Support and Transport in Plants and Animals

Living things must transport materials and support their bodies.

In plants:

• Xylem carries water and minerals up from the roots. Water is pulled up because it evaporates from the leaves in a process called transpiration.
• Phloem carries dissolved sugars made in the leaves to the rest of the plant.
• Support comes from thickened tissues (collenchyma and sclerenchyma) and, in soft green plants, from turgor pressure - water pushing the cell contents against the cell wall to keep the plant firm. When a plant loses too much water it wilts.

In animals:

• Vertebrates such as humans have an internal skeleton (endoskeleton) made of bone and cartilage. It gives support and shape, allows movement (muscles pull on bones), and protects organs (the skull protects the brain).
• Insects and crayfish instead have a hard outer exoskeleton.