Vertebrates Flashcards
Are vertebrates protostomes or deuterotomes? What is one of the characteristics?
Dueterostomes
All have pharyngeal slits
Characteristics of chordates
1) Dorsal hollow nerve cord
2) Notochord (rigidity- rapid locomotion)
3) Muscular post-anal tail (present in humans during embryo development)
What are pharyngeal slits?
"Gill slits" - Located on surface of head - Ancestral trait in dueterostomes NOT IN ECHINODERMS - supported by arches
What is the function of pharyngeal slits?
- used for feeding and respiration (water comes in through mouth and passes through slits)
How many gill slits do bony fishes have? What are they covered by?
Bony fishes have 4 pairs of gill slits
Covered by operculum
Gil filament structure and blood flow mechanisms
- Thin, vascularized, high surface area
- Blood vessels flow through gill arches
- WATER AND BLOOD FLOW IN OPPOSITE DIRECTION
What is advantage of countercurrent exchange?
The flowing of blood and water in opposite directions ensures partial pressure gradients are maintained. It achieves maximum gas exchange.
Circulatory system of fish
- 2 chambered heart
- One way valves
Arteries –> Aterioles –> Capillaries –> Venules –> Veins
4 characteristics of vertebrates (ie, skeleton, systems)
- Axial Skeleton (cranium…)
- Appendicular Skeleton (limbs, pectoral girdle)
- Closed circulatory system
- Organs suspended in Coelom
4 characteristics of vertebrates (ie, skeleton, systems)
- Axial Skeleton (cranium…)
- Appendicular Skeleton (limbs, pectoral girdle)
- Closed circulatory system
- Organs suspended in Coelom
What distinguishes chordates and vertebrates?
All vertebrates have a vertebral column while some chordates only have notochord
What is name for jawless fish? Fish with jaws?
Jawless fish are Agnathans
Fish with jaws are Gnathostomes
Two types of agnathans + characteristics
- Lampreys: oral disk instead of jaw, often parasitic
- Hagfish: Knot- tying, mucous production, osmotic concentration, used for leather
What type of skeleton do agnathans have? What are their other main characteristics?
cartilaginous skeleton
- notochord
- no paired fins
- no swim bladder
- no scales
What are jaws?
Formed by fusion of gill arches
- Teeth evolved from scales in mouth
- improves feeding ability
What are paired fins?
- On pectoral and pelvic limb girdles
- enable active swimming
What is name for cartilaginous gnathostome fish and their characteristics?
Chondrichthyes (sharks, rays…)
- Mostly marine
- jaws (gnathostomes)
- scales
- no swim bladder
- predators, scavengers, some are filter feeders
What is name for bony fishes?
Osteichthyes
- Largest vertebrate groups
- Highly diverse
- jaws
- opercula
- paired fins
- swim bladder
What are the two types of Osteichthyes?
- Ray-finned (teleosts: angler fish) Most fish
- Lobe-finned (lungfish, Coelocanth) 2 ventral pockets formed off esophagus (SUPPLEMENTAL)
How did fish get stronger, and faster?
- Breathe oxygen with (pharyngeal slits)
- Endoskeleton
- Jaws
- Paired fins
What is a coelocanth?
“living fossil”
Really old fish (chordate) thought to be extinct until recently
What are lung fish- how do they demonstrate the transition to land?
Lungfish are a type of fish- they would live in mud during droughts
Have two pouches that can be used “as lungs” when needed
What were the 4 advantages of moving to land?
- Devonian droughts (low dissolved O2, shallow inland seas)
- Increased competition in water
- New food on land
- No predators on land (at the time)
What are the advantage of terrestrial respiration?
- Air has higher oxygen concentration than water
- Gases diffuse faster in air
What are 4 main problems encountered on land?
- Water is needed to prevent dessication
- Air is less dense than water ( skeletal structure is required)
- Air temp on land is more variable
- UV radiation is intense on land
2 main tetrapod solutions to challenges moving to land?
- Stronger limbs; vertebral column, and ribs
(tails, lungs, external and internal nostrils) - More efficient circulatory system
(3 chambered-heart, double circuit of blood
flow)
Amphibian circulatory system. How is it an advantage? A disadvantage?
- 3 Chambered heart
- Blood oxygenated in lungs and skin
- double circuit circulation
Advantage: blood under high pressure
Disadvantage: mixing of blood
What is the name for Amphibian breathing mechanism? Describe
Positive pressure breathing
- Inhalation is a 2 stroke process
4 Amphibian characteristics
- First tetrapods
- Freshwater and terrestrial
- Dependent on water
- Carnivores, have teeth
Larvae stage of amphibians (circulatory system)
- Gills,
- 2 Chambered heart
- herbivorous
- Undergo metamorphosis
Adult stage of Amphibians
- lungs
- 3 chambered heart
- carnivores