THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

Physiological and ecological constraints play key roles in the evolution of plant growth patterns, especially in relation to defenses against herbivores. Phenotypic and life history theories are unified within the growth-differentiation balance (GDB) framework, forming an integrated system of theories explaining and predicting patterns of plant defense and competitive interactions in ecological and evolutionary time. Plant activity at the cellular level can be classified as growth (cell division and enlargement) of differentiation (chemical and morphological changes leading to cell maturation and specialization). The GDB hypothesis of plant defense is premised upon a physiological trade-off between growth and differentiation processes. The trade-off between growth and defense exists because secondary metabolism and structural reinforcement are physiologically constrained in dividing and enlarging cells, and because they divert resources from the production of new leaf area. Hence the dilemma of plants: Th...

https://www.jstor.org/stable/pdfplus/2830650.pdf

The dilemma of plants: To grow or defend.

Identification of the selective forces on plant dispersal engenders theoretical argument, empirical study, and speculation. We separate evidence, testable hypotheses, and conjecture surrounding two major questions in dispersal ecology. The first asks what ecological, and ultimately evolutionary, advantages exist in seed dispersal. Astonishingly little is known about the advantages to a parent plant that are actually conferred by investment in dispersal structures. Does dispersal enable seeds and ultimately seedlings to escape mortality near the parent? Is continual recolonization of unstable habitats the primary advantage? Must seeds find rare microhabitats suitable for reestablishment? Such issues are addressed through joint consideration of dispersal and establishment-those stages both mediated by parental provisioning and subject to the highest mortality in the life of a plant. The second broad question asks what general and explicit environmental forces influence the timing and mode of dispersal. Do climates or seasons favor one dispersal mode over another? Do differences in number, size, morphology, or nutritional quality of fruits influence frugivore choice, and consequently differential dispersal of species or individuals within species? Studies of dispersal process and mode should be intimately connected. A general objective of this paper is to explore the degree to which they are integrated and, in so doing, to catalyze their union. We emphasize topics most in need of critical attention: the evolutionary ecology of dispersal process and mode. Excellent recent reviews consider such related topics as dispersal mechanism (131, 184), seed dormancy (1, 30), phytogeography (11, 115, 146), masting and predator satiation (105, 156), and succession (68, 69, 189).

https://www.jstor.org/stable/info/2097067

Ecology of Seed Dispersal

Genetics and analysis of quantitative traits

During the past decade ecologist have devoted considerable energy to demographic studies of flowers and fruits between anthesis and dispersal. These efforts have led to the growing realization that the number of flowers and fruits and the way they are clustered in time and space influence pollinator attraction...

Flower and Fruit Abortion: Proximate Causes and Ultimate Functions

CHAPTER 6 – Male Competition, Female Choice, and Sexual Selection in Plants

Catalpa speciosa regularly initiates more fruits than it matures. Most of the fruits that fail to mature are abscised from 2-5 wk after the flowering period. Catalpa speciosa has a host- specific herbivore, Ceratomia catalpae (Sphingidae), which severely defoliates some branches while causing little or no damage to leaves of other branches. The pattern of fruit abscission was examined in relation to the principal herbivore. Field observations and experiments show: (1) the larger the infructescence, the higher the probability that a given fruit will abort; (2) branches that have expe- rienced simulated herbivory have significantly more abortions than control branches; (3) if one fruit is aborted from an infructescence, the remaining fruits have a higher probability of maturing; (4) fruits accumulate <10% of their mature dry weight and total protein during the 1st 5 wk of growth and the remaining 90W in the next 4 wk (after the period of abortion). These data suggest that (1) each branch supplies the energy necessary to mature the fruits that it bears, (2) environmental stress, especially herbivory, reduces the resources available for fruit production, (3) fruit abortion is a response to limited resources, and (4) the pattern of fruit growth reduces the "cost" of abortion. The overall pattern of fruit reduction is interpreted as an adaptive trade-off between seed number and seed quality which permits the parent plant to match fruit production with available resources.

Fruit Set, Herbivory, Fruit Reduction, and the Fruiting Strategy of Catalpa Speciosa (Bignoniaceae)

Each inflorescence on Lotus corniculatus commonly aborts about half of its immature fruits. Compared to random patterns of fruit abortion, natural patterns of fruit abortion produce mature fruits that contain significantly more seeds. Moreover, these progeny are more likely to germinate, are more vigorous as seedlings, and have greater reproductive output as adults. These results indicate that L. corniculatus selectively aborts those fruits with the fewest seeds and, by doing so, increases the average quality of its offspring.

Lotus corniculatus regulates offspring quality through selective fruit abortion.

We review the effects of herbivory and other environmental factors on pollen performance in plants. We conclude that natural levels of variation in herbivory and other environmental factors during pollen development are often sufficient to cause significant differences in pollen performance, and that the differences in pollen performance are likely to be caused by differences in the provisioning of pollen grains. From an evolutionary perspective, we discuss how pollen and ovule provisioning may be negatively genetically correlated and how this would maintain genetic variation for pollen performance within populations. Furthermore, the highly plastic nature of pollen performance provides the potential for genotypes to respond differently to environmental variation (genotype–environment interactions), which would also promote the maintenance of genetic variation in pollen performance.

Andrew G. Stephenson

Papers

Flower and Fruit Abortion: Proximate Causes and Ultimate Functions

CHAPTER 6 – Male Competition, Female Choice, and Sexual Selection in Plants

Fruit Set, Herbivory, Fruit Reduction, and the Fruiting Strategy of Catalpa Speciosa (Bignoniaceae)

Lotus corniculatus regulates offspring quality through selective fruit abortion.

How environmental factors affect pollen performance: ecological and evolutionary perspectives