Myriapods These are the centipedes and millipedes. Characteristics: ♦♦ body consists of many segments ♦♦ each segment has jointed legs. Centipede
Fern
frond
sporangia with spores
long, thin segmented body
rhizome – an underground stem roots
jointed legs on each segment
0.5 cm
Figure 1.19 An example of a myriapod.
Flowering plants
Questions S
Figure 1.20 An example of a fern.
1.7 List three ways in which all mammals differ from all birds. 1.8 Explain why bats are classified as mammals, even though they have wings.
1.6 Classifying plants
We have seen that plants are organisms that have cells with cell walls made of cellulose. At least some parts of a plant are green. The green colour is caused by a pigment called chlorophyll, which absorbs energy from sunlight. The plant uses this energy to make glucose, using carbon dioxide and water from its environment. This is called photosynthesis. Plants include small organisms such as mosses, as well as ferns (Figure 1.20) and flowering plants (Figure 1.21).
These are the plants that are most familiar to us. They can be tiny, or very large – many trees are flowering plants. Characteristics: ♦♦ plants with roots, stems and leaves ♦♦ reproduce by means of flowers and seeds ♦♦ seeds are produced inside the ovary, in the flower Flowering plants can be divided into two main groups, the monocotyledonous plants and the dicotyledonous plants, often abbreviated to monocots and dicots (Figure 1.21). Monocots have only one cotyledon in their seeds. They usually have a branching root system, and often have leaves in which the veins run in parallel to one another. Dicots have two cotyledons in their seeds. They frequently have a tap root system, and their leaves are often broader than those of monocots, and have a network of branching veins. Corn (monocot)
Ferns Ferns have leaves called fronds. They do not produce flowers, but reproduce by means of spores produced on the underside of the fronds. Characteristics: ♦♦ plants with roots, stems and leaves ♦♦ have leaves called fronds ♦♦ do not produce flowers ♦♦ reproduce by spores
Pea (dicot)
parallel veins strap-shaped leaves
broad leaves network of branching veins
Figure 1.21 Flowering plants.
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Cambridge IGCSE Biology
Original material © Cambridge University Press 2014
Chapter 1: Classification