Week 8: Fish Flashcards
1
Q
Evolution of vertebrates (Chordates) primary devlopments were
A
- Dorsal, hollow nerve cord
- Notocord
- Pharyngeal pouches (to be gills)
- Tail
2
Q
3 sub phyla of vertebrate
A
- Urochordata (Tunicates, larvaceans and salps)
- Cephalochordata (amphioxus)
- Vertebrata (animals)
3
Q
7 Agnatha characteristics
A
- Ectothermic
- Benthic predators, parasites and scavengers
- Cartilage skeleton
- No jaws or paired fins
- Chemo sensing palps
- Notochord present at all stages
- Defence = slime
4
Q
6 Chondrichthyes characteristics
A
- Cartilage skeleton
- Paired fins, paired nares, scales
- Sub class Holocephali
- Diverged from shark 400 mya
- 50 species
- Benthic preadators
5
Q
Sub class of chondrichthyes
A
Elasmobranchii (sharks, skates, rays), have massive diversity in lifestyles between 700 species
6
Q
6 Rays/skates characteristics
A
- Modified pectoral fins
- Dorso-ventrally flattened body
- Ventrally located gill slits (5 pairs) and mouth
- Large flattened teeth for feeding on molluscs and arthropods
- Long whip-like tails
- Sting rays - a spine at the base of tail with poison gland
7
Q
4 Osteichthyes characteristics
A
- Approx 37,000 species
- Bony skeleton
- Strong and flexible
- Support and muscle attachment
8
Q
2 sub phyla of osteichthyes
A
- Sarcopterygii - Lobe finned fish
- Actinopterygii - Ray finned fish
9
Q
3 Sarcoptergii characteristics
A
- Primitive
- Coelacanth and lungfish
- Ancestors of tetrapods
10
Q
2 Actinoptergii characteristics
A
- Flexible fin design
- Sturgeons, gars and teleosts
11
Q
Order Teleostei accounts for what percentage of all living fish species
A
96%
12
Q
5 Fish Adaptations to the marine environment
A
- Feeding strategies
- Movement and propulsion
- Position in the water column
- Osmoregulation
- Gas exchange
13
Q
Primary indicator in fish of feeding strategies
A
Teeth and mouth.
14
Q
What dense and viscous is water compared to air
A
Water 800x denser, 50x more viscous than air
15
Q
Resisitence to movement =
A
Drag
16
Q
What do fish adapt to resist drag
A
- Frontal area
- Body contour
- Surface texture (scales)
17
Q
Propulsion generated by
A
Tail and fins
18
Q
Drag proprtional to velocity ^2 means
A
The faster you go, the more drag is produced
19
Q
Fast swimming fish require
A
Most streamlined body shape
20
Q
Caudal fin =
A
Tail fin
21
Q
Caudal peduncle =
A
The narrow part of a fishs body to which the caudal or tail fin is attached
22
Q
Homocercal =
A
Symmetrical
23
Q
Heterocercal =
A
Assymetrical
24
Q
How do chondrichthyes keep their position in the water column
A
- Cartilage skeleton reduces density
- Pectoral fins generate lift
- Produce and store squalene
25
How do Osteichthyes keep their position in the water column
1. Gas filled bladder for buoyancy
2. Swim bladder evolved from primitive lung (lost in benthic sp.)
3. Gas volume adjusted by gas gland and muscular contraction
26
Fish adaptations to living in hypertonic environment
Osmoregulation
27
Osmoregulation adaptations
1. Kidneys produce very concentrated urine
2. Active secretion of salts across gills
3. Elasmobranchs reabsorb urea into blood, raising osmolarity
4. This is accompanied by keeping urea in the bloodstream
28
Fish exchange gas by
Diffusion through gill membranes (very high surface area take in dissolved O2 from water and release CO2)
29
Fish have unidirectional water flow by
Ram ventilation or pumping
30
Countercurrent flow is
The opposite movement of water against the flow of blood in the fishs gills
31
What has allowed teleosts to become the most diverse and speciose of fish taxa
Flexible body design
32
Density and viscosity of water present challenges for
Streamlining and buoyancy
33
Efficient gas exchange achieved by
Counter current flow
34
5 fish sensory systems
1. Hearing
2. Olfaction
3. Lateral line
4. Vision
5. Taste
35
Mechanoreception
A sensory receptor that responds to mechanical pressure or distortion
36
2 major systems of mechanoreception
Lateral line and the inner ear -(acoustico-lateralis system)
37
The mechano sensory transducers of sound for both lateral line and hearing systems
Hair cells
38
How do fish hear
Through the swim bladder - compressed by sound waves
39
Gas in the swim bladder has a _____ density than seawater and the fishs body
Lower
40
How does the swim bladder obtain hearing information
The swim bladder changes in volume as sound waves pass, transmitting sound to the otoliths
41
Why do animals rely on sound
To acoustically sense their surroundings, communicate, locate food and protect themselves underwater
42
Lateral line system is a system of
Tactile sense organs
43
Mechanoreceptors (neuromasts) form an
Interconnected network along the head and body
44
Neuromasts can either
1. Appear on the surface of the skin
2. Lie embedded in the floor of mucus filled structures called lateral line canals
45
Electroreception
The capacity to percieve weak electric fields
46
How long ago did electroreception arise and in what phylum
Chondrichthyes
47
Electroreception is important for
1. Prey detection
2. Predator avoidance
3. Mate detection
4. Geo-navigation
5. Communication
48
What do animals emit during osmoregulation
Low frequency electric fields, which can be detected by Ampullae
49
Ampullae of Lorenzini
Special sensing organs called electroreceptors, where they can form a network of mucus-filled pores, mostly found in cartilaginous fish
50
The concentration of ions within an animals body is lower than that of
Sea water
51
Important system in larval fishes thats important for finding habitat and avoiding predators
Olfaction
52
Fish use chemoreception to
1. Identify predators, prey.
2. To warn conspecifics/heterospecifics (chemical alarm cues)
53
Fish eyes are similar to terrestrial vertebrates eyes, but have
More spherical lens
54
Fish retinas generally have both
Rod cells and cone cells (for scotopic and phototopic vision), and most species have color vision
55
Some fish can see
Ultraviolet
56
Some fish are sensitive to
Polarised light
57
Eye development in fish
1. Blind upon hatch
2. Pigmentation occurs a few days later with rods and cones rapidly developing
58
Fish rely heavily on visual acuity to
Avoid predation, find food, find mates and select habitat
59
Lateral line and neuromasts detect
Changes in water movement
60
Transduction of electrical systems
Electroreception
61
Olfaction important for
Finding mates, home and predators
