Final answer:
In a drought, large seeds with hard cases are more likely to survive, which places selective pressure on birds, favoring those with large and broad beaks. If the drought continues, we can predict an evolutionary shift toward these traits in the bird population, reflecting the broader theme of survival mechanisms and evolutionary history in response to environmental conditions.
Step-by-step explanation:
Natural Selection in Drought Conditions and Seed Survival
During a drought, the types of seeds that survive and the traits of the surviving organisms are influenced by natural selection. In the scenario described, large seeds with hard cases become increasingly common because they are less susceptible to water loss and can sustain the harsh conditions of a drought. It is mentioned that these seeds are successfully eaten by birds with large and broad beaks. Hence, under the influence of natural selection, if the drought persists and the bird population remains isolated, we can predict that birds with these beak traits will dominate the population over time, as they are the ones able to access food resources effectively.
Small seeds with thin shells become rare, indicating they have a lower survival rate during the drought. This change in seed availability puts selective pressure on the bird population, favoring those with traits suitable for the conditions. As a result, over time, there could be an evolutionary shift in the bird population toward these advantageous traits. As seed plants evolved in response to changing climates, those with adaptations to conserve water, like waxy coatings and needle-like leaves, prevailed. This is reflected in the survival of large, hard seeds during drought conditions.
Utilizing the reference information, it's apparent that seed traits have played a significant role throughout the evolutionary history of plants, influenced by factors such as climate and water availability. The survival of specific seed types is not only critical for the plants themselves but also impacts the wildlife that depends on them for sustenance, thus shaping the ecosystem through natural selection.