Thursday, April 28, 2011

Angiosperms


I see that I'm not alone in not knowing a lot about Angiosperms as Daphne has done her slides on this topic as well! Angiosperms are the flowering plants and they are the most diverse group of land plants. Like the gymnosperms, angiosperms are seed-producing plants, but the angiosperms have derived characteristics that set them apart from the gymnosperms.

One of the most significant derived characteristics that distinguishes the angiosperms from other seed plants is the flowers. The flowers are the reproductive organs and can aid angiosperms by enabling adaptability and broadening the ecological niches open to them. Due to this fact, the angiosperms dominate terrestrial ecosystems. The seeds that were mentioned are enclosed and contain an endosperm and endosperm formation generally begins after fertilization and the endosperm is a highly nutritive tissue that can provide food for the seedling when it first appears.Some other derived characteristics include stamens with two pairs of pollen sacs causing adaptations to specialized
pollination and well as to prevent self fertilization, as well as a closed carpel that encloses the ovules. The carpel and accessory parts may become the fruit. This enclosed carpel is another way to prevent self-fertilization and therefore increase diversity. Angiosperms also have reduced male and female gametophytes which decrease the time from pollination to fertilization of the ovary. This more rapid seed set has led to such flowering plant adaptations as annual herbaceous life cycles.

Even with all this information that distinguishes angiosperms from other plants, it is still hard to picture what exactly we are looking at here. When looking at the agricultural significance of angiosperms, we can see many different foods that are used in our everyday life.
Products of angiosperms include members of the rose family which include apples, pears, cherries, apricots, plums and other fruits as well as members of the legume family which include plants that have pods with their seeds inside such as various types of beans and peas. The gourd family is also included in the angiosperms and pumpkins and melons are found in this category. Tomatoes and peppers which are found in the nightshade family as well as wheat, oat, rice, and barley which are found in the grass family are all produced by angiosperms. The grass family is most significant when it comes to feedstock for animals. With all of these different families all found within the angiosperms, it is not surprising that angiosperms make up 90% of today's plant species. Next time you look at the meal you're about to consume, I bet you think of angiosperms!

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