How Populations Grow
What term refers to the locations where a population of organisms is found, which can vary greatly in size depending on the species?
geographic range
What term describes any factor, either biotic or abiotic, that controls the growth of a population, influencing its size within a given environment?
limiting factor
What term describes the rapid increase in the global human population due to factors such as improved nutrition, sanitation, medicine, and public health, leading to a doubling of the population from 1 billion in 1804 to 2 billion in 1927?
exponential human population growth
Brianna is mapping trees in a section of land. She observes that some of the trees are clumped together, some are uniformly separated, and some appear to be spaced randomly. What is she describing?
The population distribution
Termites are able to digest wood because of microbes that live in their gut. The relationship between a termite and the microbes inside it is an example of what type of symbiosis?
mutualism
What factor determines whether the size of a population will remain constant, increase, or decrease over time?
the growth rate of the population
What term describes limiting factors that significantly impact a population when its density reaches a certain threshold, encompassing both biotic and abiotic factors such as competition, predation, and disease?
density-dependent limiting factors
Give an example of a country that has an old population and another that has a young population.
Old: Japan, Italy, and Germany have the world's oldest populations, USA, other countries in Europe are also a correct answer.
Young: Niger, Mali, Chad, Uganda, Somalia, Jordan
A scientist concludes that a population of bison has reached the carrying capacity of the prairie where it lives. The birthrate and death rate of the bison population are equal to each other. What can be concluded about the rates of immigration and emigration?
The rates of immigration and emigration are equal to each other.
Food production, purifying water, storing carbon, and regulating pests are all examples of what?
Ecosystem services
What term refers to the number of individuals per unit area in a given area, and what term describes the way individuals are spaced out across their range?
population density and population distribution
What term describes the struggle among individuals of the same or different species for resources like food, water, and space, which can impact birthrates, death rates, and territorial establishment?
competition
What scientific field focuses on studying human populations, examining characteristics such as birthrates, death rates, and age structure to predict population changes over time?
Demography
A rabbit population is affected by parasitism and disease, both of which are density-dependent limiting factors. Describe the effects of parasitism and disease on the rabbits?
As the density of the rabbit population increases, parasites and disease weaken or kill a greater percentage of rabbits.
Scientists have observed that all cheetahs have very similar body structures, markings, and other physical traits. These observations provide evidence for which conclusion about diversity?
Cheetahs have low genetic diversity.
What term describes the composition of a population in terms of the ages of its individuals, along with the proportion of males and females?
age structure
What term describes interactions where organisms weaken their hosts by feeding on them, leading to stress or death, and are considered density-dependent effects due to their increased transmission in denser host populations?
parasitism and disease
What term describes the transition from high birthrates and death rates to low birthrates and death rates, observed in countries like the United States, Japan, and much of Europe during the past century?
The demographic transition
A hurricane blows across a Caribbean island. The storm flattens trees, and it drowns or washes away a large number of plants and animals. As a result of the storm, the carrying capacity of the island is temporarily reduced for many of the island species. How is the storm classified as a limiting factor?
The storm is a density-independent limiting factor, because population size and density do not alter the storm's effect.
Scientists have classified the sea otter as a keystone species in communities along the Pacific coast of North America. This classification depends on which property of the sea otters?
Sea otters act to maintain a wide variety of other populations in the community.
What term refers to the balance between the number of individuals born and the number that die in a population during a specific period, influencing whether the population increases, remains stable, or decreases?
birthrate and death rate
What term describes limiting factors that impact populations regardless of their size or density, including environmental extremes such as hurricanes, droughts, floods, and wildfires?
density-independent limiting factors
State the 3 stages that are predicted for the growth of the human population.
Stage 1: Human birthrates and death rates were high for most of history
Stage 2: Exponential Growth, Birthrates remained high for a time, so births greatly exceeded deaths
Stage 3: As levels of education and living standards rose, families had fewer children, and the birthrate fell, and population growth slowed.
Bamboo is a type of grass. In the wild, pandas eat bamboo almost exclusively. For this reason, the availability of bamboo is a significant limiting factor on the panda population. Describe how pandas could become extinct in the wild?
The bamboo population decreases so low that the carrying capacity for pandas becomes zero.
Dr. Osgood decides to continue the simulation, but with the introduction of a second predator species. Both the original and new predators hunt the same prey in the same environment, and they do not hunt or eat other food. As predicted by the competitive exclusion principle, what is most likely to happen?
The population of one predator species, but not both, decreases to a small number or zero.