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

highlights

Teens and E-Cigarettes: 6 Things You Must Know
For the first time in a generation, tobacco use has risen among the nation's youth, due to the rising use of e-cigarettes. Learn more about the dangerous and addictive e-cigarette trend, and get tips to talk to your teen.

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, brought to you by Galactic Hot Dogs.

Printable Lists of the Top 100 Baby Names
Need help with baby name ideas? Use our printable list of the top 100 girl names and top 100 boy names of 2015 to help you brainstorm and narrow down your favorites.

Registered for Kindergarten — Now What?
Wondering what to do now that you've signed your child up for kindergarten? Try our award-winning Kindergarten Readiness app! This easy-to-use checklist comes with games and activities to help your child build essential skills for kindergarten. Download the Kindergarten Readiness app today!

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 Facebook icon Follow Us on Pinterest

editor’s picks