Posts Tagged ‘ecology’

Hitching a Ride: Biological Relationships in the Natural World

While breezing through National Geographic‘s online magazine a few weeks ago I came across a remarkable photograph that had been taken off the coast of New South Wales, Australia: a seal riding on the back of a humpback whale. Scientists say this event is indeed rare, but not unheard of.  It’s not clear whether this was an example of a special biological relationship between the seal and whale or if the seal was just joy riding. This got me to thinking about other biological relationships that occur quite often in nature, such as the one between the oxpecker and the African buffalo, or the common relationships between insects and plants.

eLibrary can assist ecology and biology educators in teaching students the world of these complex relationships with specific resources in the fields of biology and ecology.

In ecology, the interaction and relationship between two different species is called symbiosis. Within symbiosis, there are three major types of relationships: mutualism, commensalism, and parasitism.

These relationships can occur not only between species in the animal world but also in the plant and microbial worlds. Anyone who has seen the bright orange or yellow plant-like covering on some rocks are probably looking at lichen, a symbiotic relationship between algae and fungus. And relationships can also exist between biological kingdoms such as between plant and animal (for example, the flower and the bee). It might also surprise your students to learn that we humans, as well as other animals, have symbiotic relationships with microorganisms within our own bodies.

In the case of the relationship between the red-billed oxpecker and the African buffalo, this is considered a mutualistic relationship (sometimes called cleaning symbiosis) where each benefits from the other’s existence and behavior. The oxpecker will perch somewhere on the buffalo and feed on ticks (parasites) and other insects that have taken up residence and pester them. In this way, both mutually benefit from each other: the oxpeckers get a hardy meal and the ungulates are happily rid of the annoying parasites.

You can learn more about the other types of symbiosis (commensalism and parasitism), and other animal and biological relationships in eLibrary. We have a wealth of biological and ecological resources to assist you in helping your students explore the world of symbiosis and biological relationships. We have Research Topics on Symbiosis, Community Ecology, Biomes and Ecosystems, Population Ecology, as well as the broader subjects of Biology and Ecology that can enrich your instruction.

Earth Day History

For more than four decades, people in the United States have marked April 22 as Earth Day, which celebrates the planet and promotes environmental protection. Since 1990, it has been a global event that is said to be the largest secular holiday in the world, with more than a billion observers.


What is today known as Earth Day was founded in 1970 by U.S. Senator Gaylord Nelson. The stirrings of the ecology movement had begun in the 1960s, largely due to theEarth Day 1970 in New York City publication of “Silent Spring,” Rachel Carson’s 1962 book about the environmental impacts of the pesticide DDT. Seizing upon the tactics of the anti-Vietnam War movement, Nelson hoped to use public demonstrations to bring environmental issues to the national attention and into the political arena. The date of April 22 was chosen in order to maximize the participation of college students in what Nelson termed “teach-ins,” and, with the help of national coordinator Denis Hayes, Earth Day events involving 20 million people were organized across the country.

Going Global

Over the years, Earth Day continued to grow, and in 1990, Hayes was tapped to organize the 20th-year event, which took Earth Day global to 200 million people in 141 countries. At the 30-year mark, Hayes led the push for awareness about global warming and clean energy in an Earth Day that reached 184 countries. On Earth Day 2010, around quarter of a million people gathered at the National Mall in Washington DC for a Climate Rally.


As a result of his environmental efforts and founding of Earth Day, Gaylord Nelson was presented with the National Medal of Freedom by President Bill Clinton in 1995. His creation, which now is said to reach a billion people in more than 192 nations, is widely credited with leading to the creation of the Environmental Protection Agency and the Clean Air Act, the Clean Water Act and the Endangered Species Act. While some over the years have wrestled with what Earth Day is, what it should be and what its impact is, there is no doubt that it has struck a nerve with people across the globe and has helped bring environmental awareness to the mainstream.

Follow the links above and below to see some of eLibrary’s resources related to this topic and others, but don’t stop there. Use eLibrary’s Basic and Advanced search tools, Topic browse and Research Topics browse to find much more.

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Earth Day Research Topic

Earth Day Research Topic

Environmentalism, Pollution, Air Pollution, Water Pollution, Projects & Experiments: Ecology, Religion and the Environment

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Ecology, Pollution