Evolutionary radiation in polychaete ovaries and vitellogenic mechanisms: their possible role in life history patterns

1983 ◽  
Vol 61 (3) ◽  
pp. 487-504 ◽  
Author(s):  
Kevin J. Eckelbarger
Keyword(s):  
Life History ◽  
Germ Cells ◽  
Comparative Studies ◽  
Significant Variation ◽  
Important Process ◽  
Nutrient Storage ◽  
Coelomic Cavity ◽  
Evolutionary Radiation ◽  
Life History Patterns

Two types of oogenesis have evolved in polychaetes: one (extraovarian) in which germ cells are ovulated into the coelomic cavity where they undergo vitellogenesis, and another (intraovarian) in which the germ cells are released from the ovary after or near the completion of vitellogenesis. There are many mechanisms of yolk synthesis and significant variation as to the sources of yolk precursors, their route of entry into developing oocytes, and the oocytic organelles involved in yolk synthesis. The evolution of the coelom and its role in nutrient storage and transfer, as well as the origin of germ cells, are intimately related to the evolution of vitellogenic mechanisms in polychaetes. Comparative studies have revealed a correlation between mechanisms of yolk synthesis and the breeding patterns of polychaetes with the rate and type of vitellogenesis being related to the frequency of breeding. Vitellogenic mechanisms in polychaetes are compared with those of other metazoans in an effort to better understand the evolution of this important process and to identify primitive and derived features of yolk synthesis within the Polychaeta.

Recognition of larvae of the Tetrabothriidae (Eucestoda): implications for the origin of tapeworms in marine homeotherms

1987 ◽  
Vol 65 (4) ◽  
pp. 997-1000 ◽  
Author(s):  
Eric P. Hoberg
Keyword(s):  
Life History ◽  
Phylogenetic Relationships ◽  
Host Switching ◽  
Larval Morphology ◽  
Dominant Group ◽  
Marine Birds ◽  
Marine Communities ◽  
Definitive Evidence ◽  
Life History Patterns ◽  
Ecological Associations

The Tetrabothriidae represent the dominant group of cestodes, previously known only as adult parasites, in marine birds and mammals. Recognition of their unique plerocercoid larvae provides the first definitive evidence for life history patterns and phylogenetic relationships with other cestodes. Affinities of the Tetrabothriidae and Tetraphyllidea, cestodes of elasmobranchs, are indicated by larval morphology and ontogeny. However, patterns of sequential heterochrony in the ontogeny of the adult scolex of Tetrabothrius sp. appear to be unique among the Eucestoda. Tetrabothriids constitute a fauna that originated by host switching from elasmobranchs to homeotherms, via ecological associations, following invasion of marine communities by birds and mammals in the Tertiary.

scholarly journals Effects of Climate and Biotic Factors on Life History Characteristics and Vital Rates of Yellowstone Cutthroat Trout in Spread Creek, Wyoming

2013 ◽  
Vol 36 ◽  
pp. 160-174
Author(s):  
Patrick Uthe ◽  
Robert Al-Chokhachy
Keyword(s):  
Life History ◽  
Brook Trout ◽  
Cutthroat Trout ◽  
Conservation Strategies ◽  
Snake River ◽  
Vital Rates ◽  
Factors Influencing ◽  
Yellowstone Cutthroat Trout ◽  
Life History Patterns ◽  
Diversity Of Life

The Upper Snake River represents one of the largest remaining strongholds of Yellowstone cutthroat across its native range. Understanding the effects of restoration activities and the diversity of life-history patterns and factors influencing such patterns remains paramount for long-term conservation strategies. In 2011, we initiated a project to quantify the success of the removal of a historic barrier on Spread Creek and to evaluate the relative influence of different climate attributes on native Yellowstone cutthroat trout and non-native brook trout behavior and fitness. Our results to date have demonstrated the partial success of the dam removal with large, fluvial Yellowstone cutthroat trout migrating up Spread Creek to spawn, thus reconnecting this population to the greater Snake River metapopulation. Early indications from mark-recapture data demonstrate considerable differences in life-history and demographic patterns across tributaries within the Spread Creek drainage. Our results highlight the diversity of life-history patterns of resident and fluvial Yellowstone cutthroat trout with considerable differences in seasonal and annual growth rates and behavior across populations. Continuing to understand the factors influencing such patterns will provide a template for prioritizing restoration activities in the context of future challenges to conservation (e.g., climate change).

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