Issue 20 | June 2014

Lichens are not a single organism, but populations of fungi and algae living in symbiosis.


What’s the first thing that pops into your mind when you read the word population? Most likely it’s the ever-increasing human population on earth. The term population isn’t just used to describe humans; it includes other animals, plants and microbes too. In this issue, we learn more about how populations grow, change and move, and why understanding them is so important.

Download the PDF, browse through the individual articles, check out our multimedia content and consider our lesson ideas. We’ve also picked out content from other issues that we think is especially relevant.

Foundations of populations

First things first

Our primer explains why it’s important to study populations

Populations picture infographic

A snapshot of populations around the world

Ecology and the environment

Studying populations in place

Demography dynamics

Using statistics to study populations

Time for a check-up

Epidemiology looks at a population’s health

Gene pool

Studying populations through genetics

Extreme locations

Finding life where you least expect it

Hindsight is 20/20

Fields of scientific study often overlap, and population studies are a case in point

Changes big and small


The implications of persistent population growth

Malthus vs Boserup

Humans, like members of all populations of plants and animals, are in competition with one another for the Earth’s resources

Behind the scenes

Abiotic and biotic factors influence ecosystem and population change

Evolutionary forces

What’s Darwin got to do with it?

Movers and shakers

The role of migration and travel in population change

An uneasy relationship

How are populations and disease intertwined?

Complex networks

The game of life

Organisms must compete for survival


Some species are natural partners, or even bedfellows


What efforts are humans making to preserve biodiversity?

Sources of sustenance

How do humans and plant populations interact?

Talk talk

Bacteria communicate with each other using quorum sensing

Fight to the finish

Understanding host–pathogen interactions

Herd mentality

Childhood vaccination against infectious diseases has saved countless lives. The main beneficiary, of course, is the child who gets vaccinated

Find out for yourself

Video: What’s up, buttercup?

Watch or download our video on population sampling techniques

Animation: Surveying populations

Watch or download our animation, which demonstrates the range of methods that can be used to investigate different populations in a woodland ecosystem

How to set up a population study

Set up your own population study with our short guide

Presentation is key

Help the data you collect to reach their full potential

Beating bias

How researchers try to reduce bias

Grand designs

Why the design of your experiment will depend on the question you’re asking

Citizen science

This approach to science involves members of the public – from schoolchildren to birdwatchers and fishermen – taking part in scientific research

Ecology and geography fieldwork techniques

Excellent resources on practical fieldwork, be it a handy how-to guide or a bit of advice on investigating specific animals or habitats

Bacterial basics

What are the challenges of investigating bacterial populations?

Treasure hunt

Using data on human populations

Population problems

Cervical cancer vaccinations case study

In the UK 12-year-old girls are offered the vaccine – why? Read on and decide what you think about this population problem

Antibiotic resistance case study

Why are our antibiotics not working? What will happen if this continues? Debate and discuss this issue

Birth control case study

How do you cope with the combination of soaring populations and ageing populations? 

Genetic modification case study

Are genetically modified crops a good or a bad thing? Decide what you think

The ethics of population studies

A population study is a scientific investigation that looks at a group of individual plants or animals of the same species living in a given area or habitat

Real Voices interviews

Real Voices interview: Rupert Houghton

Meet Rupert, a PhD student at the University of Aberdeen studying crayfish populations

Real Voices interview: Philip Taylor

Meet Philip, an apple farmer from Chelmsford, Essex

Real Voices interview: Tejovathi and Gopal Rao

Meet Tejovathi and Gopal, a married couple living in Chandanagar, Hyderabad, India

Activities and lesson ideas

Lesson ideas for ‘Big Picture: Populations’

Suggestions for using this issue in the classroom

Further resources and activities on populations

The Wellcome Trust has funded many organisations to produce activities and resources to engage and educate young people on the topic of populations

Fast Facts

Each issue of 'Big Picture' comes with a sprinkling of Fast Facts, fascinating snippets of information on the topic covered.

Browse through all of our Fast Facts indexed by topic