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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
Q

Modern Amphibians

A

6,770 sp in three clades of subclass Lissamphibia
* Urodela, Anura, Apoda

26
Q

Urodela

A

– 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
Q

Anura

A

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
Q

Apoda

A

Caecilians – 185 sp.
No limbs, evolved from limbed ancestor
* Resemble earthworm – with teeth and jaws
* Internal fertilization, oviparous or viviparous

29
Q

Reptiles: Characteristics of Amniotes

A
  • 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
Q

Evolution of Amniotes

A
  • 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
Q

Diapsids

A

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
Q

Characteristics of Reptiles

A
  • 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
Q

Evolution of Reptiles

A
  • 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
Q

Modern Reptiles: Crocodilia

A

Middle Triassic – alligators, crocodiles, gharials, caimans
*Fresh and saltwater of Africa, Australia, Asia, South America, southern North America

35
Q

Modern Reptiles: Sphenodontia

A

Early mesozoic - Two species today – tautara

36
Q

Modern Reptiles: Squamata

A

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
Q

Modern Reptiles: Testudines

A

– 200mya
* Carapace (dorsal shell) includes backbone & ribs
* Plastron (ventral shell)
* Scutes – scales covering both shells

38
Q

Characteristics of Birds

A
  • 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
Q

birds: bones

A
  • Hallow bones = pneumatic bones
  • Specialized furcula (fused clavicles) = wishbone
  • Fused T – vertebrae
  • Keel
40
Q

birds: cloaca

A

– common opening
- concentrates urine to urate salts

41
Q

birds respiration

A
  • Non-inflatable lungs
  • Air sacs
  • Unidirectional flow TEST!!!
42
Q

Evolution of Birds

A

Diapsid: Archosaurs (Crocodilians, Pterosaurs, Dinosaurs)
* Birds from Saurischians (theropods)
- Clade Neornithes

  • Neornithes gave rise to Archeopteryx
43
Q

Evolution of Flight

A
  • Arboreal hypothesis – gliding from branch to branch
  • Terrestrial hypothesis- pursuit of prey with wings out
44
Q

Characteristics of Mammals

A

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
Q

Evolution of Mammals

A

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
Q

Living Mammals

A
  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
Q

Eutherians (Placentals)

A

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
Q

Characteristics of Primates

A

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
Q

Primate Orders

A

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
Q

Primate Evolution

A

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
Q

Great Apes

A

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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