. Advanced biology. Biology; Physiology; Reproduction. 296 PROTECTION OF YOUNG KjsJ- IkMIK^^ ^ '"%#~'^ 1»^'.^I»-V!^HIHII -I-^^ ^^ at"^-^ i W MM .. Ml I f i ? 1 ^ * /^ m There is very little care of the young among the lower animals such as frogs and fishes. In many cases the parent dies before the egg has had time to hatch. The fertilized eggs are usually left unprotected. In an occasional species there is some evidence of what may be called parental care. For example, in some fishes, the parent may find a protected spot, as under a rock, and lav a mass of eggs. The salmon and other
. Advanced biology. Biology; Physiology; Reproduction. 296 PROTECTION OF YOUNG KjsJ- IkMIK^^ ^ '"%#~'^ 1»^'.^I»-V!^HIHII -I-^^ ^^ at"^-^ i W MM .. Ml I f i ? 1 ^ * /^ m There is very little care of the young among the lower animals such as frogs and fishes. In many cases the parent dies before the egg has had time to hatch. The fertilized eggs are usually left unprotected. In an occasional species there is some evidence of what may be called parental care. For example, in some fishes, the parent may find a protected spot, as under a rock, and lav a mass of eggs. The salmon and other fish that spend part of their lives in salt water and part in fresh water, migrate many miles up large rivers and deposit eggs in shallow water far from their natural en- emies. Yet, of the one or two million eggs laid by each female, only a very few will ever reach maturity. Among the crustaceans (lobsters, crabs, shrimps) the female sometimes produces a sticky fluid about the eggs. As the eggs come out of the body and be- come fertilized, they are at- tached to the swimmerets on the abdomen of the female and remain there until the embryos are ready to hatch. Among the mollusks (ovsters , , , „ ... " The female crayfish not only carries her eggs and clams) the lertllized eggs attached to the swimmerets, but by straightening . , . , '. £ her abdomen and waving the swimmerets brings remain Wltlim the cavity or the eggs in contact with a supply of oxygen. the mother's mantle and so are protected by the shell until the young hatch and are able to swim. Museum of Natural History The female lobster carries the eggs while they are developing. Special hairs attached to the appendages of the abdomen secrete a sticky substance which holds the eggs in place. This secures Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resem
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Keywords: ., bookcentury1900, bookdecade1920, booksubje, booksubjectphysiology
