Circadian Rhythms

Animal Defences

Recap - what do you remember?

Multiple Select

Which of the following are examples of animal defences?

• Group Living

• Camouflage

• Weapons

• Armour

• Circadian Rhythm

Multiple Select

And which of these are also examples of animal defences?

• Stamina

• Yawning

• Vocalisations

• Bluffs

• Territory Maintenance

Circadian Rhythms

What do you know?

Multiple Select

Which of these is correct? (you can select more than one)

• A Circadian Rhythm is an internal body clock that tells the animal what to do and when to do it.

• A Circadian Rhythm is an external clock that tells the animal what to do and when to do it.

• A Circadian Rhythm only controls the animals sleeping cycle.

• A Circadian Rhythm is usually around 24 hours long.

• A Circadian Rhythm is usually around 12 hours long.

A little bit about Circadian Rhythms

• Are internal body clocks that operate on a daily time schedule.

• They generally operate independently off other external stimuli

• Some are slightly less than 24hrs, some slightly more.

Multiple Choice

Being Crepuscular means being most active during....

• The day

• The night

• At dusk and dawn

• The evening

Multiple Choice

Being Nocturnal means being most active during....

• The day

• The night

• At dusk and dawn

• The evening

Open Ended

Name 3 animals that are classed as Crepuscular.

Open Ended

Name 3 animals that are classed as Diurnal.

Feedback Loops

• There are 2 feedback loops that control a circadian rhythm - 'Per' and 'Tim'

• Per is regulated by reoccurring and regular changes to the environment - such as the moon, tides, and seasons.

• Tim is regulated by light only.

• Their Circadian Rhythm allows an animal to anticipate and prepare for the changes in the physical environment that are associated with day and night.

• This ensures they will “do the right thing” at the right time of the day".

Open Ended

Why are Circadian Rhythms important? What types of activities might be impacted by them? (Be sure to discuss a few options - don't just name 1!)

Examples - watch the videos

• http://www.bbc.co.uk/programmes/p01myn60

• https://m.facebook.com/story.php?story_fbid=1790549777630807&id=118883634811868

Activity

Research the following animals and identify the impacts of their Circadian Rhythms have on their behaviours. Create a short factsheet on them ready to hand in next week!

Speckled Sea Louse

Arctic Reindeer

Honeybees

Killer Whale - new-borns and mums