ecosystem A natural unit composed of all the living forms in an area, functioning together
with all the abiotic components of the environment.
population Organisms belonging to the same species that occupy the same area and in-
teract with one another.
Points to Consider
- How do you think the study of ecology would be applied at the level of the population
and what study methods do you think might be used? - What do you think causes populations to grow?
23.2 Lesson 23.2: Populations
Lesson Objectives
- Explain what a population is.
- Describe how births, deaths and migration affect population size.
- Explain how populations grow.
- Describe how limiting factors affect population growth.
- Describe growth of the human population.
Check Your Understanding
- What is ecology?
- How does an organism interact with its environment?
Introduction
The study of populations is important to better understand the health and stability of a
population. Such factors as births, deaths and migration influence population size. Different
models explain how populations grow. Limiting factors can help determine how fast a
population grows. All of these aspects of population biology can be applied to the study of
human population growth.
What is a Population?
Apopulationis comprised of organisms belonging to the same species, all living in the same
area and interacting with each other. Since they live together in one area, members of the