Animal Adventure Camp: Week 1

Why Do Animals Have Different Types of Mouths?

Hummingbird

Rabbit

Birds have beaks, cats have sharp teeth, and rabbits have buckteeth.  Why do different animals have such different types of mouths? Animals have different types of mouths because different animals eat different types of food.  Imagine if you wanted to eat a carrot but all you had was a straw.  It would be pretty difficult to eat the carrot using a straw, a fork would work much better.  On the other hand, if you wanted to drink some juice, it would be a lot easier to drink it using a straw than a fork. Animals have evolved mouths that help them eat their food so they can grow strong, survive, and have babies.  For example, hummingbirds have a straw-like beak that they use to drink nectar from plants, while rabbits have big front teeth that help them nibble carrots.  A rabbit would be in trouble if it tried to eat a carrot using a hummingbird beak!

By looking at different animal’s mouths, we can guess what they eat. Take a look at the animal skull pictures  below.  What do you think these animals might eat?  Hint: think about how the animal’s mouth could act like a utensil. Did you notice that the bird’s beak looks kind of like tweezers?  This tweezer-like mouth is very important for the bird because it helps it pick up small seeds from the ground.  The bird’s mouth looks pretty different from the cat’s mouth, huh?  The cat’s sharp teeth wouldn’t be as useful for picking up little seeds in the grass.  However, the cat’s sharp teeth are important for the cat because cats eat meat and they need sharp teeth to cut through the meat, kind of like a knife.

cat skull

 What Can Skulls tell us about what Different Animals Eat?

At the Common Ground Animal Adventures Camp, we demonstrated how different animals have evolved different types of mouths by showing the campers skulls of cats, pigs, birds, orangutans, gorillas, humans, turtles, Neanderthals, etc. and asked them to look at the mouths of the skulls and try to figure out what the animals might eat.

The Best Beak for Beans

Next, we played a game with the campers to demonstrate how different mouthparts have evolved in different animals.  In this game, we separated the campers into 3 groups and gave each group a different utensil: forks, chopsticks, or wooden skewers.  We then scattered dried beans on the ground and had the teams use their utensils to collect as many beans as they could in a five-minute period.  When the five-minutes were up, each group tallied up the number of beans they collected.  The team that collected the fewest beans went “extinct” and so the members of this team had to join one of the other teams.  We played the game for several rounds and in the end one team collected the most beans…by a long slide!  Do you think it was the spoon team, the chopstick team, or the skewer team?  We finished up by the activity by relating the outcome of the game to the real life case of bird beak evolution in the Galapagos Finches.

A Real Life Example of Evolution: THe Galapagos Finches

Large Ground Finch

Small Ground Finch

Scientists think that a very, very, long time ago there was originally only one type of finch on the Galapagos islands.  This one type of finch flew to the islands from the mainland.  Once on the islands, the finches stayed, they found food to eat and had babies. These baby finches shared a lot of traits with their parents, however, some of the babies had slightly bigger beaks and some had slightly smaller beaks. As it turned out, big beaks were slightly better for eating big seeds, while small beaks were slightly better for eating small seeds.  Over a very long time the finches with big beaks evolved even bigger beaks, that were even better for eating the big seeds on one island, and the finches with the small beaks evolved beaks that were even smaller and even better for eating small seeds on different island.  Eventually, these finches evolved into different species.  Now there are 15 different finch species on the islands.

The Galapagos finches were first found by Charles Darwin, the scientist that discovered the theory of evolution, which is why we sometimes call them “Darwin’s Finches.”  Darwin discovered these finches a long time ago, in the 1800’s, but even today, scientists are going out to the Galapagos Islands to study these finches so that we can better understand how evolution works.

If you are interested in learning more about current research on the Galapagos finches then check out these links:

https://www.princeton.edu/eeb/people/display_person.xml?netid=rgrant&display=All http://www.oeb.harvard.edu/faculty/abzhanov/abzhanov-oeb.html