Vertebrates Flashcards
Chordates + characteristic
- group of animals that include fish
1) dorsal hollow nerve cord
2) notochord
3) muscular post-and tail
Explain pharyngeal slits, gills filaments, gill arches
Pharyngeal slits are located on lateral surface of head, function is for filter feeding, respiration in vertebrates, the water comes in mouth and passes through the slits, 02 and C02 can also be exchanged across the gills, the bars between the slits are gill arches that is bone or cartilage, gill filaments on the gill arches.
How many pairs of gill arches do bony fish have?
- 4 pairs of gill arches, each has a pair of gill filaments
- also have a gill cover (operculum)
Gill filament structure:
- thin, vascularized, high surface area
- blood vessels flow through arches
- gas exchange
- water and blood flow in opposite direction
What is concurrent change?
When blood and water flow in opposite directions. It ensures that partial pressure gradients are maintained and achieves the max amount of gas exchange.
Fish circulatory system
- closed system
- arteries (away from heart) -> arterioles -> capillaries -> venules (to heart) -> veins
Fish heart <3
- 2 chambers (auricle/atrium and ventricle)
- strong, muscular pump
- maintain blood flow
- one-way valves inside
Gnathostomes vs agnathans
Agnathan has jaw, other does not
What are two types of skeleton that vertebrates can have?
Axial skeleton: - cranium (skull) - vertebral column (spine) -ribs Appendicular skeleton: - pectoral girdle - pelvic girdle
What are two groups of Gnathostomes?
1) Lampreys: very distinct larval form, are parasite on fishes
2) Hagfish: knot tying, used for leather products, produces mucous
How were jaws formed?
Formed by fusion of gill arches, teeth evolved from scales in mouth, they improved feeding and diversify
What is a PRO about paired fins?
- more active swimming, steering, stabilizing, life
- on pectoral and pelvic limb girdles
Characteristics about Gnathostomes
- shark, skates, rays
- mostly marine
- paired fins
- scales
- predators, scavengers, filter-feeders
- no swim bladder
What is swim bladder?
Flotation device
Enables neutral buoyancy (float)
Gas regulated by gland in bladder or by swallowing/burping air
What is swim bladder?
Flotation device
Enables neutral buoyancy (float)
Gas regulated by gland in bladder or by swallowing/burping air
What are two groups of bony fish?
1) Ray-finned fishes
2) Lobe-finned fishes
What are types of amphibians?
frogs, toads, newts ect.
Coelacanth
” a living fossil”
thought to be extinct but then found in south africa and in indonesia market
Why did amphibians move on land?
Devonian droughts that caused shallow inland seas, swamps, pond,
Low dissolved 02
Caused increase in competition in the water, crowding
New recourses on land and no predators yet
What are some key differences between life on land vs water for Amphibians?
- availability of water/moisture
- density of medium
- oxygen (more oxygen on land so it was better, also gases dissolved faster on land)
- temperature
- UV radiation
Lung Evolution (lobe-finned fishes)
- 2 ventral pockets formed off esophagus, used as supplemental respiratory device
What are some of the problems experienced when amphibians moved onto land?
1) water needed to survive (stay moist)
2) air less dense than water (stronger skeletal support and need more energy)
3) air temp. so body temp will fluctuate more
4) UV radiation more intense on land
Once amphibians switched too on land, they needed to improve their skeletal support. How did they do this?
Tetrapods!!!! Stronger limbs, vertebral column, ribs, more efficient circulatory system (3 chamber heart, double circuit blood flow)
Compare the Fish circulatory system vs the Amphibians?
Fish: 2 chambered heart, blood oxygenated in gills (in water) , single circuit circulation (less pressure)
Amphibians: 3 chambered heart, blood oxygenated in lungs and skin (on land), double circuit circulation (higher pressure)