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For Further Reading

Darwin, C. R. 1859. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life.

Reference for: Chapter 12, The Foundations of Evolutionary Theory

Haldane, J. B. S. 1932. The Causes of Evolution. Longman: UK.

Reference for: Chapter 12, The Foundations of Evolutionary Theory


*Long, John A. 1995. The Rise of Fishes: 500 Million Years of Evolution. John Hopkins University Press: MD

This lavish overview of the evolution of fishes is not the most detailed but its illustrations and photographs give a rich sense of the evidence on which our understanding of fish evolution is based. It makes a highly readable reference for students and a terrific desk reference for instructors called upon to teach aspects of fish evolution.

Reference for: Chapter 12, Spotlight 12.1

*Raup, David. 1991. Extinction: Bad Genes or Bad Luck? W.W. Norton: NY

This “little” book summarizes the evidence for five major extinctions in the geologic records and their causes. It’s a highly readable and engaging account that will quickly bring the reader up to date on this fascinating topic.

Reference for: Chapter 12, The Foundations of Evolutionary Theory


*Stott, Rebecca. 2003. Darwin and the Barnacle: The Story of One Tiny Creature and History’s Most Spectacular Scientific Breakthrough. Norton: NY

This book brings to the forefront Darwin’s painstaking and highly important work on barnacles. It might be argued that Darwin formulated his ideas about evolution and natural selection from studying barnacles. Although this is a “storybook”, in the sense that it weaves a narrative about Darwin’s barnacle work, it does illuminate this important and little known work in an engaging and instructive manner.

Reference for: Chapter 12, The Foundations of Evolutionary Theory

*Carroll, Sean B. 2006. The Making of the Fittest: DNA and the Ultimate Forensic Record of Evolution. W. W. Norton: NY

The evolutionary record is contained in the DNA of organisms. It is a history that we can finally begin to read.



*Coyne, Jerry A., and H. Allen Orr. 2004. Speciation. Sinauer Associates: MA.

Coyne and Orr have written a textbook covering all aspects of speciation, emphasizing modern research on this topic.


*Ellis, Richard. 2001. Aquagenesis: The Origin and Evolution of Life in the Sea. Viking Penguin Books: NY

Ellis is a masterful storyteller and illustrator. There are better books on this subject but if you like Ellis way of weaving facts, this book should please you.


*Fortey, Richard. 1997. Life: A Natural History of the First Four Billion Years of Life on Earth. Vintage Books: NY

Fortey narrates the history of life on Earth, citing his own work and the research of other scientists to piece together the puzzles of how life evolved.


*Fortey, Richard. 2000. Trilobite! Eyewitness to Evolution. Alfred A. Knopf: NY

All you ever wanted to know about trilobites in an engaging, delightful prose.

*Gould, Stephen Jay. 1989. Wonderful Life: The Burgess Shale and the Nature of History. W. W. Norton: NY

Stephen Jay Gould delights some and irritates others but he always manages to inspire thoughtful reflection on a topic. In this book, he discusses in great detail the Burgess Shale and how it paints a picture of the “progression” of evolution unlike what is commonly perceived. Gould sees evolution not only as “survival of the fittest” but also as “survival of the lucky.”

*Gould, Stephen Jay. 2001. The Book of Life: An Illustrated History of the Evolution of Life on Earth. W.W. Norton: IA

*Gould, Stephen Jay. 2002. The Structure of Evolutionary Theory. Belknap Press of Harvard University Press: MA

This immense volume details Gould’s provocative and often controversial views on the evolution of life on Earth. To his credit, Gould is typically entertaining, and this book reads like a good novel. Unfortunately, you have to read a lot of it if you are generally unfamiliar with his ideas or the nuances of evolution. Nonetheless, it’s an essential reference for a biologist’s library.

*Hull, David L. 2001. Science and Selection: Essays on Biological Evolution and the Philosophy of Science. Cambridge University Press: UK

Hull’s essays educate and entertain and get the reader to thinking more deeply about science and its effects on humanity. His essays on evolution are a big help to those who need a refresher or those who require greater ammunition in the verbal wars with antievolutionists.

*Johnson, Kirk R., and Richard K. Stucky. 1995. Prehistoric Journey: A History of Life on Earth. Roberts Rinehart Publishers: CO.

Based on dioramas at the Denver Museum of Natural History, this delightfully illustrated book traces the history of life from microbes to mammals, with an emphasis on dinosaurs. Its brevity notwithstanding, this book does a great job of providing the fossil evidence on which the scientific interpretation of the history of life is based.

*Kirschner, Marc W. and John C. Gerhart. 2005. The Plausibility of Life: Resolving Darwin’s Dilemma. Yale University Press: CT

Kirscner and Gerhart tackle the origins of new species and evolutionary complexity.

*Knoll, Andrew. 2003. Life on a Young Planet: The First Three Billion Years of Evolution on Earth. Princeton University Press: NJ

This is an outstanding book on the evolution of Earth and its biota. Knoll is one of the pioneers in the field of geobiology and his up-to-date scientific account of the field makes this an excellent reference and an entertaining read. Knoll exposes the controversies and examines the evidence that surrounding them. Most narratives don’t make good reference books but Knoll’s is an exception. If you are trying to choose between “histories of life on Earth”, pick this one.

*Larson, Edward J. 2004. Evolution: The Remarkable History of a Scientific Theory. Modern Library: NY

This book sketches the development of evolutionary theory. It’s primarily written for general audiences and so loses some of the detail required for students and instructors.

*Margulis, Lynn, and Dorion Sagan. 1986. Microcosmos: Four Billion Years of Microbial Evolution. Simon and Schuster: NY.

A provocative hypothesis about the interdependency of higher organisms and bacteria.

*Margulis, Lynn. 1998. The Symbiotic Planet: A New Look at Evolution. Weidenfeld & Nicolson: UK

Margulis is not one to shy away from controversy. Her endosymbiotic hypothesis was met with great skepticism originally but is now widely accepted. In this book, she applies her principles of symbiosis to the full range of life and its communities, including Earth.

*Margulis, Lynn, and Michael F. Dolan. 2002. Early Life: Evolution of the PreCambrian Earth, 2nd Edition. Jones and Bartlett: MA

*Mayr, Ernst. 1982. The Growth of Biological Thought: Diversity, Evolution, and Inheritance. Belknap Press of Harvard University Press: MA

Professor Sean thinks this is one of the most important books ever written. It defends the place of biology in science and retells the history of evolutionary thinking from pre- to neo-Darwinism. At more than 900 pages, it’s an intimidating volume, but Mayr’s prose and his way of explaining concepts makes this book a delight to read. You will only want to read several pages of it at a time as Mayr provokes deep reverie with every page. But you will have a more comprehensive and deeper understanding of evolution upon reading this book than is possible with just about any other book.

*Mayr, Ernst. 2001. What Evolution Is. Basic Books: NY

Any book by Ernst Mayr is worth reading, according to Professor Sean. This book provides a solid foundation for different aspects of evolution and evolutionary processes.

*Weiner, Jonathan. 1994. The Beak of the Finch. Vintage Books: NY

This Pulitzer Prize-winning book has become a textbook for learning about evolution.

*Zimmer, Carl. 1998. At the Water’s Edge: Fish With Fingers, Whales With Legs, and How Life Came Ashore but Then Went Back to Sea. Simon and Schuster: NY

An excellent narrative on macroevolution.

*Zimmer, Carl. 2001. Evolution: The Triumph of an Idea. HarperCollins: NY

This is the companion book to the Evolution video series by PBS.

*Moorehead, Alan. 1969. Darwin and the Beagle. Harper & Row: NY

This “old” book is notable for its abundant photos, illustrations and drawings, many of which are full page and stunning, and for its highly readable and intimate account of Charles Darwin’s voyage aboard HMS Beagle. It’s not as dense with information as other books on Darwin but it captures the spirit of his curiosity and scientific reasoning.

Reference for: Chapter 12, The Foundations of Evolutionary Theory

The Endless Voyage: Building Blocks, Water World and Survivors (written by W. S. Chamberlin) (Episodes 18, 19 and 21). 2002 (VHS and DVD). Intelecom.

Professor Sean appeared in several of the episodes of this series and helped develop learning activities to support it. While some episodes are better than others, The Endless Voyage provides one of the most complete and up-to-date series on oceanography available

: : Encyclopedia of the Sea : :
Chapter Two Image

What Makes an Arthropod? by Sean Chamberlin

Among animals on Earth, the arthropods are king. More than a million species, perhaps tens of millions, roam the land, sea and sky. Their diversity is literally beyond description and their role as movers of energy and material through global ecosystems is perhaps unrivaled. In many ecosystems, they represent a central link between primary producers and higher level consumers.

Phylogeny helps us organize this vast taxon by recognizing two major taxa within it: the Chelicerata, which include sea spiders and horseshoe crabs; and the Mandibulata, which include every crustacean you have ever met (or eaten) and many you have not. The Crustacea comprise by far the most abundant arthropods in the ocean and we will focus our inquiry here. First, however, let’s visit the body plan of arthropods and explore how the adaptations of arthropods account for their success and importance in the ocean.

The arthropidization of animals involves several key adaptations:
  1. segmentation of the body
  2. cephalization and other segmental specializations (tagmosis)
  3. a hard exoskeleton that grows by molting (ecdysis)
  4. paired, jointed appendages
  5. lack of flagella and cilia

Like annelids, arthropods are segmented whereby their bodies are arranged in a series of specific and recognizable compartments. This compartmentalization allows essentially for specialization within a particular segment and “division of labor” between the parts of an animal as a whole. As with annelids, arthropods exhibit a “head” and a “tail” which act to compartmentalize sensory, nervous system and feeding functions and circulatory, digestive, reproductive and excretory functions. Cephalization resulted in adaptations of head and mouth parts to better find, capture and process food. The other end of the body was “free” for improvements in locomotion, burrowing, defense and reproduction. The degree to which segmentation and specialization takes hold in arthropods equips them with a set of tools for survival that rivals all animals.

The evolution of a hard exoskeleton in arthropods represents one of their most important adaptations but at the same time creates one of their greatest challenges. How do you grow when your skeleton is fully formed and worn outside your body? How do you move around when encased in a chitinous shell? The analogy to a medieval knight is not a bad one. While offering superior protection, a suit of armor must be tailored to fit each knight. Once encased, a knight’s movements are limited to a slow ramble, at best. The same constraints face arthropods.

To overcome the limitations on growth imposed by a hard exoskeleton (cuticle), arthropods evolved a hormonally-controlled processes known as molting (ecdysis). Molting enables the arthropod to shed its old skeleton (molting) and form a new and larger one. For many arthropods (especially marine ones), ecdysis is a way of life: they continue to molt their entire lives, which is why lobsters left alone can achieve enormous sizes. Molting involves four stages: 1) intermolt (between molting), during which the animal conducts its life normally and tissue growth occurs; 2) premolt, a non-feeding stage during which the animal’s epidermis secretes a new cuticle and releases molting fluid, a mixture of enzymes that loosen the old cuticle; 3) molt, during which the animal swells with water to “break’ the old cuticle and enlarge it’s body size before hardening of the new cuticle; and 4) post-molt, the stage in which the animal’s exoskeleton remains soft until sclerotization (tanning) and/or mineralization (calcification) is complete. Molting is generally a risky business for arthropods and many find shelter under a rock or in a burrow during this process. Complications arising from incomplete molting and difficulty shedding the old cuticle as well as their soft body at the completion of molting make them vulnerable to predators (like humans hungry for a soft-shelled crab). Once the new and larger cuticle is hardened, the animal returns to feeding and proceeds to grow into its new exoskeleton as it feeds and gains new body mass.

The challenge of movement for an animal bearing an exoskeleton was achieved through the evolution of antagonistic muscles attached to the exoskeleton by tendons. Equally important was the segmentation and specialization of appendages for locomotion and feeding. Crustaceans may walk across the bottom using their insect-like walking legs (pereopods) and swim, jet and thrust backwards using their paddle-like swimming legs (pleopods). They may also use their tail appendage (uropod) to provide a backwards thrust for quick escape. The familiar crab-walk or lobster-march result from alternating power and recovery strokes where the tip of the appendage remains anchored during the power stroke (the body moves forward as the appendage is drawn backwards) and the tip is lifted during the recovery stroke (allowing the appendage to be brought forward for the next step). Spiny lobsters (clawless relatives of the Maine lobster found in southern Florida and the Caribbean) are legendary for their mass migrations (called the “march of the spineys”) across the sea floor. For a period of a few to several days, hundreds to thousands of lobsters (in lines of up to 65 individuals) will “march” head-to-tail some 15-30 miles seaward but the reason for these mass migrations remains one of the ocean’s great mysteries.

Specialized mouthparts (mandibles, maxillae, maxillipeds) provide a kind of “flatware” for feeding in any number of ways. These mouthparts work in concert to create currents of water for filtering small food particles (suspension feeding) or they may grab large bits of food and cut, tear or gnash them apart (scavenger feeding). Crabs will tear at dead fish using a specialized pereopod called a cheliped, known to most of us simply as a claw. In predatory mantis shrimp, the claw may be modified as a spear or a “club” whereby it stabs or smashes its prey.

Cephalization in arthropods has led to spectacular adaptations for vision and sensing. Arthropods exhibit a brain (dorsal ganglion) from which a central nervous system extends and branches throughout their body. Studies of the giant axons (nerve cells) in some species (like the Alaskan king crab) have led to a greater understanding of neuromuscular functions in humans. Arthropods have compound eyes; in crabs and lobsters, these eyes are placed on stalks to enhance visibility from burrows or when buried. Some species of mantis shrimp have color vision systems that can be “tuned” to the spectral distribution of light in their habitat (Cheroske et al., 2003). In at least one species, the color vision system detects the fluorescent patches of potential rivals—a kind of interspecies communication—used to warn or be warned of a competitor seeking a better burrow (Mazel et al., 2004). The spiny lobsters have been shown to possess a type of magnetic sense that enables them to move in straight lines from place to place for feeding, such as from a feeding ground to a shelter or den (Lohmann et al., 1995). Numerous adaptations for chemoreception, mechanical reception, pressure reception, sound reception, gravitational balance and other types of reception abound in these animals.

Reproduction in arthropods is equally diverse. While most maintain separate sexes, some, like the barnacles, are hermaphroditic. External release of gametes, brooding, copulation or simple sperm transfer may occur. Planktonic larvae typically undergo a number of transformations before final metamorphosis and settling. As temporary residents of the plankton known as meroplankton (temporary plankton), the crustacean larvae are among the most bizarre-looking zooplankton in the ocean. Some would make outstanding candidates for future Alien-like movies.