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Bruce D Smith

Smithsonian Institution, Anthropology, Curator of North American Archaeology, Senior Research scientist

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Address: 45 Gold Trail
Santa Fe, New Mexico 87508

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Smithsonian Institution

University of Arizona

Jade d'Alpoim Guedes

University of California, San Diego

University of Connecticut

Alejandro Fábregas-Tejeda

KU Leuven

Francisco Vergara-Silva

Universidad Nacional Autónoma de México

David Guilfoyle

The University of Western Australia

BrieAnna Langlie

Binghamton University

Université de la Réunion

Santa Clara University

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Papers by Bruce D Smith

Neo-Darwinism, niche construction theory, and the initial domestication of plants and animals

The initial domestication of plants and animals and the subsequent emergence of agricultural econ... more The initial domestication of plants and animals and the subsequent emergence of agricultural economies, which began independently more than 10,000 years ago in a number of different world regions, represent a major evolutionary transition in earth history. It is these domesticates, and the agricultural economies based on them, that have formed the lever with which humans have substantially modified the earth's terrestrial ecosystems over the past ten millennia. General explanations for this transition from hunting and gathering to food production economies formulated over the past 40 years have been based on standard evolutionary theory (SET) and employ the assumption of unidirectional adaptation—that environments change and species adapt. Here I compare these proposed SET—based externalist explanations for domestication with a recently formulated alternative developed from niche construction theory (NCT). Archaeological and paleoenvironmental records from two independent centers of domestication in the Americas—eastern North America and the Neotropics of northern South America, are found to support the NCT-based explanatory approach but not the SET explanations, underscoring the limitations of externalist SET approaches and the need for broader conceptualization of the processes that direct evolutionary change in order to gain a better general understanding of initial domestication as well as other major evolutionary transitions.

Gourds and squashes (Cucurbita spp.) adapted to megafaunal extinction and ecological anachronism through domestication

by Andrew Clarke and Bruce D Smith

The genus Cucurbita (squashes, pumpkins, gourds) contains numerous domesticated lineages with anc... more The genus Cucurbita (squashes, pumpkins, gourds) contains numerous domesticated lineages with ancient New World origins. It was broadly distributed in the past but has declined to the point that several of the crops’ progenitor species are scarce or unknown in the wild. We hypothesize that Holocene ecological shifts and megafaunal extinctions severely impacted wild Cucurbita, whereas their domestic counterparts adapted to changing conditions via symbiosis with human cultivators. First, we used high-throughput sequencing to analyze complete plastid genomes of 91 total Cucurbita samples, comprising ancient (n = 19), modern wild (n = 30), and modern domestic (n = 42) taxa. This analysis demonstrates independent domestication in eastern North America, evidence of a previously unknown pathway to domestication in northeastern Mexico, and broad archaeological distributions of taxa currently unknown in the wild. Further, sequence similarity between distant wild populations suggests recent fragmentation. Collectively, these results point to wild-type declines coinciding with widespread domestication. Second, we hypothesize that the disappearance of large herbivores struck a critical ecological blow against wild Cucurbita, and we take initial steps to consider this hypothesis through cross-mammal analyses of bitter taste receptor gene repertoires. Directly, megafauna consumed Cucurbita fruits and dispersed their seeds; wild Cucurbita were likely left without mutualistic dispersal partners in the Holocene because they are unpalatable to smaller surviving mammals with more bitter taste receptor genes. Indirectly, megafauna maintained mosaic-like landscapes ideal for Cucurbita, and vegetative changes following the megafaunal extinctions likely crowded out their disturbed-ground niche. Thus, anthropogenic landscapes provided favorable growth habitats and willing dispersal partners in the wake of ecological upheaval.

Gourds and squashes (Cucurbita spp.) adapted to megafaunal extinction and ecological anachronism through domestication

The genus Cucurbita (squashes, pumpkins, gourds) contains numerous domesticated lineages with anc... more The genus Cucurbita (squashes, pumpkins, gourds) contains numerous domesticated lineages with ancient New World origins. It was broadly distributed in the past but has declined to the point that several of the crops’ progenitor species are scarce or unknown in the wild. We hy- pothesize that Holocene ecological shifts and megafaunal extinctions severely impacted wild Cucurbita, whereas their domestic counterparts adapted to changing conditions via symbiosis with human cultivators. First, we used high-throughput sequencing to analyze complete plastid genomes of 91 total Cucurbita samples, comprising ancient (n = 19), modern wild (n = 30), and modern domestic (n = 42) taxa. This analysis demonstrates independent domestication in eastern North America, evidence of a previously unknown pathway to domestication in north- eastern Mexico, and broad archaeological distributions of taxa cur- rently unknown in the wild. Further, sequence similarity between distant wild populations suggests recent fragmentation. Collectively, these results point to wild-type declines coinciding with widespread domestication. Second, we hypothesize that the disappearance of large herbivores struck a critical ecological blow against wild Cucurbita, and we take initial steps to consider this hypothesis through cross- mammal analyses of bitter taste receptor gene repertoires. Directly, megafauna consumed Cucurbita fruits and dispersed their seeds; wild Cucurbita were likely left without mutualistic dispersal partners in the Holocene because they are unpalatable to smaller surviving mammals with more bitter taste receptor genes. Indirectly, megafauna main- tained mosaic-like landscapes ideal for Cucurbita, and vegetative changes following the megafaunal extinctions likely crowded out their disturbed-ground niche. Thus, anthropogenic landscapes pro- vided favorable growth habitats and willing dispersal partners in the wake of ecological upheaval.

A Comparison of Niche Construction Theory and Diet Breadth Models as Explanatory Frameworks for the Initial Domestication of Plants and Animals

The initial domestication of plants and animals and the subsequent emergence of agricultural econ... more The initial domestication of plants and animals and the subsequent emergence of agricultural economies in different world regions represent a major evolutionary transition in human history. Here, two alternative and antithetical explanatory frameworks for initial domestication are compared—one based on diet breadth modeling and the other on niche construction theory. This side-by-side comparison of these two alternative explanations follows them through the basic sequence of stages involved in the scientific method: hypothesis formulation, plausibility consideration, and actual testing of the two hypothetical explanations by measuring their relative strengths with the available archaeological and paleoenvironmental data from two independent centers of domestication in the Americas— eastern North America and the Neotropics. Although focused on the question of initial domestication, this comparative analysis also addresses the broader issues of the appropriate role of theory in the development of hypotheses of past human behavior and the proper use of the scientific method in archaeological inference. Explanations based on diet breadth modeling are found to have a number of conceptual, theoretical, and methodological flaws; approaches based on niche construction theory are far better supported by the available evidence in the two regions considered.

Failure of optimal foraging theory to appeal to researchers working on the origins of agriculture worldwide

A Cultural Niche Construction Theory of Domestication

Biological Theory, 2012

I present a general theory for the initial domestication of plants and animals that is based on n... more I present a general theory for the initial domestication of plants and animals that is based on niche construction theory and incorporates several behavioral ecological concepts, including central-place provisioning, resource catchment, resource ownership and defensibility, and traditional ecological knowledge. This theory provides an alternative to, and replacement for, current explanations, including diet breadth models of optimal foraging theory, that are based on an outmoded concept of asymmetrical adaptation and that attempt to explain domestication as an adaptive response to resource imbalance resulting from either environmental decline or human population growth. The small-scale human societies that first domesticated plants and animals share a number of basic interrelated attributes that when considered as an integrated and coherent set of behaviors provide the context for explaining initial domestication not as an adaptive response to an adverse environmental shift or to human population growth or packing but rather as the result of deliberate human enhancement of resource-rich environments in situations where evidence of resource imbalance is absent.

General patterns of niche construction and the management of "wild" plant and animal resources by small-scale societies

Philosophical Transactions of the Royal Society B, 2011

Documenting domesticated plants in the archaeological record

Documenting Domestication: New genetic and archaeological paradigms, 2006

The Onset of the Anthropocene

Anthropocene, 2013

Reconsidering the Ocampo Caves and the era of incipient cultivation in Mesoamerica

LAtin AMerican Antiquity, 1997

In northeastern Mexico, near Ocampo, Romerok and Valenzuela S caves have been central to explanat... more In northeastern Mexico, near Ocampo, Romerok and Valenzuela S caves have been central to explanations of agricultural origins in Mesoamerica for more than four decades. Along with caves in Tehuacdn and Oaxaca, these "Ocampo caves" have provided almost all of the available evidence for the initial appearance of a number of key Mesoamerican crop plants, including maize, beans, and squash. This article reanalyzes the cultural and temporal context offive crop plant assemblages in the Ocampo caves: maize (Zea mays), bottle gourd (Lagenaria siceraria), and three species of squash (Cucurbita argyrosperma, C. moschata, C. pepo). Fifteen AMS radiocarbon dates on early domesticates both confirm the stratigraphic integrity of the two caves and substantially revise the temporal framework for initial appearance of core domesticates in northeastern Mexico, showing the transition to food production in Tamaulipas took place more recently than previously thought. A suhstantially foreshortened chronology for Ocampo crop plants confirms the northern periphery role of Tamaulipas in the origins of agriculture in Mexico, while also underscoring the need for establishing AMS-based archaeobotanical sequences across Mesoamerica to gain an adequate context for understanding the temporal, environmental, and cultural contexts of initial plant domestication in the region.

The initial domestication of Cucurbita pepo in the Americas 10,000 years ago

Science, 1997

Between foraging and farming

Science, 1998

Documenting plant domestication: the consilience of genetic and archaeological approaches

PNAS, 2001

Low Level Food Production

Journal of Archaeological Research, 2001

Societies with low-level food production economies occupy the vast and diverse middle ground betw... more Societies with low-level food production economies occupy the vast and diverse middle ground between hunting-fishing-foraging and agriculture. Efforts by Ford, Harris, Rindos, Zvelebil, and others to characterize this "in-between" territory are discussed, and a new conceptual framework is proposed. Domestication, the central landmark of this middle ground, is situated well away from the boundaries with hunting-gathering and agriculture, and separates low-level food production economies into two broad categories. Key issues and questions concerning societies with low-level food production, both with and without domesticates, are discussed. Hunter-gatherer and agriculture boundary zones on either side of the middle ground are considered, as are the developmental pathways that traverse them.

Early Allelic selection in maize as revealed by ancient DNA

Science, 2003

National Academy of Sciences profile of Bruce D. Smith

PNAS, 2005

Reassessing Coxcatlan Cave and the early history of domesticated plants in Mesoamerica

PNAS, 2005

Reanalysis and direct accelerator mass spectrometry radiocarbon dating of the cucurbit assemblage... more Reanalysis and direct accelerator mass spectrometry radiocarbon dating of the cucurbit assemblage from Coxcatlan Cave provide information on the timing and sequence of the initial appearance of three domesticated plants in the Tehuacá n Valley (Puebla, Mexico) and allow reassessment of the overall temporal context of plant domestication in Mexico. Cucurbita pepo is the earliest documented domesticate in the cave, dating to 7,920 calibrated calendrical (cal) years B.P. The bottle gourd (Lagenaria siceraria) is dated at 7,200 cal years B.P. Cucurbita argyrosperma does not appear until 2,065 cal years B.P. The earlier identification of Cucurbita moschata specimens is not confirmed. Seventy-one radiocarbon dates, including 23 accelerator mass spectrometry dates on cucurbits, provide ample evidence of postdepositional vertical displacement of organic materials in the western half of Coxcatlan Cave, but they also indicate that the eastern half of the cave was largely undisturbed.

Documenting domestication: the intersection of genetics and archaeology

Trends in Genetics, 2006

Domestication, a process of increasing mutual dependence between human societies and the plant an... more Domestication, a process of increasing mutual dependence between human societies and the plant and animal populations they target, has long been an area of interest in genetics and archaeology. Geneticists seek out markers of domestication in the genomes of domesticated species, both past and present day. Archaeologists examine the archaeological record for complementary markers -evidence of the human behavior patterns that cause the genetic changes associated with domestication, and the morphological changes in target species that result from them. In this article, we summarize the recent advances in genetics and archaeology in documenting plant and animal domestication, and highlight several promising areas where the complementary perspectives of both disciplines provide reciprocal illumination.

Eastern North America as an independent center of plant domestication

PNAS, 2006

† Marshelder and sunflower fruits (achenes) consist of a single seed enclosed in a dry indehiscen... more

The molecular genetics of crop domestication

Cell, 2006

Ten thousand years ago human societies around the globe began to transition from hunting and gath... more Ten thousand years ago human societies around the globe began to transition from hunting and gathering to agriculture. By 4000 years ago, ancient peoples had completed the domestication of all major crop species upon which human survival is dependent, including rice, wheat, and maize. Recent research has begun to reveal the genes responsible for this agricultural revolution. The list of genes to date tentatively suggests that diverse plant developmental pathways were the targets of Neolithic "genetic tinkering," and we are now closer to understanding how plant development was redirected to meet the needs of a hungry world.

Neo-Darwinism, niche construction theory, and the initial domestication of plants and animals

The initial domestication of plants and animals and the subsequent emergence of agricultural econ... more The initial domestication of plants and animals and the subsequent emergence of agricultural economies, which began independently more than 10,000 years ago in a number of different world regions, represent a major evolutionary transition in earth history. It is these domesticates, and the agricultural economies based on them, that have formed the lever with which humans have substantially modified the earth's terrestrial ecosystems over the past ten millennia. General explanations for this transition from hunting and gathering to food production economies formulated over the past 40 years have been based on standard evolutionary theory (SET) and employ the assumption of unidirectional adaptation—that environments change and species adapt. Here I compare these proposed SET—based externalist explanations for domestication with a recently formulated alternative developed from niche construction theory (NCT). Archaeological and paleoenvironmental records from two independent centers of domestication in the Americas—eastern North America and the Neotropics of northern South America, are found to support the NCT-based explanatory approach but not the SET explanations, underscoring the limitations of externalist SET approaches and the need for broader conceptualization of the processes that direct evolutionary change in order to gain a better general understanding of initial domestication as well as other major evolutionary transitions.

Gourds and squashes (Cucurbita spp.) adapted to megafaunal extinction and ecological anachronism through domestication

by Andrew Clarke and Bruce D Smith

The genus Cucurbita (squashes, pumpkins, gourds) contains numerous domesticated lineages with anc... more The genus Cucurbita (squashes, pumpkins, gourds) contains numerous domesticated lineages with ancient New World origins. It was broadly distributed in the past but has declined to the point that several of the crops’ progenitor species are scarce or unknown in the wild. We hypothesize that Holocene ecological shifts and megafaunal extinctions severely impacted wild Cucurbita, whereas their domestic counterparts adapted to changing conditions via symbiosis with human cultivators. First, we used high-throughput sequencing to analyze complete plastid genomes of 91 total Cucurbita samples, comprising ancient (n = 19), modern wild (n = 30), and modern domestic (n = 42) taxa. This analysis demonstrates independent domestication in eastern North America, evidence of a previously unknown pathway to domestication in northeastern Mexico, and broad archaeological distributions of taxa currently unknown in the wild. Further, sequence similarity between distant wild populations suggests recent fragmentation. Collectively, these results point to wild-type declines coinciding with widespread domestication. Second, we hypothesize that the disappearance of large herbivores struck a critical ecological blow against wild Cucurbita, and we take initial steps to consider this hypothesis through cross-mammal analyses of bitter taste receptor gene repertoires. Directly, megafauna consumed Cucurbita fruits and dispersed their seeds; wild Cucurbita were likely left without mutualistic dispersal partners in the Holocene because they are unpalatable to smaller surviving mammals with more bitter taste receptor genes. Indirectly, megafauna maintained mosaic-like landscapes ideal for Cucurbita, and vegetative changes following the megafaunal extinctions likely crowded out their disturbed-ground niche. Thus, anthropogenic landscapes provided favorable growth habitats and willing dispersal partners in the wake of ecological upheaval.

Gourds and squashes (Cucurbita spp.) adapted to megafaunal extinction and ecological anachronism through domestication

The genus Cucurbita (squashes, pumpkins, gourds) contains numerous domesticated lineages with anc... more The genus Cucurbita (squashes, pumpkins, gourds) contains numerous domesticated lineages with ancient New World origins. It was broadly distributed in the past but has declined to the point that several of the crops’ progenitor species are scarce or unknown in the wild. We hy- pothesize that Holocene ecological shifts and megafaunal extinctions severely impacted wild Cucurbita, whereas their domestic counterparts adapted to changing conditions via symbiosis with human cultivators. First, we used high-throughput sequencing to analyze complete plastid genomes of 91 total Cucurbita samples, comprising ancient (n = 19), modern wild (n = 30), and modern domestic (n = 42) taxa. This analysis demonstrates independent domestication in eastern North America, evidence of a previously unknown pathway to domestication in north- eastern Mexico, and broad archaeological distributions of taxa cur- rently unknown in the wild. Further, sequence similarity between distant wild populations suggests recent fragmentation. Collectively, these results point to wild-type declines coinciding with widespread domestication. Second, we hypothesize that the disappearance of large herbivores struck a critical ecological blow against wild Cucurbita, and we take initial steps to consider this hypothesis through cross- mammal analyses of bitter taste receptor gene repertoires. Directly, megafauna consumed Cucurbita fruits and dispersed their seeds; wild Cucurbita were likely left without mutualistic dispersal partners in the Holocene because they are unpalatable to smaller surviving mammals with more bitter taste receptor genes. Indirectly, megafauna main- tained mosaic-like landscapes ideal for Cucurbita, and vegetative changes following the megafaunal extinctions likely crowded out their disturbed-ground niche. Thus, anthropogenic landscapes pro- vided favorable growth habitats and willing dispersal partners in the wake of ecological upheaval.

A Comparison of Niche Construction Theory and Diet Breadth Models as Explanatory Frameworks for the Initial Domestication of Plants and Animals

The initial domestication of plants and animals and the subsequent emergence of agricultural econ... more The initial domestication of plants and animals and the subsequent emergence of agricultural economies in different world regions represent a major evolutionary transition in human history. Here, two alternative and antithetical explanatory frameworks for initial domestication are compared—one based on diet breadth modeling and the other on niche construction theory. This side-by-side comparison of these two alternative explanations follows them through the basic sequence of stages involved in the scientific method: hypothesis formulation, plausibility consideration, and actual testing of the two hypothetical explanations by measuring their relative strengths with the available archaeological and paleoenvironmental data from two independent centers of domestication in the Americas— eastern North America and the Neotropics. Although focused on the question of initial domestication, this comparative analysis also addresses the broader issues of the appropriate role of theory in the development of hypotheses of past human behavior and the proper use of the scientific method in archaeological inference. Explanations based on diet breadth modeling are found to have a number of conceptual, theoretical, and methodological flaws; approaches based on niche construction theory are far better supported by the available evidence in the two regions considered.

Failure of optimal foraging theory to appeal to researchers working on the origins of agriculture worldwide

A Cultural Niche Construction Theory of Domestication

Biological Theory, 2012

I present a general theory for the initial domestication of plants and animals that is based on n... more I present a general theory for the initial domestication of plants and animals that is based on niche construction theory and incorporates several behavioral ecological concepts, including central-place provisioning, resource catchment, resource ownership and defensibility, and traditional ecological knowledge. This theory provides an alternative to, and replacement for, current explanations, including diet breadth models of optimal foraging theory, that are based on an outmoded concept of asymmetrical adaptation and that attempt to explain domestication as an adaptive response to resource imbalance resulting from either environmental decline or human population growth. The small-scale human societies that first domesticated plants and animals share a number of basic interrelated attributes that when considered as an integrated and coherent set of behaviors provide the context for explaining initial domestication not as an adaptive response to an adverse environmental shift or to human population growth or packing but rather as the result of deliberate human enhancement of resource-rich environments in situations where evidence of resource imbalance is absent.

General patterns of niche construction and the management of "wild" plant and animal resources by small-scale societies

Philosophical Transactions of the Royal Society B, 2011

Documenting domesticated plants in the archaeological record

Documenting Domestication: New genetic and archaeological paradigms, 2006

The Onset of the Anthropocene

Anthropocene, 2013

Reconsidering the Ocampo Caves and the era of incipient cultivation in Mesoamerica

LAtin AMerican Antiquity, 1997

In northeastern Mexico, near Ocampo, Romerok and Valenzuela S caves have been central to explanat... more In northeastern Mexico, near Ocampo, Romerok and Valenzuela S caves have been central to explanations of agricultural origins in Mesoamerica for more than four decades. Along with caves in Tehuacdn and Oaxaca, these "Ocampo caves" have provided almost all of the available evidence for the initial appearance of a number of key Mesoamerican crop plants, including maize, beans, and squash. This article reanalyzes the cultural and temporal context offive crop plant assemblages in the Ocampo caves: maize (Zea mays), bottle gourd (Lagenaria siceraria), and three species of squash (Cucurbita argyrosperma, C. moschata, C. pepo). Fifteen AMS radiocarbon dates on early domesticates both confirm the stratigraphic integrity of the two caves and substantially revise the temporal framework for initial appearance of core domesticates in northeastern Mexico, showing the transition to food production in Tamaulipas took place more recently than previously thought. A suhstantially foreshortened chronology for Ocampo crop plants confirms the northern periphery role of Tamaulipas in the origins of agriculture in Mexico, while also underscoring the need for establishing AMS-based archaeobotanical sequences across Mesoamerica to gain an adequate context for understanding the temporal, environmental, and cultural contexts of initial plant domestication in the region.

The initial domestication of Cucurbita pepo in the Americas 10,000 years ago

Science, 1997

Between foraging and farming

Science, 1998

Documenting plant domestication: the consilience of genetic and archaeological approaches

PNAS, 2001

Low Level Food Production

Journal of Archaeological Research, 2001

Societies with low-level food production economies occupy the vast and diverse middle ground betw... more Societies with low-level food production economies occupy the vast and diverse middle ground between hunting-fishing-foraging and agriculture. Efforts by Ford, Harris, Rindos, Zvelebil, and others to characterize this "in-between" territory are discussed, and a new conceptual framework is proposed. Domestication, the central landmark of this middle ground, is situated well away from the boundaries with hunting-gathering and agriculture, and separates low-level food production economies into two broad categories. Key issues and questions concerning societies with low-level food production, both with and without domesticates, are discussed. Hunter-gatherer and agriculture boundary zones on either side of the middle ground are considered, as are the developmental pathways that traverse them.

Early Allelic selection in maize as revealed by ancient DNA

Science, 2003

National Academy of Sciences profile of Bruce D. Smith

PNAS, 2005

Reassessing Coxcatlan Cave and the early history of domesticated plants in Mesoamerica

PNAS, 2005

Reanalysis and direct accelerator mass spectrometry radiocarbon dating of the cucurbit assemblage... more Reanalysis and direct accelerator mass spectrometry radiocarbon dating of the cucurbit assemblage from Coxcatlan Cave provide information on the timing and sequence of the initial appearance of three domesticated plants in the Tehuacá n Valley (Puebla, Mexico) and allow reassessment of the overall temporal context of plant domestication in Mexico. Cucurbita pepo is the earliest documented domesticate in the cave, dating to 7,920 calibrated calendrical (cal) years B.P. The bottle gourd (Lagenaria siceraria) is dated at 7,200 cal years B.P. Cucurbita argyrosperma does not appear until 2,065 cal years B.P. The earlier identification of Cucurbita moschata specimens is not confirmed. Seventy-one radiocarbon dates, including 23 accelerator mass spectrometry dates on cucurbits, provide ample evidence of postdepositional vertical displacement of organic materials in the western half of Coxcatlan Cave, but they also indicate that the eastern half of the cave was largely undisturbed.

Documenting domestication: the intersection of genetics and archaeology

Trends in Genetics, 2006

Domestication, a process of increasing mutual dependence between human societies and the plant an... more Domestication, a process of increasing mutual dependence between human societies and the plant and animal populations they target, has long been an area of interest in genetics and archaeology. Geneticists seek out markers of domestication in the genomes of domesticated species, both past and present day. Archaeologists examine the archaeological record for complementary markers -evidence of the human behavior patterns that cause the genetic changes associated with domestication, and the morphological changes in target species that result from them. In this article, we summarize the recent advances in genetics and archaeology in documenting plant and animal domestication, and highlight several promising areas where the complementary perspectives of both disciplines provide reciprocal illumination.

Eastern North America as an independent center of plant domestication

PNAS, 2006

† Marshelder and sunflower fruits (achenes) consist of a single seed enclosed in a dry indehiscen... more

The molecular genetics of crop domestication

Cell, 2006

Ten thousand years ago human societies around the globe began to transition from hunting and gath... more Ten thousand years ago human societies around the globe began to transition from hunting and gathering to agriculture. By 4000 years ago, ancient peoples had completed the domestication of all major crop species upon which human survival is dependent, including rice, wheat, and maize. Recent research has begun to reveal the genes responsible for this agricultural revolution. The list of genes to date tentatively suggests that diverse plant developmental pathways were the targets of Neolithic "genetic tinkering," and we are now closer to understanding how plant development was redirected to meet the needs of a hungry world.