Even so, taxonomists describe many new species annually, and estimates of total angiosperm diversity reach as high as , species. There are about families of flowering plants, displaying extremely diverse life histories and ecological adaptations.
In addition to dominating plant biodiversity, angiosperms are the dominant photosynthetic organisms primary producers in most terrestrial ecosystems an important exception to this rule are the boreal forests, which are often dominated by conifers.
All important food plants are angiosperms. Angiosperms are also the youngest of the plant divisions, having arisen relatively late in the history of terrestrial plant life. The first land plants are about million years old, but the earliest definitive angiosperm fossils are only about million years old, placing their known origins within the Early Cretaceous period. However, indirect evidence leads some scientists to estimate that angiosperms may have originated as early as million years ago, that is, at the end of the Permian period.
By about million years ago, during the Late Cretaceous period, angiosperms experienced a rapid diversification in form. The factors driving this diversification have long been of interest to evolutionary biologists.
Many scientists hypothesize that specialized mutualistic relationships with animal pollinators played an important role in the development of angiosperm diversity and perhaps insect diversity as well. Angiosperms are anatomically distinguished from other plant groups by several developmental and anatomical features.
They produce flowers, which are very short branches bearing a series of closely spaced leaves modified to facilitate pollination sepals and petals or to bear the organs involved in sexual reproduction stamens and pistils. Developing seeds are completely enclosed in an ovary derived from a portion of the pistil the word angiosperm is of Greek derivation, meaning covered seed.
Ovary tissues mature to form a fruit that is generally involved in protecting the seed and facilitating its dispersal only angiosperms bear true fruits. Seeds at some point in their development contain a distinctive tissue, the triploid endosperm, which serves as a nutritional reserve for the developing embryo. Angiosperms comprise such a large group, it is difficult to single out a mere few of the most intriguing, but here are some of the most important and diverse and delicious!
The composite or daisy family Asteraceae has about 24, named species, and may be the largest plant family. The orchid family Orchidaceae rivals the daisy family in diversity, with about 17, species named. Bumble bees were found to be less sensitive to temperature change than managed honey bees [ 9 ]. According to [ 16 ], expected climate change will negatively affect the geographical distribution of five native bees in Brazil which will potentially decrees tomato production by the year Pollinators are necessary for ecosystem services and crop production productivity.
Changes in ecosystems due to global warming as well as agricultural production systems will need to be studied and managed in order to keep ecosystem productivity and crop production sustainable and to feed an increasing world population. Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3.
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We are IntechOpen, the world's leading publisher of Open Access books. Built by scientists, for scientists. Our readership spans scientists, professors, researchers, librarians, and students, as well as business professionals. Downloaded: Introduction Pollination is the transfer of pollen grains from the anther, which is the male part of the flower, to the stigma, which is on the female part.
Cantharophily The flowers in beetle pollinated plants are unspecialized. Chiropterophily Flowers pollinated by bats are large, bowl-shaped, dark to green in color, produce large amounts of nectar and pollen, and smell like rotten fruit.
Melittophily Bees are known to forage flowers for pollen and nectar for their hives. Myophily Flies are attracted by the mimicry of carrion and feces, a phenomenon called sapromyiophily [ 8 ].
Ornithophily Flowers pollinated by birds are red in color, tubular in shape, scented, and nectariferous Medan. Other pollination syndromes In wind pollinated flowers anemophily , the pollen grains are very fine released on dangling anthers. More Print chapter. How to cite and reference Link to this chapter Copy to clipboard. Available from:. Over 21, IntechOpen readers like this topic Help us write another book on this subject and reach those readers Suggest a book topic Books open for submissions.
More statistics for editors and authors Login to your personal dashboard for more detailed statistics on your publications. For ethnobotanists, plants are not viewed solely as biological organisms to be studied in a laboratory; they are seen as an integral part of human culture. The convergence of molecular biology, anthropology, and ecology make the field of ethnobotany a truly multidisciplinary science.
Plant biodiversity, vital to ecosystems, food crops, and medicine production, is threatened by habitat destruction and species extinction. Plants play a key role in ecosystems. They are a source of food and medicinal compounds while also providing raw materials for many industries. Rapid deforestation and industrialization, however, threaten plant biodiversity.
In turn, this threatens the ecosystem. Biodiversity of plants ensures a resource for new food crops and medicines.
Plant life balances ecosystems, protects watersheds, mitigates erosion, moderates climate, and provides shelter for many animal species. Threats to plant diversity, however, come from many angles. The explosion of the human population, especially in tropical countries where birth rates are highest and economic development is in full swing, is leading to human encroachment into forested areas.
To feed the larger population, humans need to obtain arable land which leads to massive clearing of trees. The need for more energy to power larger cities and economic growth results in the construction of dams, the consequent flooding of ecosystems, and increased emissions of pollutants.
Other threats to tropical forests come from poachers who log trees for their precious wood. Ebony and Brazilian rosewood, both on the endangered list, are examples of tree species driven almost to extinction by indiscriminate logging. Indiscriminate logging : Indiscriminate logging, which leads to the clearing of whole habitats, has become a severe threat to plant biodiversity and has led to species extinction.
The number of plant species becoming extinct is increasing at an alarming rate. Because ecosystems are in a delicate balance and because seed plants maintain close symbiotic relationships with animals, whether predators or pollinators, the disappearance of a single plant can lead to the extinction of connected animal species.
A real and pressing issue is that many plant species have not yet been cataloged; their place in the ecosystem is unknown. These unknown species are threatened by logging, habitat destruction, and loss of pollinators. They may become extinct before we have the chance to begin to understand the possible impacts resulting from their disappearance.
Efforts to preserve biodiversity take several lines of action, from preserving heirloom seeds to barcoding species. Heirloom seeds come from plants that were traditionally grown in human populations, as opposed to the seeds used for large-scale agricultural production. Barcoding is a technique in which one or more short gene sequences, taken from a well-characterized portion of the genome, are used to identify a species through DNA analysis.
Privacy Policy. Skip to main content. Seed Plants. Search for:. The Role of Seed Plants. Herbivory and Pollination The diversity of plants can be attributed to pollination and herbivory, both examples of coevolution between animals and plants. Learning Objectives Describe the interaction of plants and animals in achieving pollination. They need a constant source of nectar and pollen throughout the entire season.
The few flowering plants most people grow will not suffice. A related problem is fragmentation of plant communities. Plants must be pollinated in order to set seed for the next generation.
Without pollinators, no seed is set and the plants eventually die out, leading to local extinction. Isolated patches of forest, grassland, or desert are particularly vulnerable.
A small patch may not sustain enough pollinators, or may be too far from other patches for pollinators to travel. As a result, plants do not reproduce. Pesticides have also reduced pollinator populations. Bees are often killed by chemicals applied to eliminate other pests.
Honeybees are being destroyed by diseases and parasitic mites. The crisis is not just affecting native ecosystems. Fruit trees and many other food crops depend on pollination for production. We stand to lose over three quarters of our edible crops if we lose pollinators. What can be done? Encourage pollinators by planting a diverse mixture of adult and larval food plants in your garden.
Erect bat and bird houses, as well as bee hives. Reduce or eliminate pesticide use. Help restore native plant communities not only in your yard, but also in parks and along roadways, and connect them through corridors to preserves and other natural areas. No two plants can occupy the same spot.
In order to have room to grow, seeds must be dispersed away from the parent plant. Seed dispersal is accomplished by a variety of means, including wind, water, and animals. Animal dispersal is accomplished by two different methods: ingestion and hitch-hiking. Animals consume a wide variety of fruits, and in so doing disperse the seeds in their droppings. Many seeds benefit not only from the dispersal, but the trip through the intestine as well. Digestive acids scarify seeds, helping them to break out of thick seed coats.
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