Annual Reviews
Công bố khoa học tiêu biểu
* Dữ liệu chỉ mang tính chất tham khảo
Sắp xếp:
Chaos in Ecology: Is Mother Nature a Strange Attractor?
Annual Reviews - Tập 24 Số 1 - Trang 1-33 - 1993
EXTINCTION BY HYBRIDIZATION AND INTROGRESSION ▪ Abstract Nonindigenous species can bring about a form of extinction of native flora and fauna by hybridization and introgression either through purposeful introduction by humans or through habitat modification, bringing previously isolated species into contact. These phenomena can be especially problematic for rare species coming into contact with more abundant ones. Increased use of molecular techniques focuses attention on the extent of this underappreciated problem that is not always apparent from morphological observations alone. Some degree of gene flow is a normal, evolutionarily constructive process, and all constellations of genes and genotypes cannot be preserved. However, hybridization with or without introgression may, nevertheless, threaten a rare species' existence.
Annual Reviews - Tập 27 Số 1 - Trang 83-109 - 1996
Global Amphibian Declines: A Problem in Applied Ecology ▪ Abstract Declines and losses of amphibian populations are a global problem with complex local causes. These may include ultraviolet radiation, predation, habitat modification, environmental acidity and toxicants, diseases, changes in climate or weather patterns, and interactions among these factors. Understanding the extent of the problem and its nature requires an understanding of how local factors affect the dynamics of local populations. Hypotheses about population behavior must be tested against appropriate null hypotheses. We generated null hypotheses for the behavior of amphibian populations using a model, and we used them to test hypotheses about the behavior of 85 time series taken from the literature. Our results suggest that most amphibian populations should decrease more often than they increase, due to highly variable recruitment and less variable adult mortality. During the period covered by our data (1951–1997), more amphibian populations decreased than our model predicted. However, there was no indication that the proportion of populations decreasing changed over time. In addition, our review of the literature suggests that many if not most amphibians exist in metapopulations. Understanding the dynamics of amphibian populations will require an integration of studies on and within local populations and at the metapopulation level.
Annual Reviews - Tập 30 Số 1 - Trang 133-165 - 1999
INTRASPECIFIC PHYLOGEOGRAPHY: The Mitochondrial DNA Bridge Between Population Genetics and Systematics
Annual Reviews - Tập 18 Số 1 - Trang 489-522 - 1987
Ecological Determinants of Genetic Structure in Plant Populations
Annual Reviews - Tập 15 Số 1 - Trang 65-95 - 1984
MOLECULAR TRANS-SPECIES POLYMORPHISM ▪ Abstract Trans-species polymorphism (TSP) is the occurrence of similar alleles in related species. Excluding instances in which the similarity arose by convergent evolution, TSP is generated by the passage of alleles from ancestral to descendant species. Closely related, recently diverged species, such as those of the Lake Victoria cichlid flock, may share neutral alleles, but long-lasting TSPs occur only in genetic systems evolving under balancing selection. Two such systems have been studied extensively, the major histocompatibility complex (Mhc) of jawed vertebrates and the self-incompatibility (SI) system of flowering plants. Allelic lineages that diverged many millions of years ago and passed through numerous speciation events have been described in both systems. The lineages may differ at up to 50% of their coding sites, both synonymous and nonsynonymous. The differences arise by the process of incorporation of mutations, which is different from the process of fixation. TSP, on the one hand, complicates phylogenetic analysis, but on the other, it is a useful tool for the study of speciation.
Annual Reviews - Tập 29 Số 1 - Trang 1-21 - 1998
Evolutionary and Ecological Aspects of Photosynthetic Pathway Variation
Annual Reviews - Tập 24 Số 1 - Trang 411-439 - 1993
Tree-Grass Interactions in Savannas Savannas occur where trees and grasses interact to create a biome that is neither grassland nor forest. Woody and gramineous plants interact by many mechanisms, some negative (competition) and some positive (facilitation). The strength and sign of the interaction varies in both time and space, allowing a rich array of possible outcomes but no universal predictive model. Simple models of coexistence of trees and grasses, based on separation in rooting depth, are theoretically and experimentally inadequate. Explanation of the widely observed increase in tree biomass following introduction of commercial ranching into savannas requires inclusion of interactions among browsers, grazers, and fires, and their effects on tree recruitment. Prediction of the consequences of manipulating tree biomass through clearing further requires an understanding of how trees modify light, water, and nutrient environments of grasses. Understanding the nature of coexistence between trees and grass, which under other circumstances are mutually exclusive or unequal partners, yields theoretical insights and has practical implications.
Annual Reviews - Tập 28 Số 1 - Trang 517-544 - 1997
Tổng số: 69
- 1
- 2
- 3
- 4
- 5
- 6
- 7