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fall semester 2024-25 LSSU > Unit 7: Chordates > Flashcards

Unit 7: Chordates Flashcards

1
Q

5 Characteristics of Chordates: Notochord

A

Between the digestive tube and nerve cord
* Replaced by vertebral column in craniates

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2
Q

5 Characteristics of Chordates: Dorsal hallow nerve cord

A

Derived from endoderm

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3
Q

5 Characteristics of Chordates: pharyngeal slits

A

openings in pharynx
– allow H2O out of mouth after feeding

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4
Q

5 Characteristics of Chordates: Endostyle/thyroid gland

A

ciliated mucous producing tissue on
floor of the pharynx – produces similar substance to thyroid hormone

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5
Q

5 Characteristics of Chordates: Post-anal tail

A

locomotion for fish, balance in some terrestrial species
* Vestigial coccyx aids in balance while sitting in humans

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6
Q

Non-vertebrate Chordate Groups: Invert Clade #1: Cephalochordata

A

– Lancets – retain 5 characteristics into adulthood
* Fossil representatives from Cambrian (500 MYA)
* Few cm blade-like shaped body, live in sand of warm/tropical seas
*H2O in mouth, exits pharyngeal slits that filter food particles, trapped food particles
caught by endostyle, carried to the gut.
* Dioecious

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7
Q

Non-vertebrate Chordate Groups: Invert Clade #2: Urochordata

A

– Tunicates – 1,600 sp. –
* only Pharyngeal slits and endostyle as adults
* Hermaphrodites (serial in some cases)
* Single or colonial filter feeders

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8
Q

Cranium

A

Bony, cartilaginous, or fibrous structure surrounding brain, jaw and facial bones

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9
Q

Craniata

A

includes all vertebrates, presence of cranium

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10
Q

Craniata: Contain a vertebrae

A

series of separate, irregularly shaped bones joined to form a backbone
* Initially form in segments around notochord – but replace it in adults
* Notochord becomes nucleus pulposus – discs between vertebrae

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11
Q

how many craniata

A

62,000 species described

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12
Q

Craniata: Agnatha vs Gnathostomes

A

jawless vertebrates vs jawed vertebrates

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13
Q

Superclass Agnatha

A

Monophyletic group
- Myxini and Petromyzontidae
- Once thought to be individual lineages

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14
Q

Myxini

A
  • 70 sp. – Hagfishes – all marine
  • Almost blind, sensory barbules near mouth locate prey
  • Unique slime glands on the skin
  • Cartilaginous skull, fibrous & cartilaginous skeleton
  • Notochord length of body – major structural support
  • Not replaced by spinal column = sister clade to vertebrates
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15
Q

Petromyzontidae

A
  • 40 sp – Lamprey – Marine and Freshwater
  • All spawn in freshwater
  • Eye muscles, true cerebellum, vertebral elements
  • One of earliest divergences from vertebrate*
  • Suspension-feeding juveniles
  • Adults may be parasitic - Rasping tongue
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16
Q

Gnathostomes

A
  • True jaws & paired fins
  • From 1st set of gill arches ** ON TEST
  • Chondrichthyes – cartilaginous skeletons
  • Osteichthyes – Bony skeleton
    Actinopterygii – ray-finned fishes
    Sarcopterygii – Lobe-finned fishes
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17
Q

Chondrichthyes

A
  • 370 MYA – today 1,000 sp – sharks, skates, rays, sawfishes
  • Paired fins, cartilage skeleton
  • Sensitive to vibrations and electrical currents:

Ampullae of Lorenzini – Sharks – electromagnetic fields produced by all living things
Lateral line – detect movement and vibration analogous to hearing in terrestrial vertebrates

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18
Q

Chondrichthyes - Sexual reproduction – sharks

A
  • internal fertilization (sharks – can be oviviviparous (hatch from egg while in uterus))
  • Mermaid’s purse – oviparous (egg-laying)
  • Hammerheads & Tiger sharks - viviparous (live-bearing)
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19
Q

Rays and Skates

A
  • 500 sp
  • Flattened bodies, pectoral fins fused to the head
  • Gill slits on the ventral surface
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20
Q

Amphibian Characteristics

A
  • 4 limbs (Caecilians – evolutionary reversal)
  • Moist, permeable skin
  • Respiration through the skin, buccal cavity, lungs
  • All carnivores and have teeth
  • Vomerine teeth in roof of mouth
  • Image-forming eyes and colour vision
  • Ears with extra bone (operculum) in the ear
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21
Q

Osteichthyes

A
  • 30,000 sp. Most numerous vertebrates
  • Ossified skeleton
  • Gills, swim bladder, lateral line
  • Actinopterygii (Ray-finned fishes) – the most numerous group of fish
  • Tuna, Bass, Trout…slender bones that support fins
  • Sarcopterygii (lobe-finned fishes)
  • Precursor to tetrapod limbs
    -Coelacanths alive today
22
Q

Amphibian Evolution: First tetrapods

A

– 400 MYA
* Evolved from lobe-finned fishes
* Transition to breathing air and moving on land = 50 MY

23
Q

Amphibian Evolution: Devonian

A

Early aquatic tetrapods in Devonian
* Aquatic – body not supported out of water

24
Q

Amphibian Evolution: Carboniferous

A

moved to land with few predators/competitors

25
Modern Amphibians
6,770 sp in three clades of subclass Lissamphibia * Urodela, Anura, Apoda
26
Urodela
– Salamanders (620 sp) * Movement through lateral undulation * No lungs or primitive lungs, some gills and lungs * Reproduction - courtship, spermatophore, oviparous, eggs in water (sperm packets) * Metamorphosis before hatching
27
Anura
Frogs & Toads – 5,965 sp. "no tail" * Limbs adapted for jumping * Some skin glands modified for toxin release * Reproduction – external fertilization (female egg, male fertilizes) * Parental care varied – none to carrying tadpoles/eggs on back * Metamorphosis after hatching
28
Apoda
Caecilians – 185 sp. No limbs, evolved from limbed ancestor * Resemble earthworm – with teeth and jaws * Internal fertilization, oviparous or viviparous
29
Reptiles: Characteristics of Amniotes
* Terrestrially adapted egg – Amniotic Egg *breathes!! AMNIOTIC EGG: Blood vessels in the yolk sac – transport nutrients to the embryo * Chorion – O2 & CO2 exchange – embryo and eggs external environment * Allantois – Stores N – wastes, also facilitates respiration * Amnion – protects the embryo from mechanical shock – supports hydration The extra-embryonic membranes have various functions
30
Evolution of Amniotes
* Early tetrapod ancestor 340 MYA – 2 main lineages Synapsids: - Therapsids (mammals evolved from) Sauropsids: - Anapsids. -Diapsids (gave rise to reptiles) * Temporal fenestrae – post-orbital openings in the skull: Anapsids – no fenestrae Synapsids – 1 fenestrae Diapsids – 2 fenestrae
31
Diapsids
Diverged into Archosauromorpha & Lepidosauromorpha * Archosaurs (ancient lizard form) – crocodilians, ichthyosaurs, pterosaurs, dinosaurs, birds "WHICH GROUP DOES BIRD/CROC BELONG TO"** * Lepidosaurs (scaly lizard form) – lizards, snakes, tuataras
32
Characteristics of Reptiles
* Tetrapods, amniotic eggs (some oviviviparous, some viviparous) * Scaly skin – rich in Keratin & Waxy lipids * Ventilation of lungs with muscles * Ectothermic: Crocodilians – regional endotherms (thoracic temps, pretty constant) Can survive on about 10% energy of comparable endotherm** * Burmation – metabolism slowed in cold temps
33
Evolution of Reptiles
* Archosaurs give rise to Dinosaurs: Saurischia (lizard-hipped) Ornithischia (bird-hipped) * Archosaurs give rise to Pterosaurs: More than 200 sp described – aerial 100 sp terrestrial * Age of dinosaurs ended 65 MYA
34
Modern Reptiles: Crocodilia
Middle Triassic – alligators, crocodiles, gharials, caimans *Fresh and saltwater of Africa, Australia, Asia, South America, southern North America
35
Modern Reptiles: Sphenodontia
Early mesozoic - Two species today – tautara
36
Modern Reptiles: Squamata
Late Permian – Lizards (6,000 sp) and Snakes (3,600 sp) * Snakes– specialized jaw in snakes– 8 rotational joints * Snakes–single lung (long slender body) * Venom glands * No eyelids–but transparent scale
37
Modern Reptiles: Testudines
– 200mya * Carapace (dorsal shell) includes backbone & ribs * Plastron (ventral shell) * Scutes – scales covering both shells
38
Characteristics of Birds
* 10,000 described species – most of any land animal group * Homeotherms – maintain elevated and constant body temp * Produce feathers – modified scales --> Contour feathers – barbs maintain tight configuration - interlock --> Down feathers – barbs do not interlock -->Flight feathers: - Primary feathers: at wing tips–provide thrust - Closer to body– provide lift - Contour feathers– reduce drag– shingle like action
39
birds: bones
* Hallow bones = pneumatic bones * Specialized furcula (fused clavicles) = wishbone * Fused T – vertebrae * Keel
40
birds: cloaca
– common opening - concentrates urine to urate salts
41
birds respiration
* Non-inflatable lungs * Air sacs * Unidirectional flow TEST!!!
42
Evolution of Birds
Diapsid: Archosaurs (Crocodilians, Pterosaurs, Dinosaurs) * Birds from Saurischians (theropods) - Clade Neornithes - Neornithes gave rise to Archeopteryx
43
Evolution of Flight
* Arboreal hypothesis – gliding from branch to branch * Terrestrial hypothesis- pursuit of prey with wings out
44
Characteristics of Mammals
Hair: composed of keratin - Functions – maintaining heat, sensory, communication Skin glands: - Sebaceous glands – lipids for hair and skin - Eccrine – Sweat (perspiration) – mostly water and metabolic wastes - Apocrine glands – scent glands - Mammary glands – produce milk * Single lower jaw * Inner ear bones – modified jaw bones
45
Evolution of Mammals
Synapsids: single, ancestrally fused, postorbital opening in the skull * Evolved from therapsids in late Triassic * Earliest mammal fossils from the early Jurassic - Morganucodonts: both mammalian and reptilian jaws – nocturnal insectivores
46
Living Mammals
1. Monotremes (egg-laying mammals): Ornithorhynchidae (Bird beak), Tachyglossidae (sticky tongue) 2. Marsupials: 2/3 in Australia, Incomplete fetal development (in many) 3. Eutherians (Placentals) : Chorioallantoic placenta
47
Eutherians (Placentals)
Atlantogeneta: * Afrotheria (Elephants, hyraxes, manatees) * Xenarthra (anteaters, armadillos, and sloths) Boreoeutheria: * Euarchontoglires (tree shrews, rodents, lagomorphs, primates) * Laurasiatherian: - Perissodactyla– rhinos and horses - Cetartiodactyla– cows, giraffes, pigs, hippos, whales - Carnivora– dogs, cats, bears - Chiroptera– bats and flying foxes
48
Characteristics of Primates
Hands and feet adapted for brachiation (swinging through trees): * Rotating shoulder joint * Big toe separated from others, opposable thumbs * Stereoscopic vision * Larger brains * Claws flattened into nails * Typically 1 offspring per pregnancy * Trend toward upright body position
49
Primate Orders
Strepsirrhini: turned nosed --> Prosimians – bush babies and lemurs Haplorhini: simple nosed --> Tarsiers --> Simians – New world moneys, old world monkeys, new world monkeys, apes, humans
50
Primate Evolution
1) Proto-primates – North Africa – squirrel sized – 65-85MYA 2) True primates – 55 MYA – N.A., Europe, Asia, Africa - Resembled present-day prosimians such as lemurs 3) Anthropoid – 40 MYA * S.A. (New World) – all arboreal * Africa & Asia (Old World) – arboreal and ground-dwelling 4) Apes – 25MYA Africa * Lesser apes – Halobatidae – gibbons, siamangs * Great Apes - Pan (chimps), Gorilla (gorillas), Pongo (orangutans), Homo (humans)
51
Great Apes
Gorillas: strong sexual dimorphism Chimps/Humans: Lineages Separated 6MYA --> Chimps / bonobo – 2 MYA – Congo River Humans: our species only surviving member from original split --> Non-linear related species – H. neanderthalensis, H. rhodesienses, H. heidelbergensis --> Paranthropus --> Australopithecus

fall semester 2024-25 LSSU (10 decks)

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