Locomotor Evolution 2 Flashcards
(15 cards)
What does the fossil record of ichthyosaurs reveal about their shape
Their body outlines strongly resemble modern dolphins
How do deals and sauropterygians show convergent evolution
Both have large, paddle like hind flippers and elongated necks
What is a convergent trait seen in marine tetrapod forelimbs
Forelimbs are modified into paddles
How do forelimbs differ between forelimbs and tail driven swimmers
Forelimb-driven swimmers have a longer humeri than tail-driven swimmers
Why is hippo swimming behaviour debated
They often walk underwater, possibly due to dense bones, but have reached remote islands
What changes occur in whale forelimbs during evolution
They become shorter, thicker and more paddle like to move water effectively and reduce stress
How do whale nares evolve
They migrate from the snout to the top of the head to allow easier breathing at the surface
What is baleen
A keratinous structure hanging from the upper jaw used in filter feeding
What evidence supports suction feeding as an intermediate in whale evolution
Fossil teeth with wear patterns suggesting limited chewing and horizontal movement
Why is feeding in water more complex for tetrapods
They must both capture prey and expel water from the mouth before swallowing
What are the key stages of aquatic feeding behaviour
Prey capture
Manipulation
Water removal
Swallowing
How do water opossums prevent water from entering their pouch
A muscular ting creates a watertight seal. Males use them to protect their genitals whilst swimming
What challenges do birds face when diving
Low body density due to air sacs and light bones
How do penguins use their wings in water
As hydrofoils for underwater “flight”
How do mammals and reptiles differ in flipper formation
Reptiles add digits and phalanges
Mammals lengthen existing bones and use cartilage
