Question

due: thursday, september 25

1. bears are a carnivoran mammal that live in north america, south america, europe, and asia. common characteristics of bears include large bodies with stocky legs, long snouts, small rounded ears, shaggy hair, paws with five claws, and short tails. with the exception of mothers with their young, bears are typically solitary animals. most bears are opportunistic omnivores and consume more plant than animal matter. they eat anything from leaves, roots, and berries to insects, carrion, fresh meat, and fish. all bears, however, feed on any food source that becomes seasonally available. gestation (pregnancy) lasts 6 - 9 months and litter size numbers up to four cubs. cubs are born blind and helpless with at most a thin layer of hair, relying on their mother for warmth and food.

a. **draw a graph illustrating a population exposed to limited resources on the left and a population exposed to unlimited resources on the right.
population size
time
population size
time
b. **which graph above likely represents a typical bear population? provide evidence from the text to support your response.

Explanation:

Step1: Draw population - limited resources graph

A population with limited resources follows a logistic - growth curve. Initially, the population grows exponentially as there are enough resources. But as the population approaches the carrying capacity (the maximum number of individuals the environment can support), the growth rate slows down and eventually levels off. So, on the left - hand graph, the curve starts with a steep upward slope (exponential growth phase) and then flattens out as it approaches a horizontal asymptote (carrying capacity).

Step2: Draw population - unlimited resources graph

A population with unlimited resources follows an exponential - growth curve. The population size increases at an ever - increasing rate over time. On the right - hand graph, the curve is a smooth, upward - curving line that keeps getting steeper as time progresses, with no upper limit in the short - term.

Step3: Determine bear population graph

Bears live in an environment with limited resources. Their food sources (leaves, roots, berries, insects, carrion, fresh meat, fish) are not unlimited. Also, space for living is limited. So, the graph representing a typical bear population is the one with limited resources (left - hand graph). Evidence from the text: "All bears, however, feed on any food source that becomes seasonally available", indicating that food resources are not always abundant and thus limited.

Answer:

a. Left graph: Logistic - growth curve (initially exponential growth then levels off at carrying capacity). Right graph: Exponential - growth curve (smooth, upward - curving with no upper limit in short - term).
b. The graph representing a typical bear population is the one on the left (population exposed to limited resources). Evidence: Bears feed on seasonally available food sources, indicating limited resources.