Exam 4 Questions

Distinguish between proximate and ultimate factors associated with a particular behavior.

Prox. --- related to the development/environment Ult. - related to evolution of the species

pathway of light

cornea aqueous humor iris and pupil lens vitreous humor retina optic nerve visual cortex

Interpret the graph of changes in potential across a neuron's cell membrane (of axon) over time before, during, and following an action potential.

1. Rest - voltage gated channels closed 2. Depolarization - voltage gated Na+ channels open, movement of Na+ into cell 3. Peak - Voltage-gated Na+ channels begin to inactivate + VG K+ channels begin to open. 4. Repolarization - Membrane potential becomes more negative due to Na+ and K+ out of the cell. 5. Hyperpolarization - Some VG K+ channels remain open, resulting in movement of K+ out of the cell.

Trace the pathway of sound through the vertebrate ear.

1. compression waves in air 2. through auditory canal 3. mechanical vibration of tympanum 4. mechanical vibration of ossicles 5. compression waves of fluids 6. displace membranes in Organ of Corti 7. hit hair cells 8. receptor potentials 9. action potentials that travel to brain

Describe advantages and disadvantages in living in a group, albeit uncooperative.

Adv. - Less likely to be eaten by predators, Dis. - More easily found by predators, etc. More competition for mates.

Describe how certain drugs affect the human brain and how this can lead to addiction.

Alters reward circuitry which leads to dependence.

Describe the physical and sensory adaptations that allow an insectivorous bat to find prey in the dark.

Echolocation. Biological sonar, make sounds and listen to the echos reverberating to gain information. Bats are mechanical.

Describe barriers to polyspermy

Fast block - depolarization of cell membrane Slow block - fertilization envelope (from hardening vitelline layer)

Describe the selective pressure for ornamentation in males of sexually dimorphic (differing appearances/structures between males and females) species e.g., stalk-eyed fly, peacock, deer.

Males in species like peacocks, peacocks must stand out due to intrasexual selection.

Describe a raptor's visual adaptations as explained in class.

Shallow fovea and deep fovea.

Contrast behaviors that have a strong genetic component (e.g., stereotypical behavior) vs. a strong learning component (e.g., reasoning).

Ultimate v. Proximate cause Learned v. innate behavior

Describe the sensory adaptations that enable sharks to find their prey.

Very well-developed sense of smell, also can sense electricity.

Describe the all-or-none principle of nerve impulse transmission. How, then, can signals be perceived as stronger or weaker?

Will reach threshold or will not activate at all. Strength comes in numbers, not in intensity.

Relate the extra-embryonic membranes of amniotes and those that contribute to the placenta

amnion chorion yolk sac allantois placenta dev. from allantois and endometrium umb. cord = amnion surrounding yolk sac and allantois

Describe the sensory adaptations that enable pit vipers to find their prey.

pit organ of the pit viper allows it to sense infrared radiation.