Question

1. List at least three examples of how living things can differ.
2. List at least three traits or processes that all living things have in common.

Answer 1

•examples of how living things can differ :-

1. On the basis of cellular structure, whether they are unicellular or multicellular.

2. On the basis of mode of nutrition, whether they are autotrophic, heterothropic, parasitic or saprophytic.

3.On the basis of well defined nucleus, whether they are prokaryotic or eukaryotic.

•processes that all living things have in common :-

Movement

All living things move in some way. This may be obvious, such as animals that are able to walk, or less obvious, such as plants that have parts that move to track the movement of the sun.

Earthworms use circular and longitudinal muscles to move through soil or along surfaces.

Respiration

Respiration is a chemical reaction that happens within cells to release energy from food.

The food that earthworms eat supplies their body with energy-rich molecules such as glucose. On entering the cells of their body, these molecules are broken down in a series of steps to release energy to be used by the body, producing carbon dioxide and water as waste products.

Sensitivity

The ability to detect changes in the surrounding environment.

Earthworms have light-sensitive cells scattered in their outer skin. Their skin cells are also sensitive to touch and chemicals.

Growth

All living things grow.

Earthworms hatch from eggs and can grow up to a metre or more in length! Some earthworms are also able to regrow small parts of their body that have been lost or injured.

Reproduction

The ability to reproduce and pass genetic information onto their offspring.

Earthworms have both sperm and eggs within their bodies (they are hermaphrodites) but they cannot self-fertilise and need to mate with another individual. After mating, a cocoon containing the fertilised eggs is deposited in the soil.

Nutrition

The intake and use of nutrients. This occurs in very different ways in different kinds of living things.

Earthworm nutrition comes from a variety of sources, depending on their species. Food types include manure, compost, plant material, fungi, microorganisms and decaying animals. They take in food through their mouths.