The Theory of Evolution by Natural Selection Introducing Natural Selection

Charles Darwin Born in 1809 Completed a degree in theology Became a naturalist on the HMS Beagle Noticed that fossilized animals and animals from different places look similar…

The Galápagos Islands Darwin noticed that many animals and plants on the Galápagos Islands resembled those of the nearby coast of South America. He hypothesized that the ancestors of the organisms migrated to the islands and then changed OVER TIME…

Galápagos Birds Of the 29 resident Galapagos landbirds, 22 are endemic and all of them are thought to have colonised the islands from the South American mainland. Endemic means they are found nowhere else in the world…

Darwin’s finches Darwin noticed that the many finches that are on the islands resemble South American finches.

Natural Selection Individuals that have physical or behavioral traits that better suit their environment are more likely to survive and will reproduce more successfully than those that do not have such traits. This difference in reproduction is known as natural selection.

More on natural selection Natural selection works on populations. Populations consist of all the individuals of a species that live in a specific geographical area and that can interbreed. Different habitats present different opportunities and challenges to the organisms that live there. Adaptations are the inherited traits that have become common in a population because the trait provides a selective advantage.

All living things have certain adaptations to survive. If they didn’t, they would die and become extinct eventually. Here are some of the different kinds of animal adaptation: Migration, Hibernation, Camouflage, Mimicry, Metamorphosis, Unique Defenses, Special Adaptations.

Camouflage Many animals have camouflage which helps them blend into their surroundings by matching the scenery. One of the most famous animals for camouflage is the chameleon who changes skin color depending upon where it is located at the time. Some more animals and insects that have camouflage as an adaptation are zebras, grasshoppers, rattlesnakes, and star fish.

Mimicry Some animals have the ability to ‘Mimic’ or ‘copy’ other animals or organisms. This helps them hide from or scare away their predators. The walking stick is known for being excellent at mimicry. He can look exactly like a stick so that predators don’t even see him. There are some species of butterfly that mimic other poisonous butterflies so their predators stay away. The “Mimic Octopus” is known for changing into whatever it wants at almost any time!

Unique Defenses Most animals and insects have some sort of defense that is unique to them. This allows them to defend themselves against predators. An amazing example of a Unique Defense would be a puffer fish. A puffer fish can blow itself up to twice its size so that it cannot fit inside its predators mouth! Can you do that? Other organisms with awesome defenses are the scorpion’s tail, snake’s venom, cat’s claws, bee’s stingers, a cacti’s spines and electric eels.

Migration Some animals have the instinct to migrate or “move” from one place to another to help them survive or reproduce. Most birds are known for migrating from the north to the south every winter to avoid the cold. Other animals that migrate are salmon, sea turtles, gray whales, and caribou.

Metamorphosis Most insects go through metamorphosis or ‘stages in growth’ to help them survive and reproduce. Metamorphosis can be “Complete” with 4 stages (egg, larva, pupa, adult) or “Incomplete” with 3 stages called (egg, nymph, adult). Monarch butterflies are known for their beautiful transformation from egg, larva, pupa and finally, a gorgeous adult. Other insects that go through metamorphosis are beetles, praying mantises, frogs, ants and spiders.

Special Adaptations Lots of animals have special adaptations that other animals don’t have. This helps them to survive and adapt in their environment. The most well known special adaptation is the hump on a camel’s back. The camel’s hump allows it to store water for long periods of time. Since it rarely rains in the desert, this is an important adaptation for sure. Other examples of special adaptations are flying squirrels, a polar bears layer of fat, an elephant’s trunk, a giraffes long neck, an insect laying hundreds of eggs and a bird’s beak

What’s the Point? The point of all of this is for you to understand that all living organisms (even plants) have some sort of adaptation---EVEN US! Our best adaptation happens to be our brain. Without adaptations many animals would die out and become either endangered or extinct. For example: long ago, the dinosaurs were not able to adapt their climate—this led to their extinction.