Flashcards in Vertebrate Diversity Deck (41):
What same ancestor do the phyla Chordata and Echinodermata share?
What are the three major Tunicate groups?
How many species of known Tunicates are there?
How do sea squirts catch prey?
The pharynx is enlarged into a basket which enables it to filter its prey.
How do larvacean's catch prey?
They build large delicate mucus nets that can snare organic particles.
When would a larvacean exit it's mucus net and what would happen to the old mucus 'house'?
Once it became too clogged with excess debris. The 'house' would float to the bottom of the see and can be of important nutritional value for deep sea life.
What vertebrates are Thaliaceans?
Salps and pyrosomes
How do Thaliaceans live?
They live singly or in chain like colonies.
Where would you find Thaliaceans?
In tropical and subtropical oceans down to 1,500m.
How do Lancelets respire?
They have no respiratory system so use cutaneous gas exchange.
What are Lanceletes gill slits used for?
Gill slits are used for feeding as this where the prey is filtered through the pharyngeal basket.
Give an example of a Lancelet.
How many pairs of ductless gonads do B. lanceolatum have?
How do B. lanceolatum reproduce?
The gonads rupture to release gametes into the body cavity and then into open water. This is called external fertilization.
What are the key characteristics of vertebrates?
The notochord is replaced by a jointed, dorsal vertebral column.
Anterior skull enclosing large brain.
Rigid internal skeleton.
Internal organs suspended in a coelom.
Well developed circulatory system, driven by contractions of a ventral heart.
Give examples of jawless fish.
Hagfish and Lamprey
Describe hagfish and lampreys.
Cylindrical eel like bodies with no paired fins.
What are the differences between hagfish and lampreys?
Hagfish: Weak with three accessory hearts.
Lamprey: Single, large heart.
Hagfish: Partial cranium
Lamprey: Complete skull
Hagfish: Not fully separated and jointed
Lamprey: Fully separated and jointed.
Hagfish: Direct (no larval stage)
Lamprey: Filter-feeding larvae and metamorphosis.
Hagfish: Predominantly detrivores or predators.
Lamprey: Adults parasitic or don't feed.
Hagfish: Eyes degenerate - rely on olfacation via tentacles.
Lamprey: Eyes well formed.
Hagfish: Marine, benthic.
Lamprey: Marine, freshwater or Anadromous.
Describe the evolution of the jaw in fish.
Originally skeletal rods to support gills. Some rods then modified into a primitive jaw. Additional rods then supported a stronger jaw and teeth.
What species are classed under Chondrichthyes?
Jawed fish with cartilaginous skeletons.
What has evolved in Chondrichthyes?
Paired fins have evolved.
What is the role of pectoral and pelvic fins?
To stabalize the fish's position in the water.
Describe how sharks move.
Sharks move side to side via undulations of body and caudal fin.
What is the difference between lobe / ray finned fishes and hagfishes / lampreys / cartilaginous fishes?
The flexible cartilage is replaced by calcified rigid bone in lobe / ray finned fishes.
What class do the majority of extant bony fish species belong to?
What has evolved with ray-finned fish?
Evolution of swim bladders which allow for depth control.
How many known species of ray-finned fish are there?
What complicated behaviours are seen in ray-finned fish?
Maintain schools, build nests, court mates and care for young.
What species are classed as lobe-finned fish?
Coelacanths and lungfish.
What are the features of lobe-finned fish?
Muscular paired fleshy fins, teeth coated with enamel and lungfish have lung like structures instead of swim bladders which allow air breathing.
What is the early evolutionary split between tetrapods?
Amphibians and Amniotes
Where to modern amphibians live and why?
Moist environments due to permeable skin rapidly losing water.
How many know amphibian species are there and how many groups are they divided into?
7000 species divided into three main groups.
What are the three main amphibian groups?
Frogs and toads; newts and salamanders; caecilians.
Where do Amniotes live and why?
Dry environments due to the development of the amnion.
What is an amnion?
A membranous sac enclosing the developing embryo.
Why can an amniote embryo attain a relatively advanced state before hatching?
Because the amniote egg is relatively impermeable to water and stores yolk.
What would be seen in the amniotic egg of a reptile?
Allantois Yolk sac
In mammals what has the articular and quadrate found in reptiles skulls evolved into?
Articular is the malleus and the quadrate is the incus which are found in the ears of mammals.
What are the key features of reptiles?
Covered in scales which makes cutaneous gas exchange impossible.
Breath via lungs.
Ectothermic (except leatherback sea turtles)