How do vascular plants' xylem and phloem compare to an animals' arteries and veins?

Answer 1

Xylem, phloem, arteries and veins are all specialized transport systems that serve a unique but similar function in their respective organisms. Arteries and veins make up the circulatory system of many animals and are the primary mechanism for transporting nutrients and vital compounds throughout a living organism. The arteries are specialized in the transport of oxygenated blood away from the heart while veins return blood without their oxygen back to the heart to restore the cycle. Along the way, various compounds are dropped off and picked up at various cells.

While arteries and veins are an all encompassing system for transporting anything, xylem and phloem are even more specialized to only work in transporting certain materials. Phloem is specialized in the transport of nutrients, particularly sugar, throughout a vascular plant, while xylem is almost exclusively for water. Wheres arteries and veins require the pumping of a heart to flow, xylem and phloem depend on basic physical principles. Phloem utilizes the change in concentration between sources of nutrients and sites in need of nutrients to literally draw the nutrients where they are needed. Likewise, xylem depends on osmosis and a difference in pressure at the roots and the leaves to draw water up and through the plant.