1. Identify the reproductive organs of plants.
2. Describe the parts of a seed.
3. Classify seeds and plants as monocots or dicots.
4. Recognize methods of seed dispersal.
5. Describe seedling emergence.
1. REPRODUCTIVE ORGANS The function of a flower is sexual reproduction. The male organs within a flower are the ANTHER (produces and contains pollen) and the FILAMENT (supports, or holds up, the anther). These two males parts together are called the STAMEN. The female organs within a flower are the STI GMA (the opening to the female parts), t he STYLE (t ube that connects to the ovary), and the OVARY (produces and contains the eggs). These three fem ale parts together are called the PISTIL . The flower also has PETALS and NECTAR, which are not sex organs, b ut the both play an important role in attracting pollinators.
2. SEED PARTS After an egg is fertilized, the flower wilts away as a seed is formed. The seed contains the EMBRYO (baby plant) and the COTYLEDON (food supply for the baby plant) and is covered by a SEED COAT (provides protection). The cotyledon is needed to supp ly food for the growing baby plant until it has grown up enough to spread out its leaves and receive sunlight so it can use photosynthesis for food. Seeds are classified by how many cotyledons they have. They are either MONOCOT (have just one cotyledon) or DICOT (have two cotyledons).
3. MONOCOTS and DICOTS Plants that grow from a monocot seed will have flowers with petals in groups of 3's, leaves with a parallel pattern, and roots that are thin and stringy, called fibrous. Plants that grow from a dicot seed will have flowers with petals in groups of 4's or 5's, leaves with a branching pattern, and a thick deeper root, called a tap root.
4. DISPERAL The different ways that plants spread out their seeds is called DISPERSAL (spreading out seeds). Plants disperse their seeds to prevent the baby plants from growing too close to the parent plant and reducing competition for resources. The more spread out they are, the better the chance of survival. Some plants use animals to carry their seeds (like sticker burrs that get stuck to paws, or nuts and fruits that get carried away). Some plants use wind to carry their seeds (like dandelions whose seeds are like tiny helicopters). Some plants build up pressure and "pop" out their seeds, and the force of the popping throws the seeds far away from the parent plant.
5. SEEDLING EMERGENCE When a environment is the right temperature and moisture, the seed can begin to grow. Water is absorbed by the seed and TURGOR PRESSURE (water pressure in a plant) builds up. The force of the pressure starts to inflate the seed, and the cells begin to divide, allowing the plant to grow. This growth from a seed to a plant is called EMERGENCE (the plant is emerging from the soil). The cotyledon will continue to feed the baby plant until the leaves start functioning, and when they are no longer needed they will drop off and decompose.