Initial Publication Date: August 12, 2008

Coral Reefs, the Human View

Part A: Introduction to Coral Reefs

What is Coral? What is a Reef?

Animal, vegetable, or mineral? What exactly is coral? While corals might look more like rocks or plants, they are actually made up of tiny invertebrate animals, called polypscoral polyp: a small individual coral animal with a tube-shaped body and a mouth surrounded by tentacles., that are related to sea anemones and jellyfish. In total, there are more than 4,000 different coral species of various shapes, sizes, and colors.

1. Watch the short video Coral Reef Biology. As you watch, take notes as preparation for answering the following questions.

If the video does not play, visit Blue World to watch.

Checking In

What is a coral reef?

Relationships on a Coral Reef

A coral reef is a diverse ecosystem teeming with many different organisms. Just as on land, whether in a city or a forest, relationships exist among all reef-dwelling life forms.

2. Watch the video Exploring Ecosystems to learn more about symbiotic relationships in the reef; be sure to take notes on what you learn.

If the video does not play, visit PBS Learning Media to watch.

Checking In

The video covered three main types of symbiotic relationships. Can you remember what they were called?

1. ________: both partners benefit


2. ________: one partner benefits and the other is harmed


3. ________: one partner benefits and the other is not affected

Human Benefits

Why do we care about reefs? From food source to protection from storm damage, coral reefs have many benefits for the human population.

3. Read the information sheet Why are Coral Reefs so Important? (Acrobat (PDF) 737kB Mar10 20) to learn more about what reefs do for humans.

Brain coral, a type of hard coral that resembles the human brain. Image courtesy of Wikipedia Commons.

Stop and Think

1: How do species interact on a coral reef? Describe and give examples of at least two different relationships found there and explain which organism(s) benefits or is harmed by these relationships.

2: Can you think of any human relationships with coral reefs? Would you classify any of these relationships as symbiotic? Explain.

Optional Extensions

Learn more about symbiotic relationships among different coral reef inhabitants.

Watch a NOAA video Medicines from the Sea

Watch a video from 2018's Year of the Reef Medicine Chests of the Sea

Watch a NOAA video about the Coral Reef Economy