The population size of mountain pine beetles in the American Northwest has long been held in check by freezing temperatures during the winters. As winters warm, populations of pine beetles are increasing, killing whitebark pine forest. Grizzly bears rely on the nuts of whitebark pine trees. Do you think climate change is affecting the fitness of the grizzly bear population? a. No, because climate change is not a problem yet. b. No, because climate change is affecting the beetles, not the bears. c. Yes, because climate change is decreasing the food supply of the bears, which means they will be less strong. d. Yes, because climate change is decreasing the food supply of the bears, which is likely to reduce their ability to survive or reproduce.

Verified step by step guidance

1. Identify the key ecological relationships: Grizzly bears rely on the nuts of whitebark pine trees for food.
2. Understand the impact of climate change on the ecosystem: Warmer winters are allowing mountain pine beetle populations to increase, which in turn leads to more whitebark pine trees being killed.
3. Analyze the direct consequences on the grizzly bears: With the decline in whitebark pine trees, the food source for grizzly bears is reduced.
4. Link the reduction in food supply to grizzly bear fitness: A decrease in available food can affect the bears' ability to survive and reproduce, which are key components of biological fitness.
5. Evaluate the answer choices in relation to the impact of climate change on grizzly bear fitness, considering the ecological chain of effects from climate change to pine beetles to whitebark pines to grizzly bears.

Key Concepts

Climate Change

Climate change refers to long-term alterations in temperature, precipitation, and other atmospheric conditions on Earth. It is primarily driven by human activities, such as burning fossil fuels, leading to global warming. This phenomenon can disrupt ecosystems, affecting species interactions and food availability, which is crucial for understanding its impact on wildlife.

Ecosystem Interdependence

Ecosystem interdependence describes how different species within an ecosystem rely on one another for survival. For instance, grizzly bears depend on whitebark pine nuts as a food source. Changes in one species, such as the increase in mountain pine beetles due to warmer winters, can have cascading effects on other species, including those that rely on them for sustenance.

Fitness in Ecology

In ecological terms, fitness refers to an organism's ability to survive and reproduce in its environment. Factors such as food availability, habitat conditions, and competition influence fitness. A decrease in food supply, like the nuts from whitebark pine trees due to beetle infestations, can lower the fitness of grizzly bears, impacting their survival and reproductive success.