EcologyLesson 2 of 2 in the course Population and Community Ecology

Human Population Growth, Age Structure, and Environmental Limits

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

Save course
Lesson progress
0 / 5

Your progress is kept in this browser only.Sign up to save it

Summary

This lesson explores how human population growth follows familiar ecological principles while also reflecting humanity’s unusual ability to change the environment. Understanding these patterns helps explain both population expansion and its effects on ecosystems.

The world’s human population has grown exponentially for much of recent history. In exponential growth, a population increases by a proportion of its current size, so the number added over a given period can become larger as the population grows. One visible consequence is that successive billions were added in less time: it took about 123 years to add one billion people between 1804 and 1930, while two billion were added in the 24 years from 1975 to 1999.

All flashcards

What is exponential population growth?
Growth in which a population increases by a proportion of its current size. As the population becomes larger, the number of individuals added over a period can also increase.
What is carrying capacity?
The population size an environment can support over time, given its resources and environmental conditions.
How do humans weaken some density-dependent limits?
People use shelter, agriculture, domesticated animals, migration, communication, sanitation, and medicine to reduce risks or expand access to resources.
Why have fossil fuels contributed to human population growth?
Fossil-fuel energy has supported industrial technologies, mechanized agriculture, and the production and distribution of food, helping increase resources available to people.
Name two large-scale environmental changes associated with human activity.
Examples include global climate change, ozone-layer depletion, desertification, and topsoil loss.

Quiz questions

  1. What does carrying capacity mean in population ecology?Answer: The population size an environment can support over time under its resource conditions.
  2. What pattern describes human population growth over much of recent history?Answer: Exponential growth, in which increase is proportional to current population size.
  3. What does a broad-based pyramidal age-structure diagram commonly suggest?Answer: A large young cohort and likely rapid population growth.
  4. How can public health advances contribute to human population growth?Answer: Sanitation, vaccines, and antibiotics can reduce deaths from infectious diseases.
  5. How can environmental degradation affect future human carrying capacity?Answer: It can damage ecosystems and resources, reducing the planet’s ability to support people.

Based on Concepts of Biology by Samantha Fowler, Rebecca Roush, James Wise (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

More in Ecology

All Ecology lessons
EcologyEnvironmental Controls on Species Distributions and Ecosystem Processes5 flashcards · 5 quiz questions · 4 gamesPlay free →EcologyPrimary Production: Ecosystem Controls, Measurement, and Human Impacts5 flashcards · 5 quiz questions · 4 gamesPlay free →EcologyPredation: Foraging, Adaptations, and Ecosystem Effects5 flashcards · 5 quiz questions · 4 gamesPlay free →EcologyPopulation Growth, Regulation, and Life-History Strategies5 flashcards · 5 quiz questions · 4 gamesPlay free →EcologyBiogeochemical Cycles of Water, Carbon, Nitrogen, Phosphorus, and Sulfur5 flashcards · 5 quiz questions · 4 gamesPlay free →EcologyPopulation Regulation and K–r Life-History Strategies5 flashcards · 5 quiz questions · 4 gamesPlay free →