The Advantage of Sex

Why did sex evolve? The likely answers, in this essay for the Evolution Web site by science journalist Matt Ridley, may surprise you.

All in the Family

In this Evolution Web feature, test your skills at judging who's who on the tree of life while you learn about the tools and methods of cladistics.

Alzheimer's Disease

This video segment from the Secret of Life School Video: "Genetic Medicine: Tinkering with Our Genes" explores the potential for gene therapy to cure diseases like Alzheimer's.

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American Chestnut Tree

This annotated slideshow adapted from KET's Electronic Field Trip to the Forest illustrates how blight decimated the American chestnut tree and the methods scientists use to identify and pollinate the remaining trees to create blight-resistant trees.

Animal Babies

This interactive slide show illustrates the variety of animal babies that exist on earth -- some completely independent and others deeply reliant on parental care.

Animal Body Plans: Homeobox Genes

The homeobox genes that define the basic body plan of mice and fruit flies are illustrated in this graphic from The Human Evolution Coloring Book by Adrienne Zihlman. The accompanying article describes how these genes act as "molecular architects" in all animal species.

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Animal Cloning 101

Learn about clones and explore the methods scientists use to create clones in the lab in this interactive activity from the Dolan DNA Learning Center.

Animal Coverings

It takes a thick skin to withstand the hardships that life has to offer. This collection of images shows a variety of animals, each with a slightly different type of protective covering.

Asexual Reproducers

This video segment explores the benefits and pitfalls of cloning as a means of reproduction. From Evolution: "Why Sex?"

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Becoming a Mosquito

Join students as they observe mosquitoes in different stages of development and learn about the insect's life cycle in this video from Curious George.

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Bioengineered Foods?

Students compare the processes of selective breeding and transgenic manipulation of plants. They consider the pros and cons of growing genetically modified crops.

Bird Beak Gallery

This collection of images of 10 different birds illustrates the diversity of bird beaks.

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Birth, Growth, and Development

By examining the developmental stages of animals, students learn about the life cycles of living things.

Bt Corn

This video segment from FRONTLINE/NOVA: "Harvest of Fear" looks at corn that has been genetically modified to resist one insect pest, and the multiple concerns it raises.

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Build a Family Tree

Both sexes can use this interactive feature that lets you use DNA information from the Y chromosome to complete a male family tree. From the NOVA: "Lost Tribes of Israel" Web site.

Can We Slow Aging?

In this video segment adapted from NOVA scienceNOW, scientists discuss a family of genes called FOXO that can significantly extend life span in worms—and in humans.

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Cell Membrane: Just Passing Through

This interactive feature describes some of the most important structures and functions of the cell membrane.

Cell Replication

Students explore the structure and function of cells and mitosis.

Cell Transcription and Translation

In this interactive activity adapted from the University of Nebraska, learn how and where transcription and translation occur within a cell and observe both processes in detail.

Chromosome Viewer

This interactive feature provides a microscopic view of the 24 Human chromosomes. Each chromosome is labeled with the names of some of the genetic conditions and traits associated with particular regions on that chromosome.