How living things adapt to environments
Identify how animals and plants are adapted to suit their environment and understand that adaptation may lead to evolution over time
What a learner can do afterwards
- Define adaptation as a feature that helps an organism survive in its environment
- Give at least three examples of adaptations in different organisms and explain how each helps survival
- Explain that over many generations, organisms with helpful adaptations survive and reproduce more, leading to evolution
1 · Read
Every animal and plant lives somewhere different: a hot desert, a frozen icecap, a dry grassland. To survive there, a living thing needs a feature that fits that place. This is called an adaptation. An adaptation is a feature that helps an organism survive in its environment.
A camel lives in the desert, where water and food are hard to find. Its hump stores fat, and the camel's body turns that fat into energy and water when supplies run low. This adaptation lets the camel travel for days without eating or drinking.
A cactus lives in the same dry desert. Its thick, waxy skin holds water inside and stops it from escaping in the heat. Sharp spines instead of leaves also keep thirsty animals from eating it. Both are adaptations to a place with almost no rain.
A polar bear lives on Arctic ice, where cold can be deadly. Its thick white fur traps warm air against the skin and blends in with the snow, hiding the bear from prey. Warmth and camouflage together are exactly what its environment demands.
Adaptations do not appear overnight. Over many generations, the animals and plants born with a helpful feature survive and have more offspring than the ones without it. Slowly, that feature becomes common in the whole species. That slow change over time is evolution.
An adaptation is a feature that helps an organism survive where it lives, and helpful adaptations passed down over many generations lead to evolution.
The rewritten readings were written for this dataset.
More to read
Features that help in a habitat
An adaptation is an inherited body feature or behavior that helps an organism survive and reproduce in its surroundings. Living things often have adaptations suited to their habitats, though none is perfectly equipped for every situation.
A saguaro cactus in the Sonoran Desert can absorb about 750 liters during a rainstorm. Its stored water helps it survive months without rain. In Peru's mountains, a small lizard uses both water and land, with features suited to each.
The cactus's water-storage trunk would not suit river life, and the swimming lizard would struggle in a desert. A useful feature depends on the habitat. Across generations, inherited differences that help reproduction can become more common. This population change is part of evolution.
How natural selection spreads adaptations
People noticed changes in living things long before they understood the process. Studying plants and animals helped scientists such as Charles Darwin explain natural selection.
Individuals within a species differ. One may have a longer beak; another may have thicker fur. If an inherited difference helps its owner survive and reproduce, offspring may receive it too. Across generations, that feature can become more common, changing the population.
Adaptations are inherited features that help survival and reproduction in a particular environment. Distantly related animals can develop similar adaptations in similar surroundings, such as the fins of sharks and dolphins.
Evolution can involve many small changes over long periods, but its pace varies. It is not always slow.
Which inherited traits become common?
Fur color, beak shape and plant height are traits. Individuals vary, and some differences can pass to their young. Natural selection occurs when inherited traits affect survival and reproduction. Traits linked to greater reproductive success tend to spread; those linked to lower success tend to decline.
Selection can favor one end of a range, such as longer giraffe necks. It can favor the middle, such as medium-sized newborn animals. Or it can favor both extremes, increasing differences within a group that may eventually split.
These changes can make a population better suited to its surroundings. That process is adaptive evolution. It depends on which inherited traits help in the current environment.
Variation, inheritance and population change
Evolution means inherited characteristics change across generations. Its pace varies. Natural selection is one process that can produce adaptations.
Members of a population differ in appearance and body function. When an inherited difference helps survival and reproduction, individuals carrying it tend to leave more offspring. Their descendants may inherit it, making the feature more common.
After many generations, a population may be better suited to its habitat. Populations can also diverge enough to form different species.
Selection needs variation that can be inherited, together with differences in reproductive success across generations. Without variation, it cannot favor one trait over another. This process helps explain adaptations in organisms as different as desert cacti and deep-sea fish.
Leaves suited to different habitats
Plants stay rooted, so body features help them cope with light and water conditions.
Broad leaves give many rainforest plants a large area for collecting light. Even where sunlight is plentiful above the forest, leaves lower down may be shaded. Pointed drip tips help rain drain away, reducing water buildup on leaves.
Many desert plants have very small leaves or spines that limit water loss. A cactus's spines are modified leaves. In shaded forests, thin, wide leaves help plants collect scarce light. Some plants in cold regions have small, tough, waxy leaves that can survive freezing weather.
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