lecture 6 Flashcards

1
Q

what characteristics of the living hagfishes and lampreys suggest that their lineages arose very early in vertebrate evolution?

A

Hagfishes lack bone, paired fins, and scales in their skin. Hagfishes have neither a cranium nor vertebral column.

Lampreys have only rudimentary traces of vertebrae.

These observations suggest that their lineages arose before these structures appeared in vertebrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what traits in conodonts and ostracoderms are derived (more advanced) relative to those in hagfishes and lampreys?

A

structures made of bone or bone-like material and, in some ostracoderms, a brain sub-divided into 3 regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

why was the evolution of jaws so important for the evolution of vertebrates? 4

A
  1. increased flexibility and efficiency
  2. increased diversity of diet
  3. more food= bigger individuals
  4. moveable fins increased agility in movements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how do the air bladder and fins of Actinopterygii increase their locomotor abilities?2

A
  1. allowing them to rise or sink easily in the water column.

2. Their fin rays allow them to engage in precise movements during locomotion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what characteristics do bony fishes possess that make them so competitive? 5

A
  1. strong light bones
  2. moveable fins
  3. scales and mucus (=streamlining and anit-bacterial)
  4. swim bladder (=improved buoyancy control)
  5. operculum (=improved breathing)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what characteristics of sharks make them more efficient predators than the acanthodians or placoderm? 4

A
  1. well developed sensory system to detect prey
  2. lightweight skeleton and absence of a heavy body armor allow them to ursue prey rapidly
  3. numerous teeth that are replaced when damaged or worn
  4. loosely attached jaws that permit them to suck in large chunks of food
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do the lungs of lungfishes allow them to survive in stressful environments?

A

allow them to survive in environments with low oxygen content because they can acquire oxygen from the air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Ghathostomata includes the evolution of 2 things?

A
  1. hinged jaws

2. movable fins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

common name for myxinoidea

A

hagfish

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

petromyzontoidea common name

A

lampreys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

which agnathan hasnt got a specialised structure around the dorsal nerve cord? (no rudimentary vertebrae)

A

myxinoidea -hagfishes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

which agnathan has an oral disk

A

petromyzontoidea-lampreys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Condonts (cone tooth) :

2 identifying features (rest are in the phylogeny tree)

A
  1. movable eyes

2. bone/bone-like tissue: bone-like feeding structures made of dentine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

2 characteristic of ostracoderms

A
  1. armored skin with bony plates and scales

2. no true vertebral column or fins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

jaws evolved from…..

A

gill arches in the pharynx of jawless ancestor.

  • one pair of ancestral gill arches formed bones in the upper and lower jaws
  • 2nd pair attached the jaws to the cranium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

4 functions of movable fins

A
  1. stability (e.g. dorsal fin and anal fin)
  2. steering (paired pectoral fins as well as paired pelvic fins)
  3. power and trust (e.g. caudal fin)
  4. deters predators
17
Q

4 reasons why the development of the jaws and fins were so NB

A
  1. increased flexibility and strength
  2. increased diversity of diet
  3. more food= bigger individuals
  4. moveable fins increased agility in movement
18
Q

3 characteristics of placoderms (could compare them with acanthodii= same characteristics are very different)

A
  1. covered by heavy bony plates & scales
  2. no separate teeth
  3. fins with internal skeletal support and muscle
19
Q

3 characteristics of acanthodii (spiny sharks)

A
  1. smell, light scales, streamline bodies
  2. well developed eyes, large jaws and numerous teeth
  3. ventral spines and fins with internal skeletal support
20
Q

chrondrichthyes are referred to as …branchs

A

elasmobranches

21
Q

elasmobranchs (chondrichthyes )include 3 species

A
  1. skates
  2. rays
  3. sharks
22
Q

skates and rays are both

A

dorsoventrally-flattened bottom dwellers

23
Q

sharks 6 characteristics

A
  1. streamlined
  2. dominant predators
  3. flexible fins but not movable
  4. lightweight skeleton
  5. buoyant livers
  6. no gill cover- breathing=less efficient
24
Q

Elasmobranch feeding adaptations 2

A
  1. teeth develop in spirals(new teeth migrate forward as old break off)
  2. digestive system modified to incr time food stays in digestive system and SA for absorption
25
Q

Definition of olfaction

A

the sense of smell

26
Q

elasmobranch sensory systems are composed of 4 things

A

1, vision

  1. olfaction - smell
  2. electroreceptors
  3. lateral-line system
27
Q

what is the function of the electroreceptors of elasmobranch

A

to detect weak electric currents produced by prey

28
Q

what is it and the function of the lateral-line system of elasmobranch

A

It is a row of tiny sensors in canals along both sides of the body

function = detects vibrations in the water

29
Q

elasmobranch undergo internal/external fertilisation

A

internal

30
Q

the embryos of elasmobranch are nourished in 3 ways

A
  1. produce large yolky eggs with tough leathery shells
  2. retain eggs within the oviduct until young hatch
  3. nourish young within a uterus
31
Q

2 lineages of bony fishes

A
  1. actinopterygii-ray-finned fishes

2. sarcopterygii-fleshy-finned fishes

32
Q

actinopterygii have fins supported by?

A

thin, flexible bony rays

33
Q

sarcopterygii have fins supported by…..2

A
  1. muscles

2. internal bony skeleton

34
Q

actinopterygii branch to form

A

teleosts e.g. seahorses

35
Q

2 NB structures in teleost

A
  1. operculum

2. swim bladder

36
Q

difference between reproduction of teleost reproduction in marine fishes vs freshwater fish

A

Marine= produce planktonic larvae-eggs fertilised and hatch in water

Freshwater= direct development - eggs hatch into baby fish or sometimes gives birth to live young (frequently parental care)

37
Q

sarcopterygii species lobe-finned fishes example

A
  • 2 species of the coelacanths in Indian ocean
38
Q

sarcoptrygii have 2 species

A
  1. lobed-finned fish

2. lungfishes

39
Q

NB adaptation lungfish have

A

primitive lungs supplement/ replace breathing with gills