Nervous Systems I

Question 1

What are the three parts to a behavior? Briefly explain each.

Answer 1

1. Cue: sign stimulus/releaser
2. Fixed Action pattern: full behavior pattern
3. Innate Releasing Mechanism (translated detection of sign stimulus to FA)

Question 2

What was Tinbergen’s herring gull experiment? What were its results?

Answer 2

1. Off chicks cardboard representations of real head, bill w/o head w/ spot, full head w/o spot, stick with red/white bars
2. Showed most response to the stick showing that the spot is a sign stimulus and that this was innate (no learning)

Question 3

What was Tinbergen and Lorenz’s egg experiment? Results? What happened if they replaced the egg with a super stimulus?

Answer 3

1. Replace egg with egg-shaped object = goose goes through sequence and remove egg in middle = finish sequence
2. Giant egg = female preferred this one

Question 4

What is an example of a neural representation of a sign stimulus? Elaborate. Why do prey not need to be sensitive to sound as the bat?

Answer 4

1. Bat and moths (specifically hearing in moths that are preyed on by bats). Bats give ultrasonic pulses for echolocation (higher frequency = find smaller object because the wave doesn’t go through the object (20 kHz))
2. Prey just need to hear the sound, not locate it or attack it or anything else.

Question 5

How many nerve cells are attached to a tympanum in a moth? What are they called? How do their functions differ? In what nervous system is sound processed? Why?

Answer 5

1. 2
2. A1 and A2
3. A1: weak firing rate that increases as sound gets louder… A2: only turns on if sound is loud (LEAVE!!)

**Bonus: neither cell can detect tone, and yes the moth can tell which direction the sound comes from (wings obscure sound, effect volume)

4. Peripheral nervous system
5. Faster than sending it to brain

Question 6

What types of clicks do bats use when hunting (2)? What is the purpose of this change? When do A1 and A2 fire in this sequence?

Answer 6

1. Slow approach click –> rapid buzz when close to striking
2. Precision and clarity when striking
3. A1: just after click in slow phase and increases during buzz

A2: Fires at beginning of buzz not the end (implies perhaps it’s just to detect the buzz)

Question 7

What are other species that detect clicks? What are their typical responses?

Answer 7

1. Preying mantis (one ear on thorax) - extends forelegs forward to reduce aerodynamics (loop and dive)
2. Lacewings - power dive