Chapter 22: Q22.-8TYU (page 483)

Write a short essay (about 100鈥�150 words) evaluating whether changes to an organism鈥檚 physical environment are likely to result in evolutionary change. Use an example to support your reasoning.

Short Answer

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Evolution often occurs in response to environmental forces. The drastic changes in the environment force organisms to adapt to fit the changing environment.

For example, the penguin ancestors physically appeared more like birds. With the change in the external temperatures, the environment became colder and wetter. To adapt to their environment, the penguins evolved webbed feet and flaps for swimming.

Step by step solution

Penguin

Penguins, though they do not appear as birds, belong to the class Aves. The penguins possess feathers instead of hair, which is an essential feature of birds. The penguins lay eggs instead of producing offspring; this is a common feature of birds. Hence, penguins are considered birds

Evolution due to physical environmental changes

The changes in the physical environments force species to make appropriate changes in their morphology and physiology. Changes are required for the survival of the population as the population which does not adapt to the changes in the physical environment gets eliminated over time.

The evolution follows the Darwinian idea of survival of the fittest.

Adaptation of penguins

The organisms that do not adapt to the environmental changes tend to reproduce lesser than the adapted ones and eventually die out or even lead to the formation of new species.

The penguins are believed to have evolved from the ancestors who had bird-like appearance morphologically. Due to the changes in their physical environments, the penguins adapted body modifications such as flaps and webbed feet.

These modifications allowed penguins to adapt to new environments and sustain their population.