José M. Fariña, Alvaro T. Palma, and F. Patricio Ojeda
- Published in print:
- 2008
- Published Online:
- May 2008
- ISBN:
- 9780195319958
- eISBN:
- 9780199869596
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195319958.003.0004
- Subject:
- Biology, Aquatic Biology
The chapter describes the oceanography, biogeography, and the important role that the El Niño cycle plays in Chilean kelp forest ecology. The structure of the food web from primary producers to ...
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The chapter describes the oceanography, biogeography, and the important role that the El Niño cycle plays in Chilean kelp forest ecology. The structure of the food web from primary producers to consumers is described and the potential effect of the artisanal fishery and effect of the loss of kelp forests on the on the food web and fishery are discussed.Less
The chapter describes the oceanography, biogeography, and the important role that the El Niño cycle plays in Chilean kelp forest ecology. The structure of the food web from primary producers to consumers is described and the potential effect of the artisanal fishery and effect of the loss of kelp forests on the on the food web and fishery are discussed.
Thomas W. Cronin, Sönke Johnsen, N. Justin Marshall, and Eric J. Warrant
- Published in print:
- 2014
- Published Online:
- October 2017
- ISBN:
- 9780691151847
- eISBN:
- 9781400853021
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691151847.003.0003
- Subject:
- Biology, Evolutionary Biology / Genetics
This chapter focuses on visual pigments and photoreceptors. In living things, photoreception inevitably begins with a photochemical event—a molecule intercepts a photon of light and is somehow ...
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This chapter focuses on visual pigments and photoreceptors. In living things, photoreception inevitably begins with a photochemical event—a molecule intercepts a photon of light and is somehow changed. Various molecules, generally known as photopigments, perform this function in animals and plants. The molecules involved in vision are called visual pigments. In all animals, vision ultimately depends on a single family of proteins that all have descended from one common ancestor—these are the opsins. The chapter cites the hydrothermal vent crab as a good example of how changes of visual pigments appearing in various developmental states reflect ecological adaptation. The animal's life stages require visual systems sampling opposite ends of the visual spectrum.Less
This chapter focuses on visual pigments and photoreceptors. In living things, photoreception inevitably begins with a photochemical event—a molecule intercepts a photon of light and is somehow changed. Various molecules, generally known as photopigments, perform this function in animals and plants. The molecules involved in vision are called visual pigments. In all animals, vision ultimately depends on a single family of proteins that all have descended from one common ancestor—these are the opsins. The chapter cites the hydrothermal vent crab as a good example of how changes of visual pigments appearing in various developmental states reflect ecological adaptation. The animal's life stages require visual systems sampling opposite ends of the visual spectrum.
Judith S. Weis
- Published in print:
- 2012
- Published Online:
- August 2016
- ISBN:
- 9780801450501
- eISBN:
- 9780801466045
- Item type:
- book
- Publisher:
- Cornell University Press
- DOI:
- 10.7591/cornell/9780801450501.001.0001
- Subject:
- Biology, Animal Biology
The world’s nearly 7,000 species of crabs are immediately recognizable by their claws, sideways movement, stalked eyes, and thick outer shells. These common crustaceans are found internationally, ...
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The world’s nearly 7,000 species of crabs are immediately recognizable by their claws, sideways movement, stalked eyes, and thick outer shells. These common crustaceans are found internationally, thriving in various habitats from the edge of the sea to the depths of the ocean, in fresh water or on land. Despite having the same basic body type as decapod crustaceans—true crabs have heavy exoskeletons and ten limbs with front pincer claws—crabs come in an enormous variety of shapes and sizes, from the near microscopic to the giant Japanese spider crab. This book provides an engaging and informative tour of the remarkable world of crabs, highlighting their unique biology and natural history. It introduces recently discovered crabs such as the Yeti crab found in deep sea vents, explains what scientists are learning about blue and hermit crabs commonly found at the shore, and gives us insight into the lifecycles of the king and Dungeness crabs typically seen only on dinner plates. Among the topics covered are the evolution and classification of crabs, their habitats, unique adaptations to water and land, reproduction and development, behavior, ecology, and threats, including up-to-date research. Crabs are of special interest to biologists for their communication behaviors, sexual dimorphism, and use of chemical stimuli and touch receptors, and the book explains the importance of new scientific discoveries.Less
The world’s nearly 7,000 species of crabs are immediately recognizable by their claws, sideways movement, stalked eyes, and thick outer shells. These common crustaceans are found internationally, thriving in various habitats from the edge of the sea to the depths of the ocean, in fresh water or on land. Despite having the same basic body type as decapod crustaceans—true crabs have heavy exoskeletons and ten limbs with front pincer claws—crabs come in an enormous variety of shapes and sizes, from the near microscopic to the giant Japanese spider crab. This book provides an engaging and informative tour of the remarkable world of crabs, highlighting their unique biology and natural history. It introduces recently discovered crabs such as the Yeti crab found in deep sea vents, explains what scientists are learning about blue and hermit crabs commonly found at the shore, and gives us insight into the lifecycles of the king and Dungeness crabs typically seen only on dinner plates. Among the topics covered are the evolution and classification of crabs, their habitats, unique adaptations to water and land, reproduction and development, behavior, ecology, and threats, including up-to-date research. Crabs are of special interest to biologists for their communication behaviors, sexual dimorphism, and use of chemical stimuli and touch receptors, and the book explains the importance of new scientific discoveries.
Judith S. Weis
- Published in print:
- 2012
- Published Online:
- August 2016
- ISBN:
- 9780801450501
- eISBN:
- 9780801466045
- Item type:
- chapter
- Publisher:
- Cornell University Press
- DOI:
- 10.7591/cornell/9780801450501.003.0001
- Subject:
- Biology, Animal Biology
This introductory chapter looks into the physiology and diversity of crabs, including certain species which defy conventional definitions of what a crab is. It largely concerns itself with the ...
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This introductory chapter looks into the physiology and diversity of crabs, including certain species which defy conventional definitions of what a crab is. It largely concerns itself with the question of what makes a crab recognizable as a crab, by delving into the world of crustaceans, arthropods, decapods, and so on, in order to differentiate crabs from other similar marine life—such as lobsters. The chapter then provides classifications on the major families of Brachyuran (true) crabs, which are the largest group of crabs, as well as those of the anomuran crabs. Finally, the chapter highlights some notable species of crabs, rounding out the discussion by providing information on the largest, smallest, and oddest crabs to date.Less
This introductory chapter looks into the physiology and diversity of crabs, including certain species which defy conventional definitions of what a crab is. It largely concerns itself with the question of what makes a crab recognizable as a crab, by delving into the world of crustaceans, arthropods, decapods, and so on, in order to differentiate crabs from other similar marine life—such as lobsters. The chapter then provides classifications on the major families of Brachyuran (true) crabs, which are the largest group of crabs, as well as those of the anomuran crabs. Finally, the chapter highlights some notable species of crabs, rounding out the discussion by providing information on the largest, smallest, and oddest crabs to date.
Judith S. Weis
- Published in print:
- 2012
- Published Online:
- August 2016
- ISBN:
- 9780801450501
- eISBN:
- 9780801466045
- Item type:
- chapter
- Publisher:
- Cornell University Press
- DOI:
- 10.7591/cornell/9780801450501.003.0008
- Subject:
- Biology, Animal Biology
This chapter presents an overview of crab fisheries and commercial crabbing. Millions earn their living in commercial fisheries, and many people still depend on seafood as their primary source of ...
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This chapter presents an overview of crab fisheries and commercial crabbing. Millions earn their living in commercial fisheries, and many people still depend on seafood as their primary source of protein. Although dwarfed by fisheries for finfish, crab fisheries are important in many countries. Hence the chapter looks at the gear used in crabbing, as well as the regulations and management in place for such ventures. The chapter also shows how the very high catch rates of modern industrialized fishing fleets have had widespread effects on fished species, nontarget species, and marine habitats. Overfishing continues to be a major threat to marine ecosystems and vulnerable species throughout the world.Less
This chapter presents an overview of crab fisheries and commercial crabbing. Millions earn their living in commercial fisheries, and many people still depend on seafood as their primary source of protein. Although dwarfed by fisheries for finfish, crab fisheries are important in many countries. Hence the chapter looks at the gear used in crabbing, as well as the regulations and management in place for such ventures. The chapter also shows how the very high catch rates of modern industrialized fishing fleets have had widespread effects on fished species, nontarget species, and marine habitats. Overfishing continues to be a major threat to marine ecosystems and vulnerable species throughout the world.
Judith S. Weis
- Published in print:
- 2012
- Published Online:
- August 2016
- ISBN:
- 9780801450501
- eISBN:
- 9780801466045
- Item type:
- chapter
- Publisher:
- Cornell University Press
- DOI:
- 10.7591/cornell/9780801450501.003.0006
- Subject:
- Biology, Animal Biology
This chapter is an overview of crab ecology—beginning with the transition from larva to juvenile, and covering hibernation, migrations, navigation, interactions with other kinds of organisms, and the ...
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This chapter is an overview of crab ecology—beginning with the transition from larva to juvenile, and covering hibernation, migrations, navigation, interactions with other kinds of organisms, and the effects of crabs on the environment. As crabs reside in a large variety of habitats, their ecologies have become as equally diverse, thus this chapter seeks to examine these aspects of crab ecology in particular. The chapter also devotes a section on the unique habits of hermit crabs in their shells. These shells serve various functions. For terrestrial hermits, these include water storage: the crabs can carry water in their snail shell, which enables them to colonize relatively dry areas. All hermit crabs depend on a properly fitting shell for protection from predators.Less
This chapter is an overview of crab ecology—beginning with the transition from larva to juvenile, and covering hibernation, migrations, navigation, interactions with other kinds of organisms, and the effects of crabs on the environment. As crabs reside in a large variety of habitats, their ecologies have become as equally diverse, thus this chapter seeks to examine these aspects of crab ecology in particular. The chapter also devotes a section on the unique habits of hermit crabs in their shells. These shells serve various functions. For terrestrial hermits, these include water storage: the crabs can carry water in their snail shell, which enables them to colonize relatively dry areas. All hermit crabs depend on a properly fitting shell for protection from predators.
Judith S. Weis
- Published in print:
- 2012
- Published Online:
- August 2016
- ISBN:
- 9780801450501
- eISBN:
- 9780801466045
- Item type:
- chapter
- Publisher:
- Cornell University Press
- DOI:
- 10.7591/cornell/9780801450501.003.0007
- Subject:
- Biology, Animal Biology
This chapter explores how the problems affecting crab populations, and how, in turn, crabs affect other animals and even people. Crabs are subject to a great variety of diseases—from viruses, ...
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This chapter explores how the problems affecting crab populations, and how, in turn, crabs affect other animals and even people. Crabs are subject to a great variety of diseases—from viruses, bacteria, and pathogenic ciliates and amoebas; they are also susceptible to many forms of parasites, which can cause little, moderate, or severe damage to their hosts and come in the form of other crustaceans, flatworms, and others. Crabs also face external dangers, such as numerous predators, habitat loss, damage by invasive species, and pollution. In addition, the crabs themselves can cause problems for other living things, namely, by behaving as parasites and invasive species in their own right.Less
This chapter explores how the problems affecting crab populations, and how, in turn, crabs affect other animals and even people. Crabs are subject to a great variety of diseases—from viruses, bacteria, and pathogenic ciliates and amoebas; they are also susceptible to many forms of parasites, which can cause little, moderate, or severe damage to their hosts and come in the form of other crustaceans, flatworms, and others. Crabs also face external dangers, such as numerous predators, habitat loss, damage by invasive species, and pollution. In addition, the crabs themselves can cause problems for other living things, namely, by behaving as parasites and invasive species in their own right.
Judith S. Weis
- Published in print:
- 2012
- Published Online:
- August 2016
- ISBN:
- 9780801450501
- eISBN:
- 9780801466045
- Item type:
- chapter
- Publisher:
- Cornell University Press
- DOI:
- 10.7591/cornell/9780801450501.003.0010
- Subject:
- Biology, Animal Biology
This chapter looks at the other ways in which human beings interact with crabs. Though crabs are often encountered on the dinner plate, one can also interact with them by taking up such activities as ...
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This chapter looks at the other ways in which human beings interact with crabs. Though crabs are often encountered on the dinner plate, one can also interact with them by taking up such activities as crab watching and recreational crabbing, as well as keeping crabs as pets. The chapter also provides a brief overview of the field of carcinology—the study of crabs—and presents a number of reasons as to why some people have come to study crabs professionally. It notes some prominent women carcinologists in the field and lists some ways in which crabs are being studied. Finally, the chapter discusses crabs as they appear in popular culture, primarily in films, cartoons, and TV.Less
This chapter looks at the other ways in which human beings interact with crabs. Though crabs are often encountered on the dinner plate, one can also interact with them by taking up such activities as crab watching and recreational crabbing, as well as keeping crabs as pets. The chapter also provides a brief overview of the field of carcinology—the study of crabs—and presents a number of reasons as to why some people have come to study crabs professionally. It notes some prominent women carcinologists in the field and lists some ways in which crabs are being studied. Finally, the chapter discusses crabs as they appear in popular culture, primarily in films, cartoons, and TV.
Judith S. Weis
- Published in print:
- 2012
- Published Online:
- August 2016
- ISBN:
- 9780801450501
- eISBN:
- 9780801466045
- Item type:
- chapter
- Publisher:
- Cornell University Press
- DOI:
- 10.7591/cornell/9780801450501.003.0003
- Subject:
- Biology, Animal Biology
This chapter looks at basic crab anatomy. It examines the biological aspects common to many crabs, such as their digestive processes, respiration, metabolic rates, biological rhythms, excretion, ...
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This chapter looks at basic crab anatomy. It examines the biological aspects common to many crabs, such as their digestive processes, respiration, metabolic rates, biological rhythms, excretion, osmoregulation, their five senses, their nervous system, and even their pigmentation. A crab’s major anatomical features are the boundary between the head and thorax, as well as the segments of the thorax and the attachment of the legs to the thorax. Furthermore, the chapter notes that while many aspects of crab anatomy and physiology are similar to those of other animals, some may come as a surprise, such as their blue blood, the taste buds on their toes, or even the kidneys in their head.Less
This chapter looks at basic crab anatomy. It examines the biological aspects common to many crabs, such as their digestive processes, respiration, metabolic rates, biological rhythms, excretion, osmoregulation, their five senses, their nervous system, and even their pigmentation. A crab’s major anatomical features are the boundary between the head and thorax, as well as the segments of the thorax and the attachment of the legs to the thorax. Furthermore, the chapter notes that while many aspects of crab anatomy and physiology are similar to those of other animals, some may come as a surprise, such as their blue blood, the taste buds on their toes, or even the kidneys in their head.
Judith S. Weis
- Published in print:
- 2012
- Published Online:
- August 2016
- ISBN:
- 9780801450501
- eISBN:
- 9780801466045
- Item type:
- chapter
- Publisher:
- Cornell University Press
- DOI:
- 10.7591/cornell/9780801450501.003.0004
- Subject:
- Biology, Animal Biology
This chapter analyzes the crab’s reproductive system and life cycles as well as the major differences between its sexes. It shows how one can determine a crab’s sex through certain physical markers. ...
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This chapter analyzes the crab’s reproductive system and life cycles as well as the major differences between its sexes. It shows how one can determine a crab’s sex through certain physical markers. Furthermore, the chapter considers how the age and size at which crabs become sexually mature vary among species and geographic location. Genetics is only one factor responsible for the development of males and females, and a few types of crabs can change sex as they mature. Environmental factors such as day length, temperature, food availability, social conditions, and parasites can also play a role. For many crabs, reproduction is a seasonal event. Some, mainly tropical, crabs, however, may produce broods all year round, taking more sperm from storage following a single mating. Deep-sea crabs live in a nearly seasonless environment and may not have a particular reproductive season.Less
This chapter analyzes the crab’s reproductive system and life cycles as well as the major differences between its sexes. It shows how one can determine a crab’s sex through certain physical markers. Furthermore, the chapter considers how the age and size at which crabs become sexually mature vary among species and geographic location. Genetics is only one factor responsible for the development of males and females, and a few types of crabs can change sex as they mature. Environmental factors such as day length, temperature, food availability, social conditions, and parasites can also play a role. For many crabs, reproduction is a seasonal event. Some, mainly tropical, crabs, however, may produce broods all year round, taking more sperm from storage following a single mating. Deep-sea crabs live in a nearly seasonless environment and may not have a particular reproductive season.
