Living Things Biology is the study of life or living things Another name for a living thing is an Organism

Living Things Every living thing is composed of (or made up of) Cells Cells are called the building blocks of life

Cells Some living things are composed of just a single cell eg bacteria Some living things are composed of a small number of simple and similar cells eg fungi Some living things are composed of very many cells, with many different structures and functions eg humans nerve cell muscle cells blood cells bone cells

How do we know if something is a living thing? Living things (or organisms) must have all seven of the following 7 features or characteristics

Characteristics of Living Things Movement Respiration Sensitivity Growth Reproduction Excretion Nutrition An easy way to remember These are M R S G R E N

Movement Movement means The ability of an organism to change position Some organisms can move the entire body eg single-celled organisms Some organisms can move part of the body eg plants Some organisms can move both their entire body, and each section of the body eg insects, amphibians, reptiles, mammals Most organisms move towards things they need and away from things that harm them

Respiration Respiration means releasing energy from food Glucose in the food is broken down inside cells, and energy is released Most organisms use oxygen for this process – so it is called aerobic respiration

Sensitivity/Response Response means the ability of an organism to gather information and respond to it Some of the things that cause living organisms to respond are light, sound, touch, chemicals, gravity…eg: Roots grow downwards in response to gravity, shoots grow towards light Both plants and animals use their sense of touch when climbing Predators use sound and smell to hunt for prey

Growth Growth means the organism develops into an adult For micro-organisms, this means their cell grows to full size before reproducing For multi-celled organisms, this means that cells divide, organs grow in size, and systems develop maturity

Reproduction Reproduction means producing more organisms of the species Some organisms reproduce from one parent only – this is called ASEXUAL reproduction Other organisms reproduce by combining one cell from a male with one cell from a female – this is called SEXUAL reproduction Scientists have a name for the “children” of all living organisms – they say OFFSPRING

Excretion Excretion means the removal of toxic chemical substances Toxic substances are poisonous and may harm cells if not removed Examples of toxic substances are carbon dioxide and urea Sweat is a form of Excretion!

Nutrition Nutrition means obtaining food All living organisms need food as a source of energy Plants can make their own food using energy from the sun (photosynthesis) Animals need to find an external source of food