Chapter 24: Fishes, Osteichthyes, Class: Sarcopterygii Flashcards
Lung Fishes:
-Australian lungfishes rely on what that their close relatives do not?
- gill respiration since
South American and African Lung fishes are different from Australian lungfishes in what way?
- they can live out of water for long periods of time
When did Rhipidistians flourish and when did they go extinct?
- Late Paleozoic
- after that they became extinct
The Coelacanth:
- Arose in what time period, peaked when?
- Living Coelacanth are descendants of what?
- They have a Diphycercal tail, meaning what?
- Describe their young?
- Devonian, Mesozoic than dramatically declined
- Devonian freshwater stock
- small lobe between the upper and lower caudal lobes
- young are born fully formed after hatching from eggs.
Most fishes swim maximally at __ body lengths per second but larger fish therefore swim __ than smaller ones.
- ten
- faster
The __ and __ musculature propels a fish. Muscles are arranged in zigzag bands called what?
- trunk and tail
- myomeres
L> shape of W on the side of fish, internally the bands are folded and nested, each myomere pulls on several vertebrae.
Fishes are slightly heavier than water. To keep from sinking, a shark must do what?
- continually move forward fins keeping them angled up
Sharks liver has a special fatty hydrocarbon also called what? Whats its function?
- Squaline
- acts to keep the shark buoyant
What is a swim bladder and its function?
- gas filled space, the most efficient flotation device
What did the swim bladder arise from?
- What organism are they absent in?
- How does the fish control depth?
- How does the fish counteract pressure as it descends?
- Ascends?
- Tunas, abyssal fishes and most bottom dwellers
- via adjusting volume of gas in swim bladder
- the bladder is compressed making the total density of the fish greater
- the bladder expands making the fish lighter and it will rise faster
What two ways is gas removed?
- Primitive Physostomous
- Advanced Teleosts are physoclistous
- Pneumatic duct connecting swim bladder and esophagus
- Pneumatic duct is lost and gas must be secreted into the blood from a vascularized area.
Both types of gas removal require gas to be secreted into what?
- the bladder from the blood via gas gland
What makes up the countercurrent exchange system used to trap gases.
- network of capillaries and rete mirabile
Gas glands secrete what?
- lactic acid that forces hemoglobin to release its load of oxygen
Describe rete capillaries! Deep fish vs surface dwelling
- short in surface- dwelling fish and very long in deep sea fishes
A few shallow water inhabiting physostomes do what to fill their swim bladder?
- gulp air to fill the swim bladder
- Fish gills are ___ with thin epidermal membranes folded into plate like ___.
- Gills are inside the __ cavity and covered with a movable flap called the ___.
- filaments
- pharyngeal
- operculum
What does the operculum do?
- protects delicate gill filaments and streamlines body
- pumping action by this helps move water through gills
- water flow over the gills is continuous
Water flow is ___ to blood flow.
- opposite
- countercurrent exchange maximises exchange of gases
What is ram ventilation? (used by active fishes)
- forward movement is sufficient to force water across gills
- such fishes are asphyxiated in restrictive aquarium even if the water is saturated with oxygen.
Freshwater is ___ to fish blood. Water enters the body and __ is lost by diffusion. Scaled and mucous covered body is mostly ___, but gills allow water and salt __.
- hypotonic (less of a concentration)
- salt
- permeable
- fluxes
Freshwater fishes are ___ regulators. The ____ pumps excess water out. Special salt absorbing cells located in the ____ actively move salt ions from water into fishes blood. They devote ___ energy to maintaining osmotic balance.
- hyperosmotic
- Opisthonephric kidney
- epithelium
- little
Euryhaline fishes live where?
- estuaries where salinity fluctuates throughout thee day
Marine bony fishes are ___ regulators.
- hypoosmotic
- blood is hypotonic to seawater
- tend to lose water and gain salt and risk drying out.
