In order to be classified as a green plant, an organism should be eukaryotic, have double-membraned chloroplasts, cell walls, an
d go through the process of _______. Land plants likely evolved from _______.
Plants have a life cycle that is called the alternation of generations. The two phases of this life cycle are the diploid stage and the _______ stage.
A plant structure that contains a full set of paired chromosomes is called a _______.
There are two key transport tissues in plants. _______ transports water from the roots to the rest of the plant, while phloem transports sugar and nutrients.
Match the term on the left to its definition on the right.
6. Angiosperm a. Has vascular tissue, but does not use seeds to reproduce
7. Fern b. Reproduces using cones
8. Moss c. Has no vascular tissue and uses spores to reproduce
9. Gymnosperm d. Reproduces by using flowers to attract pollinators
Respond to the following based on your reading.
The earliest land plants were liverworts, mosses and ferns. Using the information that you learned in the section, why do you think that these plants were successful in the humid and moist ancient environment? What about these plants makes them unable to thrive in areas with drier climates today? What makes angiosperms and gymnosperms more successful in these climates?
Early land plants like mosses did not have vascular tissue. They must absorb their water directly from their surroundings, such as growing on rocks or trees that are moist. You find mosses in damp areas for this reason. They cannot grow in drier climates because they cannot pull water from the ground like vascular plants. Ferns are also suited to reproduce in more moist/humid climates because water must be present for their gametes (sperm and eggs) to find one another for fertilization. Seeds are adaptations by angiosperms and gymnosperms that allow for waterless fertilization. Either wind or animal pollinators help spread pollen and help the sperm reach egg cells for fertilization to occur. For that reason, these plants are better suited to survive in drier, modern climates.
