$200 $300 $400 $500 $100 $200 $300 $400 $500 $100 $200 $300 $400 $500 $100 $200 $300 $400 $500 $100 $200 $300 $400 $500 $100 Vocabulary Charles Darwin Natural Selection The Galapagos Evolution

An adaptation in which a specific action, such as nest building, allows a species to survive in its environment.

behavioral adaptation

A structural adaptation that allows an organism to blend in with its surroundings.

camouflage

Change in a species over time.

evolution

The process by which organisms, with traits that help them adapt to a changing environment, are able to successfully reproduce.

natural selection

Inheritance of traits that allow an organism to survive in a particular environment.

adaptation

Who was Charles Darwin?

Charles Darwin was a British naturalist. He sailed his ship the Beagle exploring South America and its remote islands the Galapagos Isalnds.

Why is Darwin’s work important?

Based on his extensive observations he developed the theory of evolution by means of natural selection. His work serves as the basis of much biological research today.

What did Darwin reason from his observations on the Galapagos Islands?

Darwin reasoned that perhaps the organisms in the Galapagos originally came from South America and over time, they had evolved. He reasoned that each new population changed slightly, or evolved, to fit its unique environment on the island.

What observations did Darwin make of the tortoises and finches on the Galapagos Islands?

Darwin made observations about the diversity and uniqueness of organisms. Many of the animals were similar, but not the same as organisms in Mainland South America.

What did Darwin observe regarding the different finches on the different islands?

Finches had evolved bird beak types that best suited the food available in their new environment.

What is Darwin’s theory of natural selection?

Organisms with traits that allowed them to survive under particular environmental conditions produced more offspring. Eventually those traits would be common in the species.

List the four steps or requirements for natural selection.

1. overproduction 2. variation 3. inherited variation and 4. natural selection.

Explain each step pictured below.

Overproduction Too many offspring are born for the environment to support. Variation Some offspring are born with certain traits that others do not share. Inherited Variation Offspring inherit these varying traits from their parents. Natural Selection Some animals’ traits help them survive in their particular environments.

What are the two main categories that scientists divide adaptations into?

Scientists divide adaptations into two main categories – structural and behavioral.

List two types of structural adaptations and explain each. How can these adaptations benefit an organism’s survival in its environment?

Camouflage—coloring that blends with the environment—makes organisms difficult to see. Mimicry is when one species (the mimic) looks like another species (the model) in order to deceive a third species.

Where did Darwin observe the most diversity and uniqueness in life?

The Galapagos Islands

Where did Darwin reason the organisms on the Galapagos had originally come from?

Mainlaind South America

What beak type is pictured below and what food type is best suited for it?

Long, narrow beak for eating insects.

What beak type is pictured below and what food type is best suited for it?

Short, large beaks for “crushing”. Useful for breaking seeds.

How were the tortoises of the Galapagos different than the Mainland?

They were similar but much larger! They were giant tortoises.

Explain why genetic variation is important for evolution to occur. What are some sources of genetic variation?

Genetic variation is necessary for evolution to occur. Sources of genetic variation include mutations, formation of the gametes, and sexual reproduction.

List two examples of behavioral adaptations. How can these adaptations benefit an organism’s survival in its environment?

Nesting Instinct: Male bower bird decorates its nest to attract females. Herding Instinct: Animals that live in large groups or herds are less likely to be attacked by a predator than one animal alone.

What are some environmental factors associated with extinction?

Environmental factors associated with extinction include climate change, volcanoes, earthquakes and meteor strikes.

List four causes for extinction and explain each.

Loss of habitat: As humans develop, occupy more space, and use more resources, they habitats of plants and animals shrink. Loss of genetic diversity: If there are only a few individuals or if they individuals have limited genetic variability, environmental conditions may more easily cause extinction. Competition with exotic species: If a species has no natural consumer in the new environment, it may outcompete the native species and push them toward extinction. Inability to adapt: If climate changes suddenly, a species may not have any individuals that have genetic traits that allow them to survive.

If a mouse population develops an adaptation that results in white fur and they live in a forest with hawks, what can you predict will happen to the mouse population over time?

The population of white mice will most likely decrease.