Special habitats Flashcards
Explain the principle of convergence.
Animals exposed to similar selection pressures are likely to evolve similar adaptations.
The stronger the selection pressure, the more similar unrelated animals will appear.
Traits of deep sea fishes
-Light-emitting organs
-Large or long mouths with dagger like teeth
-Chin barbels or dorsal fin rays modified as lures (anglerfish)
-Long, thin bones to save energy
-Greatly enlarged tubular eyes (200-1000 m) or greatly reduced eyes (1000-4000m)
True or false: Deep sea fishes tend to be physoclisitc
True
What are some adaptations for dealing with high pressure?
-Several deep sea fishes have evolved proteins that are much less sensitive to the effects of pressure.
-The rete mirabile, main gas-secreting organ, is 7-20 times longer in deep sea fishes
Traits of open sea fishes:
-Countershaded and silvery
-Round or slightly compressed
-Streamlined with forked or lunate tails
-Schooling
-High percentage of red muscle and lipids
Traits of polar fishes:
-Have blood which contains antifreeze compounds
-There are various forms of AFPs
-Some have evolved neutral buoyancy to take advantage of opportunities in the water column
Traits of desert and arid fishes:
-Have a life cycle that includes an egg resting period so they can survive the dry season
-Many fishes use accessory respiratory structures that are similar to lungs
Some fishes estivate
Traits of cave fishes:
-Lack pigmentation
-Have reduced scales
-Have reduced or have lost light receptors/eyes
-Have a greatly expanded lateral line
-Have greater chemosensory capabilities
Similarities between cave and deep sea fishes:
-Loss of pigmentation
-Reduced light receptors
-Expanded lateral line and chemosensory abilities
-Reduced body size
-Modified gas bladders
-Reduction of body musculature and skeletal ossification
