Meh Flashcards
Describe claspers in sharks
Are ropes of cartilage that become stiffened with calcium in the adult. Males have paired tested, the right one more developed than the left, which even may be absent.
Describe the cloacal opening
Females have no claspers but a cloacal opening (as go the males) between the pelvic fins. The ovaries are paired, but the left side is often reduced and releases very few or no eggs
What were the first lineage to evolve jointed fins?
Lobe-finned fish
There is a good chance that the gulping of water did not occur due to buoyancy but for what?
To cope with reduced oxygen levels in the water
What did the proto-tetrapod evolved from?
A Sarcopterygian (with lungfish as closest extant relatives)
Larvae that develop in streams tend to be more what?
More streamline and tend to have the gills at the side
What is the cranium?
An outer shell that supports and protects the brain (common feature of vertebrates)
Where are the ampullae of Lorenzini found?
Around the head/ around the snout
What do the ampullae of lorenzini appear as?
Dark spots
What are ‘pit organs’?
Surface neuromasts
How is the lateral line open to the environment?
Via a series of openings called lateral line pores
In what animals has the external opening into the inner ear been lost?
In bony fish and tetrapods
By January 2014, 1041 of all Chondrichthyes species had been evaluated at a global scale, what percent of species are categorised as be safe, or of “least concern”?
23 percent of the species are categorised as being safe, or of “least concern” (so 77 percent of elasmobranchs are considered threatened to some extent)
What is the estimated number of sharks killed each year due to commercial and recreational fishing?
40-100 million
Teleosts account for what percent of all living fishes?
96 percent
In penguins why is lift not so important but forward motion is?
Lift is not so important because is it not needed for elevation as they are supported by the fluid. However, forward trust is to move through the water
In Humbolt penguins what percentage of the forward thrust is generated by the upstroke?
63%
What are the percentages of wing asymmetry in hovering birds lift in the downstroke and upstroke?
Wing asymmetry, 75% lift in downstroke, 25% upstroke
What does the supracoracoideus facilitate in hovering?
Facilitated rapid recovery
Why are there a lot of secondary feathers in birds with high aspect ratio wings?
Because they provide a lift generating function in soaring flight
What are secondary feathers inserted over?
The ulna
What do strap or strip-like tail feathers resemble?
Both reptilian scales and modern feathers
What is evolutionary model for the strap or strip-like feathers the early stages of feathers evolution?
- Elongation if scales (on the epidermis)
- Appearance of central shaft (to keep it fairly rigid)
- Differentiation of vanes into barbs
- Appearance of barbules and barbicels
Which group of vertebrates has the highest metabolic rate?
Passerines (and almonds birds 50-60% higher than equivalent size non-passerines
