Living Things

LIVING THINGS

When you look at the world around you, how do you categorize or group what you see? In science, the broadest groupings are living and non-living. This may sound simple, but it is sometimes difficult to decide whether something is truly alive or not.

All living things share life processes such as growth and reproduction. Most scientists use seven life processes or characteristics to determine whether something is living or non-living.

Plants and Algae

 Did you know that seaweed is not a plant? First of all, algae may be unicellular, colonial, or multi-cellular. Plants, on the other hand, are only multi-cellular. Holdfasts, stapes and blades compose multi-cellular algae. In comparison, plants have roots, stems, leaves, flowers, fruits, seeds and cones. The roots of plants not only hold them in place, they nourish them. Plants possess vascular systems, which allow for the uptake and transport of water and nutrients. In contrast, each cell in algae must obtain its own nutrients from water for survival.

Animals and Fungi

Fungi and animals are very different from each other and classified as completely separate kingdoms. At the cellular level, both animals and fungi are composed of eukaryotic cells. Fungal cells differ from plant cells in that they do not have chloroplasts and cannot carry out photosynthesis to make their own food. They are similar to animal cells in that fungal cells have centrioles, the structures that organize the spindle during mitosis.

Human Body