Characteristics of Life Junior Cycle Science Characteristics of Life Biology

What is Biology Biology is the study of living things Living things must have all of the following characteristics: Movement Respiration Sensitivity Feeding Excretion Reproduction Growth

Movement All living things can move. Animals move more quickly than plants do. Animals can run, swim or even fly. It is hard to notice plants move. But their roots move towards water. And their stems move towards light. Even some bacteria can move using tails.

Respiration Respiration is the way living things break down their food. Respiration supplies living things with ENERGY. This happens in all living cells. Energy is needed for organisms to move, reproduce, grow and carry out all their daily activities. Some organisms need oxygen to respire. These organisms are called AEROBIC RESPIRATION.

Sensitivity Living things are aware of their surroundings. They are sensitive to different STIMULI and can RESPOND as required. Animals are sensitive to light, sound, touch, taste and smell. Plants are sensitive to light, gravity, water and sometimes even touch.

Feeding (Nutrition) All living things need food to survive. Animals get their food by eating other animals or plants. Plants make their own food in a process called PHOTOSYNTHESIS.

Excretion During respiration, waste materials are made in your body. All living things make waste and it must be removed because it can be poisonous. Excretion is the removal of wastes from the body. Animals produce wastes like CO2, salts and H2O.

Reproduction Reproduction is the formation of new living things. Without reproduction a type of organism would become extinct.

Growth All living cells grow. Cells also increase in size as they get older. Growth happens when cells divide to form new cells. The average human being contains 10,000,000,000,000,000,000,000 cells. But all humans started off as just one cell.

Classifying Organisms Organisms or Living Things can be classified into groups. The main groups are Bacteria, Fungi, Plants and Animals. Animals and plants can be told apart by looking at: How they move – Animals move from place to place, while plants only move parts. How they get food – plants make their food by photosynthesis. Their cells – plants cells have cell walls.

Invertebrates & Vertebrates Animals that have a backbone are called VERTEBRATES. Examples: Humans, sheep, crocodiles etc. Animals without a backbone are called INVERTEBRATES. 97% of all animals are invertebrates. Examples: Worm, Jellyfish, Ant, Crab etc.

Using a Simple Key 1 (a)Animal with backbone ……………………… Go to 2   (b)Animal without backbone …………………… Go to 3 2 (a) Covering of feathers ………………………… Go to 4   (b) Covering of hair ……………………………… Go to 5  3 (a) Tough hard outer body ……………………… Go to 6   (b) Soft body ……………………………………. Go to 7  4 (a) Red feathers on chest ………………………… Robin   (b) Black and white feathers..……………… Magpie  5 (a) Long bushy tail……………………………….. Fox   (b) Long ears, short white tail……………………. Rabbit  6 (a) 3 pairs of legs……………………………….. Ground beetle   (b) Four pairs of legs……………………………… Spider    7 (a) Segmented body……………………………… Earthworm  (b) Un-segmented body…………………………… Slug