Vertebrata and fish Flashcards

Jawless and Jawed fish

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1
Q

What advantages do vertebrate have over invertebrates?

A
  • increased complexity
  • increased body size
  • increased activity
  • capturing food and avoiding predators
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2
Q

6 shared, derived characterisitcs of vertebrates?

A

Vertebral column
Braincase enclosing brain
2 or more sets of Hox genes
Neural crest cells
Dorsal, anal and tail fins stiffened by fin rays
Complex, circulatory system

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3
Q

What is the vertebral column and what does it do?

A

Skeletal elements enclose and protect the nerve cord
- replaces the function of the notochord
- enhances rigidity and provides muscle attachment points
- improved food capture and evasion

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4
Q

Cranium and head structure and functions?

A

Associated with pronounced cephalization
- head has brain, sense organs and cranium without jaws
- evolution of cranium allowed exapansion of nerve cord into brain and nervous system
- cranium does not completely encase brain in some vertebrates

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5
Q

What are neural crest cells and what do they do?

A
  • develop along neural tube edge in vertebrate embryos
  • migrate within embryo, contribute to teeth, skull bones/cartilage and diverse types of neurons
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6
Q

What are fins and what do they do?

A

membrane extensions supported by cartilaginous or bony spines
- provide balance and propulsion during swimming
- lost in tetrapods

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7
Q

How does the vertebrate circulatory system function?

A
  • closed circulatory system
  • heart with atleast 2 chambers
  • O2 transporting hemoglobin in red blood cells; oxygenated via gills or lungs
  • kidneys remove waste from blood
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8
Q

What is the clade of vertebrates that lacks jaws called? What animals does it comprise? (2)

A

Cyclostomes
hagfish, lampreys

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9
Q

Hagfish characteristics? cranium, vertebrae? anatomy? feeding? defense?

A
  • cartilaginous cranium and reduced vertebrae
  • flexible rod of cartilage derived from notochord
  • small brain, eyes and mouth
  • tooth-like keratin projections that protract and retract to pull in food
  • absorb nutrients through skin
  • exude fibrous slime for defense which absorbs water and swells rapidly choking predators
  • bottom-dwelling scavengers
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10
Q

Lamprey characteristics? skeleton and vertebrae? fins? feeding?

A
  • cartilaginous skeleton, more elaborate cranium with gill basket
  • rudimentary vertebral elements
  • notochord surrounded by cartilaginous segments
  • no paired lateral fins; dorsal and tail fins
  • suspension-feeding by burying into substrate
  • parasitize fish by funnel-like sucking mouth
  • rasping tongue with keratin spines
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11
Q

What was clade Conodonts and its characteristics?

A
  • earliest vertebrates
  • cartilaginous cranium and vertebral column
  • jawless but had mineralized skeletal elements in mouth and pharynx
  • defensive plates made of dermal bone on their skin
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12
Q

What clade makes up jawed fish and what are its shared, derived characteristics? (6)

A

Clade Gnathostomes
Opposing jaws
2 pairs of lateral appendaged
Mineralization of skeleton
Genome duplication
Enlarged forebrain
Lateral line system

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13
Q

What was the structure and purpose of opposing jaws?

A
  • evolved from skeletal supports of pharyngeal slits
  • open and close forecefully to capture and process food
  • 2 pairs of branchial elements - hinged skeletal rods supporting gill arches - open and close mouth effectively to pump water over gills
  • evolution of larger, wider mouths to capture larger prey
  • posterior branchial elements for gas exchange (gill slits)
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14
Q

What can the 2 pairs of lateral appendages be?

A

fins or legs

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15
Q

What is the significance of genome duplication?

A

duplication of Hox genes (4 sets)
More specialization and differentiation

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16
Q

What is the significance of an enlarged forebrain?

A

Enhanced smell and vision

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17
Q

What does the lateral line system do?

A

Detects vibrations in water
Lost in terrestrials

18
Q

What is the significance of a mineralized skeleton?

A
  • increased structural support
  • protection of internal organs
  • ability to support increased size
19
Q

Why did mineralization of the skeleton and evolution of jaws emerge simulataneously?

A

natural selection favoured mineralization in jaw area enhancing strength and durability
- improved effectiveness of jaws as predatory structures
- mineralization of axial skeleton occurred later for better bodily support and locomotion

20
Q

What are the 2 types of bones in gnathostomes?

A

Preformed cartilage
Intramembranous ossification

21
Q

How is the endoskeleton derived from preformed cartilage?

A

Cartilage undergoes ossification with calcium phosphate as embryo develops

22
Q

What is the significance of intramembranous ossofication?

A

Developed dermal skeletal structures.
- formed external armour in armoured fish
- retained in bony fin rays in fish, facial and pectoral bones and teeth

23
Q

What are the 3 lineages of extant gnathostomes?

A

Chondrichthyans, lobe-fins, ray-fins

24
Q

Chondrichthyan structure?

A

-cartilaginous skeletons and endoskeleton
- bony teeth, bony placoid (tooth-shaped scales)
- derived from bony skeletal elements in ancestors

25
Q

How do sharks swim?

A
  • propulsion by tail fin
  • lift by pectoral fins
  • streamlined body
  • swim continuously to maintain buoyancy due to density
  • no gas-filled swim bladder
26
Q

How do sharks exchange gas?

A

ram ventilation - swim with mouth open allowing water to pass over gills, facilitating ventilation
- may use buccal pumping - force water over gills by opening and closing mouth forcefully

27
Q

Shark anatomy and sensory structures?

A

Digestive, urinary and reproductive tracts empty through cloaca
- acute senses; olfactory receptors, electroreceptors, lateral line system

28
Q

How do sharks reproduce?

A

copulation
males have modified pelvic fins called claspers which deliver sperm to female cloaca
eggs are fertilized internally and develop through all 3 methods
oviparous - fertilized eggs laid outside body, encased in protective, leathery casing
ovoviparous - embryo development in uterus, embryo nourished by egg yolk
viviparous - embro development in uterus, nourished through yolk-sac placenta connected to mothers bloodstream

29
Q

What is the Clade of bony fish called and what does it refer to? 3 shared dervived characteristics?

A

Clade Osteichthyans
aquatic bony vertebrates (paraphyletic)
- Lungs/lung derivatives
- Operculum
- Maneuverable fins

30
Q

What is a swim bladder and how did it evolve?

A

Air sac that maintains neutral buoyancy of fish by adjusting its inflation via gas exchange with blood.
Evolved from simple lungs in ancestors
- homologous to tetrapod lungs
- in primitive ray-fins pneumatic duct connects gut to swim bladder
- lost in most ray-fins, resulting in closed swim bladder

31
Q

What is a simple lung and its function?

A

Dorsal out-pocketing of gut filled with gas
- augments gas exchange in gills
- gulp air in O2 poor waters

32
Q

What is the operculum and its function?

A

Plate of dermal bone that covers and protects gill arches and gills
- fishes breathe by drawing water over operculum-protected gills
- mouth and operculum function as valves in an efficient buccal pump allowing for ventilation even when staitonary

33
Q

What does the fin structure look like in Osteichthyans? What is their function?

A
  • slender, flexible bony rays or spines portruding from the body are covered in skin to form maneuverable fins
  • pectoral and pelvic girdles support maneuverable fins from bony, basal elements
  • only the tail fin is directly connected to the vertebral column, rest are supported by muscles
  • function in propulsion, maneuvering and defense through spines
34
Q

How do bony fish reproduce?

A

Broadcast spawners and external fertilization
- fertilized eggs and young may recieve paternal care
- some species exhibit internal fertilization and ovoviparity

35
Q

What are some chacrateristics of bony fish?

A
  • ossified endoskeleton
  • lateral line system
  • dermal armour of thin, plate-like bony scales (protection + flexibility)
36
Q

What are the 2 groups of bony fish, their phylogeny and fin structure?

A

Ray-fins
- monophyletic
- fins supported by elongated, fleible bony rays connected to basal bony elements
Lobe-fins
- paraphyletic
- fleshy, lobed fins

37
Q

Lobe-fin structure and skeleton?

A
  • fleshy, muscular pectoral and pelvic fins supported by bony elements
  • lobe-fins are shared, derived trait
  • single basal skeletal bone and central supporting bones
  • skeletal elements homologous with tetrapod limb bones
38
Q

3 surviving lineages of lobe-fins?

A

Coelocanths, lungfish, tetrapods

39
Q

Coelocanth characteristics? Fins? Movement? Gas exchange?

A
  • muscular pectoral anf pelvic fins to swim and walk underwater
  • lungs and gills
  • extant genus has vestigial lung
40
Q

Lungfish characteristics? gas exchange? survival?

A
  • gills and lungs
  • buccal pump system to gulp air from surface by raising and lowering the floor of their mouth cavity
  • 2 lungs, homologous to tetrapods
  • burrow into mud in dry conditions