Plants species extinction

Because not all of the species in the world are known, it is difficult to determine the exact rate of species extinction. Unfortunately, there are plants with medicinal properties that have gone extinct. The first case of a medicinal plant extinction documented in an herbal text is silphium [37]. 

If biodiversity decreases, natural product diversity also decreases, because of a link between the two (Part II). Modem times have seen the greatest natural product diversity. With the increase in plant species from 100,000 before the end-Cretaceous mass extinction to the 250,000 species of modem age, natural product diversity must also have increased. The estimate depends on how natural product diversity is evaluated, i.e. from the molecular skeletons or the actual metabolites. Metabolites of insects, fungi, and bacteria must be added to the list. The present man-made mass extinction may thus result in a larger numerical impact than any previous mass extinction, even if the loss of natiual product diversity occurs at the same percentage of previous catastrophes. 

Associated organisms have also to be considered. A large tree may host as many as 500 different species of insects, part of which go extinct with the tree. It is also believed that the diversity of symbionts correlates with that of the host, such as mycorrhizal fiingi with terrestrial plants (van der Heijden 1998). Pathogens and herbivores may also control the plant species distribution, both in the tropics and temperate areas (Packer 2000). 

Currently pest control by natural plant extracts is practiced primarily by subsistence farmers in those less developed part of the world where it is still an economic necessity.(ref. 3). Of the approximately 2000 plant species with known insecticidal properties (ref. 4), few have been developed commercially. These include the pyrethrins, rotenones and some of the alkaloids. Pyrethrins were the most important natural plant extracts in the early commercial insecticide formulations and were already in use in Persia and Yugoslavia during the early 1800s. By 1939 pyrethrum imports to the United States were 13-5 million lbs, declining from this peak as the synthetic analogs (e.g., the allethrins) appeared on the market. The addition of stabilizers (antioxidants) and synergists to the original pyrethrum formulations saved the natural product from commercial extinction. Currently the demand for pyrethrum flowers is still over 25,000 tons per annum—met by hand-harvested crops from Ecuador, Kenya and Tanzania (ref. 5) ... 

An aspect not covered by the models discussed so far is the extra level of integration for species assemblage-level problems, that is, ecological interactions. When quantitative risks can be established for separate subgroups, it might become possible to address this issue further. When a mixture of photosynthesis inhibitors would affect 100% of the plant species, simple reasoning suggests that other species will go extinct... 

However, according to climate scientists, the world may soon be approaching greenhouse gas levels dangerously close to tipping points , beyond which nothing can be done to reverse an accelerated warming [9-15], The predicted effects of this would be a massive rise in sea levels, extreme weather conditions and widespread extinction of animal and plant species [16]. 

Scientists have concluded from the fossil record that under normal conditions, and prior to the rise of human civilization, the background extinction rate is about one species extinction a year for every million species on earth. No one knows how many separate species of plants, animals, and microbes there are on earth now but if there were 10 million, this would mean that every year, ten different species would become extinct under normal conditions, ffowever, normal conditions have not existed since the rise of civilization. The evolutionary biologist E. O. Wilson of ffarvard University has estimated that there are a total of 27,000 extinctions a year worldwide Niles Eldridge, curator at the American Museum of Natural ffistory, has put the number at 30,000... 

Great concern should be expressed about the continuing erosion of tropical rain forest species, which is accelerating as the twenty-first century begins (22). Approximately 25 hot spots of especially high biodiversity have been proposed that represent 44% of all vascular plant species and 35% of all species of vertebrates in approximately 1.4% of the earth s surface (23). At present, many of the endemic (or native) species to these biodiversity hot spot areas have been reported to be undergoing massive habitat loss and are threatened with extinction, especially in tropical regions (22,23). 

As to the values ofTable 3, Sj section shonld receive greatest attention. In this section, higher losses associated with the likely consequences of accidents are expected. Sj section is situated next to an area of environmental preservation comprising Atlantic forest of great importance to the region, which possesses animal and plant species near- extinction, found only in this locality. 

Norse, E.A. (1985). The value of animal and plant species for agriculture, medicine, and industry, in Animal Extinctions, Hoage, R.J., Ed. Smithsonian Institution Press, Washington, DC, pp. 59-70. 

Today, effects that kill or threaten a branch of an ecosystem can help the ecosystem as a whole. Take modern rainforests these are diverse hot spots of life because of pathogens. Fungal diseases thrive in the rainforest, and if any one plant species dominates, the pathogens evolve to attack that species. They eventually succeed, creating an ecological void that other species fill. Extinctions created similar voids on a planetary scale that convergent evolution filled with life. 

Herbal Medicinal Products Directive (2004/24/ EC) (THMPD) (European Union, 2004). Coming into force in 2011, the Directive will bring consistency and regulation to the herbal medicines market across Europe. In additional to concerns over safety, the increased amount of wild crafting is raising sustainability questions. Of the 40,000-50,000 plant species used in herbal medicines, 70% are wild crafted and 4,000 of those face extinction. The opportunity for commercial cultivation of medicinal herbs has been reviewed (Williamson and MacTavish, 2007). The study identified up to 36 species of plants suitable for cultivation in Northem European agroclimatic conditions or under controlled conditions. The authors reviewed potential volumes and prices and the species with greatest potential for economic development are shown in Table 3. 

Acid rain affects plants by changing the conditions in the soil. For example, nitric acid deposits nitrates, which fertilize the land. The nitrates allow fast-growing weeds such as quack grass to replace valuable prairie species. If these species were to become extinct, their genetic material would no longer be available for agricultural research. 

Cretaceous 138 Myr Gondwana begins to break up. Continued radiation of flowering plants mammals begin diversifying. Meteorite strikes Yucatan Peninsula at end of period causing mass extinction (ca. 75% of all species disappear)... 

A downside of the rise of mammals, specifically including humans, is that the sixth major extinction of life on Earth is happening now. As noted above, we are losing 4-6 species an hour, 27,000 0,000 species a year, mostly in the tropical and subtropical forests. The tremendous loss of species is the result of habitat destruction, overhunting, introduction of exotic species of animals and plants into new habitats, and the diseases carried by these exotics. One of the most valuable resources on Earth— biodiversity—is being sacrificed, fhe result of a burgeoning human population and its activities. 

The popularity of ginseng has already led to its extinction in some parts of the world (such as South Korea) and to its classihcation as an endangered species in other parts (such as China) due to overharvesting. Today, more than 65 tons of the root are harvested in the United States each year, most of it going to the Far East. At this rate, the plant faces possible extinction in this country also. 

As in other environments, so also in arid regions, allelopathy is associated with plant-plant competition, but here the paucity of resources may lead to considerable mutual interference resulting not only in diminution in size or number of the plants, but also in total extinction of a vulnerable species. 

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