Climate Change: Species Responses — Reading Comprehension

Climate change is causing rapid changes in global temperatures, weather patterns, and ecosystems. Many species now face a challenge: they must adapt, move to new locations, or risk extinction. Scientists study these responses to understand how living things cope with environmental stress. The fate of countless species depends on the speed and nature of their responses to a rapidly changing world.

Mechanisms of Survival: Adapt, Move, or Die

When the environment changes, species have three main options. First, they can adapt by evolving new traits. This evolutionary process requires genetic variation and usually takes many generations. However, because climate is changing so quickly—at rates faster than most species have ever experienced—many organisms cannot evolve fast enough. Some species can use behavioral or physiological plasticity, which means individuals can alter their actions or body functions without genetic changes. For example, some birds may change what they eat or when they build nests.

Migration and Range Shifts

Many species are responding by moving to new habitats where conditions are more suitable. This is called a range shift. For instance, butterflies in Europe have shifted their ranges northward by about 35-240 kilometers in recent decades. Birds and fish are also moving to higher elevations or cooler waters. Plants, although rooted, can shift ranges over generations as seeds disperse further north or uphill. Another observed response is changes in migration timing. Birds now often arrive earlier in spring and leave later in fall. These changes can help them survive but also risk mismatches with food supplies or breeding partners.

Challenges, Risks, and Human Actions

Not all species can move or adapt easily. Those with small geographic ranges, slow reproduction, or specialized needs are most vulnerable to extinction. Scientific studies have documented evolutionary responses, such as some birds breeding earlier or mosquitoes evolving resistance to heat. However, many species cannot keep up. This has led to debates about assisted migration—the idea of humans moving species to safer habitats. While this could save some species, it might also disrupt new ecosystems. Another problem is ecological mismatch: for example, if plants flower earlier because of warmer springs but their pollinators do not arrive in time, both can suffer. Scientists use data on shifting ranges, timing, and population trends to predict which species are most at risk.

Understanding how species respond to climate change involves studying genetics, behavior, ecosystems, and even human ethics. The balance between adaptation, movement, and extinction will shape the future of Earth’s biodiversity. Protecting habitats and slowing climate change are crucial for giving species a chance to survive.

Interesting Fact: Some Arctic fish have shifted their ranges northward by up to 1,000 kilometers in the last 40 years, showing how quickly species can respond to environmental change.

What are the three main responses species have to climate change according to the passage?

What does the term 'range shift' mean in the context of the passage?

How much have some butterflies in Europe shifted their ranges in recent decades?

According to the passage, why can’t most species adapt fast enough to climate change?

What is 'assisted migration'?

What does 'mismatch' mean in this passage?

Why might assisted migration be controversial?

What causes ecological mismatches according to the passage?

True or False: All species can easily move to new habitats when climate changes.

True or False: Evolutionary adaptation usually takes many generations.