Vertebrate/Agnathans Lecture Flashcards Preview

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Flashcards in Vertebrate/Agnathans Lecture Deck (33)
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1

vertebrate synapomorphies (4)

- size
- speed & mobility
- capacity for food location/capture (predation) & digestion
- metabolic rate

2

vertebrate musculo-skeletal modifications

endoskeleton (cartilaginous or bony)

3

vertebrate endoskeleton helps

- greatly reduce limits on body size - muscles outside of skeleton so muscle size less limited
- less energy input into skeleton since it grows w/ animal (molting unnecessary)
- "energy if the currency of life"

4

cartilaginous skeleton reflects

original condition (bony skeleton evolved later w/in vertebrates)

5

cartilaginous skeleton found in

- all vertebrate embryos (fast growth & flexible)
- adult hagfishes, lampreys, sharks

6

vertebrate musculo-skeletal modifications increased

complexity of myomeres (segmented body muscles)
- V shaped in cephalochordates
- W shaped in vertebrates

7

vertebrate physiological modifications: pharynx

functions as respiratory structure
- muscularization of the pharynx
- vascularization of the pharyngeal arches (gills (arches have bony components = increases structure strength)

8

vertebrate physiological modifications: gut

evolved from functioning by ciliary action to muscular action (like pharynx) with use of accessory glands (liver, pancreas, etc)

9

vertebrate physiological modifications: circulatory system

enhanced gas & nutrient transport
- 3 chambered heart, erythrocytes, Hb

10

2 other vertebrate physiological modifications:

- protected tripartite
- paired sensory organs (associated with predatory habitat)

11

vertebrate duplication of Hot genes: (2)
& both are!!!

- Neural crest (ectodermal) (produce most of cranium, pharyngeal skeleton, Schwann cells)
- Ectodermal placodes (produce olfactory epithelium, eye lens, inner ear epithelium)
-vertebrate synapomorphies!!!

12

Hox genes found in what organisms?

all segmented organisms

13

Hox genes are:

ancient genes that give developmental identity to body segments (ex: limbs)

14

how many copies of Hox genes genes found in invertebrates?

1

15

More copies of Hox genes happen by?

gene duplication events

16

Hox genes may have facilitated:

evolution of increased complexity of segments in vertebrates

17

"Agnatha"

"no jaws"

18

Agantha =

ostracoderms (extinct) + hagfishes & lampreys (extant)

19

Agnatha is monophyletic or paraphyletic?

paraphyletic

20

Agnathan skeletons are

fibrous/cartilaginous
no internal ossification (bone growth)

21

Agnatha have notochord?

Yes

22

Agnatha lack

paired fins & scales

23

Agnatha gills?

pore-like gill openings

24

Agnatha fertilization?

internal

25

Myxini aka

"hagfishes"

26

Myxini characteristics

- rudimentary skull & no vertebrae
- one pair semicircular canals
- eyes probably degenerate (ex: reduced-derived)
- produce amazing slime

27

Myxini development?

no larval stage
feeding body (prey on invertebrates/scavenge fish & whale falls)

28

Cephalaspidomorphi aka

"lampreys"

29

Cephalaspidomorphi characteristics: (4)

- suction mouth w/ keratinized teeth
- simple cartilaginous vertebrae
- 2 pairs semicircular canals
- well developed eyes

30

Cephalaspidomorphi habitat

marine or FW