Chapter 5 - Populations

Evelyn and Arjun are on a thrilling adventure to map out the mysterious forest! As they explore, they notice that some trees are having a party clumped together, others are standing in neat rows like soldiers, and some are just chilling randomly. What fascinating phenomenon are they observing?

• the population density

• the population distribution

• the population growth

• the population outline

Liam is on a scientific adventure, observing a fascinating bacterial colony growing in agar inside a Petri dish. Did you know agar is made from seaweed? Liam discovers that this bacterial population doubles in size every 32 hours! What exciting conclusion can Liam draw from his observations?

• The agar and air in the Petri dish are providing all of the resources needed by the bacteria.

• The bacterial colony is growing in all regions of the agar in the Petri dish.

• The bacterial colony will continue doubling in size indefinitely.

• The agar and air in the Petri dish are limiting factors on the growth of the bacterial colony.

Arjun, the adventurous scientist, observes a lively population of bison on the prairie and concludes that they've reached the carrying capacity of their grassy home. With the birthrate and death rate of these bison buddies balancing perfectly, what can Arjun deduce about their immigration and emigration escapades?

• The rates of immigration and emigration are equal to each other.

• The rate of either immigration or emigration is zero.

• The rate of immigration equals the birthrate.

• The rate of emigration equals the death rate.

In the magical land of Fluffytail, a group of rabbits led by the adventurous Aiden and curious Abigail are facing challenges from parasitic pixies and the dreaded disease dragon. These are density-dependent foes. Which statement best describes how these challenges affect the rabbit clan?

• The parasitic pixies and disease dragon weaken or slay a constant percentage of the rabbit clan, regardless of its size.

• As the rabbit clan grows, the parasitic pixies and disease dragon weaken or slay a greater percentage of rabbits.

• As the rabbit clan grows, the parasitic pixies and disease dragon weaken or slay a lesser percentage of rabbits.

• The parasitic pixies and disease dragon target mostly the youngest and oldest rabbits, sparing those of average age.

Grace, Maya, and Priya are on a marine adventure in the Caribbean Sea, where they encounter the fascinating yet rapidly multiplying lionfish. Which of these exciting predictions about the future of the lionfish population is the most likely to occur?

• The lionfish population will continue growing exponentially indefinitely.

• A limiting factor will cause the growth of the lionfish population to slow down, forming a pattern of logistic growth.

• A limiting factor will cause the lionfish population to decline rapidly, and eventually decrease to near zero.

• The lionfish population will enter a cycle of increasing and decreasing numbers, typical of many predators and prey.

Evelyn and Grace are exploring the wild world of Isle Royale National Park, where wolves and moose dance in a delicate balance of predator and prey. Imagine you're joining them on this adventure! Which of the following pairs of populations would likely show a similar rise and fall pattern as the wolves and moose?

• Moose and balsam fir, which are the favorite food plants of moose

• Very old wolves and young wolf pups

• Moose and the beneficial bacteria that live in the digestive tracts of moose

• Male wolves and female wolves

A hurricane named Hurricane Liam sweeps across a Caribbean island, causing chaos and adventure! The mighty storm flattens trees like a giant's stomp, and it sweeps away a large number of plants and animals on a wild ride. As a result of Hurricane Liam's visit, the island's carrying capacity is temporarily reduced for many of its species. How is Hurricane Liam classified as a limiting factor?

• Hurricane Liam is a density-independent limiting factor, because population size and density do not alter the storm's effect.

• Hurricane Liam is a density-independent limiting factor, because its effect depends on the size and density of a population.

• Hurricane Liam is a density-dependent limiting factor, because its effect depends on the size and density of a population.

• Hurricane Liam is a density-dependent limiting factor, because its effect depends on the strengths of its wind and rainfall.

Evelyn and Isla are on a wild adventure to save the pandas! They discover that pandas munch on bamboo almost exclusively, and the availability of this tasty grass is crucial for their survival. Imagine if the bamboo supply dwindled, what could happen to our panda pals in the wild?

• The bamboo population decreases so low that other limiting factors begin to affect the panda population.

• The bamboo population decreases so low that the carrying capacity for pandas becomes zero.

• The populations of bamboo and pandas follow a cyclical pattern of increasing and decreasing, until one of them becomes extinct.

• The populations of bamboo and pandas both follow a pattern of exponential growth, and then both become extinct.

Imagine you're on a thrilling adventure with Aria and Noah, exploring the fascinating world of demographic transitions! During Stage II, which of these exciting events is most likely to happen?

• The population decreases slightly, especially in the younger age ranges.

• The population decreases slightly, especially in the older age ranges.

• The population increases slightly, due mainly to the increased rate that babies are born.

• The population increases significantly, due mainly to a decrease in death rate.

The graphs show the age structure for each of three countries. The horizontal bars show the percentages of the population in each age group, by gender. Note that for Country 1, about 20 percent of the population is between the ages of 0 and 4. This is the greatest percentage of any 4-year age span in all three countries. Imagine Isla, Abigail, and Zoe are exploring these graphs. Which conclusion about Country 1 does its age structure support?

• Young children have a lower death rate in Country 1 than in the other countries.

• Young children have a higher death rate in Country 1 than in the other countries.

• More young children live in Country 1 than in the other countries.

• Fewer young children live in Country 1 than in the other countries.