Answer. Desert transients, such as Arabidopsis thaliana, are plants that have evolved to take advantage of the very short favorable seasons of the desert. To survive in the desert environment, annual plants can use the ephemeral weed strategy. The rest of the seeds allows these species to survive the dry season. Ephemeral plants, especially those that have an annual life cycle, can benefit from temporal flight by having a life cycle that does not support consumers long enough for them to complete their life cycle. This restriction prevents the accumulation of dense populations of pests that can reach short-lived consumers in long-lived plants. Plants can also escape discovery by only appearing during seasons when consumers are scarce. Many plants in the cool season, for example, are relatively spared by insect eaters, which are much more common in hot weather. Hardy annually a plant that lives a year / completes its life cycle in a year. They are sown outdoors in March and can survive/withstand frost and temperatures below -5°C.

For example, Calendula officinalis. Biodiversity often correlates with other factors such as productivity, biomass, predation or resource availability, making it difficult to assess the impact of biodiversity separately from other factors. Few studies have investigated the influence of biodiversity, regardless of species composition, on the nitrogen cycle. These early results suggest that greater biodiversity among primary producers allows for a more complete use of available nitrogen and increases nitrogen uptake by plants. In a Minnesota grassland, the concentration of NO3− in the soil of the root zone (Figure 6) and below the root zone decreased with increasing diversity, suggesting that less NO3− was lost due to leaching and more nitrogen was retained in the ecosystem. In the same Minnesota grasslands, the concentration of nitrogen in plants and the total nitrogen content of plant biomass also increased with the number of functional groups, and the composition and diversity of functional groups had about the same impact on ecosystem processes. In the serpentine grasslands of California, temporal division of resources and facilitation by nitrogen fixers allowed for a more complete use of available nitrogen, but the identity of functional groups was more important than the number of functional groups. Hypothetically, increasing diversity and resource exploitation increases nitrogen retention, creating a positive feedback loop of increased fertility and productivity. With a more complete capture or immobilization of a limiting resource such as nitrogen, more diverse communities may be less susceptible to invasion.

Sometimes you will be asked to define these terms in the exam questions. ERS examiners note that the best definitions are those that «. In a word and give the full botanical name for the example of the plant, for example, for a perennial, it is necessary to indicate that the plant lives more than two years / seasons and not many years / seasons. Caution should be exercised to ensure that examples of plants are true representatives of the type of plant, e.g. Impatiens walleriana, although grown in this country as an annual plant, is of course a perennial plant, while Tagetes patula is a true annual. Applicants who gave only the name of the genus, for example Digitalis, as an example of a biennial could not receive a grade because the genus contains both biennial and perennial species. ERS inspectors note that it is important to mention secondary growth in any definition of woody perennials. Annuals are plants that go through their entire life cycle during a growing season. Many agricultural weeds have a short lifespan and multiply rapidly after human disturbance caused by ploughing.

Roadside weeds similarly exploit the disturbances caused by road construction and mowing. These plants rarely have commercial use and can be invasive weeds. Examples: Cardamine hirsuta and Cannabis ruderalis. Plants that have a short lifespan, rapid growth rates, and high seed production are also known as ruderals. [6] Fig. 4 shows the species-area curve on roundwood scales for all vascular plants counted from 200 plots or regions (with a sample size of 10−6 to 108 ha) in all temperate forest biomes. This is where hemispheric trends are reversed; The north has a mild total vascular flora, but significantly higher than the south on the area of the sampling areas. East Asia and the Middle East (the latter having a smaller sample size) tend to have the highest vascular plant diversity, and forests in New Zealand, South America and western North America tend to have the lowest vascular plant diversity. The forest systems of eastern North America, Europe, Australia and South Africa are generally intermediate in the areas studied. There is a dramatic decline in biodiversity towards the pole, especially in the southern hemisphere. In pairwise comparisons to average samples, trends tend to continue.