Corrections, commentary, and links pertaining to:
Darwinian Agriculture: When can humans find solutions beyond
the reach of natural selection? Quarterly
Review of Biology 78:145-168.
Commentary on Darwinian Agriculture from other web sites
A GMO discussion on
metafilter.com says Darwinian Agriculture makes a "persuasive
argument that little can be gained, certainly within the next 20 years,
in terms of overall food production by genetic modification..." and
summarizes some of the other points in the first half of the paper. A
good summary, if a bit pessimistic. It's at least possible that there
are still some significant unexploited tradeoffs between
competitiveness and yield. If so, biotech methods (including
those that use DNA-based methods to identify promising materials for
conventional breeding, producing a nontransgenic product) could speed
the development of higher-yielding (but less competitive) cultivars.
Agriculture -Related Science and Technology Priorities for Poverty
Reduction and Sustainable Development in Developing Countries to 2020
"...there is a need to establish a sound conceptual framework to guide
further investments in this area (see Denison, 2003 for such a
framework)." -- Ken Cassman
New Directions for Agriculture in Reducing Poverty
"even with biotechnology, there is only so much that research can accomplish... There are limits, which are nicely spelled out in a recent article by R. Ford
Denison, et al. titled "Darwinian Agriculture; When Can Humans Find Solutions Beyond the Reach of Natural Selection?" in the QUARTERLY
REVIEW OF BIOLOGY, June 2003. And we cannot take current yield levels for granted: an increasing amount of maintenance research will be needed
to hold on to current levels, let alone productivity-increasing research to meet the needs of an expanding, wealthier, and increasingly
urbanized population." -- Dana Dalrymple
General comments and papers we missed
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- "there seems to be little hope of improving the efficiency of the
photosynthetic process by selection or breeding" Watson (1958) Ann.
- 23 June 2003 Ulrich Mueller points out that ants have been
for 40 million years and may have something to teach us about
See for example PNAS 99:15247.
- 16 June 2003 RFD. Johnson and Mayeux (J. Range Mgt. 45:322)
questioned the "balance of nature" as it applies to rangeland.
point out that creosotebush expanded so quickly it makes one doubt that
the previous community was self-maintaining. (Similar examples of
rapid invasions have been noted at least since Origin of Species,
3.) They also point out that individual creosotebush plants live
long enough that the "first generation" may still be dominant, limiting
opportunities for coevolution of creosotebush with other species.
- 1 June 2003 RFD. Another interesting and relevant paper we
is "Artificial ecosystem selection" (PNAS 97:9110). The authors
to show that artificial selection of soil microbial communities can be
effective, even though the community presumably contains a very large
of individuals. This result appears to contrast with our Table 2,
which suggests that group selection will only work when each group
a small number of individuals. The progress with selection
was quite erratic, however. All plants died in "generation" 15,
selection was for high or low plant biomass. Apparently they had
some unselected controls, but these weren't included in the
Independent replication of this work might be worthwhile. The
also state that "Natural ecosystem selection is unlikely to occur..."
large scales, such as an entire forest. This conclusion is
with our Hypothesis 2.
- 1 June 2003 RFD. Although increasing seed yield was
a goal of the "male sterile" trait (our Table 1), it could be a side
In maize, shading of leaves by male flowers may reduce photosynthesis
Sci. 7:37). This is in addition to the direct C and N costs of
male flowers and pollen.
Biomimetics and human-directed evolution
Ingenious humans mimicking the products of individual selection or
individual- or group-selection in creative ways.