有道是海洋是生命的摇篮。在大海中与在陆地上一样,生命的形式成为数学思想的一种财富。人们能够在贝壳的形式里看到众多类型的螺线。有小室的鹦鹉螺和鹦鹉螺化石给出的是等角螺线。海狮螺和其他锥形贝壳,为我们提供了三维螺线的例子。对称充满于海洋——轴对称可见于蚶蛤等贝壳、古生代的三叶虫、龙虾、鱼和其他动物身体的形状;而中心对称则见于放射虫类和海胆等。 It is natural that the ocean is the cradle of life. In the sea, as on land, the form of life becomes a treasure of mathematical thought. People can see many types of spirals in the form of shells. Nautilus and nautilus fossils with small chambers are equiangular spirals. Sea lions and other conical shells provide us with examples of three-dimensional spirals. Symmetry fills the ocean - Axisymmetry can be seen in shells such as clam and Paleozoic trilobite, lobster, fish and other animal body shapes; central symmetry is found in radiolarians and sea urchins.