What are some examples of gymnosperms and angiosperms?
Examples are pines, cedars, spruces and firs. Some gymnosperms do drop their leaves - ginkgo, dawn redwood, and baldcypress, to name a few. --Angiosperms are a taxonomic class of plants in which the mature seed is surrounded by the ovule (think of an apple). This group is often referred to as hardwoods.
The key difference between angiosperms and gymnosperms is how their seeds are developed. The seeds of angiosperms develop in the ovaries of flowers and are surrounded by a protective fruit. Gymnosperm seeds are usually formed in unisexual cones, known as strobili, and the plants lack fruits and flowers.
- As in gymnosperms, the ovule becomes a seed, encasing the embryo and endosperm in a seed coat. But unlike gymnosperms, in angiosperms the ovary containing the ovules develops into a fruit after fertilization.
- Like gymnosperms, angiosperms are seed-producing plants. However, they are distinguished from gymnosperms by characteristics including flowers, endosperm within the seeds, and the production of fruits that contain the seeds.
- Gymnosperms were the first plants with seeds. They are vascular plants and do not produce flowers. However, the seed is beneficial because it provides protection and food for the plant embryo. Examples of gymnosperms include conifers - or evergreens - and ginkgoes.
Pollination and Fertilization. Pollination is the transfer of pollen to the female organs of seed plants. In flowering plants (angiosperms, or "covered seeds"), immature seeds (ovules) are located within carpels. Gymnosperms have simpler pollination as all transmit their pollen by wind.
- Seeds are made at the base of the pistil, in the ovule. To be pollinated, pollen must be moved from a stamen to the stigma. When pollen from a plant's stamen is transferred to that same plant's stigma, it is called self-pollination. Pollen from a rose or an apple tree would not work.
- Pollen is a collection of male reproductive cells that will fertilize ovules to produce seeds. When the flower blooms, male pollen cells are scattered by insects or by the wind. Some kinds of plants produce only complete flowers. Other plants produce both male and female incomplete flowers on the same plant.
- acid (DNA) has shown that the gymnosperms consist of four major, related groups: conifers, cycads, ginkgo, and gnetophytes.
- Conifers. With approximately 588 living species, this is the most diverse and by far the most ecologically and economically important gymnosperm group.
The ovules in angiosperms are encased in an ovary, not exposed on the sporophylls of a strobilus, as they are in gymnosperms. Angiosperm means "covered seed". The ovules develop into seeds, and the wall of the ovary forms a fruit to contain those seeds. Fruits attract animals to disperse the seeds.
- The adult, or sporophyte, phase is the main phase of an angiosperm's life cycle. As with gymnosperms, angiosperms are heterosporous. Therefore, they generate microspores, which will produce pollen grains as the male gametophytes, and megaspores, which will form an ovule that contains female gametophytes.
- The angiosperms are divided into two classes: the monocots and the dicots. (Not all dicots' seed leaves emerge during germination; for example, peas are dicots, but the pea cotyledons remain underground.) Corn is an example of a monocot. Corn seed has one cotyledon and can't readily be split.
- Two main modes of fertilization are found in gymnosperms. Cycads and Ginkgo have motile sperm that swim directly to the egg inside the ovule, whereas conifers and gnetophytes have sperm with no flagella that are moved along a pollen tube to the egg. More than one embryo is usually initiated in each gymnosperm seed.
Updated: 20th September 2018