REPRODUCTIVE and LARVAL ECOLOGY OF MARINE BOTTOM INVERTEBRATES

作者：Gunnar Thorson · 发表于：Biological reviews/Biological reviews of the Cambridge Philosophical Society · 年份：1950 · DOI：10.1111/j.1469-185x.1950.tb00585.x · 被引用次数：2410 · 研究领域：Marine and fisheries research、Food Industry and Aquatic Biology、Marine and environmental studies

Summary 1. In analysing the ecological conditions of an animal population we have above all to focus our attention upon the most sensitive stages within the life cycle of the animal, that is, the period of breeding and larval development. 2. Most animal populations on the sea bottom maintain the qualitatively composition of the species composing them, over long periods of time, though the individual species use quite different modes of reproduction and development. This shows that species producing a large number of eggs have a larger wastage of eggs and larvae than those with only a few eggs. The wastage of eggs in the sea is much larger than on the land and in fresh water. 3. In the invertebrate populations on the level sea bottom, large fluctuations in numbers from year to year indicate species with a long pelagic larval life, while a more or less constant occurrence indicates species with a very short pelagic life or a non‐pelagic development. 4. In most marine invertebrates which shed their eggs and sperm freely in the water, either (a) the males are the first to spawn, thus stimulating the females to shed their eggs, or (b) an ‘epidemic spawning’ of a whole population takes place within a few hours. Both methods greatly favour the possibility of fertilization of the eggs spawned and show that the heavy wastage of eggs and larvae takes place after fertilization, during the free swimming pelagic life. 5. Embryos with a non‐pelagic development may originate (a) from large ...