Why so many eye colors?

What caused the natural selection for eye color? Sara, Lafayette, Indiana

"This is a very puzzling question at the moment — one that may take some time to work out," emails bioscientist  Richard A. Sturm,.  Sturm is one of the leading researchers of the world who delves into eye-color genetics.  Most evolutionists think eye-color variation came about as...  Click to continue Many Eye Colors  /  Comment

1. Which way should a fan rotate during which season? Fans come with forward and reverse settings. When you click it to 'reverse', the fan reverses rotation and blows the air up. Now, when you stand under the fan, you won't feel a breeze.  During the summer, on the other hand, turn it to 'forward' to create a wind-chill effect as the air moves against your skin and cools you...
   More on ceiling fans — how to tell which way is 'forward'

1. Which animals mate for life?  Gibbon apes, wolves, termites, coyotes, barn owls, beavers, bald eagles, condors, swans, angel fish, sandhill cranes, pigeons, red-tailed hawks, anglerfish,   and black vultures — are a few that mate for life.  Of course, it depends on what you mean by "mate for life." These creatures do...

2.  What is the average size U.S. woman (and man)? 
   A: According to the U.S. Department of Health and Human Services, the average U.S. woman is 5' 3.7" (162 cm) tall and weighs...
   
   How about British, USA, Canadian and Mexican men and women sizes? 

2. Most poisonous creature could be a mystery insect.  Midday, in the depths of a jungle west of the Andes along a Pacific river. It is dark, hot, and dismal. Dusk never leaves the day below the tree canopy. "Thwoop," breaks the silence as a poison dart hurtles from a blowgun to its target: a howler...The insect, found!

3. Eye color mocks easy rules. Mom has green eyes, Dad blue. How did I get brown? You’re right. The 2-gene square chart predicts that no offspring of your mother and father should have brown eyes. But the chart's wrong.  We’re developing...
   Can eye color change as we age?

3. How do frogs hear?  Do they have ears?  It's true frogs do not have outside ears that direct sound inward to the ear drum as ours do. But they do have an ear drum of sorts, an inner ear, a brain, and most frogs have a..

4. What the heck is a swamp cooler and how does it work?
5. Does alcohol kill brain cells?
6. Which animals mate for life?
7. Most poisonous creature could be a mystery insect
8. Does the Moon rotate? Why do we always see the same side of the Moon?
9. What exactly are hazel eyes, and what color are they?
10. Jupiter Rings: how many and how were they created?

More human questions >>

4. Chameleons: How do they change color and know which color to change to?
5. What are the top 10 smartest animals?
6. Ladybugs: do ladybugs come from a nest?
7. Are sharks and dolphins enemies?
8. How Arctic plants and animals survive
9. What animal has the biggest eye?
10. Egg, fertile: How can I check to see if the egg I found is fertile or not?
    
    More animal questions >>

• Can crocodiles live in the sea?
   
• Adding salt helps to melt road ice and freeze ice cream — why the different effect?  Eye-color genetics, Unhappy scorpions
   
• Is an 'Evil' gene nonsense? If lightning strikes a tornado... 
   
• If a man has twins running in his family, can he in any way cause his sex partner to become pregnant with twins?
   
• Why are Sundogs called sundogs?
   

Now, the interesting part: why does the Moon spin about its axis at the same rate it orbits? In the distant past, the Earth's tidal pull on the Moon slowed...

Attracting Birds to Your Backyard 536 Ways to Create a Haven for Your Favorite Birds by Sally Roth

Perhaps most interesting are the sidebars titled "The Wide World of Backyard Birds" that offer anecdotes from the author's, and other birders' experience. One amusing story on page 38 details how the author found a slab of slate with a round hole bored in it, and brought it back to prop it against a tree in her garden as an ornament. Then she noticed several birds approaching, wiggling through the hole, and...

 More Reviews >>

• Projects for the Birder's Garden
• Apocalypse,  A Natural History of Global Disasters
• Five Ages of the Universe
• Krakatoa

How to Offer Wild Birds Shelter in the Winter

Not all birds migrate south for the winter.  Winter is a hard season for birds, and many risk freezing to death at night. It doesn't take much effort or money to provide shelter for them, and it can make a huge difference to the little feathered guys!

More Articles >>

• How to Offer Wild Birds Shelter in the Winter
• The Best Way to Offer Water to Wild Birds
• See the Ornate Bird Garden blog for informal tips and observations!
• Build a Backyard Bird Sanctuary
• The Best Outdoor Home for Your Turtle
• Gardening for Kids
• How to tell Male Turtles from Female Turtles
• Is a Box Turtle the Right Pet For You?
• Which Turtle Makes a Better Pet - A Male or a Female?
• Yarrow, a Battlefield Herb

More earth questions >>
 

Why and how does salt affect the boiling point of water? Adding salt to water raises the temperature that the water boils at. The more salt you add, the higher the temperature. Adding 2 tablespoons of salt to 2 cups (473 milliliters) of water can raise the boiling point from...

More physics questions >>

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