Exam 1 Flashcards
Paedocypris progenetica
Indonesia
Cyprinid
Smallest known species of fish in the world
smallest mature female measured 7.9 mm
Rhincodon typus
Class: Chondrichthyes (cartilaginous fishes)
Infraclass: Elasmobranchii (sharks and rays)
Order: Orectolobiformes (Carpet sharks)
Family: Rhincodontidae (Whale shark)
Originated ~60 million years ago.
Filter over 6,000 liters (1,585 gal) of water an hour.
Yolk-sac viviparity (ovoviviparous;)
Litter size 300+ pups
Maturity 30 years and Lifespan 70 to 100 years.
Populations depleted by harpoon
fisheries in Southeast Asia.
Only 27,000 – 180,000 individuals left
Oldest living fish species
Greenland shark
Fish possessing whole body endothermy (conserve metabolic heat and maintain its body temperature above that of the surrounding environment)?
Opah
Factors affecting blood oxygen affinity
Temperature
pH
CO2 levels
Shark gills
Most sharks have five gill arches + five gill slits. The first gill arch bears only a single row of
filaments (hemibranch).
The remaining four gill arches consists of row of filaments on either side (holobranch).
How can fish remove 80 - 90% of O2 available from water?
1) Large volume of water passes over gills: ram ventilation and branchial pumps.
2) Counter current exchange of gases at gill site.
3) Large surface area for diffusion at gill site: number and length of lamellae.
4) Short diffusion distance at gill site.
Countercurrent exchange
Allows passive diffusion via rete mirable (bundle of
capillaries that run countercurrent to one another)
Salting-out effect
solubility of gas when pH changes
Bohr and Root Effects
Bohr (hemoglobin-oxygen affinity) and Root (binding
capacity for oxygen) when pH changes
Physostomus
Gas bladder: connected to the gut via pneumatic duct Primitive soft-rayed teleosts: herrings, salmonids, pikes, etc. (sturgeons/primitive fish).
Physoclistous
Gas bladder: not connected to gut. Derived fishes.
Buoyancy Regulation
- Reduce body density:
– Lipid Accumulation
– Water accumulation in tissues
– Reduce ossification and muscular tissue - Buoyancy organ: gas bladder
Swimming in fishes
least energy consumptive movement.
No energy needed to counter gravity + regulate buoyancy. (1 km swim - 0.39kcal)
White Muscle
Fast – burst swimming
Little vascularization
Large fibers (300-400 mm-type IIb)
Very few mitochondria
Low myoglobin
Anaerobic respiration (glycolysis)
High power production
Red Muscle
Slow – cruising swimming
Highly vascularized
Smaller fibers (100-200 mm - type I)
Many mitochondria
High myoglobin
Aerobic respiration (oxidative)
Low power production
In most fish, what kind of muscle takes up to 85% of the trunk and 60% of the body?
White muscle
Number of new fish species described each year
373 (or 1/day)
Class definition of fish
Aquatic vertebrates that have functional internal gills as an adult.
Are there more species of fish in freshwater or marine water?
85% freshwater
Largest living vertebrate?
Blue Whale (30m)
Longest animal in the ocean?
Lion’s Mane Jellyfish
Largest living fish?
Whale Shark (65.6 ft)
How many species (spp.) of fishes?
~36,000 (49%)
How many species (spp.) of mammals?
~6500 (9%)
How many species (spp.) of birds?
~11,000 (15%)
How many species (spp.) of reptiles?
~11,600 (16%)
How many species (spp.) of amphibians?
~8400 (11%)
Why do we have so many freshwater fish?
More opportunity for isolation and speciation in freshwater than in marine.
How many species of shark?
550
More freshwater fish in lakes or rivers?
Rivers (85%)
What country has the highest fish biodiversity?
Australia (5,002)
What country has the highest biodiversity of marine fishes?
Australia (4,697)
What country has the highest biodiversity of freshwater fishes?
Brazil (3,513)
What is the smallest living vertebrate?
Amphibian (Paedophryne amauensis 7.7mm)
Why can you kill/suffocate a fish by CO2?
Fish produce carbon dioxide during respiration. Too much CO2 in the water increases toxicity and decrease the pH balance (becoming more acidic).
of gills that sharks have?
5
of gills that bony fish have?
4
Physiological processes behind gas bladder
Bohr and root effects
Salting-out effect
Countercurrent exchange
Which muscle type has more fat? Red or white
Red
Ceratotrichia
(Sharks)
Stiff
Unbranched
unsegmented
Lepidotrichia
(Bony fish)
Flexible
Segmented
Branched
Spines
Hard & pointed
unsegmented
unbranched
solid
Soft rays
usually soft & not pointed
segmented
branched
bilateral (left and right halves)
Endoskeleton is composed of:
Axial skeleton and Appendicular skeleton
Axial Skeleton
Skull, vertebral column, ribs
Appendicular skeleton
Fins and fin girdles (pelvic + pectoral)
Name the 2 components of the fish skull:
Neurocranium
Branchiocranium
Jaw bones
Premaxillary, maxillary, and dentary
Buccal cavity
Vomer, Palatine, glossohyal
Types of teeth
canine
villiform
molariform
cardiform
incisor
pharyngeal
Caudal fin types
Protocercal
Heterocercal
Abbreviated heterocercal
Diphycercal
Isocercal
Gephyrocercal
Homocercal
Difference b/t undulation and oscillation:
Undulation: wavelengths pass down length of body (or fin). (anguilliform - eel)
Oscillation: structure (fin) that move back and forth - pivots on a base (Tuna)
4 types of scales
Placoid
Cosmoid
Ganoid
Cycloid & ctenoid
Neurocranium
Braincase
Branchiocranium (visceral cranium)
gills
mandibular region
hyal region (hyoid arch and branchiostegal series)
branchial arches
Neurocranium composed of 2 parts:
Chondocranium (endochondral) – bones that arise from cartilage bones. Formed by replacement of cartilage.
Dermatocranium – bones that arise in the dermal layer of the skin. Formed by direct ossification.
Neurocranial Regions
Ethmoid: vomer, lateral ethmoid, median ethmoid
Orbital: pterosphenoid, frontal, suborbital, lachrymal, supraorbital
Otic: parietal, pterotic, prootic, sphenotic, epiotic
Brasicranial: parasphenoid, basioccipital, supraoccipital, exoccipital
Do catfish have true spines?
No, they have spinous soft-rays
spinous soft-rays
Scales Modifications
- Microscopic and embedded as in the freshwater eel (Anguillidae), which led to their being classified as non-kosher because of the supposed absence of scales. Similarly to adults swordfish (Xiphias gladius).
- Lost their scales: freshwater catfishes (Ictaluridae) instead thick, leathery skin, and ocean sunfish (Mola mola) has the skin reinforced by a hard cartilage layer.
- Removing scales can hurt as deep as the dermis, and not just the epidermis
4 types of swimming:
Anguilliform – the length of the body
Subcarangiform – over ½
Carangiform – limited to ½
Thunniform – Just caudal
Placoid
- Characteristic of Chondrichthyans
- Similar in structure to our teeth (covered with enameloid)
- Placoid scales often referred to as dermal denticles.
- They do not increase in size as the fish grows, instead new scales are added.
- Reduces drag (increases swimming efficiency)
- The teeth of elasmobranchs are evolutionary derivatives of placoid scales
Cosmoid
- Rhombic scales - present in fossil coelacanths and fossil lungfishes and probably arose from fusion of placoid scales
- Scale becomes larger as fish grows and new bone is added to the basal layers.
- Living coelacanths have a cosmine-free cosmoid-like scales that are thinner
Ganoid
- Found in bichirs, bowfin, and gars.
- Modified cosmoid scale
- Ganoid scales have an enamel-like covering called ganoine
- Rhomboid or diamond shape
- Armor-like plates for protection (but heavy)
- Sturgeon scales are modified into large plates (bony plates or scutes), with most of the rest of the body naked.
Cycloid & ctenoid
- Evolved from ganoid scales by thinning. Found in most bony fishes.
- Also called elasmoid. These scales overlap like shingles on a roof, which gives great flexibility and less weight.
- Both lack enamel.
- Ctenoid have ctenii (teeth on posterior margin) – breaks up turbulence at high speeds
