11.2 Mosses and Ferns

11.2 Mosses & Ferns need moisture From original water-based plant forms, plants eventually adapted to life on land Plant life appeared on Earth about 475 million years ago Plants were first to move from water environment to land. Resembled green algae They are autotrophs & producers

11.2 First Plants Plants first appeared in water (tiny, floating organisms that could photosynthesize) As ponds/rivers got crowded or dried up, some were pushed to the side. Those that could adapt and survive became ancestors to the first land plants. Advantages: land had plenty of CO2 and direct sunlight

11.2 Mosses and Ferns Mosses are simpler in structure than ferns Related plants = liverworts and hornworts are related to mosses descended from the first plants. Ferns and their relatives appeared later.

11.2 Mosses are non-vascular Each moss cell is surrounded by a thick cell wall that supports it. Their cells have special storage areas for water and nutrients and water plays an important part in the reproductive cycle. They do not grow tall or large, but they have – Simple structures that function like roots, stems, and leaves – They are non-vascular (do not have vascular tissues) so water and nutrients simply move throughout the plants’ bodies cell by cell (diffusion).

11.2 Mosses reproduce w/spores Mosses, ferns and fungi all reproduce (both asexually & sexually) with spores (which are an adaptation). Life Cycle: Generation 1 – 1 st Half: Moss grows & maintains itself – Produces male/female structures need to reproduce – 2 nd Half: If there’s enough water, plant produces spores (both sperm and egg cells) – Water must be present for sperm & egg to fertilize Offspring (Generation 2) grow into a stalk with capsule on its end

11.2 Ferns Ferns, horsetails, and club mosses are related vascular plants Ferns = first plants with a vascular tissue system (vts) Because they can transport water (etc) using vts and because the vts also provide support, they can grow larger. VTS allows for branching of root systems (which anchor the plant) and leaf systems (more sugar/energy, etc).

11.2 Fern reproduction Leaves of a fern are called fronds Spore clusters are on the back of the frond. Can reproduce sexually & asexually (branching, cuttings) Life Cycle: Generation 1 – Spores grow in structures near the ground (thumbnail sized) which contain the sperm and egg producing parts of fern. – Water is needed to stimulate & assist w/ fertilization. Gen.2 = Fern w/fronds grows from the fertilized egg. – As fronds grow, egg bearing part dies away. Fronds produce clusters of cells within which meiosis takes place and male/female spores are made. – Spores spread through air to grow into Gen.1

Fern With Spores