Living and Non-Living Things

In the primary classroom, children should be able to group things into things that are living, dead and never been alive. Something like wood is dead, because it was once living, whilst something like metal has never been alive.

There are 7 things that all living creatures do.

These can be summarised as:

• Movement
• Respiration
• Sensing / sensitivity
• Growth
• Reproduction
• Excretion
• Nutrition (feeding)

A simple mnemonic to help you remember them is “MRS GREN”. To be classed as alive, an organism needs to be able to do all 7 of these things.

All living things are able to move. Even something like a plant is able to move things such as leaves towards the light. They need food for nutrition and energy. Plants make their own food by a process called photosynthesis. Animals eat plants or eat another animal that has eaten a plant.

Everything that is alive can grow and get bigger, and reproduce to create offspring.

Respiration is the process of releasing energy from food, usually using oxygen and producing carbon dioxide. Every living thing; including animals, plants and fungi need to respire. Living things also need to get rid of their waste products in a process called excretion. This includes breathing out (or releasing gases) as well as going to the toilet.

Living things sense and react to their environment. For example, animals might run away from a predator or plants grow towards sunlight so they can make more food. When a seed germinates the roots and shoots can detect gravity – the roots grown down and the shoots grow upwards.

Taxonomy of Life

The term “taxonomy” refers specifically to sorting and classifying living organisms. We also refer to it as “scientific classification.” This was developed by Carl Linnaeus (see below)

Living things are classified into three broad domains: bacteria, archaea and eukaryotes. To make things easier, at a primary level we’ll just focus on eukaryotes.

The highest rank in a domain is the kingdom. There are five kingdoms, which mainly are based on certain characteristics that their cells have.

Animals: Any multicellular organism that feeds on plants or other animals. Cells do not have cell walls.

Plants: A living organism that is able to make its own food by the process of photosynthesis. Cells have a cell wall made of cellulose.

Fungi: A group of organisms that include microorganisms like yeast and moulds. Fungi play an important role in decomposing dead plant and animal matter. Examples of fungi include athlete’s foot, ringworm, mushrooms and toadstools. Has a cell wall that’s made of chitin (different to plant cells). Like animals they also cannot make their own food.

Prokaryotes: A simple single-celled organism without a nucleus. Prokaryotes include bacteria and blue-green algae.

Protoctista: A group of microorganisms that can either have one cell or many cells, but these are not grouped into specialist tissues. Protoctists include amoeba and protozoa

Each kingdom has many smaller groups in it, called phyla. In animals this includes all the vertebrates are in one phylum (chordata) and invertebrates have about 34 phyla such as arthropods or molluscs. Each phylum has more smaller groups in it, called classes such as insect, mammal, bird etc.

Each species is put into a group because of what it does, how and what it eats, special body parts, and so on.

A species is a class of living organism that can breed with others of the same class, to produce fertile offspring. For example all the different breeds of dog belong to the same species – they can all interbreed with each other. But a dog cannot breed with a cat, they are different species.

Sometimes, very closely related species can breed but the offspring cannot have babies. A mule is produced when a male donkey breeds with a female horse. Lions can breed with tigers. Donkeys can breed with zebras.

Invertebrates

Invertebrates have no internal skeleton or backbone. Some invertebrates, such as insects and crustaceans, have a hard exoskeleton to protect the body and allow movement, while others, such as jellyfish, are supported by water. Invertebrates are sub-divided into smaller groups according to specific similarities.

There are many groups of invertebrates, but the main ones to cover at a primary level include:

Insects: Have three body parts, six legs and two antennae. Includes bees, wasps, butterflies, ladybirds.

Arachnids: Usually have four pairs of legs, two body parts and no antennae or wings. Includes spiders and scorpions.

Crustaceans: Have two body parts and two pairs of antennae. Number of legs varies. Includes woodlice, crabs and lobsters.

Worms: Have a long soft body with many segments and no legs. Includes earthworms, lugworms.

Molluscs: Have a soft body, may have a shell. Includes slugs, snails, barnacles, squid and octopus.

Myriapiods: Have a long body with many segments and lots of legs. Includes centipedes and millipedes.

Vertebrates

Vertebrates are animals with a backbone, a spinal cord and a skull enclosing the brain and eyes. Only 1 in 20 of all species on Earth are vertebrates. Vertebrates are divided into 5 main classes – based on their features:

Mammals: Have fur and are warm blooded. They give birth to live young which are initially fed by milk from the mother. Babies develop inside the mother, directly attached to her via a placenta. Examples of mammals include humans, dogs, elephants, whales and seals.

Birds: Birds have feathers and lay eggs. They are warm-blooded and have wings and two legs. All modern birds have a beak and no teeth. Examples of birds include falcons, ostriches, sparrows and penguins. All birds have wings, but not all birds can fly.

Fish: Fish live in water, breathe through gills, and have no limbs with digits. They have scaly skin. Fish are usually cold-blooded. Most fish lay eggs. Examples of fish include salmon, trout, goldfish and sharks.

Reptiles: Reptiles lay eggs, are cold-blooded and generally have four limbs (some, like snakes, later evolved to lose them). They have dry scaly skin and lay leathery eggs. Examples of reptiles include lizards, crocodiles, snakes and turtles.

Amphibians: Amphibians have moist, slimy skin, lay jelly-like eggs, are cold-blooded and have four limbs. They are able to breathe both on land and in water. Most amphibians lay eggs in water. Examples of amphibians include frogs, toads, newts and salamanders.

These are general features. There are some members of these classes that blur things a little such as the echidna and duck-billed platypus which are mammals but lay eggs.

Plants

Plants can be divided into two main groups, depending on whether they form flowers or not. These are known as Flowering and Non-Flowering plants.

Non-flowering plants include plants such as conifers, ferns and mosses. Conifers produce cones which produce pollen and seeds in the same way as flowers. They are wind-pollinated. Ferns and Mosses do not produce seeds – they reproduce by making spores which can grow into new plants.

Flowering plants include all other plants, including many trees, grasses and shrubs. They produce flowers which produce pollen. Some flowers have adapted to attract insects for pollination, but other flowers use wind or water to spread their pollen. Once pollinated the ovary swells up into a fruit and the eggs turn into seeds.

In some flowering plants the actual flowers might not look like what we imagine a flower to look like, particularly in some grasses. Only insect-pollinated flowers need to look attractive.

Microorganisms

A microorganism is an organism that is too small to see without a microscope. Common microorganisms include bacteria and some fungi. Viruses are sometimes also included, though this can be controversial since they can’t really be considered as a living thing.

Some of these are responsible for sickness and diseases, such as Salmonella, E. coli, colds, flu and athlete’s foot, but others are beneficial – helping us digest our food, decomposing waste and making food such as beer, wine and cheese. Life on Earth could not exist without microorganisms.

A microscopic fungus such as yeast is very useful. It ferments sugar and turns it into alcohol and carbon dioxide. We use this to brew beer and wine, and also use it when baking. The bubbles of carbon dioxide make the bread rise.

Fungi

There are around 1.5 million species of fungi, including mushrooms, toadstools and moulds. Fungi are neither plant nor animal. They have their own separate kingdom.

Fungi are often thought to be plants since people think they have roots and are grown in the ground, but they do not have chlorophyll.  Without chlorophyll, they are unable to make their own food, so mushrooms are not producers. Fungi are consumers and so have to get their nutrients from other organisms.

Fungi do nto actually have roots. Most fungi are made up of networks of fibrous threads, called mycelium which they use to suck up nutrients, which are a bit like plant roots, but work differently. Most fungi feed on decaying vegetation and waste. This process is important, as it recycles vital nutrients back into the soil. Some fungi do live on living things, often as parasites.

Fungi do not make seeds, like flowering plants do. Instead they produce fruits which contain tiny spores. Fungi can release millions of spores which are carried away by wind or released on impact. While earth stars use raindrops to propel their spores into the air.

The simple answer is that mushrooms, like all fungi, do not have chlorophyll, and so are unable to make their own food. This means they cannot be plants.

Carl Linnaeus

The current system of naming all living things was proposed by a scientist called Carl Linnaeus in the mid 1700’s. The system that was used at the time was very difficult to use, with many living things being given long and complicated names. To add to the confusion, different countries and regions also had different names for the local animals and plants.

Along with his new classification system that he had developed, Linnaeus simplified names into a two-part Latin name. Each plant and animal was given a name comprised of two words in Latin. The first word is a family name, like your surname. This is called the genus. The second name is called the species, and is like your first name.

Although these names originally came from Latin, they now often include words from Greek and other languages. Sometimes they are taken from the name of the scientist that discovered it and even famous people such as David Attenborough and Beyonce.

For example the Latin name of the Horse Chestnut tree is Aesculus hippocastanum. Aesculus is the roman name for an edible acorn. Hippocastanum comes from “Hippo”, the Latin for horse and “Castanum” the Latin for chestnut

Glossary

Animal: A living organism that feeds on plants or other animals and, typically has a nervous system that enables it to respond to stimuli.

Plant: A living organism that is able to make its own food by the process of photosynthesis.

Fungi: A group of organisms that include microorganisms like yeast and moulds. Cannot make their own food and feed on dead or living animal/plant matter.

Photosynthesis: Using the energy in sunlight to convert carbon dioxide and water into sugar (glucose).

Prokaryotes: A simple single-celled organism without a nucleus. Prokaryotes include bacteria and algae.

Protoctista: A group of microorganisms that either have one cell or many cells, but no specialist tissues. Protoctists include algae, amoeba and protozoa

Kingdom: One of the five groups that many scientists use to classify living things: animal, plant, fungi, protoctista and prokaryote.

Species: A class of living organism that can breed with others of the same class, to produce fertile offspring.

Links

• Linnean Society
• Royal Entomological Society
• Field Studies Council
• Nature Detectives
• National Insect Week
• Great Plant Hunt
• What is Classification? (BBC Bitesize)
• Classification Presentation