TraitsAll organisms have traits. Traits are characteristics that are determined by their DNA. Some traits are structural and some are behavioral. An example of a trait is that humans have hair. This trait has different variations such as black, blonde, brown and red. Variations are different versions of a traits.
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AdaptationsAn adaptation is trait that helps an organism, such as a plant or animal, survive in its environment. Due to the helpful nature of the mutation, it is passed down from one generation to the next. As more and more organisms inherit the adaptation, the adaptation becomes a typical part of the species. An adaptation can be structural, meaning it is a physical part of the organism. An adaptation can also be behavioral, affecting the way an organism acts.
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Examples of AdaptationsAn example of a structural adaptation is the way some plants have adapted to life in the desert. Deserts are dry, hot places. Plants like cactus have adapted to this climate by storing water in their thick stems and leaves.
Animal migration is an example of a behavioral adaptation. Grey whales migrate thousands of miles every year as they swim from the cold Arctic Ocean to the warm waters off the coast of Mexico. Grey whale calves are born in the warm water, and then travel in groups called pods to the nutrient-rich waters of the Arctic. Some adaptations, on the other hand, become useless. These adaptations are vestigial: remaining but functionless. Whales and dolphins have vestigial leg bones, the remains of an adaptation (legs) that their ancestors used to walk. |
Environmental Pressure
Adaptations usually develop in response to a change in the organisms environment. This environmental pressure selects for adaptations that can help organisms survive in a specific habitat.
A famous example of an animal adapting to a change in its environment is the English peppered moth. Prior to the 19th century, the most common type of this moth was cream-colored with darker spots. Few peppered moths displayed a mutation of being grey or black. As the Industrial Revolution changed the environment, the appearance of the peppered moth changed. The darker-colored moths, which were rare, began to thrive in the urban atmosphere. Their sooty color blended in with the trees stained by industrial pollution. Birds couldn't see the dark moths, so they ate the cream-colored moths instead. The cream-colored moths began to make a comeback after the United Kingdom passed laws that limited air pollution. |
Unpolluted Tree Bark and 2 moths
Polluted Tree Bark and 2 moths
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