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22 Cards in this Set
- Front
- Back
What is adaptation? |
A trait that enhances fitness and that arose historically as a result of natural selection for its current biological role. Requires; - Feature - More offspring reproducing - Favoured by natural selection - Appeared in conjunction with its current function in its environment (was not previously used for another function) |
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How do we apply evolutionary methods to test for adaptations? |
- phylogenetic comparative methods |
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What are non-adaptive explanations for animal design? |
- Phylogenetic constraint or "baggage" - Design constraints prevent the optimal - Sexual selection - Neutral features ("spandrels") - Co-variation with other traits - Exaptation - Random genetic drift |
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What are some examples of important evolutionary novelties and constraints in vertebrate locomotor design? |
Earliest vertebrates: - Body segments organized into myomeres with blocks of muscle separated by myosepta - Contracted in waves to propel the body forward - Pectoral, then pelvic fins evolved to supplement role of axial column in generating thrust and lift - Both fins gained bony supports that expanded distally in fish closely related to tetrapods |
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What are adaptive features for economy and speed? |
For economy and speed; - Continuum of limb posture (Planti/Digiti/Unguligrade) - Elongation of distal limb for speed - Lightening of the distal limb to minimise cost of leg swing - Reduction in number of bones - Muscle replaced by energy- efficient tendons that act as pulleys and springs - Motion restricted to sagittal plane |
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What are adaptive features for economy? |
- High 'aerobic scope' (10-50X in athletic animals (about 5 in lizards)) Temperature regulation; evaporation (sweating, panting), brain temperature regulation (carotid rete) - Mitochondrial density in muscle - Red blood cell volume A} |
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What is 'Parasite power'? |
- The power required to overcome drag on body |
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What is the formulae for parasite power? |
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What is 'Profile power'? |
- The power required to overcome drag on wings |
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What is the formulae for profile power? |
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What is 'Induced power'? |
-The power required due to accelerating air down to support body weight |
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What is the formulae for induced power? |
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What is the formulae for aspect ratio? |
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What is the orthodox way in which wings generate lift? |
- All wings generate lift by accelerating air over the upper surface and creating a bound vortex - the result of a sharp trailing edge. |
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What is the unorthodox way in which wings generate lift? |
- Some wings have sharp leading edges too, which promotes flow separation and high forces at the expense of 'fuel economy'. |
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What defines the way in which a wing is shaped? |
- Wings are shaped by the ecological pressures imposed upon them, affecting aspect ratio, camber, planform, wing tip design, surface properties, shape changing devices, and more. |
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How do frogs maximise their jump distance? |
Jump force = mass * acceleration Takeoff speed = acceleration * duration So... Producing more force = faster acceleration mass * increased acceleration = more force - Fusion of lower limb bones achieves this Accelerating for longer = higher takeoff speed acceleration * increased duration = higher speed - Elongation of legs due to evolution achieves this |
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What is convergent evolution? |
- In evolutionary biology, convergent evolution is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches. |
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Why do frogs have a modified pelvic bones and musculature? |
- Allow increased spinal flexibility to control takeoff angle - Enhance force produced against the ground |
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Why do frogs have long, stretchy tendons? |
- Allow catapult-like jumping; increased power for jumping
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What structural modifications to meet the functional demand of avoiding crash landing is there? |
- Absorbing the energy of impact - Preparing for impact - Postural ‘reset’ - Getting ready for the next jump |
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How is evolution of animal locomotion constrained? |
- Animals don’t always move in the most ‘efficient’ or ‘effective’ way because they must maintain the ability to do multiple things. |