Rhythms and Migration

Question 1

Another phrase used for daily rhythms is…

Answer 1

Circadian

Question 2

_____ _____ _____, and some specific behaviors occur on a fairly consistent 24 hour schedule.

Answer 2

General activity levels

- occur even in absence of environmental change    - usually require environmental cue to sync internal clock (entrainment)    - Time of first light or length of light usually serves as a good cue

Question 3

How is the circadian rhythm controlled?

Answer 3

1. hypothalamus by the SupraChiasmatic Nucleus (SCN)
2. SCN in turn receives information light level from pineal gland
3. Pineal gland connected to brain entrains the daily rhythm, with or without light
4. Secretes melatonin: rhythms and melanin pigment

Question 4

What are the three daily activity patterns?

Answer 4

Diurnal - active during the day
Nocturnal - active after sundown / before sunrise
Crepuscular - active around sundown and then again around sunrise

Question 5

What are good cues for circannual rhythms?

Answer 5

1. Changes in lunar cycle
2. Changes in day length
3. Changes in temperature

Question 6

The chain of command of a circannual rhythm can be complex, with simple cues of light affecting….

Answer 6

hormone levels, which affect organs, which affect behavior

Question 7

__________ effects can control the behavior even when resources would allow activity.

Answer 7

Photoperiod

Question 8

Activities during day or year are controlled by a combo of _______ and _______ cues, and not by awareness.

Answer 8

endogenous and environmental

Question 9

What cues do animals use to to gain info on where they are and where they want to go?

Answer 9

1. Magnetic pull
2. Angle of the sun
3. Pattern of the stars at night
4. Landmark recognition
5. Odor

Question 10

Orientation often requires ability to _____ ____ internally or externally.

Answer 10

tell time

Question 11

Birds are good subjects for orientation patterns because…

Answer 11

1. migrate locally and long-distance

2. exhibit behavior even in the lab, often endogenously

Question 12

_____ orientation is well-developed in animals that _____.

Answer 12

Pinpoint, migrate

Question 13

Migration can be ____ or _____; on ____ ____ or _____.

Answer 13

local or long distance

daily basis or seasonal

Question 14

Migration is usually towards…

Answer 14

foud source, breeding / birthing area, or both

Question 15

Typically migration occurs because…

Answer 15

different resources are located in different geographic or temporal areas, or because resource abundance decreases

Question 16

Costs of migration

Answer 16

1. Must gain extra weight
2. Extra weight can slow animal down
3. Orientation cues must be precise
4. Abandon the nest

Question 17

Benefits of migration

Answer 17

1. Chance to exploit abundant but ephermal resources
2. Chance to escape harsh climate or low resource periods
3. Chance to access longer days

Question 18

Migration can be a conditional strategy, meaning…

Answer 18

different routes, not all individuals and not every year