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About Dana Krempels, Ph.D.
Expertise
I can answer biology-related questions in the areas of evolution, zoology, botany, genetics, and ecology. But I don't answer homework questions or provide ideas for your science fair projects. So students please do your learning the right way by reading your text assignments and studying!

Experience
At the University of Miami, I teach Evolution and Biodiversity, Botany, Zoology, Genetics, Ecology, and a variety of seminars (e.g., the Biology and Evolution of Human Gender Roles).

Education/Credentials
I have a B.S. in Biology and an A.B. in English from the University of Southern California (1980). I earned my Ph.D. in Biology in the area of evolutionary biology/visual physiology from the University of Miami in 1989.

Past/Present Clients
I am currently an "expert" in both the "Rabbits" and "Wild Animals" categories.

You are here: Experts > Science > Biology > Biology > SLEEPING!!

Biology - SLEEPING!!

Expert: Dana Krempels, Ph.D. - 10/23/2009

Question
HI DANA,
I WANT TO ASK WHY DO WE AUTOMATICALLY FEEL SLEEPY IN THE NIGHT?? IF WE SLEEP ALL THE DAY YET WE FELL SLEEPY IN THE NIGHT? WHY DOES IT HAPPENS?

Answer
Dear Ishan,

Almost all living organisms experience what's known as Circadian rhythms. These are natural cycles encoded in the organism's DNA, but influenced to some degree by the environment. Our old pal Wikipedia actually has a nice overview with a good illustration.

http://en.wikipedia.org/wiki/Circadian_rhythm

As you can see, your body is "programmed" by the activity of hormones and various metabolic pathways, to produce chemicals that induce sleep at certain times of the day. Humans, being diurnal primates, have a sleep clock that wants to start ticking at night. You can read another good overview here:

http://template.bio.warwick.ac.uk/Staff/amillar/andrewM/CBT%20tutorial/SLEEPWAKE...

Hope that helps.

Dana

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