Demography examples biology

What is an example of demography in biology?
For example, a large population size results in a higher birth rate because more potentially reproductive individuals are present.
In contrast, a large population size can also result in a higher death rate because of competition, disease, and the accumulation of waste..
What is biological demography?
Biodemography is a new branch of human (classical) demography concerned with understanding the complementary biological and demographic determinants of and interactions between the birth and death processes that shape individuals, cohorts and populations..
Biodemography is a new branch of human (classical) demography concerned with understanding the complementary biological and demographic determinants of and interactions between the birth and death processes that shape individuals, cohorts and populations.

Demography is the statistical study of population changes over time: birth rates, death rates, and life expectancies. Each of these measures, especially birth rates, may be affected by the population characteristics described above.

Overview

What an ecological population is. How scientists define and measure population size, density, and distribution in space

Key points

•A population consists of all the organisms of a given species that live in a particular area

What is a population?

In everyday life, we often think about population as the number of people who live in a particular place—New York City has a population of 8.6 million

Demography: describing populations and how they change

In many cases, ecologists aren't studying people in towns and cities. Instead, they're studying various kinds of plant, animal, fungal

Population size and density

To study the demographics of a population, we'll want to start off with a few baseline measures

Measuring population size

To find the size of a population, can’t we just count all the organisms in it? Ideally, yes! But in many real-life cases, this isn’t possible. For instance

Quadrat method

For immobile organisms such as plants—or for very small and slow-moving organisms—plots called quadrats may be used to determine population size and

Mark-recapture method

For organisms that move around, such as mammals, birds, or fish

Example: using the mark-recapture method

Let’s say we want to find the size of a deer population. Suppose that we capture 80 deer, tag them, and release them back into the forest

Species distribution

Often, in addition to knowing the number and density of individuals in an area, ecologists will also want to know their distribution

What are the characteristics of a population?

A population consists of all the organisms of a given species that live in a particular area

The statistical study of populations and how they change over time is called demography

Two important measures of a population are population size, the number of individuals, and population density, the number of individuals per unit area or volume

What statistics are used in demography?

The key statistics used in demography are birth rates, death rates, and life expectancies which may be influenced by population characteristics and biological factors

Birth rates, death rates, and life expectancies are the basic determinants of how a population changes over time

For example, life tables, which detail the life expectancy of individuals within a population, were initially developed by life insurance companies to set insurance rates. In fact, while the term “demographics” is commonly used when discussing humans, all living populations can be studied using this approach.For example, a large population would have a relatively-high birth rate if it has more reproductive individuals. Alternatively, a large population may also have a high death rate because of competition, disease, or waste accumulation.