Seed Plants: Gymnosperms and Angiosperms

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1 Seed Plants: Gymnosperms and Angiosperms 1. Gymnosperms: (Naked Seed) seed plant that bears its seeds directly on the surface of its cones 2. Cones and flowers: Young gymnosperms grow and mature within a sporophyte structure called a cone. Angiosperms use flowers and seed bearing structures from drying out. 3. Seeds: Seeds are embryos of plants that are enclosed in a protective covering and surrounded by a food supply for it to grow up nice and strong. An embryo is an organism in its early stage of development. The seed coat surrounds and protects that embryo and keep s the contents of the seed 4. Gymnosperms: Cone bearing plants These cone bearing plants include: Gnetophytes (more related to Angiosperms), cycads, ginkgoes, and conifers. 1

2 5. There are three major types of Gymnosperms: a. Conifers Conifers live in many habitats and biomes. They are known as evergreens. Most needles remain on the plant for 2 to 14 years at a time. Woody evergreen trees like pine, fir, cedar, hemlock, and spruce Cones are divided into male and female Male cones are long and female cones are short and fat Most conifers are dioecious, which means each tree produces both male and female cones. b. Cycads Palm like trees, that are not palms at all. There were predominant in the age of dinosaurs, which makes them very OLD! Mostly found in tropical areas. c. Ginkgoes Ginkgo tree is a living fossil. It has remained unchanged for millions of years! It is super resistant to pollution would make it popular to plant in cities, but there is a distinct rancid smell that goes from the female seeds, so only male trees are planted. They are monoecious, which means they have male and female plants. 6. Angiosperms- Flowering plants: Angiosperms: flowering plant that bears its seeds within a layer of tissue that protects the seed. 2

3 Flowers contain ovaries which surround and protect the seeds. The fertilized seed turns into a fruit. When animals eat these fruits the seeds are spread after they leave the digestive system. This is how the angiosperms spread their seeds to grown in different places without having legs! Flowers are brightly coloured to attract bees to the flower for pollination. If the flowers on a plant are reduced or non existent, they rely on wind to help them pollinate. a. Reproductive parts of flowers: i. Pistil ii. Stamen b. c. When ovules are fertilized by pollen contained on the anther, they turn into fruit! The fruit helps protect the seed until it is ready to turn into a new plant. b. Monocots vs Dicots: Cotyledon: first leaf or first pair of leaves produced by the embryo of a seed plant a. Monotcots: Monocots are seeds that only have one cotyledon, such as the corn seed. The corn seed does have a seed coat, but it does not slip off as easily as the bean seed. The corn seed will not split like the bean seed. It stays in one piece. One cotyledon surrounds the embryo. It is a lighter color than the rest of the seed and is called the endosperm. It 3

4 provides food for the growing plant. The corn seed is a monocotyledon, or monocot. ''Mono'' comes from the Greek word monos, meaning ''one'' b. Dicots: Dicots are seeds that have two parts, such as a bean seed. A bean seed that has soaked in water for a day or two has a soft outside covering. This is the seed coat. The seed coat would probably slip off the seed easily. The bean seed has a slit going down the middle of the seed. Inside is a tiny plant called an embryo. The two large parts of the seeds are called cotyledons. They supply the food for the young plant when it's growing. The bean seed has two parts. Therefore, it is a dicotyledon, or dicot for short. Monoctos Dicots Seeds Single Cotyledon (Corn) Two Cotyledons (Bean) Leaves Parallel Veins Branched Veins Flowers Floral parts are often in threes Floral parts are often in multiples of 4 or 5 Stems Roots Vascular bundles are scattered throughout the stem Fibrous Roots- part of a root system in which roots branch to such an extent that no single root grows larger than the rest. Vascular bundles are arranged in a ring Taproot- Primary root found in some plants that grown longer and thicker than other roots. 4

5 d. Annuals, biennials, perennials Annuals Flowering plants that completes a life cycle within one growing system Biennials Flowering plants that completes a life cycle in two years Perennials Flowering plants that lives more that 2 years 5