Evolution as a Consequence of Climate Change
Definition
Evolution
Evolution is defined as a change in the heritable characteristics of a population over time.
- Evolution is a process where populations change over generations due to genetic variations and environmental pressures.
- Climate change is altering habitats, creating new challenges for survival.
- Organisms must adapt or face extinction.
Definition
Climate change
Long-term shifts in temperature, precipitation, and other environmental factors that can alter the conditions of an ecosystem.
- Evolution is not a choice or a conscious decision by organisms.
- It occurs through natural selection, where traits that enhance survival and reproduction become more common over time.
The Tawny Owl: A Case Study
- Tawny owls ( Strix aluco) in Finland exhibit two plumage colors: brown and grey.
- This coloration is a heritable trait, with brown being dominant over grey.
- Snow cover plays a critical role in their survival:
- Grey owls blend into snowy landscapes, reducing predation risk.
- Brown owls are more visible in snow, making them easier targets for predators.
Imagine a grey owl perched on a snow-covered branch. Its feathers blend seamlessly with the surroundings, making it nearly invisible to predators like hawks. Now picture a brown owl in the same setting. Its darker plumage stands out, increasing its risk of being spotted and hunted.
Tawny Owl and Snow Cover
- In cold northern climates, where the snow is often present, light-colored owls are more camouflaged against the snowy background, making them harder for predators to spot.
- In contrast, dark-colored owls stand out against the snow, making them more visible and less likely to survive.
- This means that in snowy environments, light-colored owls have a higher fitness, as they are better able to evade predators.
How Climate Change Alters Fitness
- Over the past 30 years, winters in Finland have become milder, with less snow.
- As climate change leads to warmer temperatures in winter and a decrease in snow cover, the white morph becomes less advantageous.
