COMMUNITIES

A community consists of a number of different populations that interact with one another. Because environments vary considerably in size and complexity, so too do the communities that occupy them. Within any community, different animals interact with one another. Some of these interactions benefit both partners, others benefit only one. However, intense competition between species has no advantage to either animal.

ONE-WAY BENEFIT

Some relationships only benefit one of the animals, and are harmful to the other. Deer ticks are parasites that live by sucking the blood of deer. They also suck the blood of other creatures, including humans, and can pass on diseases to the animals they live off.

TWO-WAY BENEFIT

A relationship between two species from which both benefit is known as mutualism. The oxpecker bird feeds on the lice and ticks that infest African gazelles. The bird has the benefit of a constant food supply. The gazelle gains from having insects removed that would otherwise suck its blood.

MARINE COMMUNITY

Coral reefs are formed by many corals living together. They provide a very rich environment for a multitude of animals. However, the corals, which form the basis of the reef, need more food than is available around them to survive. They obtain the additional food they need from microscopic algae, which live inside them. The algae need sunlight to manufacture their food so coral reefs are only found in clear, shallow water.

Copyright © 2007 Dorling Kindersley

stay connected

Sign up for our free email newsletters and receive the latest advice and information on all things parenting.

Enter your email address to sign up or manage your account.

Facebook icon Twitter icon Follow Us on Pinterest

editor’s picks

highlights

3 Fun Thanksgiving Games for Kids
Looking for some great Thanksgiving games to play with your kids? Print our free Pin the Feathers on the Turkey game, Pin the Hat on the Pilgrim game, and Thanksgiving Parade Bingo game for loads of laughs this Turkey Day!

Kindergarten Readiness App Wins Gold
Our Kindergarten Readiness app won the Gold Award of Excellence in the educational category at the 2014 Communicator Awards. This valuable checklist comes with games and activities to help your child practice the essential skills she needs for kindergarten. Download the Kindergarten Readiness app today!

8 Surprising Sources of Caffeine in Kids' Foods
Even low doses of caffeine can have an effect on your child's health. Since the FDA doesn't require caffeine content on food labels, learn about hidden sources of caffeine in kids' diets.

Find Today's Newest & Best Children's Books!
Looking for newly released books for your child? Try our new Book Finder tool to search for new books by age, type, and theme, and create reading lists for kids!