Unit 1:The Organisation of Living

ThingsBy Caitlin Foley

“Strep throat” is an illness caused by a

live bacteria

A turtle hatches from

its shell

Plants are also living things

What do living things do?• All living things carry out

the basic life processes of interaction, nutrition, and reproduction.

– Interaction: When a living thing detects information in his or her environment and reacts to that information.

– Nutrition: When a living thing takes in essential nutrients from his or her environment. These nutrients give him or her energy and help with growth and development.

– Reproduction: When living things create members of their own species.

Interaction helps animals, such as these lions, to defend their territory

What are living things made up of?

• All living things are made up of cells. Cells are the basic units of life. – Unicellular

organisms are living things made up of only one cell.

– Multicellular organisms are living things that have many cells.

• Animal cells and plant cells are different from one another.

Yeast is an example of a

unicellular organism

Animal Cells• The membrane

surrounds and protects the cell.

• The cytoplasm is a thick, clear liquid protected by the membrane.– In the cytoplasm, we

find special organelles that carry out different life processes.

• The nucleus controls everything that happens inside the cell. The nucleus is found inside the membrane.

Diagram of an animal cell

Plant Cells• Plant cells have a rigid cell

wall around the membrane. The cell wall helps to support the plant.

• In the cytoplasm of plant cells, there are special organelles called chloroplasts. They contain a green liquid called chlorophyll. Chlorophyll carries out photosynthesis by transforming sunlight and nutrients into energy.

• Plant cells have a vacuole, which is like a bag. The vacuole fills and empties when the plant loses and gains water.

Diagram of a plant cell

Comparing plant and animal cells

How are animals organised?• Cells: Multicellular organisms

have many types of cells. The cells are different shapes according to their function.– Red blood cells are flat and circular

cells that carry oxygen from the lungs to the muscles and organs.

– Nerve cells are star-shaped cells that transmit nerve impluses from different parts of the body to the brain.

– Reproductive cells enable us to reproduce. Female reproductive cells are spherical. Male reproductive cells are oval with a long tail for swimming.

• Tissue: Cells join together to form tissue. Each type of tissue has a specific function.

• Organs: Organs are made up of different tissues. Each organ has a specific function.

• Systems: Systems are groups of organs that work together to perform a function.

Red blood cells, as they appear under

a microscope

Nerve cells, as they appear under a microscope

Reproductive cells, as they appear

under a microscope

How are plants organised?• Cells: Plant cells have a rigid

cell wall so they are usually rectangular or polygonal. Photosynthesis takes place in leaf cells. Those cells contain chlorophyll and a liquid called sap that is used to make food for the plant.

• Tissue: Plant tissue, like animal tissue, is made up of many cells joined together.

• Organs: Organs are made up of tissue.

• Systems: Systems are groups of organ and tissue that are used to carry out a function.– Roots: The function of the roots is

to absorb water and nutrients from the soil. To do this, root cells have root hairs.

– Stems: The function of the stem is to support the plant and transport water, minerals, and sap throughout the plant. Stem tissue forms rigid tubes that liquid can pass through easily.

Diagram of the stem and roots of a plant

What systems do living things have?

• Animal bodies are made up of several systems. Animals and human beings carry out the basic life processes of interaction, nutrition, and reproduction with these systems.– Nutrition: Some of our systems

take in, use, and transform the substances that we need to live and grow.

– Interaction: Some of our systems detect information about the world and enable us to react to that information.

– Reproduction: Our reproductive system enables us to reproduce by having children.

What basic life processes does each picture show?

Nutrition

Reproduction

Interaction