When you look outside the window you will see various plants, ranging from tall trees, smaller bushes to tiny moss plants growing on a wall or in the grass. Plants have an important role in our ecosystem. They provide shelter for many organisms that live in, under or on them. They are also an important food source for a lot of organisms, including ourselves. Can you think of another important role that plants have?The cells of a plant have a cell wall and cell membrane. Their cells also have a nucleus. Plants can make their own food inside their chloroplasts. These are the green structures in which photosynthesis takes place. Plants are multicellular; however some scientists say there are unicellular plants as well.
The group of plants known as algae have a special place in this kingdom; they can be either unicellular or multicellular. Seaweeds are examples of multicellular algae; they can grow very large and many of them are edible or processed in food. Some unicellular plants live as colonies of 500 or more unicellular individuals, such as Volvox (see figure 2.31). They swim together as a unit.Scientists group plants to make sense of all those species that live on our planet. They look at the appearance of the plant but also at how the plant reproduces. Therefore plants can be divided into two taxons: those that reproduce by spores and those that reproduce by seeds.Plants which produce spores are non-flowering plants: they do not make flowers. The cells these plants use for reproduction are called spores. These plants live in damp places. There are two groups of spore-making plants; one group contains mosses and liverworts; the second group contains ferns.
Mosses and liverworts
Mosses and liverworts have simple leaves. They do not have proper stems or roots. They make spores inside spore capsules.Seeds can develop in plants that produce pollen for reproduction. Plants which make seeds can be divided into two groups: gymnosperms or non-flowering plants; and angiosperms or flowering plants.
Gymnosperms (non-flowering plants)
Gymnosperms are also called conifers. Their seeds are naked and develop in cones. There are male and female cones. The male cones produce pollen. The female cones produce seeds. The leaves are needle-shaped to minimise water loss.
Maecenas vestibulum mollis diam. Pellentesque ut neque. Pellentesque habitant morbi tristique senectus et netus.
Proin sapien ipsum, porta a, auctor quis, euismod ut, mi. Aenean viverra rhoncus pede. Pellentesque morbi habitant morb.
Bedrijfsnaam | Straat 123 A | 1234 AB Stad
email: bedrijf@mijnbedrijf.nl