Biology Test 2 Ch. 34

notochord

a longitudinal, flexible rod located between the digestive tube and the nerve chord

vertebrates and tunicates share

a notochord and a dorsal, hollow nerve chord

which of the following could be considered the most recent common ancestor of living tetrapods?

a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates

ectothermic

absorbing external heat as the main source of body heat. i.e reptiles

amniotic egg

allantois-disposal sac for waste. chorion- exchange of gases between the embryo and air. amnion- cushions against mechanical shock. yolk sac- transports nutrients from the yolk into the embryo

you are a chordate, yet you lack most of the main derived characters of chordates. explain.

in humans, these characters are present only in the embryo and evolve into other body parts. i.e. the notochord becomes the disc between the vertebrae

muscular post anal tail

in many species it's lost during embryonic development, it provides much of the propelling force in many aquatic species

primates

include lemurs, tarsiers, and anthropoids (monkey and hominids). have hands and feet, a large brain and short jaws, well developed cerebral cortex, forward looking eyes that are close together, omnivorous, opposable thumbs, well developed parental care

how are differences in the anatomy of lampreys and conodonts reflected in each animal's feeding method?

parasitic lampreys have round rasping mouth which they use to attach to fish and non parasitic lampreys feed only as larvae; these larvae resemble lancelets and like them are suspension feeders. conodonts had two sets of mineralized dental elements which may have been used to impale prey and cut it into smaller pieces.

eutherians

placental mammals

ovovoiviparous

retain the fertilized eggs in the oviduct, the embryos develop into young that are born after hatching within the uterus

living vertebrates can be divided into two major clades. select the appropriate pair.

the cyclostomes and the gnathostomes

viviparous

the young develop within the uterus and obtain nourishment prior to birth

derived characters of humans

upright posture and bipedal locomotion, larger brains capable of language, symbolic thought, artistic expression, use of complex tools, reduced jawbones and jaw muscles, shorter digestive tract

gnathostomes

vertebrates that have jaws, include sharks and relatives, ray-finned fish, lobe finned fish, amphibians, reptiles, birds and mammals

are snakes tetrapods? explain.

yes, although they lack limbs, they descend from lizards with legs. some retain vestigial pelvic and leg bones, providing evidence of their descent from ancestors with legs

identify four avian adaptations for flight.

1. weight saving modifications (the absence of teeth, a urinary bladder, a second ovary in females) 2 &3. the wings and feathers are adaptations that facilitate flight, 4. as do efficient respiratory and circulatory systems that support high metabolic rate.

dorsal hollow nerve chord

1. develops from a plate of ectoderm that rolls into a tube dorsal to the notochord, 2. develops into the central nervous system: the brain and the spinal cord

identify at least five derived traits of primates

1. hands and feet adapted for grasping 2. flat nails, 3.large brain, 4.forward looking eyes on a flat face, 5. parental care, and 6. movable thumb and big toe

identify four derived characters that all chordates have at some point during their life

1. notochord, 2. a dorsal hollow nerve chord, 3. pharyngeal slits or cleft, 4. a muscular post anal tail

describe three key amniote adaptations for life on land.

1. the amniotic egg provides protection to the embryo and allows the embryo to develop on land, 2. rib cage ventilation which improves efficiency of air intake, 3. not breathing through their skin allowed amniotes to develop relatively impermeable skin

describe key adaptations of aquatic gnathostomes

1. they have jaws (an adaptation for feeding) and 2. paired fins and a tail (adaptations for swimming). 3. they typically streamlined bodies for efficient swimming and swim bladders or other mechanisms for buoyancy

identify some characters that distinguish hominins from other apes.

derived characters of hominins include bipedal locomotion and relatively larger brains

which clade does not include humans?

diapsids

neural crest

a collection of cells that appears near the dorsal margins of the closing neural tube in an embryo. give rise to a variety of structures

diapsids

a group of amniote tetrapods that have developed two holes in each side of their skulls

turtles

a group of reptiles with no holes in each side of their skull

characteristics of vertebrates

backbone, vertebrae enclosing a spinal chord, skeletal system and complex nervous system, an elaborate skull, fin rays in the aquatic forms, two or more sets of hox genes, neural crest cells

as hominins diverged from other primates, which of the following appeared first?

bipedal locomotion

osteichthyans

bony fish; ray finned fish, lobe finned fish, lung fish. breathe by drawing water over four or five pairs of gills covered by operculum. control their buoyancy with an air sac known as swim bladder

marsupials

born very early in its development and completes its embryonic development while nursing within a maternal pouch called a marsupium. includes opossums, kangaroos, and koalas

what derived characters do sharks and tuna share? what features distinguish tuna from sharks?

both are gnathostomes and have jaws, four clusters of hox genes, enlarged forebrains, and lateral line system. contrast: shark skeletons consist mainly of cartilage, whereas tuna have bony skeletons. sharks have a spiral valve. tuna have an operculum and a swim bladder, as well as flexible rays supporting their fins

endothermic

capable of keeping the body warm through metabolism. i.e. birds

chrondrichthyes

cartilaginous skeleton, have rough sand paper like skin made up of scales, paired pectoral and pelvic fins, stream lined, some sharks must swim constantly in order to keep oxygen-rich water flowing over their gills

hagfishes (myxini)

cartilaginous skull, reduced vertebrae, a flexible rod of cartliage derived from the notochord. a small brain. sensory organs. slime glands that ward off predators. most are bottom-dwelling scavaengers

characteristics of chordates

dueterstome, bilaterian animals, notochord, dorsal hollow nerve chord, pharyngeal slits/ gills, muscular post anal tail

parareptiles

extinct group of primitive anapsids

tetrapods

gnathostomes that have four limbs with digits, a neck, fusion of the pelvic girdle to the backbone, absence of gills, ears

pharyngeal slits/cleft

grooves in the pharnyx that develop into slits that open to the outside of the body, 1. function as suspension- feeding structures in many vertebrate chordates, 2. are modified for gas exchange in aquatic vertebrates, 3. develop into parts of the ear, head, and neck in terrestrial vertebrates

cyclostomes

hagfishes and lampreys. only jawless vertebrates that are still alive today. lack a backbone

skeletal system and complex nervous system

have allowed vertebrates efficiency at two essential tasks: capturing food and evading predators

lampreys (petromyzontida)

have cartilaginous segments, inhabit various marine and freshwater habitats. parasites that feed by clamping their mouth onto a live fish. have round grasping mouths that they use to attach fish. suspension feeders

lobe-finned fish

have muscular and pectoral fins that they use to swim and "walk" underwater across substrate

reptiles

have scales that create a waterproof barrier. lay shelled eggs on land. most are ectothermic. include lizards, snakes, turtles, birds, and crocodiles. can be divided into parareptiles, turtles, diapsids

unlike eutherians, both monotremes and marsupials

have some embryonic development outside of the uterus

provide an example in which different features of organisms in the hominin evolutionary lineage evolved at different rates.

in hominins, bipedal locomotion evolved long before large brain size. i.e. homo ergaster was fully upright, bipedal, and tall as modern humans, but its brain was significantly smaller than that of modern humans

characteristics of gnathostomes

jaws, enlarged forebrains, enhanced sensory systems including the lateral line system, an extensively mineralized endoskeleton, paired appendages, an additional duplication of hox genes

oviparous

lay their eggs that hatch outside the mother's body

contrast monotremes, marsupials, and eutherians in the terms of how they bear young.

monotremes lay eggs but marsupials give birth to very small live young that attach to a nipple in the mother's pouch, where they complete development. eutherians give birth give birth to more developed live young

ray-finned fish

most of the fish we are familiar with today i.e. nemo, eel, sea horse. major source of protein for humans

monotremes

small group of egg laying mammals consisting of echidnas and the platypus. don't have nipples

some amphibians never leave the water, whereas others can survive in relatively dry terrestrial environments. contrast the adaptions that facilitate these two lifestyles.

some fully aquatic species are paedomorphic, retaining larval features for life in water as adults. species that live in dry environments may avoid dehydration by burrowing or living under moist leaves and they protect their eggs with foam nests, viviparity, and other adaptations

amphibians

species in three clades: urodela (tailed ones), anura (tail-less ones), apoda (leg-less ones). means two lives.

lancelets

subphylum cephalochordata. named for their bladelike shape. marine suspension feeders that retain characteristics of the chordate body plan as adults

tunicates

subphylum urochordata. marine suspension feeders. resemble other chordates during short their larval stage.

mammals

synapsids. amniotes that have hair, produce milk through mammary glands, have kidneys, larger brains. have single opening in the temporal region on each side of the skull. have three bones in the middle ear to transmit sound

describe the origins of tetrapods and identify some of the their key derived traits

tetrapods are though to have developed 365 million years ago when the fins of some lobe-fins evolved into the limbs of tetrapods. key derived traits include four limbs with digits, a neck, and a pelvic girdle that is fused to the backbone

amniotes

tetrapods that have a terrestrially adapted amniote egg. members include reptiles (including birds), and mammals. relatively impermeable skin, ability to use the rib cage to ventilate the lungs