Posts Tagged ‘Biology’

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.

Charles Darwin Publishes “The Descent of Man”

In 1859 when Charles Darwin published “On The Origin of Species” he was roundly criticized in religious circles for what the book merely implied: that humans were descended from lower forms of life, and specifically, from the apes. In that publication Darwin did not explicitly make that connection, as his focus was on the evolution and descent of other non-human species. But the implications to his conclusions were nonetheless obvious.

In fact, over the years Darwin had been collecting notes on the origin of man but had no intention in publishing them. But twelve years after the publication of “On the Origin of Species,” on this date in 1871, Darwin dove head long into the argument with the publication of those notes with the “The Descent of Man and Selection in Relation to Sex.” He noted in his introduction  that “During many years I collected notes on the origin or descent of man, without any intention of publishing on the subject, but rather with the determination not to publish, as I thought that I should thus only add to the prejudices against my views.”(1) It was clear that Darwin was sensitive to his critics but also eager to extend his arguments to include humans for his theory of evolution.

Where Darwin differed from others who had written about human origin, such as Thomas Henry Huxley, Charles Lyell, and Alfred Russel Wallace, was his theory of sexual selection, an evolutionary process which he considered a mode natural selection. In one example, Darwin theorized that beauty was an attribute of sexual selection, and that in turn was a process of evolution that drives the continuation of the human species. This contradicted George Campbell, Duke of Argyll, in his work “The Reign of Law” which stated clearly a creationist point of view that beauty was wholly a human attribute and had no utility at all, but was of divine creation. Clearly, as with “Origin,” Darwin had once again raised the concerns of the religious establishment. If “Origin” merely hinted at the idea that man had descended from lower forms, such as the primates, then “Descent” blew the door wide open.

You can read more about Charles Darwin, evolution, and human origins in eLibrary. “Descent of Man and Selection in Relation to Sex” and “On the Origin of Species”, as well as “Voyages of the Beagle”, can be found in eLibrary in full text form. To search these and other resources, try the following:

Go to the Basic Search page and click on Advanced Search:

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In Advanced Search you can perform a document title and author search:

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In Publications, you can either browse by letter or do a search. Look for “Descent of Man” in the “History of the World” book and “Origin of Species” in “Great Books in Literature” book.

Check out more resources  below:

Research Topics:

Alfred Russel Wallace
Charles Darwin
Charles Lyell
Natural Selection and Adaptation
Thomas Henry Huxley

Browse by Topic:

Agents of Evolution (including Natural Selection)

Charles Darwin
Hominid Evolution
Evolutionary Biology
Evolutionary Biologists

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Great Works in Literature (Origin of Species & Voyage of the Beagle)
History of the World (Descent of Man)



1. Darwin, Charles. “Descent Of Man, The: Preface And Introduction.” History of the World. N.p.: Bureau of Electronic, 1992 DB – ELibrary. N. pag. Web.

For Some Animals, Autumn Means a Feeding Frenzy Before the Big Sleep

Grizzly Bear Feeding on Salmon

From the latter stages of summer into late fall large animals, such as the grizzly bear, enter a metabolic phase known as hyperphagia; that is, they begin to eat enormous amounts of food to store as fat in order to carry them through the winter. During these winter months some animals will enter a state of deep sleep known as hibernation. The function of hibernation for most animals is to conserve energy long enough to survive the adverse weather conditions and extremely low temperatures of winter when food supplies are at their lowest.

Hibernation habits vary with different animals. Hibernating Ground SquirrelWhile in hibernation some animals will achieve a deep sleep, slowing the heart rate and breathing, and lowering its body temperature and metabolism to a minimum while the body uses its body fat reserves. With this type hibernation, a much deeper sleep is achieved, as opposed to regular sleep, where the animal does not move at all — even when touched — and can take a considerably long time to wake up. Some bears may sleep through the whole winter while other bears may wake for a mid-winter’s walk. Smaller animals, like the chipmunk, cache food such as nuts and seeds, occasionally waking long enough to eat from the cache. Still other animals, like amphibians and reptiles, don’t actually hibernate but rather enter  dormant states called brumation or torpor.

Learn more about hibernation and other over-wintering animal behavior such as migration that animals use to cope with seasonal changes through eLibrary’s Research Topics. You can also browse the Animal Behavior Topic area, which includes a section on hibernation. Here are a few articles to get you started.

The Secrets of Winter Sleep

Lessons From the Torpid

Cold-Blooded in the Cold: Hibernation

Facing the Winter

The Lemur Underground