BIOL 101 EXAM 4 (Ekdale)

secondary bone palate

Allows mammals to eat and breathe at the same time

furcula

fused clavicles (wishbone) found in many theropod dinosaurs and birds

stabilizes shoulder

diphyodont

Most mammals have two generation or set of teeth

Monophyodont

An animal that has only one set of teeth that lasts its entire life

Homodont

Animal with teeth that are all similar in form and function

Heterodont

Tooth shaped differences along the front row - incisors and canines rostrally and cheek teeth (premolars and molars) caudally

Vibrissae

Long, stiff sensory hairs around face for tactile sensation (sense of touch); longer and thicker than most body hairs. Whiskers on mammals

Cloaca

A common cavity at the end of the digestive tract for the release of both excretory and genital products in vertebrates (except most mammals) and certain invertebrates

Marsupium

Pouches that protect offspring

Pinnae

External ear flaps (prominent in most species); the auricle

Placenta

Vascular structure for nutrient exchange between the mother and developing embryo; develops in the uterus during pregnancy

Derived from yolk sac in marsupials and fusion of chorion and allantois in placentals

Edentulous

Toothless

Horn

Permanent structures; consist of a horny sheath around bony horn core

Antler

Temporary, shed and regrown annually; only in males

Baleen

Strong, flexible material made of keratin that hangs in plates from the upper jaw of baleen whales; filters food

Amniota

Smallest crown clade of four limbed vertebrates (tetrapods) including reptiles, birds, and mammals. Evolution of amniotic egg, which allows them to reproduce on land without returning to water like amphibians

Reptilia

Cold-blooded, air-breathing vertebrates, with scales and typically laying eggs

Archosauria

Dinosaurs, pterosaurs, and crocodilians. Modern birds are their direct descendants. They have skull openings for muscle attachment, teeth in sockets, and an upright stance

Dinosauria

Non-avian dinosaurs and birds. Hind limbs held directly beneath the body

Saurischia

Lizard-hipped. Pelvis where the pubis bone points forward and down. Carnivorous theropods and long-necked herbivorous sauropods

Theropoda

Bipedal (two legs for walking) dinosaurs. Hollow bones, three-toed feet with claws, recurved teeth. Walk on hind legs with forelimbs used for grasping

Aves

Birds. Feathers, wings (modified forelimbs), a toothless beak, warm-blooded, laying hard-shelled eggs, a lightweight skeleton with hollow bones, a four-chambered heart, and high metabolic rates

Mammalia

Warm-blooded vertebrates, nurse their young with milk (mammary glands), have hair or fur, three middle ear bones, and viviparous

Monotremata

Platypus and echidnas. Mammals that lay eggs instead of giving live birth (oviparous). Single opening for reproduction (cloaca). Have hair and produce milk (without nipples, secreted through pores)

Theria

Marsupials and placentals. Viviparous, whiskers. Flexible and protruding nose (from modified cells involved in the development of the upper jaw in other tetrapods)

Marsupialia (metatheria)

Give birth to live young, then they complete development in a pouch (marsupium), feeding from teats inside. Kangaroos, opossums, koalas. Short gestation (brief time between conception and birth)

Didelphis Virginiana

Virginia opossum. North America’s only marsupial. Nocturnal

Thylacinus

Extinct. Wolf-like, carnivorous marsupial. Tasmanian tiger/wolf. Stiff tail

Placentalia (Eutheria)

Largest clade of mammals. Fetus develops inside the mother’s uterus and is nourished via the placenta. Wider pelvic opening for larger offspring and absence of epipubic bones, allowing abdominal expansion during pregnancy

Afrotheria

Elephants, manatees, aardvarks, etc. Specific placental formation, ankle bone structure, internal testes

Proboscidea

Trunk and tusks. Elephants and their extinct relatives

Sirenia

Aquatic plant-eating mammals. Manatees and dugong. Live in tropical coastal waters. Paddle like forelimbs and tail flipper reducing hind limbs

Xenarthra

Anteaters, sloths, armadillos. Edentates. Incisor and canine teeth. Central and South America

Boreoeutheria

All placental mammals that didn’t evolve in Africa or South America. Euarchontoglires (primates, rodents, rabbits) and Laurasiatheria (carnivores, ungulates, whales, bats). Represents over 90% of living placental mammal diversity

Rodentia

Largest order of mammals. Single pair of continuously growing incisors in both upper and lower jaws, which they gnaw to keep trimmed. No canine teeth with a gap (diastema) between incisors and cheek teeth. Mice, rats, squirrels, beavers, guinea pigs

Chiroptera

Bats. Only flying mammal. Found in every continent except Antarctica.

Cetacea

Marine mammals, hairless body, no hind limns, horizontal tail fin, blowhole for breathing. Whales, dolphins, porpoises

Odontoceti

Toothed whales

Mysticeti

Baleen whales

Primates

Grasping hands/feet with opposable digits, forward facing eyes, relatively large brains, complex social behaviors. Humans, monkeys, apes, lemurs, tarsiers

Homo habilis

Had a larger braincase than earlier hominins like Lucy, smaller teeth, and a mix of ape-like and human-like features. Lived in Africa around 2.4-1.4 million years ago

Homo sapiens

Humans. Coined by Carl Linnaeus.O

Ornithischia

Bird-hipped. Living birds are not part of this, but Saurischia

Archaeopteryx

The earliest bird from about 150 million years ago

“Ground up” hypothesis

Ancestors of birds were ground-running predators that used their forelimbs for balance while pursuing prey which later evolved into gliding and then flight

Respiration in birds vs mammals

Birds: unidirectional

Mammals: bidirectional

How does a bird fly

Asymmetrical feathers, cross-sectional area, wing shape

Diapsid vs Synapsid vs Anapsid

Diapsid: two skull openings (reptiles)

Synapsid: one skull opening (mammals)

Anapsid: no skull opening (extinct animals)

Modern birds are descendants of

Saurischia

In marsupial mammals, the placenta is composed of the chorion and the

yolk sac

What is another name for whiskers or sensory hairs used for tactile sensations?

Vibrissae

Archaeopteryx were likely capable of powered flight on account of the presence of fossilized

asymmetrical features

Three major living clades of animals

Monotermata

Marsupiala

Placentalia (largest)

Which animals belong to the clade Theria?

Marsupiala and Placentalia

Four synapomorphies that unite all mammals

Mammary glands

Hair

Single bone in lower jaw

Middle ear with three bones (ossicles)

Distinguish between the three groups of living mammals based on reproduction

Monotermes: Oviparous, altricial

Marsupials: Viviparous, precocial

Placentals: Viviparous, both altricial and precocial

Altricial

Hatched or born helpless and requiring significant parental care

Preocial

Hatched or born in an advanced state and able to feed itself and move immediately almost immediately

Evolutionary origin of the mammalian middle ear

Hammer (malleus) and anvil (incus) of the mammalian middle ear evolved from bones of the reptilian jaw

Stirrup (stapes) of mammals is homologous to that of reptiles

Urogenital openings of therian mammals vs monotremes

Monotremes have a cloaca

Therians have separate openings

All mammals have copulatory organs and reproduce using internal fertilization

Placenta in placental vs marsupial mammals

Placental: derived from chorion and allantois

Marsupial: derived from chorion and yolk sac

Delayed implantation

Freezes the development of the embryo and allows the mother to have multiple offspring at different developmental stages at the same time

What is the only species of marsupial native to the northern hemisphere?

Virginia opossum

What terrestrial placental mammal group are cetaceans descended?

Artiodactyla (ungulates which bear weight equally on two of their five toes. The other three toes are either present, absent, vestigial, or pointing posteriorly)

Only mammalian clade capable of powered flight

Chiroptera (bats)

Place the following events of human evolution in order from first (earliest, oldest, first to occur in time) to last (latest, youngest, last to occur in time): enlargement of the brain, speech, bipedal stance

1. Bipedal stance

2. Enlargement of brain

3. Speech

Primate

Have big brains and binocular vision

Mammalian

Have hair and three bones in ears

Synapsid

Have a single temporal opening

Amniote

Developed within an amniotic egg

Tetrapod

Land animals with fingers and toes

Sarcopterygian

Have internal limb bones with elbows and knees

Osteichthyan

Have air sacs developed as lungs

Gnathostome

Have jaws

Vertebrate

Bony vertebrae and a pineal gland/organ

Chordate

Endostyle/thyroid and dorsal nerve cord is hollow

Deuterostome

Nerve cord is positioned dorsally (towards back)

Bilaterian

Bilaterally symmetrical

Animal

Multicellular eukaryotes gain nutrition through ingestion

If forelimbs of birds are modified for flying, how do they catch food?

Beaks

How do wings work?

Lift is maintained by cross-sectional area plus constant angle of attack adjustment, air moves faster over wing, lowering air pressure

Origin of flight

“Ground up”

Hind limbs developed for speed, forelimbs lengthened for grasping prey (similar motion to flight stroke)

Feathers on forelimbs (already present) would provide lift

Adaption vs Exaptations for flight in birds

Adaption: keeled sternum (breast bone), endothermy

Exaptations: furcula, hollow bones, asymmetric feathers

Unique method of respiration in birds

Unidirectional flow of air through lungs. Inhalation: fresh air brought into posterior sacs, stale air from lungs drawn into anterior sacs. Exhalation: fresh air pushed into lungs from posterior sacs, stale air pushed out of trachea from anterior sacs

How can the teeth of a mammal inform us about diet?

Carnivores have canines, herbivores have flat molars, omnivores have both

Evolutionary origins of the middle ear bones

Transition of bones from jaw joint to middle ear can be seen in the evolution and embryonic development of mammals

Gestation and lactation times in marsupials vs placentals

Marsupials: gestation period is short and lactation period is long

Placentals: gestation period is long and lactation period is short

Thylacine

Tasmanian tiger, largest carnivorous marsupial of all time, but now extinct (since 1936)

What is the largest land animal?

Elephants

Wing of the only flying mammal

Bats: wings constructed from long fingers supporting a webbed membrane

Most speciose clade of placental

Boreoeutheria (rodents, bats, pigs, deer, cattle, hippos, camels, sheep, goats)

Rhino horns vs cattle horns

Rhino: solid keratin growing from skin (can regrow)

Cattle: hollow keratin sheath over a permanent bony core attached to the skull

Closest living relatives of Cetacea

Dolphins, porpoises, whales

Synapomorphies of Primates

Large brain, forward facing eyes (binocular vision), well-developed parental care and social behaviors, grasping hands

Which primate is the closest living relative of humans?

Chimpanzees

How old are the oldest homo sapiens fossils?

200,000 years ago

Humans are:

Primate, mammalian, synapsid, amniote, tetrapod, sarcopterygian, osteichthyan, gnathostome, vertebrate, chordate, deuterostome, bilaterian, animals

Rodent impact on humans

Disease, structural damage from gnawing, destruction of food