Chordates Flashcards
What are the three major subohyla of CHordata?
Cephalochordata
Urochordato (Tunicates)
Vertebrata
What lineage are Chordata part of>?
Deuterostomes
What are features of Chordates?
notochord, dorsal hollow nerve cord, pharyngeal gill slits/pouches,myotemes, postanal tail
What is the notochord?
flexible cartilaginous rodlike structure supporting the body in all embryonic and some adult chordates
What are Pharyngeal slits?
openings in the pharynx; develops into gill arches in bony fishes and into jaws and inner ear among terrestrial animals
What are characteristics of Urochordata?
marine, sessile filter-feeders as adults and motile during larval stages
possess all 5 chordate characteristics as larvae
What happens in Tunicate (Urochordata) Development?
larvae settle head-first on hard substrates and undergo metamoprhosis (tail,notochord, muscle segments and nerve cord dissapear)
Whar lineages of Chordates possess body segmentation?
Cephalochordates and Vertebrates
What are segemented muscles called?
Myotomes
What do myotomes allow?
undulatory swimming and rapid burrowing (and movement)
WHat are characterisitcs of Cephalochordata?
marine, swim as larvae, buried in sediment as adults - anterior head exposed for filter-feeding
all chordate characteristics present throughout life history
What do Cephalochordata use for filter feeding?
a wheel organ to draw a current into mouth
tentacle-like buccal cirri around mouth from a grid that keeps out large particles
(+Ciliated gills)
WHo are the closest relatives of Vertebrates?
Tunicates (Urochordata)
What are characteristics of Vertebrates?
all 5 chordate charactersitics at some point in life history
brain and many sensory structures
skull (cranium)
vertebral column
endoskeleton
muscle attached to skeleton
What type of circulatory system do vertebrates have?
closed circulatory system
What feeding behaviour did vertebrates exhibit?
active predation
WHat embryonic innovation allowed for vertebrate brain and sense organ development?
neural crest and ectodermal placodes
What is the neural crest?
a population of ectodermal cells lying along the length of the embryonic neural tube
What does the neural crest do?
contributes to the formation of the cranium, pharyngeal skeleton, tooth dentine, Schwann cells, and some endocrine glands
WHat are Ectodermal placodes?
platelike ectodermal thickenings lying along the length of the embryonic neural tube
What does the ectodermal placodes do?
contributes to formation of olfactory epithelium, eye lenses, and electroreceptors
What is a fish?
aquatic vertebrate with gills, fins, and skin covered in scales of dermal origin
What are the basal vertebrate-crainiates?
Agnathans - hagfish and lampreys
What are chracteristics of hagfish and Lampreys?
jawless, cartilage cranium, eel-like shape, scaleless skin, no paired appendages
What is a defining characterstic of the lampreys and hagfish?
the vertebral column
What is significant about the vertebral column in lamprey and hagfish?
lamprey it is made of cartilage
hagfish - lack vertebrae due to secondary loss - notochord is present
What are charactersitcs of hagfish?
marine, scavengers and predators
special glands along boy secrete fluid that becomes slime-like in contact with seawater for protection
What are differences between larvae and adult stages of Lamprey?
adults are parasitic and larvae (ammocoete larvae) are not
How do Lampreys survive?
live in burrows are use their muscular pharynx to pump in the surrounding water a d then sift out food
What is the metamorphosis of ammocoete larvae like?
develop eyes and oral disks and tongues covered with pointy teeth then begin migrating downstream to the lakes
What do adult lampreys feed on?
blood of host fish
How did Parasitic lamprey enter great lakes region and what were their effects?
in 1800s thrugh human made locks abd shipping canals; reduced native fish populations
What are Chondrichthyes?
cartilaginous fish
what are examples of Chondrichthyes?
sharks, skates, and rays
When did Chondrichthyes first appear?
425mya
What is skeleton in Chondrichthyes made of?
cartilage
What type of scales do Chondrichthyes have?
placoid scales
What are features of Chondrichthyes?
well devleoped jaws, paired pectoral and pelvic fins
What is an adaptation of sharks making them suited for predation?
streamlined bodies and caudal fin with heteroceral tail lifts and propels shark through water; pectoral and pelvic fins act as stabiliers
What are features of skates and rays?
horizontally flattened bodies for bottom dwelling, pectoral fins enlarged and fused to head used like wings in swimming
What is a predation/defense for stingrays?
slender whip-like tail armed with one or more spines with venom glands
What is a lateral line in sharks?
a system f tactile sense organs used to detect movement, vibration, and pressure
How can sharks detect bioelectric fields?
ampullary organs of Lorenzini
What is the modified portion of male’s pelvic fin in cartilaginous fishes called and used for?
clasper - to introduce sperm for internal fertilization
What is a mermaid’s purse?
an egg case or capsule that surround the fertilized eggs of some oviparous sharks, skates, and chimaeras
What is embryophagy (Sandtiger sharks)?
within-the-womb cannabilism method - in which the largest and strongest embryo actually consumes its lesser womb-mates
What is oophagy?
within-the-womb cannabilism in sharks - in which developing embryos feed on a steady supply of tiny, unfertilized eggs
What are Osteichthyes?
Bony fish
WHen did Osteichthyes appear?
400 mya
What are the 2 distinct clades of fish?
ray-fin fishes (Actinopterygii) and lobe-fin fishes (Sarcopterygii) (tertrapods evolved from sarcopterygii)
What features do bony fish and tetrapods share?
bone replaces cartilage during development
presence of lungs or swim bladder
How do Ray-fin fish (Actinopterygii) show diverse feeding behaviours?
sepcialization of jaw structure
How do Ray-fin fishes (Actinopterygiii) move?
undulatory (wave like) locomotion: reduces frictional drag
What are addaptations of skin of ray-fin fishes for movement?
light weight dermal scales and glands in skin secrete mucus reduces drag
What does the operculum do in bony fish?
increased respiratory efficiency because the outward rotation of the operculum created a negative pressure so that water could be drawn across the gills
How do gills help in respiration?
high surface area to colume ratio due to filliments with lamellae for gas exchange
lamellae have blood capillaries
4 sets of gills on each side
How are lamellae in gills orientated?
so that blood flowing through them in capillary network is opposite to that of water - countercurrent flow
What does countercurrent flow allow fish to do?
take in more oxygen get rid of more CO2
What did lungs of ancestral fish evolve into for modern fish?
swim bladders
WHat do swim bladders do?
gas filled structure keeping buoyancy
What is the most diverse group of fishes?
Teleost (ray-finned fish)
What are examples of lobe-finned fishes (sarcopterygii)?
lungfishes and coelocanths
What is a feature of Lobe-finned fish (sarcopterygii)?
possess muscular lobed-fins that allowed them to ‘walk’ along the bottom of oceans, freshwater ponds, or to other sources of water
What are the 3 living genera of lungfishes?
neoceratodus
protopterus
Lepidosiren
What are Coelocanths?
only 1 surviving genus Latimeria
What are the major disparities between air and water?
water content, oxygen content
. density, temperature, habitat richness and diversity
What is major evolutionary feature of tetrapods?
evolution of limbs from lobes
Why are Amphibians still closely related to water?
permeable skin
external fertilization
shell-less eggs not protected from dessication
Why do Amphibians have permeable skin?
allows them to absorb oxygen through skin when moist
What are Caecilians?
amphibian lineage
split from modern Salamanders
What are Caudata?
Salamanders
Where are CAudata (Salamanders) found?
temperate regions
What are features of Salamanders (Caudata)?
skin is well vscularized and used in gas exchnage
at various life stages may possess external gills, lungs, both, or neither
What is the Salamander life cycle include?
an aquatic larval stage with gills which often lost in metamorphosis
What are two examples of Salamanders that don’t undergo metamoprhosis so remain with gills?
mud puppy and axolotl
What is Paedomorphosis?
retention of juvenile or larval features in adult organisms
What are Anurans?
Frogs and Toads
Where are anurans (Forgs and TOads) found?
all vcontinents except antacticva
What type of locomotion do Anurans (Frogs and Toads have?
saltatory locomotion - jumping
What are the skeletal adaptations for Saltatory locomotion?
loss of tail, trunk is shorter and more compact, ribs well-fused to the vertebrae, vertebrae are well fused, hind limbs are both long and strong, forelimbs act as shock absorbers and their strength has been increased by the fusion of the radius and ulna
What is Anuran (Frogs ana toads) reproduction?
male clasps female (Amplexus) female release aggs and male sperm for external fertilization
eggs are jelly like masses
What type of phylogenetic grouping are reptiles?
Paraphyletic as birds left out
What are the derived characteristics of amniotes?
amniotic egg
thicker waterproof skin
rib ventilation of the lungs
What is an amniotic egg?
leathery or shelled eggs which contain food and protective membranes for supporting embryonic development on land
What are features of the skin of amniotes that make it more waterproof?
composed of keratin (fibrous structural protein)
lipids limit water loss
What type of breathing do amniotes do?
negative pressure breathing - expanding thoracic cavity using rib muscles
What type of breathing do Amphibians do?
positive pressure breathing - force air from oral cavity to the lungs
What are Testudines?
Turtles
WHen did Testudines first appear in fossil record?
260 mya
What are characteristics of Testudines?
have bony shells overlain with horn; ribs and vertebrae fused to carapace
aquatic or semiaquatic usually
toothless with a horn beak; omnivores
head and neck move backwards into shell
What are Squamata?
lizards, snakes, and worms lizards
95% of nonavian reptiles
What are Lizard characterisitcs?
4 limbs and relatively short bodies; limbs degenerate in some (glass lizards)
What are Squamata?
Snakes
What are characteristics of squamata?
lack both pectoral and pelvic girdles
pelvic girdles are vestigial characteros om pyhtons and boas
What is different about snake vertebrae allowing for?
numerous vertebrae, shorter and wider than other tetrapod vertebrae - allow quick undulations over the ground
What is chemoreception (snakes)?
chemical senses
What is a Jacobson Organ?
pair of olfactory (smell) pit organs in the roof of the mouth
What do venomous snakes have?
pair of teeth on maxillary bones modified as fangs
when thrust into prey venom is injected through a channel in fangs
What are the 3 toxins produced by snakes?
Cytotoxins, Hemotoxins, Neurotoxins
What do Cytotoxins do?
destroys cells - especially muscles cells
What type of snakes has cycotoxins?
rattlesnakes
What do hemotoxins do?
causes blood to congeal
What type of snake has hemotoxins?
vipers
What do neurotoxins do?
affect the nervous system (paralysis)
What type of snake has neurotoxins?
cobras
What is a feature of snake skulls?
mobile skull for jaw opening
Whatare Sphenodonta?
Tuatara in New Zealand
What are Crocodilia?
Crocodiles, Alligators, Caimens, and Gharials
What lineages are crocodiles and birds from?
archosaurian
Where are Gharials found and eat?
India, fish-eating
What are features of Crocodilia skulls?
elongate, robust, well-enforced with massive jaw musculature
Whta is thecodont? Crocodilia
teeth set in sockets - typical of some of earlist dinosaurs
What is the facial difference between alligators and crocodiles?
lower jaw tooth of crocodiles fits outside slender upper jaw
crocodiles have a longer, thinner V-shaped snout
What is raising younf of alligators and crocodiles like?
2-0-50 eggs in mass f vegetation guraded by mother
What are Aves?
Avian Reptiles - Birds
What is a trabsitional form between theropods and modern birds?
Archaeopteryx
What are characterisitcs of birds
Porous bones
fused bones
feathers
How do porous bones help birds?
help with oxygen intake during flight as air sacs are attahced to hollow areasin birds bones
lighter and less dense but strong
How do fused bones help birds?
strength, and light weight
How do feathers help birds?
leight-weight and tensile (straining/stretching) strength
How did feathers develop? relationship to reptilian scales?
integumentary organs formed by proliferation of cells in the epidermis (homologous to non-avian reptilian scales made of keratin)
from dinosaurs
What are the two hypotheses for terrestrials learning to fly?
tree-down hypothesis
ground-up hypothesis
What is the tree-down hypothesis?
the ancestors of birds were tree-dwellers that jumped from branch to branch
What is the ground-up hypothesis?
ancestors f birds ran along the ground, jumping into the air (Chukar partridge)
What are bird respiratory advances?
air sacs to inrease oxygen uptake
How is birds digestive system adapted?
high metabolic rate = fast digestion
large intestine size reduced = reduced weight
no gall bladder = reduced weight
What are urogenital adaptations to reduce weight?
nourinary bladder; kidneys produce uric acid, excreted as semisolid paste
only left ovary
sex organs only functional in breeding season
how does bird reproduction work?
no penis (except ducks and geese) = bringing cloacal surfaces into contact
eggs layed and incubated
What are the two types of newly hatched birds?
precocial and altricial
What are precocial young in birds?
young are covered with down when hatched and can run or swim as soon as their plumage is dry
What is Altricial young in birds?
young are naked and helpless at birth remain in nest for a week or more
When did Mammals evolve?
180mya from amniotic ancestors
What is advantage of te mammalian jaw?
improved hearing - middle ear fully separated from jaw
helpful for early nocturnal mammals
What does hair do for mammals?
guard hair provides protection from abrasion, moisture, and sunlight; underfur helps insulate and maintain constant temp
What is function of arrector pili contraction making hairs stand on end?
exaggerate size for defense, or dominance
thermoregulation
(vestigial trait in humans0
what is the function of sweat glands in mammals?
for evaporative cooling
What is a type of sweat gland?
apocrine glands
What are scent glands uses?
communication within species for territory, marking young and aggressive intent
What are sebaceous glands?
oil secreting glands that soften and lubricate the skin and hair and to prevent some kinds of bacteria from colonizing
What are uses of mammary glands?
in females produce milk to nourish young
What are the types of mammalian teeth?
incisors
canines
premolars
molars
What do incisors do?
simple crowns and sharp edges for snipping or biting
WHat do canines do?
long, conical crowns’ for piercing
What do premolars do?
compressed crowns and one or two cusps; shearing and slicing
What do molars do?
large bodies and variable cusp arrangement; crushing and grinding
What are adaptations of herbivore digesive system?
long digestive tract, large cecum for microbial digestion and storage
What are skull adpatations fro herbivores?
incisors replaced by horny pad for gnawing grass
broad and flat molars for grinding
WHat are digestive system adaptations for carnivores?
relatively short digestive tract and small or absent cecum
What are teeth adaptations of carnivores?
incisors used for biting and holding prey; sharp canines to kill; jagged premolars to cut up; molars for crushing and grinding
What are extant mammalian lineages?
Monotremes, Marsupials, Placentals
What are examples of Monotremes?
platypus and echidna
where are monotremes found?
australia and new guinea
what distinguishes monotremes from other mammals?
lay a egg shell
have a cloaca
no nipples on mammary glands
What are features of marsupial mammals?
pouched mammals
live birthas underdeveloped embryos to continue development in pouch
What are examples of marsupials?
kangaroo, opossum
Where are marsupials found most?
australia and south america
What marsupial is present in North america?
American opossum
What are features of placental mammals?
internal nourishment of embryos with a placenta
give birth to more developed indpendent young
What is the closest living relative of WHales?
Hippos
What changes occured to skeleton of artroidactyls for whale evolution?
hind legs lost, front became flippers, tail flattened to make a fluke
