Eric Knapp Photo

Great Western Divide, Sequoia National Park

Life Uprooted

The tree roots in these photographs came from a study by colleagues who dug up ponderosa pine trees with the aid of dynamite and a backhoe to figure out how much carbon and nutrients are stored underground. When the study was finished, the roots were set aside. After years of walking past this pile of discarded wood and admiring the surreal sculpture-like shapes, I eventually rescued them, filling my garage and yard.

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"Dancing at dawn" - Surprise Valley

Surprise Valley

"Gathering" - Surprise Valley

"Contemplation" - Surprise Valley

"Waiting for the storm" - Surprise Valley

Moonstone Beach

"Symmetry" - Moonstone Beach

"Emergence" - Moonstone Beach

"Infinity" - Moonstone Beach

Moonstone Beach

"Moment of reflection" - Moonstone Beach

Moonstone Beach

"Serenity I" - Moonstone Beach

"Serenity II" - Moonstone Beach

Cemetery, Old Shasta

"Remembering our roots" - Old Shasta

Burning Man, Black Rock Desert

Roots illuminated

Roots burning on the coals of the "Man"

"Transformation" - Burning Man

Natural Variation

Within plant populations, no two individuals look exactly alike. Sometimes the differences in traits such as flower color or the color of leaves in the fall are obvious. Other differences, such as leaf shape or growth form are more subtle. This variation not only provides the building blocks for evolutionary change, but adds interest and beauty to our surroundings. I began to photograph variation in nature while teaching a college course in plant evolution, when I discovered that many students had a hard time grasping the concept of within-species variation in plants. Variation within Homo sapiens is a different story - height, hair color, eye color, length of toes... the differences among all of us seem rather obvious. Do plants contain a similar array of forms, but we just don't notice? Maybe we would if we spent more time with plants and developed the eye to see it. Differences in organisms can be due to both the environment or the genes, and it is only the latter that can be inherited. To increase the odds of capturing genetic variation, I mostly work with plants growing in close proximity to each other, in one photo frame. Such plants theoretically share the same or close to the same environment, so the differences are more likely to be because of genetic variation.

Castilleja exerta (Owl's clover) flower color variation

Madia elegans color variants

Quercus wizlisenii (Interior Live Oak) acorn size variation

Clarkia unguiculata flower color variation

Linanthus ciliatus flower color variation

Clover leaf patterns

Eschscholzia californica flower color variation

Quercus douglasii (Blue oak) - variation in spring leaf-out date

Butter and eggs (Triphysaria eriantha) flower color variation

Castilleja (Indian paintbrush) color mutation

Collinsia tinctoria flower color variation

Castilleja exerta flower color variation

Fall color variation in aspen (Populus tremuloides)

Linanthus parryae flower color variation

Early evolutionary biologists puzzled about L. parryae because populations could be found that contained only white flowers while other populations contained only blue flowers. Still other populations were mixed, like this one. Was it because of natural selection or was it due to random chance (genetic drift)? Experiments done by Schemske and Bierzychudek (2001) [Evolution 55:1269-1282] showed natural selection may play a role: white-flowering plants produced more seed than blue-flowering plants in wet years and the reverse occurred in dry years. Because rainfall in the desert environment where these plants grow is so variable from year to year, both forms are maintained.