Question | Answer |
Transitional Form: Eusthenopteron | All fish; Lobed fins; Two dorsal fins |
Transitional Form: Tiktaalik | Fishpod; With no operculum which is the connection between the neck and head, allowing for better movement; Jointed pectoral fins; Retain fin rays |
Transitional Form: Ichthyostega | Tetrapods; With Robust limbs with digits, robust ribs, only scaled bellies |
Pros of Land | Lower competition for resources and more resources; Escape seas predation; Access atmospheric oxygen as sole source allows specialization on anatomies so less energy cost and more compacity to reach O2; Air is easier to move through than water |
Cons of Land | Gravity has a much greater affect on the body on land because there is not 360 water support; Gills collapse in air as they are thin slices whereas lungs are balloons |
Reproduction of Tetrapods | New egg membranes including the Amnion surrounding embryo, the chorion around everything, and the allantois to handle waste; New shells; Internal fertilization necessary |
Respiration of Tetrapod Anamniotes | Ventilated by positive pressure with a buccal pump where the mouth opens, air goes in, glottis opens, air goes out; Requires muscles and skeleton similar to gills; Only as much air as mouth is large is allowed |
Respiration of Tetrapod Amniotes | Coastal pump where muscles with ribs expand cavity for negative pressure for passive air flow; Single breath can fill lungs |
Water Conservation of Tetrapods | Lost by evaporation and waste; Urinary bladder maybe as a water storage; Layer of dead skin with oil to prevent water loss; Anamniotes have cutaneous respiration |
Temperature Control of Tetrapods | Unstable environmental temperature so behavioral or biological controls of internal environmental temperature; Low thermal conductivity environment; Huge energy costs |
Sensory of Tetrapods | Vision has eyelids and lacrimal glands for protection and moistened cornea; Hearing and lateral line mostly in fluid in inner ears; Chemoreceptors like taste and smell need moist interfaces to dissolve chemicals |
Feeding of Tetrapods | Neck allows head movements; Tongue allows positioning and capturing of prey; Salivary glands to lubricate food and moisten sensory receptors |