Biological Rhythms

Question 1

Describe what a biological rhythm is

Answer 1

Biological rhythms are natural cycles that the body uses to regulate different bodily functions and activities

Question 2

What are the four types of biological rhythms?

Answer 2

1. Circadian rhythms
2. Circannual rhythms
3. Circatidal rhythms
4. Circalunar rhythms

Question 3

Define circadian rhythm and give examples

Answer 3

Circadian rhythms are physical and behavioural changes that follow a daily 24 hour cycle

Examples:

• Humans are generally awake and active during the day and sleep or are inactive during the night
• Kiwi are nocturnal organisms that are active and night and inactive at day
• Mosquitos are crepuscular organisms that are active and sunrise and sunset and inactive for the rest of the 24 hour period

Question 4

Define circannual rhythm and give examples

Answer 4

Circannual rhythms are biological activities that follow a 365 day, yearly cycle.

Examples:

• Ducks migrate during winter to warmer areas and return to their original home back in the summer
• Bears hibernate throughout winter and only wake once it has become spring/summer again

Question 5

Define circatidal rhythm and give examples

Answer 5

Circatidal rhythms are rhythms that synchronise with the tides and that follow an approximate 12 hour cycle.

Examples:
- Organisms living in tidal zones will be active when the tide is high and inactive when the tide is low

Question 6

Define circalunar rhythm

Answer 6

Circalunar rhythms are biological activities that follow a 29.5 day, lunar cycle.