully, more melanin= sufficient vitamin D production & protection of folate

Low-UV light environment

individuals with light skin reproduce more successfully, lower melanin levels= enable sufficient vitamin D levels, folate is not destroyed in low-UV

How did birds evolve?

descendants of dinosaurs, rapid miniaturization, facial/skull changes & beak, bipedal locomotion

Bird adaptations for flight

1. forelimbs modified into wings w/ keratin contour feathers that provide lift

2. lightweight skeleton but strong (pneumatization of bones)

3. stubby feathered tail for flight maneuvers

4. no teeth, beak made of keratin over bone

5. efficient 4-chambered heart

6. highly efficient respiration system w/ air sacs (neg-pressure breathing)

7. urogenital adaptations (no bladder or urethra, only one ovary)

8. sex organs functional only during breeding season

9. muscular gizzard