Answer: To explain the difference in the numbers of hogs in the year age-group and the numbers of hogs in the year age-group shown in Figure 1, we need to consider ecological factors that influence birth and death rates at different stages of an animal's life cycle.
Reproductive Age and Fertility: Hogs in the year age-group are typically at the peak of their reproductive age. These hogs are sexually mature and capable of reproducing, leading to a higher birth rate within this age group. On the other hand, hogs in the year age-group might not have reached full reproductive maturity or may have reduced fertility, leading to fewer births in this age group.
Survival Rate and Mortality: Young hogs in the year age-group are more vulnerable to predation, disease, and environmental factors. Therefore, there may be higher mortality rates among hogs in this age group compared to hogs in the year age-group, leading to a lower number of survivors.
Competition for Resources: As hogs grow older, they may face increased competition for food, territory, and mates. This competition can lead to higher mortality rates among older hogs due to fights, injuries, or stress-related factors. Therefore, the number of hogs in the year age-group may decrease due to these ecological pressures.
Life Expectancy and Senescence: Hogs in the year age-group may be reaching the end of their natural lifespan. As animals age, they become more susceptible to age-related diseases and physiological decline, leading to increased mortality rates in older age groups.
Overall, the differences in the numbers of hogs between different age groups in Figure 1 reflect the complex interplay of ecological factors such as reproductive age, survival rates, competition, and senescence. These factors collectively shape the population age structure of hogs and contribute to the observed distribution of individuals across different age groups.
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