chapter 34 Vertebrates

Question 1

name 4 features of all chordates

Answer 1

dorsal hollow nerve cord, notochord, pharyngeal gill slits or pharyngeal pouches, postanal tail

Question 2

notochord (becomes the vertebral column)

Answer 2

longitudinal, flexible rod located between the digestive tube and the nerve cord. It’s composed of large, fluid-filled cells encased in fairly stiff, fibrous tissue. The notochord provides skeletal support throughout most of the length of a chordate, and in larvae or adults that retain it, it also provides a firm but flexible structure against which muscles can work during swimming

Question 3

dorsal, hollow nerve cord (differentiates into spinal and brain cord)

Answer 3

develops from a plate of ectoderm that rolls into a neural tube located dorsal to the notochord.The nerve cord of a chordate embryo develops into the central nervous system: the brain and spinal cord.

Question 4

pharyngeal slits

Answer 4

slits that open to the pharynx(throat). Allow water entering the mouth to exit the body without passing through entire digestive tract. In tetrapods used for gas exchange, become ears and other head/neck structures in tetrapods.

Question 5

muscular post anal tail

Answer 5

tail that extends posterior to the anus. The chordate tail contains skeletal elements and muscles, and it helps propel many aquatic species in the water.

Question 6

2 of the 3 subphyla of chordates are non vertebrate. What are they

Answer 6

Urochordata (tunicates and salps) and Cephalochordate (lancelets)

Question 7

describe body structure of an adult tunicate with that of the larval tunicate.

Answer 7

only larvae have notochord and nerve cord. adults have cilia lined pharynx that brings in water where small food particles are then trapped in sheet of mucus. Adult tunicates may be colonial and are sessile. Tadpole like larvae do not feed and are free-swimming for only a few days before attaching to substrate by sucker. Tunic is tough sac of mostly cellulose surrounds and supports animal.

Question 8

What chordate features are lost in adult tunicate?

Answer 8

notochord, tail, nerve cord

Question 9

describe lifestyle of a lancelet

Answer 9

look like two-edged surgicial knife. Notochord retained throughout life, spend most time buried in sand with anterior end exposed, can swim but don’t often, more pharyngeal gill slits than fishes, filter-feeders

Question 10

Vertebrates differ from tunicates and lancelets in what two important respects? What are some other important differences?

Answer 10

Vertebral column, distinct and well-differentiated head (craniates). Other important differences are neural crest, internal organs like liver, kidneys, heart, and closed circulatory system. Endoskeleton

Question 11

vertebrate evolution

Answer 11

evolved in oceans 545 mya, hinged jaws was major advance for food gathering; jawed fishes came to dominate sea, amphibians invaded land

Question 12

list and describe 5 key characteristics of fishes

Answer 12

vertebral column- bony/cartilaginous spine surrounding dorsal nerve cord and bony cartilaginous skull encasing brain
jaws and paired appendages- most fishes have pair of pectoral fins and pair of pelvic fins
Internal gills- for extracting dissolved oxygen from water
single loop blood circulation- pathway is from heart->gills->body tissues->back to heart and heart is 2 chambered
nutritional deficiencies- fishes must obtain amino acids phenylaline, tryptophan and tyrosine from diet cus can’t synthesize their own

Question 13

how did first fishes differ from more modern fish?

Answer 13

jawless, only had mouth positioned anteriorly, ostracoderms are extinct but had bony head and cartilaginous skeleton

Question 14

how did teeth evolve in fish?

Answer 14

sharks first to develop teeth, evolved from rough scales on skin, not set in jawbone but sit on top of it

Question 15

what is the lateral line system and what is it’s function

Answer 15

series of sensory organs projecting into a canal that runs the length of fishes body, open to exterior through series of sunken pits, fishs’s equivalent of hearing

Question 16

shark population is declining. What does this have to do with their mode of reproduction?

Answer 16

long gestation period and few offspring have led to the decline. Sharks are being captured in greater numbers

Question 17

bony fish

Answer 17

heavy internal skeleton of bone provides strong base, mobile fins, thin scales, symmetrical tails, bony fish are most species rich group of vertebrates

Question 18

function of swim bladder and gill cover in bony fish

Answer 18

swim bladder- out pocketing of pharynx; can be filled with gas or drained of gas to control buoyancy in water
gill cover- operculum; flexing operculum pumps water over gills; works like a bellows; fish remains stationary

Question 19

how do ray-finned fish differ from lobe-finned fish?

Answer 19

ray finned- parallel bony rays that support fin; no muscles within fin
lobe-finned- fins are fleshy and muscular; supported by bone with articulated joints; muscles within fins can move fins independently of one another (no ray-finned fish can do this)

Question 20

organisms found in order Anura (without a tail)

Answer 20

frogs and toads

Question 21

characteristics of frogs and toads (Anura)

Answer 21

live in deserts, mountains and ponds. both return to water to reproduce. frogs have moist skin, broad body and long hind legs and live in or near water, tadpole->adult frog
Toads have dry bumpy skin, short legs and live in dry environments, tadpole->adult toad

Question 22

organisms found in order Urodela- visible tail (also known as Caudata)

Answer 22

newts and salamanders

Question 23

characteristics of order urodela (newts and salamanders)

Answer 23

elongated bodies, long tails, smooth moist skin, live in moist habitats, some live in water, internal fertilization where female picks up sperm packets left by male, eggs laid in moist areas or in water, larval salamanders similar to adults but they live in water and have external gills

Question 24

organisms in order apoda (without legs)

Answer 24

caecilians

Question 25

characteristics of caecilians (apods)

Answer 25

legless worm like tropical burrowing amphibians, small eyes and often blind, size from 30cm to 1.3cm long, have jaws with teeth and eat worms and other invertebrates, internal fertilization

Question 26

5 distinguishing characteristics of amphibians

Answer 26

Legs- frogs and salamanders have 4 legs; caecilians have lost their legs Lungs- Cutaneous respiration- a lot of surface area of moist skin allows for diffusion of oxygen through skin which must be kept moist Pulmonary veins- return aerated blood to heart for repumping Partially divided heart- imperfect separation of pulmonary and systemic blood circulation; only one ventricle in heart where oxygenated and deoxygenated blood mix

Question 27

what are an amphibians challenges to terrestrial life

Answer 27

amphibian ancestors had large bodies and may have been difficult to support the weight of the body on land. Legs helped support animal on land. Gills need water to support them. In the air, they stick together. Lungs are better option for living on land. Modifications to heart and circulatory system allowed for more efficient delivery of oxygen to muscles (3 chamber heart). Reproduction still takes place in water so eggs don't dry out Amphibians stay near water so body doesn't dry out

Question 28

What country were the amphibians thought to have originated?

Answer 28

Greenland

Question 29

If rib cage could not expand and contract, how would an organism get air to enter the lungs?

Answer 29

floor of the mouth would lower to push air down into a windpipe

Question 30

in what ways did reptiles improve upon the innovations of amphibians

Answer 30

leg arrangement supports body better, allows animal to be bigger and run. More efficient heart and lungs. Skin covered with scales to decrease water loss. watertight covering evolved for eggs

Question 31

describe structure of the amniotic egg.

Answer 31

watertight eggs that contain a food source (yolk) and a series of 4 membranes.

Question 32

what are the functions of the 4 membranes of the egg

Answer 32

chorion= outermost membrane lies beneath the porous shell; allows for exchange of respiratory gases, but retains water amnion= encases developing embryo within fluid-filled cavity yolk sac= provides food from yolk via blood vessels connecting to embryo's gut allantois= surrounds cavity into which waste products from embryo are excreted

Question 33

describe skin of reptiles

Answer 33

dry skin; layer of scales covers bodies and prevents water loss. Scales contain keratin which is same protein that forms claws, fingernails, hair, and bird feathers

Question 34

describe thoracic breathing in reptiles

Answer 34

reptiles developed pulmonary breathing; rib cage expands and contracts to suck air into lungs and then forces it out. Capacity of this system is limited by the volume of the lungs

Question 35

synapsids gave rise to what line of organisms? Diapsids gave rise to what lines of organisms

Answer 35

synapsids gave rise to therapsids that became mammalian line. Diapsids gave rise to modern reptiles and birds

Question 36

important characteristics of modern reptiles?

Answer 36

internal fertilization. mixing of oxygenated and deoxygenated blood is lessened by extending septum partially through ventricle. Crocodiles, birds and mammals have 4 chambered heart. Ectothermic means they obtain their heat from external sources

Question 37

examples and characteristics of organisms in Order Chelonia

Answer 37

Turtles and Tortoises - no teeth but sharp beal - only reptiles to have a shell

Question 38

examples and characteristics of Order Rhynchocephalia

Answer 38

Tuataras - only found on small islands off coast of new zealand - have third eye on top of head; eye is covered by thin layer of scales; has lens and retina; connected by nerves to brain; may alert tuatara when it's been exposed to too much sunlight

Question 39

examples and characteristics of Order Squamata

Answer 39

Lizards and Snakes - lack limbs, moveable eyelids, and external ears in snakes - distinguished by paired copulatory organs in males - head and jaws have strength and mobility - most lizards and snakes are carnivorous

Question 40

examples and characteristics of order crocodylia

Answer 40

Crocodiles and alligators - all crocs are carnivores -crocodiles resemble birds more than they resemble other reptiles. They build nests to care for young, have 4 chambered heart

Question 41

function of feathers in birds

Answer 41

feathers are modified reptilian scales; made of keratin. Functions are to provide lift for flight and conserve heat

Question 42

describe the flight skeleton of modern birds

Answer 42

bones are thin and hollow, many bones are fused and makes bird skeleton more rigid than reptilian skeleton. No other living vertebrates have fused collarbone or keeled breastbone

Question 43

what is archaeopteryx

Answer 43

fossil of first known bird. found in Bavaria in 1862. Had skull with teeth, very few fused bones bones were probably solid and not hollow. had long tail no enlarged breastbone, feathers on wings and tail

Question 44

what are the 3 evolutionary novelties of birds

Answer 44

feathers hollow bone super efficient lungs that allow sustained powered flight

Question 45

for what reasons is the fossil record of birds incomplete?

Answer 45

feather impressions rarely fossilized. Hollow delicate bones were probably crushed and not fossilized

Question 46

what are 3 shared characteristics of all modern birds

Answer 46

Efficient respiration - inhale->air goes past lungs to air sacs and within hollow bones of back-> air travels back to lungs->anterior air sacs before exhaling Efficient circulation - 4 chambered heart means no mixing of oxygenated and deoxygenated blood. birds have rapid heartbeat Endothermy - feathers help conserve body heat, higher temps permit metabolism of birds flight muscles to proceed at rapid pace

Question 47

distinguishing characteristics of all mammals

Answer 47

Hair- all mammals have hair. Allows mammals to move to colder climates, serves as camoflauge, sensory structures, defensive weapon Mammary glands- found in all female mammals, secrete milk supports rapid growth of newborns Endothermy - warm blooded, mammals can be active day and night, endothermy depends on more efficient blood circulation and respiration Placenta- most carry young internally in a uterus and nourishment takes place through placenta

Question 48

what types of specialized teeth are found in mammals

Answer 48

can determine diet of mammals by looking at teeth Meat eaters have canine teeth and triangular molars and premolars for tearing off pieces of flesh Herbivores have flat, chisel like incisors for cutting off vegetation and flat ridged molars for grinding tough plant tissues

Question 49

how do ruminants digest plant material (cows, buffalo,deer etc)

Answer 49

most mammals are herbivores and cellulose comprises most of plant's tissues. Mammals don't have proper enzyme to break down cellulose and depend on bacteria to do it. They have 4 chambered stomach that acts as fermentation vat; bacteria in one stomach chamber breaks down cellulose

Question 50

how do mammals such as rodents,horses, rabbits, and elephants digest cellulose?

Answer 50

have small stomach and plant material is digested in large intestine; the bacteria that breaks down cellulose are found in cecum

Question 51

what are the differences among hooves, horns, and antlers

Answer 51

hooves of the foot protect the toes and cushion from impact. Horns made of a bony core surrounded by sheath of keratin; bony core attached to skull; horns are not shed. Antlers are made of bone; male deer grow and shed a set of antlers every year; while growing in summer, they are covered by thin layer of skin called velvet

Question 52

bats are only flying mammals. What is structure of their wings?

Answer 52

batwings are modified forelimbs. Leathery membrane of skin and muscle stretched over 4 fingers

Question 53

characteristics of monotremes (egg laying mammals0

Answer 53

duck-billed platypus and echidna lay shelled eggs and have cloaca

Question 54

characteristics of marsupials (pouched mammals)

Answer 54

different pattern of embryonic development - fertilized egg surrounded by chorion and amniotic membranes but no shell forms -nourished by yolk in egg - short-lived placenta forms before birth - within 8 days of fertilization, embryonic development marsupial born -crawls into pouch and latches onto mammary nipple where it continues developing

Question 55

characteristics of placental mammals

Answer 55

-placenta nourishes embryo through entire development period in uterus - chorion and allantois form placenta -young undergo considerable development before they are born

Question 56

what 2 innovations are seen i primates

Answer 56

Grasping fingers and toes (opposable thumb) and binocular vision