Читать книгу Oceans For Dummies - Joseph Kraynak - Страница 27

Although microbes and plants play a vital role in keeping the ocean clean and fed, they don’t draw the crowds. The stars of the show are the animals, and the cast of marine creatures is truly incredible.

Unfortunately, this book can’t possibly cover all the amazing creatures that inhabit the ocean, so what we’ve done is break them down into taxonomic groups and subgroups, describe the common traits of each group, and then present one or more representatives of each group. We cover the following groups, progressing from least to most complex, and point out where to find them in this book:

 Simple invertebrates are basic animals that have no backbone, including sponges, jellyfish, anemones, starfish, sea urchins, sand dollars, and a few different types of worms (yes, worms) that prefer the ocean over your lawn or garden. Wiggle over to Chapter 9 for more in simple invertebrates.

 Mollusks (covered in Chapter 10) are soft-bodied invertebrates, most of which have recognizable shells but some of which don’t. You may know them better as snails, slugs, clams, oysters, mussels, octopus, and squid. And some of these are colossal.

 Crustaceans (Chapter 11) are more advanced invertebrates with hard external skeletons, such as crabs, lobsters, shrimp, and krill. Just think “crusty,” like a good baguette: hard on the outside, soft on the inside.

 Fish (bony and not) comprise the first group of vertebrates (animals with a backbone or something like it). You usually know a fish when you see one — most have a head and tail, fins, gills, and scales. We break them down into two groups: cartilaginous (the real softies, as in soft-boned) such as sharks and rays, and bony (hard boned, that is) which includes just about everyone else, such as tuna, salmon, and cod. Swim over to Chapter 12 for more details.

 Reptiles (chillin’ in Chapter 13) are scaly, cold-blooded, air-breathing vertebrates that lay soft eggs on land or give birth to live young. The ocean is home to only a handful of reptiles, including sea turtles, marine iguanas, saltwater crocodiles, and a few species of sea snakes (the latter of which you really don’t want on your airplane).

 Birds are warm-blooded, air-breathing vertebrates with two legs, two wings, feathers, and a beak. Most fly, though some, such as the penguin, don’t. Most marine birds have special adaptations, such as the ability to secrete salt, oily wings to keep them from getting waterlogged, and webbed feet. Some have solid bones that enable them to dive more easily. Seabirds that dive-bomb their prey are even equipped with internal airbags to cushion their crash landings. In Chapter 14, we divide marine birds into two groups — seabirds, which spend most of their time on or flying over the ocean, and shorebirds, which spend most of their time on or near land or wading in the shallows of estuaries or marshes.

 Mammals (covered in Chapter 15) are warm-blooded vertebrates that have at least some hair or fur and must surface to breathe air. Females have mammary glands and give birth to live young. Marine mammals include everyone’s favorites — whales, dolphins, walruses, seals, sea otters, sea lions, manatees, dugongs, and polar bears.